Kay M. Johnson, MD, MPH

A plethora of studies are under way in the field of perioperative medicine. As a result, evidence-based care of surgical patients is evolving at an exponential rate.

We performed a literature search and, using consensus, identified recent articles we believe will have a great impact on perioperative cardiovascular medicine. These articles report studies that were presented at national meetings in 2018, including the Perioperative Medicine Summit, Society of General Internal Medicine, and Society of Hospital Medicine. These articles are grouped under 5 questions that will help guide clinical practice in perioperative cardiovascular medicine.

SHOULD ASPIRIN BE CONTINUED PERIOPERATIVELY IN PATIENTS WITH A CORONARY STENT?

The Perioperative Ischemic Evaluation 2 (POISE-2) trial¹ found that giving aspirin before surgery and throughout the early postoperative period had no significant effect on the rate of a composite of death or nonfatal myocardial infarction; moreover, aspirin increased the risk of major bleeding. However, many experts felt uncomfortable stopping aspirin preoperatively in patients taking it for secondary prophylaxis, particularly patients with a coronary stent.

[Graham MM, Sessler DI, Parlow JL, et al. Aspirin in patients with previous percutaneous coronary intervention undergoing noncardiac surgery. Ann Intern Med 2018; 168(4):237–244.]

This post hoc subgroup analysis² of POISE-2 evaluated the benefit and harm of perioperative aspirin in patients who had previously undergone percutaneous coronary intervention, more than 90% of whom had received a stent. Patients were age 45 or older with atherosclerotic heart disease or risk factors for it who had previously undergone percutaneous coronary intervention and were now undergoing noncardiac surgery.

Patients who had received a bare-metal stent within the previous 6 weeks or a drug-eluting stent within 12 months before surgery were excluded because guidelines at that time said to continue dual antiplatelet therapy for that long. Recommendations have since changed; the optimal duration for dual antiplatelet therapy with drug-eluting stents is now 6 months. Second-generation drug-eluting stents pose a lower risk of stent thrombosis and require a shorter duration of dual antiplatelet therapy than first-generation drug-eluting stents. Approximately 25% of the percutaneous coronary intervention subgroup had a drug-eluting stent, but the authors did not specify the type of drug-eluting stent.

The post hoc analysis² included a subgroup of 234 of 4,998 patients receiving aspirin and 236 of 5,012 patients receiving placebo initiated within 4 hours before surgery and continued postoperatively. The primary outcome measured was the rate of death or nonfatal myocardial infarction within 30 days after surgery, and bleeding was a secondary outcome.

Findings. Although the overall POISE-2 study found no benefit from aspirin, in the subgroup who had previously undergone percutaneous coronary intervention, aspirin significantly reduced the risk of the primary outcome, which occurred in 6% vs 11.5% of the patients:

• Absolute risk reduction 5.5% (95% confidence interval 0.4%–10.5%)
• Hazard ratio 0.50 (0.26–0.95).

The reduction was primarily due to fewer myocardial infarctions:

• Absolute risk reduction 5.9% (1.0%–10.8%)
• Hazard ratio 0.44 (0.22–0.87).

The type of stent had no effect on the primary outcome, although this subgroup analysis had limited power. In the nonpercutaneous coronary intervention subgroup, there was no significant difference in outcomes between the aspirin and placebo groups. This subgroup analysis was underpowered to evaluate the effect of aspirin on the composite of major and life-threatening bleeding in patients with prior percutaneous coronary intervention, which was reported as “uncertain” due to wide confidence intervals (absolute risk increase 1.3%, 95% confidence interval –2.6% to 5.2%), but the increased risk of major or life-threatening bleeding with aspirin demonstrated in the overall POISE-2 study population likely applies:

• Absolute risk increase 0.8% (0.1%–1.6%)
• Hazard ratio 1.22 (1.01–1.48).

Limitations. This was a nonspecified subgroup analysis that was underpowered and had a relatively small sample size with few events.

Conclusion. In the absence of a very high bleeding risk, continuing aspirin perioperatively in patients with prior percutaneous coronary intervention undergoing noncardiac surgery is more likely to result in benefit than harm. This finding is in agreement with current recommendations from the American College Cardiology and American Heart Association (class I; level of evidence C).³

Despite advances in anesthesia and surgical techniques, about 1% of patients over age 45 die within 30 days of noncardiac surgery.⁴ Studies have demonstrated a high mortality rate in patients who experience myocardial injury after noncardiac surgery (MINS), defined as elevations of troponin T with or without ischemic symptoms or electrocardiographic changes.⁵ Most of these studies used earlier, “non-high-sensitivity” troponin T assays. Fifth-generation, highly sensitive troponin T assays are now available that can detect troponin T at lower concentrations, but their utility in predicting postoperative outcomes remains uncertain. Two recent studies provide further insight into these issues.

[Writing Committee for the VISION Study Investigators, Devereaux PJ, Biccard BM, Sigamani A, et al. Association of postoperative high-sensitivity troponin levels with myocardial injury and 30-day mortality among patients undergoing noncardiac surgery. JAMA 2017; 317(16):1642–1651.]

The Vascular Events in Noncardiac Surgery Patients Cohort Evaluation (VISION) study⁵ was an international, prospective cohort study that initially evaluated the association between MINS and the 30-day mortality rate using a non-high-sensitivity troponin T assay (Roche fourth-generation Elecsys TnT assay) in patients age 45 or older undergoing noncardiac surgery and requiring hospital admission for at least 1 night. After the first 15,000 patients, the study switched to the Roche fifth-generation assay, with measurements at 6 to 12 hours after surgery and on postoperative days 1, 2, and 3.

A 2017 analysis by Devereaux et al⁶ included only these later-enrolled patients and correlated their high-sensitivity troponin T levels with 30-day mortality rates. Patients with a level 14 ng/L or higher, the upper limit of normal in this study, were also assessed for ischemic symptoms and electrocardiographic changes. Although not required by the study, more than 7,800 patients had their troponin T levels measured before surgery, and the absolute change was also analyzed for an association with the 30-day mortality rate.

Findings. Of the 21,842 patients, about two-thirds underwent some form of major surgery; some of them had more than 1 type. A total of 1.2% of the patients died within 30 days of surgery.

Based on their analysis, the authors proposed that MINS be defined as:

• A postoperative troponin T level of 65 ng/L or higher, or
• A level in the range of 20 ng/L to less than 65 ng/L with an absolute increase from the preoperative level at least 5 ng/L, not attributable to a nonischemic cause.

Seventeen percent of the study patients met these criteria, and of these, 21.7% met the universal definition of myocardial infarction, although only 6.9% had symptoms of it.

Limitations. Only 40.4% of the patients had a preoperative high-sensitivity troponin T measurement for comparison, and in 13.8% of patients who had an elevated perioperative measurement, their preoperative value was the same or higher than their postoperative one. Thus, the incidence of MINS may have been overestimated if patients were otherwise not known to have troponin T elevations before surgery.

[Puelacher C, Lurati Buse G, Seeberger D, et al. Perioperative myocardial injury after noncardiac surgery: incidence, mortality, and characterization. Circulation 2018; 137(12):1221–1232.]

Puelacher et al⁷ investigated the prevalence of MINS in 2,018 patients at increased cardiovascular risk (age ≥ 65, or age ≥ 45 with a history of coronary artery disease, peripheral vascular disease, or stroke) who underwent major noncardiac surgery (planned overnight stay ≥ 24 hours) at a university hospital in Switzerland. Patients had their troponin T measured with a high-sensitivity assay within 30 days before surgery and on postoperative days 1 and 2.

Instead of MINS, the investigators used the term “perioperative myocardial injury” (PMI), defined as an absolute increase in troponin T of at least 14 ng/L from before surgery to the peak postoperative reading. Similar to MINS, PMI did not require ischemic features, but in this study, noncardiac triggers (sepsis, stroke, or pulmonary embolus) were not excluded.

Findings. PMI occurred in 16% of surgeries, and of the patients with PMI, 6% had typical chest pain and 18% had any ischemic symptoms. Unlike in the POISE-2 study discussed above, PMI triggered an automatic referral to a cardiologist.

The unadjusted 30-day mortality rate was 8.9% among patients with PMI and 1.5% in those without. Multivariable logistic regression analysis showed an adjusted hazard ratio for 30-day mortality of 2.7 (95% CI 1.5–4.8) for those with PMI vs without, and this difference persisted for at least 1 year.

In patients with PMI, the authors compared the 30-day mortality rate of those with no ischemic signs or symptoms (71% of the patients) with those who met the criteria for myocardial infarction and found no difference. Patients with PMI triggered by a noncardiac event had a worse prognosis than those with a presumed cardiac etiology.

Limitations. Despite the multivariate analysis that included adjustment for age, nonelective surgery, and Revised Cardiac Risk Index (RCRI), the increased risk associated with PMI could simply reflect higher risk at baseline. Although PMI resulted in automatic referral to a cardiologist, only 10% of patients eventually underwent coronary angiography; a similar percentage were discharged with additional medical therapy such as aspirin, a statin, or a beta-blocker. The effect of these interventions is not known.

Conclusions. MINS is common and has a strong association with mortality risk proportional to the degree of troponin T elevation using high-sensitivity assays, consistent with data from previous studies of earlier assays. Because the mechanism of MINS may differ from that of myocardial infarction, its prevention and treatment may differ, and it remains unclear how serial measurement in postoperative patients should change clinical practice.

The recently published Dabigatran in Patients With Myocardial Injury After Non-cardiac Surgery (MANAGE) trial⁸ suggests that dabigatran may reduce arterial and venous complications in patients with MINS, but the study had a number of limitations that may restrict the clinical applicability of this finding.

While awaiting further clinical outcomes data, pre- and postoperative troponin T measurement may be beneficial in higher-risk patients (such as those with cardiovascular disease or multiple RCRI risk factors) if the information will change perioperative management.

Intraoperative hypotension is associated with organ ischemia, which may cause postoperative myocardial infarction, myocardial injury, and acute kidney injury.⁹ Traditional anesthesia practice is to maintain intraoperative blood pressure within 20% of the preoperative baseline, based on the notion that hypertensive patients require higher perfusion pressures.

[Futier E, Lefrant J-Y, Guinot P-G, et al. Effect of individualized vs standard blood pressure management strategies on postoperative organ dysfunction among high-risk patients undergoing major surgery: a randomized clinical trial. JAMA 2017; 318(14):1346–1357.]

Futier et al¹⁰ sought to address uncertainty in intraoperative and immediate postoperative management of systolic blood pressure. In this multicenter, randomized, parallel-group trial, 298 patients at increased risk of postoperative renal complications were randomized to blood pressure management that was either “individualized” (within 10% of resting systolic pressure) or “standard” (≥ 80 mm Hg or ≥ 40% of resting systolic pressure) from induction to 4 hours postoperatively.

Blood pressure was monitored using radial arterial lines and maintained using a combination of intravenous fluids, norepinephrine (the first-line agent for the individualized group), and ephedrine (in the standard treatment group only). The primary outcome was a composite of systemic inflammatory response syndrome (SIRS) and organ dysfunction affecting at least 1 organ system (cardiovascular, respiratory, renal, hematologic, or neurologic).

Findings. Data on the primary outcome were available for 292 of 298 patients enrolled. The mean age was 70 years, 15% were women, and 82% had previously diagnosed hypertension. Despite the requirement for an elevated risk of acute kidney injury, only 13% of the patients had a baseline estimated glomerular filtration rate of less than 60 mL/min/1.73 m², and the median was 88 mL/min/1.73 m². Ninety-five percent of patients underwent abdominal surgery, and 50% of the surgeries were elective.

The mean systolic blood pressure was 123 mm Hg in the individualized treatment group compared with 116 mm Hg in the standard treatment group. Despite this small difference, 96% of individualized treatment patients received norepinephrine, compared with 26% in the standard treatment group.

The primary outcome of SIRS with organ dysfunction occurred in 38.1% of patients in the individualized treatment group and 51.7% of those in the standard treatment group. After adjusting for center, surgical urgency, surgical site, and acute kidney injury risk index, the relative risk of developing SIRS in those receiving individualized management was 0.73 (P = .02). Renal dysfunction (based on Acute Dialysis Quality Initiative criteria¹¹) occurred in 32.7% of individualized treatment patients and 49% of standardized treatment patients.  

Limitations of this study included differences in pharmacologic approach to maintain blood pressure in the 2 protocols (ephedrine and fluids vs norepinephrine) and a modest sample size.

Conclusions. Despite this, the difference in organ dysfunction was striking, with a number needed to treat of only 7 patients. This intervention extended 4 hours postoperatively, a time when many of these patients have left the postanesthesia care unit and have returned to hospitalist care on inpatient wards.

While optimal management of intraoperative and immediate postoperative blood pressure may not be settled, this study suggests that even mild relative hypotension may justify immediate action. Further studies may be useful to delineate high- and low-risk populations, the timing of greatest risk, and indications for intraarterial blood pressure monitoring.

[Salmasi V, Maheswari K, Yang D, et al. Relationship between intraoperative hypotension, defined by either reduction from baseline or absolute thresholds, and acute kidney and myocardial injury after noncardiac surgery: a retrospective cohort analysis. Anesthesiology 2017; 126(1):47–65.]

This retrospective cohort study¹² assessed the association between myocardial or kidney injury and absolute or relative thresholds of intraoperative mean arterial pressure. It included 57,315 adults who underwent inpatient noncardiac surgery, had a preoperative and at least 1 postoperative serum creatinine measurement within 7 days, and had blood pressure recorded in preoperative appointments within 6 months. Patients with chronic kidney disease (glomerular filtration rate < 60 mL/min/1.73 m²) and those on dialysis were excluded. The outcomes were MINS⁵ and acute kidney injury as defined by the Acute Kidney Injury Network.⁹

Findings. A mean arterial pressure below an absolute threshold of 65 mm Hg or a relative threshold of 20% lower than baseline value was associated with myocardial and kidney injury. At each threshold, prolonged periods of hypotension were associated with progressively increased risk.

An important conclusion of the study was that relative thresholds of mean arterial pressure were not any more predictive than absolute thresholds. Absolute thresholds are easier to use intraoperatively, especially when baseline values are not available. The authors did not find a clinically significant interaction between baseline blood pressure and the association of hypotension and myocardial and kidney injury.

Limitations included use of cardiac enzymes postoperatively to define MINS. Since these were not routinely collected, clinically silent myocardial injury may have been missed. Baseline blood pressure may have important implications in other forms of organ injury (ie, cerebral ischemia) that were not studied.

Summary. The lowest absolute mean arterial pressure is as predictive of postoperative myocardial and kidney injury as the relative pressure reduction, at least in patients with normal renal function. Limiting exposure to intraoperative hypotension is important. Baseline blood pressure values may have limited utility for intraoperative management.

In combination, these studies confirm that intraoperative hypotension is a predictor of postoperative organ dysfunction, but the definition and management remain unclear. While aggressive intraoperative management is likely beneficial, how to manage the anti­hypertensive therapy the patient has been taking as an outpatient when he or she comes into the hospital for surgery remains uncertain.

Perioperative stroke is an uncommon, severe complication of noncardiac surgery. The pathophysiology has been better defined in cardiac than in noncardiac surgeries. In nonsurgical patients, patent foramen ovale (PFO) is associated with stroke, even in patients considered to be at low risk.¹³ Perioperative patients have additional risk for venous thromboembolism and may have periprocedural antithrombotic medications altered, increasing their risk of paradoxical embolism through the PFO.

[Ng PY, Ng AK, Subramaniam B, et al. Association of preoperatively diagnosed patent foramen ovale with perioperative ischemic stroke. JAMA 2018; 319(5):452–462.]

This retrospective cohort study of noncardiac surgery patients at 3 hospitals¹⁴ sought to determine the association of preoperatively diagnosed PFO with the risk of perioperative ischemic stroke identified by International Classification of Diseases diagnoses.

Of 150,198 patients, 1.0% had a preoperative diagnosis of PFO, and at baseline, those with PFO had significantly more comorbidities than those without PFO. Stroke occurred in 3.2% of patients with PFO vs 0.5% of those without. Patients known to have a PFO were much more likely to have cardiovascular and thromboembolic risk factors for stroke. In the adjusted analysis, the absolute risk difference between groups was 0.4% (95% CI 0.2–0.6%), with an estimated perioperative stroke risk of 5.9 per 1,000 in patients with known patent foramen ovale and 2.2 per 1,000 in those without. A diagnosis of PFO was also associated with increased risk of large-vessel-territory stroke and more severe neurologic deficit.

Further attempts to adjust for baseline risk factors and other potential bias, including a propensity score-matched cohort analysis and an analysis limited to patients who had echocardiography performed in the same healthcare system, still showed a higher risk of perioperative stroke among patients with preoperatively detected patent foramen ovale.

Limitations. The study was retrospective and observational, used administrative data, and had a low rate of PFO diagnosis (1%), compared with about 25% in population-based studies.¹⁵ Indications for preoperative echocardiography are unknown. In addition, the study specifically examined preoperatively diagnosed PFO, rather than including those diagnosed in the postoperative period.

Discussion. How does this study affect clinical practice? The absolute stroke risk was increased by 0.4% in patients with PFO compared with those without. Although this is a relatively small increase, millions of patients undergo noncardiac surgery annually. The risks of therapeutic anticoagulation or PFO closure are likely too high in this context; however, clinicians may approach the perioperative management of antiplatelet agents and venous thromboembolism prophylaxis in patients with known PFO with additional caution.

HOW DOES TIMING OF EMERGENCY SURGERY AFTER PRIOR STROKE AFFECT OUTCOMES?

A history of stroke or transient ischemic attack is a known risk factor for perioperative vascular complications. A recent large cohort study demonstrated that a history of stroke within 9 months of elective surgery was associated with increased adverse outcomes.¹⁶ Little is known, however, of the perioperative risk in patients with a history of stroke who undergo emergency surgery.

[Christiansen MN, Andersson C, Gislason GH, et al. Risks of cardiovascular adverse events and death in patients with previous stroke undergoing emergency noncardiac, nonintracranial surgery: the importance of operative timing. Anesthesiology 2017; 127(1):9–19.]

In this study,¹⁷ all emergency noncardiac and nonintracranial surgeries from 2005 to 2011 were analyzed using multiple national patient registries in Denmark according to time elapsed between previous stroke and surgery. Primary outcomes were 30-day all-cause mortality and 30-day major adverse cardiac events (MACE), defined as nonfatal ischemic stroke, nonfatal myocardial infarction, and cardiovascular death. Statistical analysis to assess the risk of adverse outcomes included logistic regression models, spline analyses, and propensity-score matching.

Findings. The authors identified 146,694 emergency surgeries, with 7,861 patients (5.4%) having had a previous stroke (transient ischemic attacks and hemorrhagic strokes were not included). Rates of postoperative stroke were as follows:

• 9.9% in patents with a history of ischemic stroke within 3 months of surgery
• 2.8% in patients with a history of stroke 3 to 9 months before surgery
• 0.3% in patients with no previous stroke.

The risk plateaued when the time between stroke and surgery exceeded 4 to 5 months.¹⁵

Interestingly, in patients who underwent emergency surgery within 14 days of stroke, the risk of MACE was significantly lower immediately after surgery (1–3 days after stroke) compared with surgery that took place 4 to 14 days after stroke. The authors hypothesized that because cerebral autoregulation does not become compromised until approximately 5 days after a stroke, the risk was lower 1 to 3 days after surgery and increased thereafter.

Limitations of this study included the possibility of residual confounding, given its retrospective design using administrative data, not accounting for preoperative antithrombotic and anticoagulation therapy, and lack of information regarding the etiology of recurrent stroke (eg, thromboembolic, atherothrombotic, hypoperfusion).

Conclusions. Although it would be impractical to postpone emergency surgery in a patient who recently had a stroke, this study shows that the incidence rates of postoperative recurrent stroke and MACE are high. Therefore, it is important that the patient and perioperative team be aware of the risk. Further research is needed to confirm these estimates of postoperative adverse events in more diverse patient populations.

A plethora of studies are under way in the field of perioperative medicine. As a result, evidence-based care of surgical patients is evolving at an exponential rate.

We performed a literature search and, using consensus, identified recent articles we believe will have a great impact on perioperative cardiovascular medicine. These articles report studies that were presented at national meetings in 2018, including the Perioperative Medicine Summit, Society of General Internal Medicine, and Society of Hospital Medicine. These articles are grouped under 5 questions that will help guide clinical practice in perioperative cardiovascular medicine.

SHOULD ASPIRIN BE CONTINUED PERIOPERATIVELY IN PATIENTS WITH A CORONARY STENT?

The Perioperative Ischemic Evaluation 2 (POISE-2) trial¹ found that giving aspirin before surgery and throughout the early postoperative period had no significant effect on the rate of a composite of death or nonfatal myocardial infarction; moreover, aspirin increased the risk of major bleeding. However, many experts felt uncomfortable stopping aspirin preoperatively in patients taking it for secondary prophylaxis, particularly patients with a coronary stent.

[Graham MM, Sessler DI, Parlow JL, et al. Aspirin in patients with previous percutaneous coronary intervention undergoing noncardiac surgery. Ann Intern Med 2018; 168(4):237–244.]

This post hoc subgroup analysis² of POISE-2 evaluated the benefit and harm of perioperative aspirin in patients who had previously undergone percutaneous coronary intervention, more than 90% of whom had received a stent. Patients were age 45 or older with atherosclerotic heart disease or risk factors for it who had previously undergone percutaneous coronary intervention and were now undergoing noncardiac surgery.

Patients who had received a bare-metal stent within the previous 6 weeks or a drug-eluting stent within 12 months before surgery were excluded because guidelines at that time said to continue dual antiplatelet therapy for that long. Recommendations have since changed; the optimal duration for dual antiplatelet therapy with drug-eluting stents is now 6 months. Second-generation drug-eluting stents pose a lower risk of stent thrombosis and require a shorter duration of dual antiplatelet therapy than first-generation drug-eluting stents. Approximately 25% of the percutaneous coronary intervention subgroup had a drug-eluting stent, but the authors did not specify the type of drug-eluting stent.

The post hoc analysis² included a subgroup of 234 of 4,998 patients receiving aspirin and 236 of 5,012 patients receiving placebo initiated within 4 hours before surgery and continued postoperatively. The primary outcome measured was the rate of death or nonfatal myocardial infarction within 30 days after surgery, and bleeding was a secondary outcome.

Findings. Although the overall POISE-2 study found no benefit from aspirin, in the subgroup who had previously undergone percutaneous coronary intervention, aspirin significantly reduced the risk of the primary outcome, which occurred in 6% vs 11.5% of the patients:

• Absolute risk reduction 5.5% (95% confidence interval 0.4%–10.5%)
• Hazard ratio 0.50 (0.26–0.95).

The reduction was primarily due to fewer myocardial infarctions:

• Absolute risk reduction 5.9% (1.0%–10.8%)
• Hazard ratio 0.44 (0.22–0.87).

The type of stent had no effect on the primary outcome, although this subgroup analysis had limited power. In the nonpercutaneous coronary intervention subgroup, there was no significant difference in outcomes between the aspirin and placebo groups. This subgroup analysis was underpowered to evaluate the effect of aspirin on the composite of major and life-threatening bleeding in patients with prior percutaneous coronary intervention, which was reported as “uncertain” due to wide confidence intervals (absolute risk increase 1.3%, 95% confidence interval –2.6% to 5.2%), but the increased risk of major or life-threatening bleeding with aspirin demonstrated in the overall POISE-2 study population likely applies:

• Absolute risk increase 0.8% (0.1%–1.6%)
• Hazard ratio 1.22 (1.01–1.48).

Limitations. This was a nonspecified subgroup analysis that was underpowered and had a relatively small sample size with few events.

Conclusion. In the absence of a very high bleeding risk, continuing aspirin perioperatively in patients with prior percutaneous coronary intervention undergoing noncardiac surgery is more likely to result in benefit than harm. This finding is in agreement with current recommendations from the American College Cardiology and American Heart Association (class I; level of evidence C).³

Despite advances in anesthesia and surgical techniques, about 1% of patients over age 45 die within 30 days of noncardiac surgery.⁴ Studies have demonstrated a high mortality rate in patients who experience myocardial injury after noncardiac surgery (MINS), defined as elevations of troponin T with or without ischemic symptoms or electrocardiographic changes.⁵ Most of these studies used earlier, “non-high-sensitivity” troponin T assays. Fifth-generation, highly sensitive troponin T assays are now available that can detect troponin T at lower concentrations, but their utility in predicting postoperative outcomes remains uncertain. Two recent studies provide further insight into these issues.

[Writing Committee for the VISION Study Investigators, Devereaux PJ, Biccard BM, Sigamani A, et al. Association of postoperative high-sensitivity troponin levels with myocardial injury and 30-day mortality among patients undergoing noncardiac surgery. JAMA 2017; 317(16):1642–1651.]

The Vascular Events in Noncardiac Surgery Patients Cohort Evaluation (VISION) study⁵ was an international, prospective cohort study that initially evaluated the association between MINS and the 30-day mortality rate using a non-high-sensitivity troponin T assay (Roche fourth-generation Elecsys TnT assay) in patients age 45 or older undergoing noncardiac surgery and requiring hospital admission for at least 1 night. After the first 15,000 patients, the study switched to the Roche fifth-generation assay, with measurements at 6 to 12 hours after surgery and on postoperative days 1, 2, and 3.

A 2017 analysis by Devereaux et al⁶ included only these later-enrolled patients and correlated their high-sensitivity troponin T levels with 30-day mortality rates. Patients with a level 14 ng/L or higher, the upper limit of normal in this study, were also assessed for ischemic symptoms and electrocardiographic changes. Although not required by the study, more than 7,800 patients had their troponin T levels measured before surgery, and the absolute change was also analyzed for an association with the 30-day mortality rate.

Findings. Of the 21,842 patients, about two-thirds underwent some form of major surgery; some of them had more than 1 type. A total of 1.2% of the patients died within 30 days of surgery.

Based on their analysis, the authors proposed that MINS be defined as:

• A postoperative troponin T level of 65 ng/L or higher, or
• A level in the range of 20 ng/L to less than 65 ng/L with an absolute increase from the preoperative level at least 5 ng/L, not attributable to a nonischemic cause.

Seventeen percent of the study patients met these criteria, and of these, 21.7% met the universal definition of myocardial infarction, although only 6.9% had symptoms of it.

Limitations. Only 40.4% of the patients had a preoperative high-sensitivity troponin T measurement for comparison, and in 13.8% of patients who had an elevated perioperative measurement, their preoperative value was the same or higher than their postoperative one. Thus, the incidence of MINS may have been overestimated if patients were otherwise not known to have troponin T elevations before surgery.

[Puelacher C, Lurati Buse G, Seeberger D, et al. Perioperative myocardial injury after noncardiac surgery: incidence, mortality, and characterization. Circulation 2018; 137(12):1221–1232.]

Puelacher et al⁷ investigated the prevalence of MINS in 2,018 patients at increased cardiovascular risk (age ≥ 65, or age ≥ 45 with a history of coronary artery disease, peripheral vascular disease, or stroke) who underwent major noncardiac surgery (planned overnight stay ≥ 24 hours) at a university hospital in Switzerland. Patients had their troponin T measured with a high-sensitivity assay within 30 days before surgery and on postoperative days 1 and 2.

Instead of MINS, the investigators used the term “perioperative myocardial injury” (PMI), defined as an absolute increase in troponin T of at least 14 ng/L from before surgery to the peak postoperative reading. Similar to MINS, PMI did not require ischemic features, but in this study, noncardiac triggers (sepsis, stroke, or pulmonary embolus) were not excluded.

Findings. PMI occurred in 16% of surgeries, and of the patients with PMI, 6% had typical chest pain and 18% had any ischemic symptoms. Unlike in the POISE-2 study discussed above, PMI triggered an automatic referral to a cardiologist.

The unadjusted 30-day mortality rate was 8.9% among patients with PMI and 1.5% in those without. Multivariable logistic regression analysis showed an adjusted hazard ratio for 30-day mortality of 2.7 (95% CI 1.5–4.8) for those with PMI vs without, and this difference persisted for at least 1 year.

In patients with PMI, the authors compared the 30-day mortality rate of those with no ischemic signs or symptoms (71% of the patients) with those who met the criteria for myocardial infarction and found no difference. Patients with PMI triggered by a noncardiac event had a worse prognosis than those with a presumed cardiac etiology.

Limitations. Despite the multivariate analysis that included adjustment for age, nonelective surgery, and Revised Cardiac Risk Index (RCRI), the increased risk associated with PMI could simply reflect higher risk at baseline. Although PMI resulted in automatic referral to a cardiologist, only 10% of patients eventually underwent coronary angiography; a similar percentage were discharged with additional medical therapy such as aspirin, a statin, or a beta-blocker. The effect of these interventions is not known.

Conclusions. MINS is common and has a strong association with mortality risk proportional to the degree of troponin T elevation using high-sensitivity assays, consistent with data from previous studies of earlier assays. Because the mechanism of MINS may differ from that of myocardial infarction, its prevention and treatment may differ, and it remains unclear how serial measurement in postoperative patients should change clinical practice.

The recently published Dabigatran in Patients With Myocardial Injury After Non-cardiac Surgery (MANAGE) trial⁸ suggests that dabigatran may reduce arterial and venous complications in patients with MINS, but the study had a number of limitations that may restrict the clinical applicability of this finding.

While awaiting further clinical outcomes data, pre- and postoperative troponin T measurement may be beneficial in higher-risk patients (such as those with cardiovascular disease or multiple RCRI risk factors) if the information will change perioperative management.

Intraoperative hypotension is associated with organ ischemia, which may cause postoperative myocardial infarction, myocardial injury, and acute kidney injury.⁹ Traditional anesthesia practice is to maintain intraoperative blood pressure within 20% of the preoperative baseline, based on the notion that hypertensive patients require higher perfusion pressures.

[Futier E, Lefrant J-Y, Guinot P-G, et al. Effect of individualized vs standard blood pressure management strategies on postoperative organ dysfunction among high-risk patients undergoing major surgery: a randomized clinical trial. JAMA 2017; 318(14):1346–1357.]

Futier et al¹⁰ sought to address uncertainty in intraoperative and immediate postoperative management of systolic blood pressure. In this multicenter, randomized, parallel-group trial, 298 patients at increased risk of postoperative renal complications were randomized to blood pressure management that was either “individualized” (within 10% of resting systolic pressure) or “standard” (≥ 80 mm Hg or ≥ 40% of resting systolic pressure) from induction to 4 hours postoperatively.

Blood pressure was monitored using radial arterial lines and maintained using a combination of intravenous fluids, norepinephrine (the first-line agent for the individualized group), and ephedrine (in the standard treatment group only). The primary outcome was a composite of systemic inflammatory response syndrome (SIRS) and organ dysfunction affecting at least 1 organ system (cardiovascular, respiratory, renal, hematologic, or neurologic).

Findings. Data on the primary outcome were available for 292 of 298 patients enrolled. The mean age was 70 years, 15% were women, and 82% had previously diagnosed hypertension. Despite the requirement for an elevated risk of acute kidney injury, only 13% of the patients had a baseline estimated glomerular filtration rate of less than 60 mL/min/1.73 m², and the median was 88 mL/min/1.73 m². Ninety-five percent of patients underwent abdominal surgery, and 50% of the surgeries were elective.

The mean systolic blood pressure was 123 mm Hg in the individualized treatment group compared with 116 mm Hg in the standard treatment group. Despite this small difference, 96% of individualized treatment patients received norepinephrine, compared with 26% in the standard treatment group.

The primary outcome of SIRS with organ dysfunction occurred in 38.1% of patients in the individualized treatment group and 51.7% of those in the standard treatment group. After adjusting for center, surgical urgency, surgical site, and acute kidney injury risk index, the relative risk of developing SIRS in those receiving individualized management was 0.73 (P = .02). Renal dysfunction (based on Acute Dialysis Quality Initiative criteria¹¹) occurred in 32.7% of individualized treatment patients and 49% of standardized treatment patients.  

Limitations of this study included differences in pharmacologic approach to maintain blood pressure in the 2 protocols (ephedrine and fluids vs norepinephrine) and a modest sample size.

Conclusions. Despite this, the difference in organ dysfunction was striking, with a number needed to treat of only 7 patients. This intervention extended 4 hours postoperatively, a time when many of these patients have left the postanesthesia care unit and have returned to hospitalist care on inpatient wards.

While optimal management of intraoperative and immediate postoperative blood pressure may not be settled, this study suggests that even mild relative hypotension may justify immediate action. Further studies may be useful to delineate high- and low-risk populations, the timing of greatest risk, and indications for intraarterial blood pressure monitoring.

[Salmasi V, Maheswari K, Yang D, et al. Relationship between intraoperative hypotension, defined by either reduction from baseline or absolute thresholds, and acute kidney and myocardial injury after noncardiac surgery: a retrospective cohort analysis. Anesthesiology 2017; 126(1):47–65.]

This retrospective cohort study¹² assessed the association between myocardial or kidney injury and absolute or relative thresholds of intraoperative mean arterial pressure. It included 57,315 adults who underwent inpatient noncardiac surgery, had a preoperative and at least 1 postoperative serum creatinine measurement within 7 days, and had blood pressure recorded in preoperative appointments within 6 months. Patients with chronic kidney disease (glomerular filtration rate < 60 mL/min/1.73 m²) and those on dialysis were excluded. The outcomes were MINS⁵ and acute kidney injury as defined by the Acute Kidney Injury Network.⁹

Findings. A mean arterial pressure below an absolute threshold of 65 mm Hg or a relative threshold of 20% lower than baseline value was associated with myocardial and kidney injury. At each threshold, prolonged periods of hypotension were associated with progressively increased risk.

An important conclusion of the study was that relative thresholds of mean arterial pressure were not any more predictive than absolute thresholds. Absolute thresholds are easier to use intraoperatively, especially when baseline values are not available. The authors did not find a clinically significant interaction between baseline blood pressure and the association of hypotension and myocardial and kidney injury.

Limitations included use of cardiac enzymes postoperatively to define MINS. Since these were not routinely collected, clinically silent myocardial injury may have been missed. Baseline blood pressure may have important implications in other forms of organ injury (ie, cerebral ischemia) that were not studied.

Summary. The lowest absolute mean arterial pressure is as predictive of postoperative myocardial and kidney injury as the relative pressure reduction, at least in patients with normal renal function. Limiting exposure to intraoperative hypotension is important. Baseline blood pressure values may have limited utility for intraoperative management.

In combination, these studies confirm that intraoperative hypotension is a predictor of postoperative organ dysfunction, but the definition and management remain unclear. While aggressive intraoperative management is likely beneficial, how to manage the anti­hypertensive therapy the patient has been taking as an outpatient when he or she comes into the hospital for surgery remains uncertain.

Perioperative stroke is an uncommon, severe complication of noncardiac surgery. The pathophysiology has been better defined in cardiac than in noncardiac surgeries. In nonsurgical patients, patent foramen ovale (PFO) is associated with stroke, even in patients considered to be at low risk.¹³ Perioperative patients have additional risk for venous thromboembolism and may have periprocedural antithrombotic medications altered, increasing their risk of paradoxical embolism through the PFO.

[Ng PY, Ng AK, Subramaniam B, et al. Association of preoperatively diagnosed patent foramen ovale with perioperative ischemic stroke. JAMA 2018; 319(5):452–462.]

This retrospective cohort study of noncardiac surgery patients at 3 hospitals¹⁴ sought to determine the association of preoperatively diagnosed PFO with the risk of perioperative ischemic stroke identified by International Classification of Diseases diagnoses.

Of 150,198 patients, 1.0% had a preoperative diagnosis of PFO, and at baseline, those with PFO had significantly more comorbidities than those without PFO. Stroke occurred in 3.2% of patients with PFO vs 0.5% of those without. Patients known to have a PFO were much more likely to have cardiovascular and thromboembolic risk factors for stroke. In the adjusted analysis, the absolute risk difference between groups was 0.4% (95% CI 0.2–0.6%), with an estimated perioperative stroke risk of 5.9 per 1,000 in patients with known patent foramen ovale and 2.2 per 1,000 in those without. A diagnosis of PFO was also associated with increased risk of large-vessel-territory stroke and more severe neurologic deficit.

Further attempts to adjust for baseline risk factors and other potential bias, including a propensity score-matched cohort analysis and an analysis limited to patients who had echocardiography performed in the same healthcare system, still showed a higher risk of perioperative stroke among patients with preoperatively detected patent foramen ovale.

Limitations. The study was retrospective and observational, used administrative data, and had a low rate of PFO diagnosis (1%), compared with about 25% in population-based studies.¹⁵ Indications for preoperative echocardiography are unknown. In addition, the study specifically examined preoperatively diagnosed PFO, rather than including those diagnosed in the postoperative period.

Discussion. How does this study affect clinical practice? The absolute stroke risk was increased by 0.4% in patients with PFO compared with those without. Although this is a relatively small increase, millions of patients undergo noncardiac surgery annually. The risks of therapeutic anticoagulation or PFO closure are likely too high in this context; however, clinicians may approach the perioperative management of antiplatelet agents and venous thromboembolism prophylaxis in patients with known PFO with additional caution.

HOW DOES TIMING OF EMERGENCY SURGERY AFTER PRIOR STROKE AFFECT OUTCOMES?

A history of stroke or transient ischemic attack is a known risk factor for perioperative vascular complications. A recent large cohort study demonstrated that a history of stroke within 9 months of elective surgery was associated with increased adverse outcomes.¹⁶ Little is known, however, of the perioperative risk in patients with a history of stroke who undergo emergency surgery.

[Christiansen MN, Andersson C, Gislason GH, et al. Risks of cardiovascular adverse events and death in patients with previous stroke undergoing emergency noncardiac, nonintracranial surgery: the importance of operative timing. Anesthesiology 2017; 127(1):9–19.]

In this study,¹⁷ all emergency noncardiac and nonintracranial surgeries from 2005 to 2011 were analyzed using multiple national patient registries in Denmark according to time elapsed between previous stroke and surgery. Primary outcomes were 30-day all-cause mortality and 30-day major adverse cardiac events (MACE), defined as nonfatal ischemic stroke, nonfatal myocardial infarction, and cardiovascular death. Statistical analysis to assess the risk of adverse outcomes included logistic regression models, spline analyses, and propensity-score matching.

Findings. The authors identified 146,694 emergency surgeries, with 7,861 patients (5.4%) having had a previous stroke (transient ischemic attacks and hemorrhagic strokes were not included). Rates of postoperative stroke were as follows:

• 9.9% in patents with a history of ischemic stroke within 3 months of surgery
• 2.8% in patients with a history of stroke 3 to 9 months before surgery
• 0.3% in patients with no previous stroke.

The risk plateaued when the time between stroke and surgery exceeded 4 to 5 months.¹⁵

Interestingly, in patients who underwent emergency surgery within 14 days of stroke, the risk of MACE was significantly lower immediately after surgery (1–3 days after stroke) compared with surgery that took place 4 to 14 days after stroke. The authors hypothesized that because cerebral autoregulation does not become compromised until approximately 5 days after a stroke, the risk was lower 1 to 3 days after surgery and increased thereafter.

Limitations of this study included the possibility of residual confounding, given its retrospective design using administrative data, not accounting for preoperative antithrombotic and anticoagulation therapy, and lack of information regarding the etiology of recurrent stroke (eg, thromboembolic, atherothrombotic, hypoperfusion).

Conclusions. Although it would be impractical to postpone emergency surgery in a patient who recently had a stroke, this study shows that the incidence rates of postoperative recurrent stroke and MACE are high. Therefore, it is important that the patient and perioperative team be aware of the risk. Further research is needed to confirm these estimates of postoperative adverse events in more diverse patient populations.

A plethora of studies are under way in the field of perioperative medicine. As a result, evidence-based care of surgical patients is evolving at an exponential rate.

We performed a literature search and, using consensus, identified recent articles we believe will have a great impact on perioperative cardiovascular medicine. These articles report studies that were presented at national meetings in 2018, including the Perioperative Medicine Summit, Society of General Internal Medicine, and Society of Hospital Medicine. These articles are grouped under 5 questions that will help guide clinical practice in perioperative cardiovascular medicine.

SHOULD ASPIRIN BE CONTINUED PERIOPERATIVELY IN PATIENTS WITH A CORONARY STENT?

The Perioperative Ischemic Evaluation 2 (POISE-2) trial¹ found that giving aspirin before surgery and throughout the early postoperative period had no significant effect on the rate of a composite of death or nonfatal myocardial infarction; moreover, aspirin increased the risk of major bleeding. However, many experts felt uncomfortable stopping aspirin preoperatively in patients taking it for secondary prophylaxis, particularly patients with a coronary stent.

[Graham MM, Sessler DI, Parlow JL, et al. Aspirin in patients with previous percutaneous coronary intervention undergoing noncardiac surgery. Ann Intern Med 2018; 168(4):237–244.]

This post hoc subgroup analysis² of POISE-2 evaluated the benefit and harm of perioperative aspirin in patients who had previously undergone percutaneous coronary intervention, more than 90% of whom had received a stent. Patients were age 45 or older with atherosclerotic heart disease or risk factors for it who had previously undergone percutaneous coronary intervention and were now undergoing noncardiac surgery.

Patients who had received a bare-metal stent within the previous 6 weeks or a drug-eluting stent within 12 months before surgery were excluded because guidelines at that time said to continue dual antiplatelet therapy for that long. Recommendations have since changed; the optimal duration for dual antiplatelet therapy with drug-eluting stents is now 6 months. Second-generation drug-eluting stents pose a lower risk of stent thrombosis and require a shorter duration of dual antiplatelet therapy than first-generation drug-eluting stents. Approximately 25% of the percutaneous coronary intervention subgroup had a drug-eluting stent, but the authors did not specify the type of drug-eluting stent.

The post hoc analysis² included a subgroup of 234 of 4,998 patients receiving aspirin and 236 of 5,012 patients receiving placebo initiated within 4 hours before surgery and continued postoperatively. The primary outcome measured was the rate of death or nonfatal myocardial infarction within 30 days after surgery, and bleeding was a secondary outcome.

Findings. Although the overall POISE-2 study found no benefit from aspirin, in the subgroup who had previously undergone percutaneous coronary intervention, aspirin significantly reduced the risk of the primary outcome, which occurred in 6% vs 11.5% of the patients:

• Absolute risk reduction 5.5% (95% confidence interval 0.4%–10.5%)
• Hazard ratio 0.50 (0.26–0.95).

The reduction was primarily due to fewer myocardial infarctions:

• Absolute risk reduction 5.9% (1.0%–10.8%)
• Hazard ratio 0.44 (0.22–0.87).

The type of stent had no effect on the primary outcome, although this subgroup analysis had limited power. In the nonpercutaneous coronary intervention subgroup, there was no significant difference in outcomes between the aspirin and placebo groups. This subgroup analysis was underpowered to evaluate the effect of aspirin on the composite of major and life-threatening bleeding in patients with prior percutaneous coronary intervention, which was reported as “uncertain” due to wide confidence intervals (absolute risk increase 1.3%, 95% confidence interval –2.6% to 5.2%), but the increased risk of major or life-threatening bleeding with aspirin demonstrated in the overall POISE-2 study population likely applies:

• Absolute risk increase 0.8% (0.1%–1.6%)
• Hazard ratio 1.22 (1.01–1.48).

Limitations. This was a nonspecified subgroup analysis that was underpowered and had a relatively small sample size with few events.

Conclusion. In the absence of a very high bleeding risk, continuing aspirin perioperatively in patients with prior percutaneous coronary intervention undergoing noncardiac surgery is more likely to result in benefit than harm. This finding is in agreement with current recommendations from the American College Cardiology and American Heart Association (class I; level of evidence C).³

Despite advances in anesthesia and surgical techniques, about 1% of patients over age 45 die within 30 days of noncardiac surgery.⁴ Studies have demonstrated a high mortality rate in patients who experience myocardial injury after noncardiac surgery (MINS), defined as elevations of troponin T with or without ischemic symptoms or electrocardiographic changes.⁵ Most of these studies used earlier, “non-high-sensitivity” troponin T assays. Fifth-generation, highly sensitive troponin T assays are now available that can detect troponin T at lower concentrations, but their utility in predicting postoperative outcomes remains uncertain. Two recent studies provide further insight into these issues.

[Writing Committee for the VISION Study Investigators, Devereaux PJ, Biccard BM, Sigamani A, et al. Association of postoperative high-sensitivity troponin levels with myocardial injury and 30-day mortality among patients undergoing noncardiac surgery. JAMA 2017; 317(16):1642–1651.]

The Vascular Events in Noncardiac Surgery Patients Cohort Evaluation (VISION) study⁵ was an international, prospective cohort study that initially evaluated the association between MINS and the 30-day mortality rate using a non-high-sensitivity troponin T assay (Roche fourth-generation Elecsys TnT assay) in patients age 45 or older undergoing noncardiac surgery and requiring hospital admission for at least 1 night. After the first 15,000 patients, the study switched to the Roche fifth-generation assay, with measurements at 6 to 12 hours after surgery and on postoperative days 1, 2, and 3.

A 2017 analysis by Devereaux et al⁶ included only these later-enrolled patients and correlated their high-sensitivity troponin T levels with 30-day mortality rates. Patients with a level 14 ng/L or higher, the upper limit of normal in this study, were also assessed for ischemic symptoms and electrocardiographic changes. Although not required by the study, more than 7,800 patients had their troponin T levels measured before surgery, and the absolute change was also analyzed for an association with the 30-day mortality rate.

Findings. Of the 21,842 patients, about two-thirds underwent some form of major surgery; some of them had more than 1 type. A total of 1.2% of the patients died within 30 days of surgery.

Based on their analysis, the authors proposed that MINS be defined as:

• A postoperative troponin T level of 65 ng/L or higher, or
• A level in the range of 20 ng/L to less than 65 ng/L with an absolute increase from the preoperative level at least 5 ng/L, not attributable to a nonischemic cause.

Seventeen percent of the study patients met these criteria, and of these, 21.7% met the universal definition of myocardial infarction, although only 6.9% had symptoms of it.

Limitations. Only 40.4% of the patients had a preoperative high-sensitivity troponin T measurement for comparison, and in 13.8% of patients who had an elevated perioperative measurement, their preoperative value was the same or higher than their postoperative one. Thus, the incidence of MINS may have been overestimated if patients were otherwise not known to have troponin T elevations before surgery.

[Puelacher C, Lurati Buse G, Seeberger D, et al. Perioperative myocardial injury after noncardiac surgery: incidence, mortality, and characterization. Circulation 2018; 137(12):1221–1232.]

Puelacher et al⁷ investigated the prevalence of MINS in 2,018 patients at increased cardiovascular risk (age ≥ 65, or age ≥ 45 with a history of coronary artery disease, peripheral vascular disease, or stroke) who underwent major noncardiac surgery (planned overnight stay ≥ 24 hours) at a university hospital in Switzerland. Patients had their troponin T measured with a high-sensitivity assay within 30 days before surgery and on postoperative days 1 and 2.

Instead of MINS, the investigators used the term “perioperative myocardial injury” (PMI), defined as an absolute increase in troponin T of at least 14 ng/L from before surgery to the peak postoperative reading. Similar to MINS, PMI did not require ischemic features, but in this study, noncardiac triggers (sepsis, stroke, or pulmonary embolus) were not excluded.

Findings. PMI occurred in 16% of surgeries, and of the patients with PMI, 6% had typical chest pain and 18% had any ischemic symptoms. Unlike in the POISE-2 study discussed above, PMI triggered an automatic referral to a cardiologist.

The unadjusted 30-day mortality rate was 8.9% among patients with PMI and 1.5% in those without. Multivariable logistic regression analysis showed an adjusted hazard ratio for 30-day mortality of 2.7 (95% CI 1.5–4.8) for those with PMI vs without, and this difference persisted for at least 1 year.

In patients with PMI, the authors compared the 30-day mortality rate of those with no ischemic signs or symptoms (71% of the patients) with those who met the criteria for myocardial infarction and found no difference. Patients with PMI triggered by a noncardiac event had a worse prognosis than those with a presumed cardiac etiology.

Limitations. Despite the multivariate analysis that included adjustment for age, nonelective surgery, and Revised Cardiac Risk Index (RCRI), the increased risk associated with PMI could simply reflect higher risk at baseline. Although PMI resulted in automatic referral to a cardiologist, only 10% of patients eventually underwent coronary angiography; a similar percentage were discharged with additional medical therapy such as aspirin, a statin, or a beta-blocker. The effect of these interventions is not known.

Conclusions. MINS is common and has a strong association with mortality risk proportional to the degree of troponin T elevation using high-sensitivity assays, consistent with data from previous studies of earlier assays. Because the mechanism of MINS may differ from that of myocardial infarction, its prevention and treatment may differ, and it remains unclear how serial measurement in postoperative patients should change clinical practice.

The recently published Dabigatran in Patients With Myocardial Injury After Non-cardiac Surgery (MANAGE) trial⁸ suggests that dabigatran may reduce arterial and venous complications in patients with MINS, but the study had a number of limitations that may restrict the clinical applicability of this finding.

While awaiting further clinical outcomes data, pre- and postoperative troponin T measurement may be beneficial in higher-risk patients (such as those with cardiovascular disease or multiple RCRI risk factors) if the information will change perioperative management.

Intraoperative hypotension is associated with organ ischemia, which may cause postoperative myocardial infarction, myocardial injury, and acute kidney injury.⁹ Traditional anesthesia practice is to maintain intraoperative blood pressure within 20% of the preoperative baseline, based on the notion that hypertensive patients require higher perfusion pressures.

[Futier E, Lefrant J-Y, Guinot P-G, et al. Effect of individualized vs standard blood pressure management strategies on postoperative organ dysfunction among high-risk patients undergoing major surgery: a randomized clinical trial. JAMA 2017; 318(14):1346–1357.]

Futier et al¹⁰ sought to address uncertainty in intraoperative and immediate postoperative management of systolic blood pressure. In this multicenter, randomized, parallel-group trial, 298 patients at increased risk of postoperative renal complications were randomized to blood pressure management that was either “individualized” (within 10% of resting systolic pressure) or “standard” (≥ 80 mm Hg or ≥ 40% of resting systolic pressure) from induction to 4 hours postoperatively.

Blood pressure was monitored using radial arterial lines and maintained using a combination of intravenous fluids, norepinephrine (the first-line agent for the individualized group), and ephedrine (in the standard treatment group only). The primary outcome was a composite of systemic inflammatory response syndrome (SIRS) and organ dysfunction affecting at least 1 organ system (cardiovascular, respiratory, renal, hematologic, or neurologic).

Findings. Data on the primary outcome were available for 292 of 298 patients enrolled. The mean age was 70 years, 15% were women, and 82% had previously diagnosed hypertension. Despite the requirement for an elevated risk of acute kidney injury, only 13% of the patients had a baseline estimated glomerular filtration rate of less than 60 mL/min/1.73 m², and the median was 88 mL/min/1.73 m². Ninety-five percent of patients underwent abdominal surgery, and 50% of the surgeries were elective.

The mean systolic blood pressure was 123 mm Hg in the individualized treatment group compared with 116 mm Hg in the standard treatment group. Despite this small difference, 96% of individualized treatment patients received norepinephrine, compared with 26% in the standard treatment group.

The primary outcome of SIRS with organ dysfunction occurred in 38.1% of patients in the individualized treatment group and 51.7% of those in the standard treatment group. After adjusting for center, surgical urgency, surgical site, and acute kidney injury risk index, the relative risk of developing SIRS in those receiving individualized management was 0.73 (P = .02). Renal dysfunction (based on Acute Dialysis Quality Initiative criteria¹¹) occurred in 32.7% of individualized treatment patients and 49% of standardized treatment patients.  

Limitations of this study included differences in pharmacologic approach to maintain blood pressure in the 2 protocols (ephedrine and fluids vs norepinephrine) and a modest sample size.

Conclusions. Despite this, the difference in organ dysfunction was striking, with a number needed to treat of only 7 patients. This intervention extended 4 hours postoperatively, a time when many of these patients have left the postanesthesia care unit and have returned to hospitalist care on inpatient wards.

While optimal management of intraoperative and immediate postoperative blood pressure may not be settled, this study suggests that even mild relative hypotension may justify immediate action. Further studies may be useful to delineate high- and low-risk populations, the timing of greatest risk, and indications for intraarterial blood pressure monitoring.

[Salmasi V, Maheswari K, Yang D, et al. Relationship between intraoperative hypotension, defined by either reduction from baseline or absolute thresholds, and acute kidney and myocardial injury after noncardiac surgery: a retrospective cohort analysis. Anesthesiology 2017; 126(1):47–65.]

This retrospective cohort study¹² assessed the association between myocardial or kidney injury and absolute or relative thresholds of intraoperative mean arterial pressure. It included 57,315 adults who underwent inpatient noncardiac surgery, had a preoperative and at least 1 postoperative serum creatinine measurement within 7 days, and had blood pressure recorded in preoperative appointments within 6 months. Patients with chronic kidney disease (glomerular filtration rate < 60 mL/min/1.73 m²) and those on dialysis were excluded. The outcomes were MINS⁵ and acute kidney injury as defined by the Acute Kidney Injury Network.⁹

Findings. A mean arterial pressure below an absolute threshold of 65 mm Hg or a relative threshold of 20% lower than baseline value was associated with myocardial and kidney injury. At each threshold, prolonged periods of hypotension were associated with progressively increased risk.

An important conclusion of the study was that relative thresholds of mean arterial pressure were not any more predictive than absolute thresholds. Absolute thresholds are easier to use intraoperatively, especially when baseline values are not available. The authors did not find a clinically significant interaction between baseline blood pressure and the association of hypotension and myocardial and kidney injury.

Limitations included use of cardiac enzymes postoperatively to define MINS. Since these were not routinely collected, clinically silent myocardial injury may have been missed. Baseline blood pressure may have important implications in other forms of organ injury (ie, cerebral ischemia) that were not studied.

Summary. The lowest absolute mean arterial pressure is as predictive of postoperative myocardial and kidney injury as the relative pressure reduction, at least in patients with normal renal function. Limiting exposure to intraoperative hypotension is important. Baseline blood pressure values may have limited utility for intraoperative management.

In combination, these studies confirm that intraoperative hypotension is a predictor of postoperative organ dysfunction, but the definition and management remain unclear. While aggressive intraoperative management is likely beneficial, how to manage the anti­hypertensive therapy the patient has been taking as an outpatient when he or she comes into the hospital for surgery remains uncertain.

Perioperative stroke is an uncommon, severe complication of noncardiac surgery. The pathophysiology has been better defined in cardiac than in noncardiac surgeries. In nonsurgical patients, patent foramen ovale (PFO) is associated with stroke, even in patients considered to be at low risk.¹³ Perioperative patients have additional risk for venous thromboembolism and may have periprocedural antithrombotic medications altered, increasing their risk of paradoxical embolism through the PFO.

[Ng PY, Ng AK, Subramaniam B, et al. Association of preoperatively diagnosed patent foramen ovale with perioperative ischemic stroke. JAMA 2018; 319(5):452–462.]

This retrospective cohort study of noncardiac surgery patients at 3 hospitals¹⁴ sought to determine the association of preoperatively diagnosed PFO with the risk of perioperative ischemic stroke identified by International Classification of Diseases diagnoses.

Of 150,198 patients, 1.0% had a preoperative diagnosis of PFO, and at baseline, those with PFO had significantly more comorbidities than those without PFO. Stroke occurred in 3.2% of patients with PFO vs 0.5% of those without. Patients known to have a PFO were much more likely to have cardiovascular and thromboembolic risk factors for stroke. In the adjusted analysis, the absolute risk difference between groups was 0.4% (95% CI 0.2–0.6%), with an estimated perioperative stroke risk of 5.9 per 1,000 in patients with known patent foramen ovale and 2.2 per 1,000 in those without. A diagnosis of PFO was also associated with increased risk of large-vessel-territory stroke and more severe neurologic deficit.

Further attempts to adjust for baseline risk factors and other potential bias, including a propensity score-matched cohort analysis and an analysis limited to patients who had echocardiography performed in the same healthcare system, still showed a higher risk of perioperative stroke among patients with preoperatively detected patent foramen ovale.

Limitations. The study was retrospective and observational, used administrative data, and had a low rate of PFO diagnosis (1%), compared with about 25% in population-based studies.¹⁵ Indications for preoperative echocardiography are unknown. In addition, the study specifically examined preoperatively diagnosed PFO, rather than including those diagnosed in the postoperative period.

Discussion. How does this study affect clinical practice? The absolute stroke risk was increased by 0.4% in patients with PFO compared with those without. Although this is a relatively small increase, millions of patients undergo noncardiac surgery annually. The risks of therapeutic anticoagulation or PFO closure are likely too high in this context; however, clinicians may approach the perioperative management of antiplatelet agents and venous thromboembolism prophylaxis in patients with known PFO with additional caution.

HOW DOES TIMING OF EMERGENCY SURGERY AFTER PRIOR STROKE AFFECT OUTCOMES?

A history of stroke or transient ischemic attack is a known risk factor for perioperative vascular complications. A recent large cohort study demonstrated that a history of stroke within 9 months of elective surgery was associated with increased adverse outcomes.¹⁶ Little is known, however, of the perioperative risk in patients with a history of stroke who undergo emergency surgery.

[Christiansen MN, Andersson C, Gislason GH, et al. Risks of cardiovascular adverse events and death in patients with previous stroke undergoing emergency noncardiac, nonintracranial surgery: the importance of operative timing. Anesthesiology 2017; 127(1):9–19.]

In this study,¹⁷ all emergency noncardiac and nonintracranial surgeries from 2005 to 2011 were analyzed using multiple national patient registries in Denmark according to time elapsed between previous stroke and surgery. Primary outcomes were 30-day all-cause mortality and 30-day major adverse cardiac events (MACE), defined as nonfatal ischemic stroke, nonfatal myocardial infarction, and cardiovascular death. Statistical analysis to assess the risk of adverse outcomes included logistic regression models, spline analyses, and propensity-score matching.

Findings. The authors identified 146,694 emergency surgeries, with 7,861 patients (5.4%) having had a previous stroke (transient ischemic attacks and hemorrhagic strokes were not included). Rates of postoperative stroke were as follows:

• 9.9% in patents with a history of ischemic stroke within 3 months of surgery
• 2.8% in patients with a history of stroke 3 to 9 months before surgery
• 0.3% in patients with no previous stroke.

The risk plateaued when the time between stroke and surgery exceeded 4 to 5 months.¹⁵

Interestingly, in patients who underwent emergency surgery within 14 days of stroke, the risk of MACE was significantly lower immediately after surgery (1–3 days after stroke) compared with surgery that took place 4 to 14 days after stroke. The authors hypothesized that because cerebral autoregulation does not become compromised until approximately 5 days after a stroke, the risk was lower 1 to 3 days after surgery and increased thereafter.

Limitations of this study included the possibility of residual confounding, given its retrospective design using administrative data, not accounting for preoperative antithrombotic and anticoagulation therapy, and lack of information regarding the etiology of recurrent stroke (eg, thromboembolic, atherothrombotic, hypoperfusion).

Conclusions. Although it would be impractical to postpone emergency surgery in a patient who recently had a stroke, this study shows that the incidence rates of postoperative recurrent stroke and MACE are high. Therefore, it is important that the patient and perioperative team be aware of the risk. Further research is needed to confirm these estimates of postoperative adverse events in more diverse patient populations.

Each year, millions of women undergo mammography in the hope of decreasing their risk of dying of breast cancer. The effectiveness of screening mammography, however, continues to be debated.

While most randomized controlled trials have demonstrated significantly lower mortality rates in women who undergo screening, not all trials have. Most experts agree that screening mammography programs decrease breast cancer mortality rates by 12% to 33%.^1,2 But some point out that although mammography programs clearly detect more cases of breast cancer, some proportion of this detection may include “overdiagnosis” of cancers that would not have caused morbidity or mortality, including ductal carcinoma in situ. Also, although deaths from breast cancer have decreased in the United States, at least some of the decrease may be due to more effective treatment rather than early detection.

Moreover, screening has well-documented harms. False-positive results cause alarm and expose women to needless follow-up imaging and biopsies, with their attendant inconvenience, discomfort, risks, and costs. Conversely, false-negative results (especially common in women with dense breasts) lead to missed diagnosis and a false sense of security.

How could programs and technology be improved to make screening more beneficial, both for patients and for society as a whole? A major improvement would be if mammography could be made more sensitive and specific for detecting invasive cancers, with fewer false-positive results. Lower cost and less frequent screening would also be major improvements.

Digital breast tomosynthesis (DBT), also known as 3-dimensional (3D) mammography, may be a way to improve the value of breast cancer screening programs. In 2011, the US Food and Drug Administration (FDA) approved DBT for all mammographic indications, including screening.

WHAT IS TOMOSYNTHESIS?

In DBT, the x-ray source is rotated in an arc around the patient’s breast (Figure 1), generating a 3D image.³ DBT is now routinely built into newer-generation mammography units. The 3D projections of DBT are obtained during the same breast compression required for standard 2D digital mammography. Thus, DBT requires minimal additional time on the part of the patient and the technologist.⁴

The 3D images are processed and sent to a viewing station, where a radiologist can interpret them next to 2D images. The radiologist has the ability to scroll through the DBT projections slice by slice, as in other cross-sectional imaging examinations. However, given the larger number of images compared with digital mammography, DBT requires more time for interpretation, interrupting the workflow. A population-based observational study suggested that combined digital mammography and DBT screening examinations take twice as long to interpret.⁵

The main advantage of DBT is that it can mitigate the problem of overlapping breast tissue on standard digital projections. These areas of focal asymmetry may represent suspicious masses—or merely overlapping breast parenchyma. When areas of focal asymmetry are found on 2D digital mammography without DBT, patients need to come back for further diagnostic imaging to resolve the finding.⁶ In addition, especially in women with dense breasts, areas of overlapping tissue can have a masking effect, obscuring small breast cancers.⁷

Images courtesy of Diana L. Lam, MD, University of Washington, Seattle.

For breast cancer screening, DBT is read in conjunction with standard digital mammography. By allowing examination of the breast parenchyma in thin slices, DBT decreases the interpretive issue of overlapping breast parenchyma and the masking effect, potentially leading to fewer false-positive results and higher rates of cancer detection (Figure 2).

EFFECTIVENESS OF TOMOSYNTHESIS

There is limited evidence at this time to support the addition of DBT to digital mammography for primary breast cancer screening, with no published randomized trials that assessed outcomes. However, 2 population-based trials in Europe have prospectively assessed DBT plus digital mammography as a primary screening strategy: the Screening With Tomosynthesis or Standard Mammography (STORM) trial⁸ and the Oslo tomosynthesis screening trial.⁵ Only the STORM trial reported first-year interval cancer rates, from which the sensitivity and specificity of DBT plus 2D digital mammography could be calculated and compared with those of 2D digital mammography alone.⁸

In April 2013, the Oslo tomosynthesis screening trial published interim results of its prospective cohort study of 12,631 Norwegian women ages 50 to 69.⁵ Women were invited to participate based on the availability of technical staff and imaging systems at the time of screening, and all participants underwent digital mammography and DBT. Images were read independently by 4 radiologists using a double-reader protocol.

The interim results suggest that adding DBT to digital mammography increased cancer detection rates by 31% and decreased the false-positive rate by 13% compared with 2D digital mammography alone (Table 1). However, the double-reader protocol in this study differs from typical single-reader protocols in the United States, limiting the applicability of the findings.

The STORM trial: Low sensitivity

The STORM trial is a prospective cohort study that included 7,292 women without symptoms, at average risk, age 48 and older, who participated in national breast cancer screening services in northern Italy. Each participant underwent digital mammography and DBT. The examinations were read sequentially (digital mammography first, then DBT plus digital mammography) either by a single radiologist, as is most common in the United States, or by 2 radiologists, as is standard in Europe.

Using the single-reader strategy, adding DBT significantly increased cancer detection rates and reduced the total recall rate (Table 1). Sensitivity was 85% vs 54%, and specificity was 97% vs 96%.^8,9

Of note, the sensitivity of 54% for digital mammography in the STORM trial is substantially lower than the sensitivity of digital mammography reported in the United States.¹⁰

Friedewald et al confirmed Oslo and STORM

To date, the largest US study of DBT plus digital mammography for breast cancer screening was a multicenter retrospective cohort study by Friedewald et al in 2014.¹¹ This study compared cancer detection and recall rates before and after the implementation of DBT at 13 breast centers and evaluated a total of 454,850 examinations (173,663 with DBT plus digital mammography and 281,187 with digital mammography only).

Overall, the recall rate decreased significantly after DBT was adopted and the cancer detection rate increased, findings consistent with those of the STORM and Oslo trials (Table 1). Adding DBT detected invasive cancers at a higher rate than 2D digital mammography alone (4.1/1000 vs 2.9/1,000), while there was no significant difference in ductal carcinoma in situ detection rates. This suggests that the additional cancers detected by DBT may be more clinically important. Nevertheless, the number of biopsies with negative results also increased, suggesting that adding DBT may pose potential harms.

In 2016, Rafferty et al¹² published an additional analysis of the data from Friedewald et al, concluding that adding DBT to 2D digital mammography increased the cancer detection rate more in women with heterogeneously dense breasts than in those with either nondense breasts or extremely dense breasts.¹² The reduction in recall rate was also greatest in the heterogeneously dense subgroup.

Insufficient evidence to recommend

Most other cohort studies comparing DBT and digital mammography have had findings similar to those of the European prospective studies and the large US retrospective cohort study, with the addition of DBT to mammography reducing recall rates and increasing cancer detection rates.¹³ However, many of these studies were subject to potential selection bias and did not provide information on the cancer risk of the participants. In addition, no studies have assessed clinical outcomes such as breast cancer stage at diagnosis or interval cancers, let alone breast cancer mortality.

Rigorous studies need to be done in the United States, using the standard single-reader protocol most often used in this country, to ascertain the clinical outcomes of DBT plus digital mammography for breast cancer screening for women at average risk. A 2016 review cited a dearth of high-quality US studies assessing the role of DBT in primary breast cancer.¹³

The US Preventive Services Task Force, in its 2016 guidelines for breast cancer screening, concluded that there was insufficient evidence to assess the harms and benefits of DBT as a method of breast cancer screening, including adjunctive screening in women with dense breasts.¹

Similarly, the American College of Physicians has advised against screening average-risk women for breast cancer using DBT.¹⁴

APPROVAL, DISSEMINATION, COSTS, AND CHOICE FOR PATIENTS

Even with early promising data suggesting that DBT can increase cancer detection rates and decrease false-positive results when added to routine screening mammography, the rapid diffusion of DBT into clinical practice is outpacing evidence of its effectiveness.⁴ This adoption was spurred in January 2015 when the Centers for Medicare and Medicaid Services added a Current Procedural Terminology code for DBT, allowing for additional reimbursement for it for all mammography indications.¹⁵ Still, the use of DBT in community settings is inconsistent, given the significant up-front costs associated with equipment purchases and variable reimbursement by private insurers who consider the technology experimental.

For the US healthcare system as a whole, it is uncertain whether the purported benefits of DBT will outweigh the additional costs associated with its use. The average reimbursement for a routine digital mammography examination is $135; adding DBT adds an average of $56 to the cost.¹⁵

Using an established, discrete-event breast cancer simulation model, a team of investigators evaluated the cost-effectiveness of combined biennial digital mammography and DBT screening compared with biennial digital mammography screening alone in US women with dense breasts.¹⁶ They found that biennial combined screening is likely to be cost-effective in US women with dense breasts. They also found that for every 2,000 women screened from age 50 to age 74, adding DBT would prevent 1 breast cancer death and 810 false-positive screening examinations.¹⁶

In addition, some have expressed concern that adding DBT to standard digital mammography increases radiation exposure. In fact, the radiation dose with DBT is similar to that with standard 2D digital mammography. Thus, when acquired together, combined digital mammography and DBT screening leads to twice the radiation dose compared with digital mammography alone.¹⁷ Nevertheless, this increased dose remains well below the FDA limits for a screening examination. In addition, the FDA has approved software that allows reconstruction of 2D synthetic views from the 3D data set, which will eventually bring radiation dose levels down to levels comparable to those of conventional digital mammography.¹⁷

Given that DBT is built into newer mammography units and is available as an add-on feature for existing units, its use is likely to increase even faster than digital mammography did when it replaced screen-film mammography in the previous decade.⁴ Its adoption by screening facilities, however, remains variable, and patients wishing to obtain combined DBT and digital mammography screening may have to travel to a different facility from their usual place of screening.¹⁸

Moreover, not all insurance companies cover DBT, resulting in additional out-of-pocket costs to the patient. It is currently unclear how individual facilities are offering DBT services, including how patients are selected for additional DBT and if they are offered the choice to add or forego DBT screening in combination with standard digital mammography.

SUMMARY: AN EMERGING TECHNOLOGY

DBT is an emerging imaging technology that allows the radiologist to view breast images in slices, as in computed tomography. DBT images can be obtained using the same breast compression that women already undergo for 2D digital mammography for breast cancer screening.

At this time, adding DBT to digital mammography screening nearly doubles the radiation exposure to the patient. However, new software is available that allows creation of synthetic 2D views from the 3D data set, resulting in radiation exposure that is similar to conventional digital mammography.

Although there are no published randomized controlled trials assessing the benefit of DBT over 2D digital mammography for breast cancer screening, prospective observational studies suggest that DBT may reduce false-positive recall rates and increase cancer detection rates when used in population-based screening programs. Assuming that additional breast cancer detection contributes to improved clinical outcomes, women with dense breasts may benefit more than women without dense breasts.

No national organizations currently recommend DBT for primary breast cancer screening. Ideally, future studies would determine whether DBT screening reduces breast cancer mortality. Since this research may not be feasible, surrogate clinical outcomes, such as a decrease in interval breast cancer rates and impact on stage at time of diagnosis, would allow us to more confidently recommend this new technology.

Each year, millions of women undergo mammography in the hope of decreasing their risk of dying of breast cancer. The effectiveness of screening mammography, however, continues to be debated.

While most randomized controlled trials have demonstrated significantly lower mortality rates in women who undergo screening, not all trials have. Most experts agree that screening mammography programs decrease breast cancer mortality rates by 12% to 33%.^1,2 But some point out that although mammography programs clearly detect more cases of breast cancer, some proportion of this detection may include “overdiagnosis” of cancers that would not have caused morbidity or mortality, including ductal carcinoma in situ. Also, although deaths from breast cancer have decreased in the United States, at least some of the decrease may be due to more effective treatment rather than early detection.

Moreover, screening has well-documented harms. False-positive results cause alarm and expose women to needless follow-up imaging and biopsies, with their attendant inconvenience, discomfort, risks, and costs. Conversely, false-negative results (especially common in women with dense breasts) lead to missed diagnosis and a false sense of security.

How could programs and technology be improved to make screening more beneficial, both for patients and for society as a whole? A major improvement would be if mammography could be made more sensitive and specific for detecting invasive cancers, with fewer false-positive results. Lower cost and less frequent screening would also be major improvements.

Digital breast tomosynthesis (DBT), also known as 3-dimensional (3D) mammography, may be a way to improve the value of breast cancer screening programs. In 2011, the US Food and Drug Administration (FDA) approved DBT for all mammographic indications, including screening.

WHAT IS TOMOSYNTHESIS?

In DBT, the x-ray source is rotated in an arc around the patient’s breast (Figure 1), generating a 3D image.³ DBT is now routinely built into newer-generation mammography units. The 3D projections of DBT are obtained during the same breast compression required for standard 2D digital mammography. Thus, DBT requires minimal additional time on the part of the patient and the technologist.⁴

The 3D images are processed and sent to a viewing station, where a radiologist can interpret them next to 2D images. The radiologist has the ability to scroll through the DBT projections slice by slice, as in other cross-sectional imaging examinations. However, given the larger number of images compared with digital mammography, DBT requires more time for interpretation, interrupting the workflow. A population-based observational study suggested that combined digital mammography and DBT screening examinations take twice as long to interpret.⁵

The main advantage of DBT is that it can mitigate the problem of overlapping breast tissue on standard digital projections. These areas of focal asymmetry may represent suspicious masses—or merely overlapping breast parenchyma. When areas of focal asymmetry are found on 2D digital mammography without DBT, patients need to come back for further diagnostic imaging to resolve the finding.⁶ In addition, especially in women with dense breasts, areas of overlapping tissue can have a masking effect, obscuring small breast cancers.⁷

Images courtesy of Diana L. Lam, MD, University of Washington, Seattle.

For breast cancer screening, DBT is read in conjunction with standard digital mammography. By allowing examination of the breast parenchyma in thin slices, DBT decreases the interpretive issue of overlapping breast parenchyma and the masking effect, potentially leading to fewer false-positive results and higher rates of cancer detection (Figure 2).

EFFECTIVENESS OF TOMOSYNTHESIS

There is limited evidence at this time to support the addition of DBT to digital mammography for primary breast cancer screening, with no published randomized trials that assessed outcomes. However, 2 population-based trials in Europe have prospectively assessed DBT plus digital mammography as a primary screening strategy: the Screening With Tomosynthesis or Standard Mammography (STORM) trial⁸ and the Oslo tomosynthesis screening trial.⁵ Only the STORM trial reported first-year interval cancer rates, from which the sensitivity and specificity of DBT plus 2D digital mammography could be calculated and compared with those of 2D digital mammography alone.⁸

In April 2013, the Oslo tomosynthesis screening trial published interim results of its prospective cohort study of 12,631 Norwegian women ages 50 to 69.⁵ Women were invited to participate based on the availability of technical staff and imaging systems at the time of screening, and all participants underwent digital mammography and DBT. Images were read independently by 4 radiologists using a double-reader protocol.

The interim results suggest that adding DBT to digital mammography increased cancer detection rates by 31% and decreased the false-positive rate by 13% compared with 2D digital mammography alone (Table 1). However, the double-reader protocol in this study differs from typical single-reader protocols in the United States, limiting the applicability of the findings.

The STORM trial: Low sensitivity

The STORM trial is a prospective cohort study that included 7,292 women without symptoms, at average risk, age 48 and older, who participated in national breast cancer screening services in northern Italy. Each participant underwent digital mammography and DBT. The examinations were read sequentially (digital mammography first, then DBT plus digital mammography) either by a single radiologist, as is most common in the United States, or by 2 radiologists, as is standard in Europe.

Using the single-reader strategy, adding DBT significantly increased cancer detection rates and reduced the total recall rate (Table 1). Sensitivity was 85% vs 54%, and specificity was 97% vs 96%.^8,9

Of note, the sensitivity of 54% for digital mammography in the STORM trial is substantially lower than the sensitivity of digital mammography reported in the United States.¹⁰

Friedewald et al confirmed Oslo and STORM

To date, the largest US study of DBT plus digital mammography for breast cancer screening was a multicenter retrospective cohort study by Friedewald et al in 2014.¹¹ This study compared cancer detection and recall rates before and after the implementation of DBT at 13 breast centers and evaluated a total of 454,850 examinations (173,663 with DBT plus digital mammography and 281,187 with digital mammography only).

Overall, the recall rate decreased significantly after DBT was adopted and the cancer detection rate increased, findings consistent with those of the STORM and Oslo trials (Table 1). Adding DBT detected invasive cancers at a higher rate than 2D digital mammography alone (4.1/1000 vs 2.9/1,000), while there was no significant difference in ductal carcinoma in situ detection rates. This suggests that the additional cancers detected by DBT may be more clinically important. Nevertheless, the number of biopsies with negative results also increased, suggesting that adding DBT may pose potential harms.

In 2016, Rafferty et al¹² published an additional analysis of the data from Friedewald et al, concluding that adding DBT to 2D digital mammography increased the cancer detection rate more in women with heterogeneously dense breasts than in those with either nondense breasts or extremely dense breasts.¹² The reduction in recall rate was also greatest in the heterogeneously dense subgroup.

Insufficient evidence to recommend

Most other cohort studies comparing DBT and digital mammography have had findings similar to those of the European prospective studies and the large US retrospective cohort study, with the addition of DBT to mammography reducing recall rates and increasing cancer detection rates.¹³ However, many of these studies were subject to potential selection bias and did not provide information on the cancer risk of the participants. In addition, no studies have assessed clinical outcomes such as breast cancer stage at diagnosis or interval cancers, let alone breast cancer mortality.

Rigorous studies need to be done in the United States, using the standard single-reader protocol most often used in this country, to ascertain the clinical outcomes of DBT plus digital mammography for breast cancer screening for women at average risk. A 2016 review cited a dearth of high-quality US studies assessing the role of DBT in primary breast cancer.¹³

The US Preventive Services Task Force, in its 2016 guidelines for breast cancer screening, concluded that there was insufficient evidence to assess the harms and benefits of DBT as a method of breast cancer screening, including adjunctive screening in women with dense breasts.¹

Similarly, the American College of Physicians has advised against screening average-risk women for breast cancer using DBT.¹⁴

APPROVAL, DISSEMINATION, COSTS, AND CHOICE FOR PATIENTS

Even with early promising data suggesting that DBT can increase cancer detection rates and decrease false-positive results when added to routine screening mammography, the rapid diffusion of DBT into clinical practice is outpacing evidence of its effectiveness.⁴ This adoption was spurred in January 2015 when the Centers for Medicare and Medicaid Services added a Current Procedural Terminology code for DBT, allowing for additional reimbursement for it for all mammography indications.¹⁵ Still, the use of DBT in community settings is inconsistent, given the significant up-front costs associated with equipment purchases and variable reimbursement by private insurers who consider the technology experimental.

For the US healthcare system as a whole, it is uncertain whether the purported benefits of DBT will outweigh the additional costs associated with its use. The average reimbursement for a routine digital mammography examination is $135; adding DBT adds an average of $56 to the cost.¹⁵

Using an established, discrete-event breast cancer simulation model, a team of investigators evaluated the cost-effectiveness of combined biennial digital mammography and DBT screening compared with biennial digital mammography screening alone in US women with dense breasts.¹⁶ They found that biennial combined screening is likely to be cost-effective in US women with dense breasts. They also found that for every 2,000 women screened from age 50 to age 74, adding DBT would prevent 1 breast cancer death and 810 false-positive screening examinations.¹⁶

In addition, some have expressed concern that adding DBT to standard digital mammography increases radiation exposure. In fact, the radiation dose with DBT is similar to that with standard 2D digital mammography. Thus, when acquired together, combined digital mammography and DBT screening leads to twice the radiation dose compared with digital mammography alone.¹⁷ Nevertheless, this increased dose remains well below the FDA limits for a screening examination. In addition, the FDA has approved software that allows reconstruction of 2D synthetic views from the 3D data set, which will eventually bring radiation dose levels down to levels comparable to those of conventional digital mammography.¹⁷

Given that DBT is built into newer mammography units and is available as an add-on feature for existing units, its use is likely to increase even faster than digital mammography did when it replaced screen-film mammography in the previous decade.⁴ Its adoption by screening facilities, however, remains variable, and patients wishing to obtain combined DBT and digital mammography screening may have to travel to a different facility from their usual place of screening.¹⁸

Moreover, not all insurance companies cover DBT, resulting in additional out-of-pocket costs to the patient. It is currently unclear how individual facilities are offering DBT services, including how patients are selected for additional DBT and if they are offered the choice to add or forego DBT screening in combination with standard digital mammography.

SUMMARY: AN EMERGING TECHNOLOGY

DBT is an emerging imaging technology that allows the radiologist to view breast images in slices, as in computed tomography. DBT images can be obtained using the same breast compression that women already undergo for 2D digital mammography for breast cancer screening.

At this time, adding DBT to digital mammography screening nearly doubles the radiation exposure to the patient. However, new software is available that allows creation of synthetic 2D views from the 3D data set, resulting in radiation exposure that is similar to conventional digital mammography.

Although there are no published randomized controlled trials assessing the benefit of DBT over 2D digital mammography for breast cancer screening, prospective observational studies suggest that DBT may reduce false-positive recall rates and increase cancer detection rates when used in population-based screening programs. Assuming that additional breast cancer detection contributes to improved clinical outcomes, women with dense breasts may benefit more than women without dense breasts.

No national organizations currently recommend DBT for primary breast cancer screening. Ideally, future studies would determine whether DBT screening reduces breast cancer mortality. Since this research may not be feasible, surrogate clinical outcomes, such as a decrease in interval breast cancer rates and impact on stage at time of diagnosis, would allow us to more confidently recommend this new technology.

Each year, millions of women undergo mammography in the hope of decreasing their risk of dying of breast cancer. The effectiveness of screening mammography, however, continues to be debated.

While most randomized controlled trials have demonstrated significantly lower mortality rates in women who undergo screening, not all trials have. Most experts agree that screening mammography programs decrease breast cancer mortality rates by 12% to 33%.^1,2 But some point out that although mammography programs clearly detect more cases of breast cancer, some proportion of this detection may include “overdiagnosis” of cancers that would not have caused morbidity or mortality, including ductal carcinoma in situ. Also, although deaths from breast cancer have decreased in the United States, at least some of the decrease may be due to more effective treatment rather than early detection.

Moreover, screening has well-documented harms. False-positive results cause alarm and expose women to needless follow-up imaging and biopsies, with their attendant inconvenience, discomfort, risks, and costs. Conversely, false-negative results (especially common in women with dense breasts) lead to missed diagnosis and a false sense of security.

How could programs and technology be improved to make screening more beneficial, both for patients and for society as a whole? A major improvement would be if mammography could be made more sensitive and specific for detecting invasive cancers, with fewer false-positive results. Lower cost and less frequent screening would also be major improvements.

Digital breast tomosynthesis (DBT), also known as 3-dimensional (3D) mammography, may be a way to improve the value of breast cancer screening programs. In 2011, the US Food and Drug Administration (FDA) approved DBT for all mammographic indications, including screening.

WHAT IS TOMOSYNTHESIS?

In DBT, the x-ray source is rotated in an arc around the patient’s breast (Figure 1), generating a 3D image.³ DBT is now routinely built into newer-generation mammography units. The 3D projections of DBT are obtained during the same breast compression required for standard 2D digital mammography. Thus, DBT requires minimal additional time on the part of the patient and the technologist.⁴

The 3D images are processed and sent to a viewing station, where a radiologist can interpret them next to 2D images. The radiologist has the ability to scroll through the DBT projections slice by slice, as in other cross-sectional imaging examinations. However, given the larger number of images compared with digital mammography, DBT requires more time for interpretation, interrupting the workflow. A population-based observational study suggested that combined digital mammography and DBT screening examinations take twice as long to interpret.⁵

The main advantage of DBT is that it can mitigate the problem of overlapping breast tissue on standard digital projections. These areas of focal asymmetry may represent suspicious masses—or merely overlapping breast parenchyma. When areas of focal asymmetry are found on 2D digital mammography without DBT, patients need to come back for further diagnostic imaging to resolve the finding.⁶ In addition, especially in women with dense breasts, areas of overlapping tissue can have a masking effect, obscuring small breast cancers.⁷

Images courtesy of Diana L. Lam, MD, University of Washington, Seattle.

For breast cancer screening, DBT is read in conjunction with standard digital mammography. By allowing examination of the breast parenchyma in thin slices, DBT decreases the interpretive issue of overlapping breast parenchyma and the masking effect, potentially leading to fewer false-positive results and higher rates of cancer detection (Figure 2).

EFFECTIVENESS OF TOMOSYNTHESIS

There is limited evidence at this time to support the addition of DBT to digital mammography for primary breast cancer screening, with no published randomized trials that assessed outcomes. However, 2 population-based trials in Europe have prospectively assessed DBT plus digital mammography as a primary screening strategy: the Screening With Tomosynthesis or Standard Mammography (STORM) trial⁸ and the Oslo tomosynthesis screening trial.⁵ Only the STORM trial reported first-year interval cancer rates, from which the sensitivity and specificity of DBT plus 2D digital mammography could be calculated and compared with those of 2D digital mammography alone.⁸

In April 2013, the Oslo tomosynthesis screening trial published interim results of its prospective cohort study of 12,631 Norwegian women ages 50 to 69.⁵ Women were invited to participate based on the availability of technical staff and imaging systems at the time of screening, and all participants underwent digital mammography and DBT. Images were read independently by 4 radiologists using a double-reader protocol.

The interim results suggest that adding DBT to digital mammography increased cancer detection rates by 31% and decreased the false-positive rate by 13% compared with 2D digital mammography alone (Table 1). However, the double-reader protocol in this study differs from typical single-reader protocols in the United States, limiting the applicability of the findings.

The STORM trial: Low sensitivity

The STORM trial is a prospective cohort study that included 7,292 women without symptoms, at average risk, age 48 and older, who participated in national breast cancer screening services in northern Italy. Each participant underwent digital mammography and DBT. The examinations were read sequentially (digital mammography first, then DBT plus digital mammography) either by a single radiologist, as is most common in the United States, or by 2 radiologists, as is standard in Europe.

Using the single-reader strategy, adding DBT significantly increased cancer detection rates and reduced the total recall rate (Table 1). Sensitivity was 85% vs 54%, and specificity was 97% vs 96%.^8,9

Of note, the sensitivity of 54% for digital mammography in the STORM trial is substantially lower than the sensitivity of digital mammography reported in the United States.¹⁰

Friedewald et al confirmed Oslo and STORM

To date, the largest US study of DBT plus digital mammography for breast cancer screening was a multicenter retrospective cohort study by Friedewald et al in 2014.¹¹ This study compared cancer detection and recall rates before and after the implementation of DBT at 13 breast centers and evaluated a total of 454,850 examinations (173,663 with DBT plus digital mammography and 281,187 with digital mammography only).

Overall, the recall rate decreased significantly after DBT was adopted and the cancer detection rate increased, findings consistent with those of the STORM and Oslo trials (Table 1). Adding DBT detected invasive cancers at a higher rate than 2D digital mammography alone (4.1/1000 vs 2.9/1,000), while there was no significant difference in ductal carcinoma in situ detection rates. This suggests that the additional cancers detected by DBT may be more clinically important. Nevertheless, the number of biopsies with negative results also increased, suggesting that adding DBT may pose potential harms.

In 2016, Rafferty et al¹² published an additional analysis of the data from Friedewald et al, concluding that adding DBT to 2D digital mammography increased the cancer detection rate more in women with heterogeneously dense breasts than in those with either nondense breasts or extremely dense breasts.¹² The reduction in recall rate was also greatest in the heterogeneously dense subgroup.

Insufficient evidence to recommend

Most other cohort studies comparing DBT and digital mammography have had findings similar to those of the European prospective studies and the large US retrospective cohort study, with the addition of DBT to mammography reducing recall rates and increasing cancer detection rates.¹³ However, many of these studies were subject to potential selection bias and did not provide information on the cancer risk of the participants. In addition, no studies have assessed clinical outcomes such as breast cancer stage at diagnosis or interval cancers, let alone breast cancer mortality.

Rigorous studies need to be done in the United States, using the standard single-reader protocol most often used in this country, to ascertain the clinical outcomes of DBT plus digital mammography for breast cancer screening for women at average risk. A 2016 review cited a dearth of high-quality US studies assessing the role of DBT in primary breast cancer.¹³

The US Preventive Services Task Force, in its 2016 guidelines for breast cancer screening, concluded that there was insufficient evidence to assess the harms and benefits of DBT as a method of breast cancer screening, including adjunctive screening in women with dense breasts.¹

Similarly, the American College of Physicians has advised against screening average-risk women for breast cancer using DBT.¹⁴

APPROVAL, DISSEMINATION, COSTS, AND CHOICE FOR PATIENTS

Even with early promising data suggesting that DBT can increase cancer detection rates and decrease false-positive results when added to routine screening mammography, the rapid diffusion of DBT into clinical practice is outpacing evidence of its effectiveness.⁴ This adoption was spurred in January 2015 when the Centers for Medicare and Medicaid Services added a Current Procedural Terminology code for DBT, allowing for additional reimbursement for it for all mammography indications.¹⁵ Still, the use of DBT in community settings is inconsistent, given the significant up-front costs associated with equipment purchases and variable reimbursement by private insurers who consider the technology experimental.

For the US healthcare system as a whole, it is uncertain whether the purported benefits of DBT will outweigh the additional costs associated with its use. The average reimbursement for a routine digital mammography examination is $135; adding DBT adds an average of $56 to the cost.¹⁵

Using an established, discrete-event breast cancer simulation model, a team of investigators evaluated the cost-effectiveness of combined biennial digital mammography and DBT screening compared with biennial digital mammography screening alone in US women with dense breasts.¹⁶ They found that biennial combined screening is likely to be cost-effective in US women with dense breasts. They also found that for every 2,000 women screened from age 50 to age 74, adding DBT would prevent 1 breast cancer death and 810 false-positive screening examinations.¹⁶

In addition, some have expressed concern that adding DBT to standard digital mammography increases radiation exposure. In fact, the radiation dose with DBT is similar to that with standard 2D digital mammography. Thus, when acquired together, combined digital mammography and DBT screening leads to twice the radiation dose compared with digital mammography alone.¹⁷ Nevertheless, this increased dose remains well below the FDA limits for a screening examination. In addition, the FDA has approved software that allows reconstruction of 2D synthetic views from the 3D data set, which will eventually bring radiation dose levels down to levels comparable to those of conventional digital mammography.¹⁷

Given that DBT is built into newer mammography units and is available as an add-on feature for existing units, its use is likely to increase even faster than digital mammography did when it replaced screen-film mammography in the previous decade.⁴ Its adoption by screening facilities, however, remains variable, and patients wishing to obtain combined DBT and digital mammography screening may have to travel to a different facility from their usual place of screening.¹⁸

Moreover, not all insurance companies cover DBT, resulting in additional out-of-pocket costs to the patient. It is currently unclear how individual facilities are offering DBT services, including how patients are selected for additional DBT and if they are offered the choice to add or forego DBT screening in combination with standard digital mammography.

SUMMARY: AN EMERGING TECHNOLOGY

DBT is an emerging imaging technology that allows the radiologist to view breast images in slices, as in computed tomography. DBT images can be obtained using the same breast compression that women already undergo for 2D digital mammography for breast cancer screening.

At this time, adding DBT to digital mammography screening nearly doubles the radiation exposure to the patient. However, new software is available that allows creation of synthetic 2D views from the 3D data set, resulting in radiation exposure that is similar to conventional digital mammography.

Although there are no published randomized controlled trials assessing the benefit of DBT over 2D digital mammography for breast cancer screening, prospective observational studies suggest that DBT may reduce false-positive recall rates and increase cancer detection rates when used in population-based screening programs. Assuming that additional breast cancer detection contributes to improved clinical outcomes, women with dense breasts may benefit more than women without dense breasts.

No national organizations currently recommend DBT for primary breast cancer screening. Ideally, future studies would determine whether DBT screening reduces breast cancer mortality. Since this research may not be feasible, surrogate clinical outcomes, such as a decrease in interval breast cancer rates and impact on stage at time of diagnosis, would allow us to more confidently recommend this new technology.

Women's health encompasses a variety of topics relevant to the daily practice of internists. Staying up to date with the evidence in this wide field is a challenge.

This article reviews important studies published in 2015 and early 2016 on treatment of urinary tract infections, the optimal duration of bisphosphonate use, ovarian cancer screening, the impact of oral contraceptives and lactation on mortality rates, and the risks and benefits of intrauterine contraception. We critically appraised the studies and judged that their methodology was strong and appropriate for inclusion in this review.

IBUPROFEN FOR URINARY TRACT INFECTIONS

A 36-year-old woman reports 4 days of mild to moderate dysuria, frequency, and urgency. She denies fever, nausea, or back pain. Her last urinary tract infection was 2 years ago. Office urinalysis reveals leukocyte esterase and nitrites. She has read an article about antibiotic resistance and Clostridium difficile infection and asks you if antibiotics are truly necessary. What do you recommend?

Urinary tract infections are often self-limited

Uncomplicated urinary tract infections account for 25% of antibiotic prescriptions in primary care.¹

Several small studies have suggested that many of these infections are self-limited, resolving within 3 to 14 days without antibiotics (Table 1).^2–6 A potential disadvantage of withholding treatment is slower bacterial clearance and resolution of symptoms, but reducing the number of antibiotic prescriptions may help slow antibiotic resistance.^7,8 Surveys and qualitative studies have suggested that women are concerned about the harms of antibiotic treatment and so may be willing to avoid or postpone antibiotic use.^9–11

Ibuprofen vs fosfomycin

Gágyor et al⁶ conducted a double-blind, randomized multicenter trial in 42 general practices in Germany to assess whether treating the symptoms of uncomplicated urinary tract infection with ibuprofen would reduce antibiotic use without worsening outcomes.

Of the 779 eligible women with suspected urinary tract infection, 281 declined to participate in the study, 4 did not participate for reasons not specified, 246 received a single dose of fosfomycin 3 g, and 248 were treated with ibuprofen 400 mg three times a day for 3 days. Participants scored their daily symptoms and activity impairment, and safety data were collected for adverse events and relapses up to day 28 and within 6 and 12 months. In both groups, if symptoms worsened or persisted, antibiotic therapy was initiated at the discretion of the treating physician.

Exclusion criteria included fever, “loin” (back) tenderness, pregnancy, renal disease, a previous urinary tract infection within 2 weeks, urinary catheterization, and a contraindication to nonsteroidal anti-inflammatory medications.

Results. Within 28 days of symptom onset, women in the ibuprofen group had received 81 courses of antibiotics for symptoms of urinary tract infection (plus another 13 courses for other reasons), compared with 277 courses for urinary tract infection in the fosfomycin group (plus 6 courses for other reasons), for a relative rate reduction in antibiotic use of 66.5% (95% confidence interval [CI] 58.8%–74.4%, P < .001). The women who received ibuprofen were more likely to need antibiotics after initial treatment because of refractory symptoms but were still less likely to receive antibiotics overall (Table 1).

The mean duration of symptoms was slightly shorter in the fosfomycin group (4.6 vs 5.6 days, P < .001). However, the percentage of patients who had a recurrent urinary tract infection within 2 to 4 weeks was higher in the fosfomycin-treated patients (11% vs 6% P = .049).

Although the study was not powered to show significant differences in pyelonephritis, five patients in the ibuprofen group developed pyelonephritis compared with one in the antibiotic-treated group (P = .12).

An important limitation of the study was that nonparticipants had higher symptom scores, which may mean that the results are not generalizable to women who have recurrent urinary tract infections, longer duration of symptoms, or symptoms that are more severe. The strengths of the study were that more than half of all potentially eligible women were enrolled, and baseline data were collected from nonparticipants.

Can our patient avoid antibiotics?

Given the mild nature of her symptoms, the clinician should discuss with her the risks vs benefits of delaying antibiotics, once it has been determined that she has no risk factors for severe urinary tract infection. Her symptoms are likely to resolve within 1 week even if she declines antibiotic treatment, though they may last a day longer with ibuprofen alone than if she had received antibiotics. She should watch for symptoms of pyelonephritis (eg, flank pain, fever, chills, vomiting) and should seek prompt medical care if such symptoms occur.

DISCONTINUING BISPHOSPHONATES

A 64-year-old woman has taken alendronate for her osteoporosis for 5 years. She has no history of fractures. Her original bone density scans showed a T-score of –2.6 at the spine and –1.5 at the hip. Since she started to take alendronate, there has been no further loss in bone mineral density. She is tolerating the drug well and does not take any other medications. Should she continue the bisphosphonate?

Optimal duration of therapy unknown

The risks and benefits of long-term bisphosphonate use are debated.

In the Fracture Intervention Trial (FIT),¹² women with low bone mineral density of the femoral neck were randomized to receive alendronate or placebo and were followed for 36 months. The alendronate group had significantly fewer vertebral fractures and clinical fractures overall. Then, in the FIT Long-term Extension (FLEX) study,¹³ 1,009 alendronate-treated women in the FIT study were rerandomized to receive 5 years of additional treatment or to stop treatment. Bone density in the untreated women decreased, although not to the level it was before treatment. At the end of the study, there was no difference in hip fracture rate between the two groups (3% of each group had had a hip fracture), although women in the treated group had a lower rate of clinical vertebral fracture (2% vs 5%, relative risk 0.5, 95% CI 0.2–0.8).

In addition, rare but serious risks have been associated with bisphosphonate use, specifically atypical femoral fracture and osteonecrosis of the jaw. A US Food and Drug Administration (FDA) evaluation of long-term bisphosphonate use concluded that there was evidence of an increased risk of osteonecrosis of the jaw with longer duration of use, but causality was not established. The evaluation also noted conflicting results about the association with atypical femoral fracture.¹⁴

Based on this report and focusing on the absence of nonspine benefit after 5 years, the FDA suggested that bisphosphonates may be safely discontinued in some patients without compromising therapeutic gains, but no adequate clinical trial has yet delineated how long the benefits of treatment are maintained after cessation. A periodic reevaluation of continued need was recommended.¹⁴

New recommendations from the American Society for Bone and Mineral Research

Age is the greatest risk factor for fracture.¹⁵ Therefore, deciding whether to discontinue a bisphosphonate when a woman is older, and hence at higher risk, is a challenge.

A task force of the American Society for Bone and Mineral Research (ASBMR) has developed an evidence-based guideline on managing osteoporosis in patients on long-term bisphosphonate treatment.¹⁶ The goal was to provide guidance on the duration of bisphosphonate therapy from the perspective of risk vs benefit. The authors conducted a systematic review focusing on two randomized controlled trials (FLEX¹³ and the Health Outcomes and Reduced Incidence With Zoledronic Acid Once Yearly Pivotal Fracture Trial¹⁷) that provided data on long-term bisphosphonate use.

The task force recommended¹⁶ that after 5 years of oral bisphosphonates or 3 years of intravenous bisphosphonates, risk should be reassessed. In women at high fracture risk, they recommended continuing the oral bisphosphonate for 10 years or the intravenous bisphosphonate for 6 years. Factors that favored continuation of bisphosphonate therapy were as follows:

• An osteoporotic fracture before or during therapy
• A hip bone mineral density T-score ≤ –2.5
• High risk of fracture, defined as age older than 70 or 75, other strong risk factors for fracture, or a FRAX fracture risk score¹⁸ above a country-specific threshold.

(The FRAX score is based on age, sex, weight, height, previous fracture, hip fracture in a parent, current smoking, use of glucocorticoids, rheumatoid arthritis, secondary osteoporosis, alcohol use, and bone mineral density in the femoral neck. It gives an estimate of the 10-year risk of major osteoporotic fracture and hip fracture. High risk would be a 10-year risk of major osteoporotic fracture greater than 20% or a 10-year risk of hip fracture greater than 3%.)

For women at high risk, the risks of atypical femoral fracture and osteonecrosis of the jaw are outweighed by the benefit of a reduction in vertebral fracture risk. For women not at high risk of fracture, a drug holiday of 2 to 3 years can be considered after 3 to 5 years of treatment.

Although the task force recommended reassessment after 2 to 3 years of drug holiday, how best to do this is not clear. The task force did not recommend a specific approach to reassessment, so decisions about when to restart therapy after a drug holiday could potentially be informed by subsequent bone mineral density testing if it were to show persistent bone loss. Another option could be to restart bisphosphonates after a defined amount of time (eg, 3–5 years) for women who have previously experienced benefit.

The task force recommendations are in line with those of other societies, the FDA, and expert opinion.^19–23

The American Association of Clinical Endocrinologists recommends considering a drug holiday in low-risk patients after 4 to 5 years of treatment. For high-risk patients, they recommend 1 to 2 years of drug holiday after 10 years of treatment. They encourage restarting treatment if bone mineral density decreases, bone turnover markers rise, or fracture occurs.¹⁹ This is a grade C recommendation, meaning the advice is based on descriptive studies and expert opinion.

Although some clinicians restart bisphosphonates when markers of bone turnover such as NTX (N-telopeptide of type 1 collagen) rise to premenopausal levels, there is no evidence to support this strategy.²⁴

The task force recommendations are based on limited evidence that primarily comes from white postmenopausal women. Another important limitation is that the outcomes are primarily vertebral fractures. However, until additional evidence is available, these guidelines can be useful in guiding decision-making.

Should our patient continue therapy?

Our patient is relatively young and does not have any of the high-risk features noted within the task force recommendations. She has responded well to bisphosphonate treatment and so can consider a drug holiday at this time.

OVARIAN CANCER SCREENING

A 50-year-old woman requests screening for ovarian cancer. She is postmenopausal and has no personal or family history of cancer. She is concerned because a friend forwarded an e-mail stating, “Please tell all your female friends and relatives to insist on a cancer antigen (CA) 125 blood test every year as part of their annual exam. This is an inexpensive and simple blood test. Don’t take no for an answer. If I had known then what I know now, we would have caught my cancer much earlier, before it was stage III!” What should you tell the patient?

Ovarian cancer is the most deadly of female reproductive cancers, largely because in most patients the cancer has already spread beyond the ovary by the time of clinical detection. Death rates from ovarian cancer have decreased only slightly in the past 30 years.

Little benefit and considerable harm of screening

In 2011, the Prostate Lung Colorectal Ovarian (PLCO) Cancer Screening trial²⁵ randomized more than 68,000 women ages 55 to 74 from the general US population to annual screening with CA 125 testing and transvaginal ultrasonography compared with usual care. They were followed for a median of 12.4 years.

Screening did not affect stage at diagnosis (77%–78% were in stage III or IV in both the screening and usual care groups), nor did it reduce the rate of death from ovarian cancer. In addition, false-positive findings led to some harm: nearly one in three women who had a positive screening test underwent surgery. Of 3,285 women with false-positive results, 1,080 underwent surgery, and 15% of these had at least one serious complication. The trial was stopped early due to evidence of futility.

A new UK study also found no benefit from screening

In the PLCO study, a CA 125 result of 35 U/mL or greater was classified as abnormal. However, researchers in the United Kingdom postulated that instead of using a single cutoff for a normal or abnormal CA 125 level, it would be better to interpret the CA 125 result according to a somewhat complicated (and proprietary) algorithm called the Risk of Ovarian Cancer Algorithm (ROCA).^26,27 The ROCA takes into account a woman’s age, menopausal status, known genetic mutations (BRCA 1 or 2 or Lynch syndrome), Ashkenazi Jewish descent, and family history of ovarian or breast cancer, as well as any change in CA 125 level over time.

In a 2016 UK study,²⁶ 202,638 postmenopausal women ages 50 to 74 were randomized to no screening, annual screening with transvaginal ultrasonography, or multimodal screening with an annual CA 125 blood test interpreted with the ROCA algorithm, adding transvaginal ultrasonography as a second-line test when needed if the CA 125 level was abnormal based on the ROCA. Women with abnormal findings on multimodal screening or ultrasonography had repeat tests, and women with persistent abnormalities underwent clinical evaluation and, when appropriate, surgery.

Participants were at average risk of ovarian cancer; those with suspected familial ovarian cancer syndrome were excluded, as were those with a personal history of ovarian cancer or other active cancer.

Results. At a median follow-up of 11.1 years, the percentage of women who were diagnosed with ovarian cancer was 0.7% in the multimodal screening group, 0.6% in the screening ultrasonography group, and 0.6% in the no-screening group. Comparing either multimodal or screening ultrasonography with no screening, there was no statistically significant reduction in mortality rate over 14 years of follow-up.

Screening had significant costs and potential harms. For every ovarian or peritoneal cancer detected by screening, an additional 2 women in the multimodal screening group and 10 women in the ultrasonography group underwent needless surgery.

Strengths of this trial included its large size, allowing adequate power to detect differences in outcomes, its multicenter setting, its high compliance rate, and the low crossover rate in the no-screening group. However, the design of the study makes it difficult to anticipate the late effects of screening. Also, the patient must purchase ROCA testing online and must also pay a consultation fee. Insurance providers do not cover this test.

Should our patient proceed with ovarian cancer screening?

No. Current evidence shows no clear benefit to ovarian cancer screening for average-risk women, and we should not recommend yearly ultrasonography and CA 125 level testing, as they are likely to cause harm without providing benefit. The US Preventive Services Task Force recommends against screening for ovarian cancer.²⁸ For premenopausal women, pregnancy, hormonal contraception, and breastfeeding all significantly decrease ovarian cancer risk by suppressing ovulation.^29–31

REPRODUCTIVE FACTORS AND THE RISK OF DEATH

A 26-year-old woman comes in to discuss her contraceptive options. She has been breastfeeding since the birth of her first baby 6 months ago, and wonders how lactation and contraception may affect her long-term health.

Questions about the safety of contraceptive options are common, especially in breastfeeding mothers.

In 2010, the long-term Royal College of General Practitioners’ Oral Contraceptive Study reported that the all-cause mortality rate was actually lower in women who used oral contraceptives.³² Similarly, in 2013, an Oxford study that followed 17,032 women for over 30 years reported no association between oral contraceptives and breast cancer.³³

However, in 2014, results from the Nurses’ Health Study indicated that breast cancer rates were higher in oral contraceptive users, although reassuringly, the study found no difference in all-cause mortality rates in women who had used oral contraception.³⁴

The European Prospective Investigation Into Cancer and Nutrition

To further characterize relationships between reproductive characteristics and mortality rates, investigators analyzed data from the European Prospective Investigation Into Cancer and Nutrition,³⁵ which recruited 322,972 women from 10 countries between 1992 and 2000. Analyses were stratified by study center and participant age and were adjusted for body mass index, physical activity, education level, smoking, and menopausal status; alcohol intake was examined as a potential confounder but was excluded from final models.

Findings. Over an average 13 years of follow-up, the rate of all-cause mortality was 20% lower in parous than in nulliparous women. In parous women, the all-cause mortality rate was additionally 18% lower in those who had breastfed vs those who had never breastfed, although breastfeeding duration was not associated with mortality. Use of oral contraceptives lowered all-cause mortality by 10% among nonsmokers; in smokers, no association with all-cause mortality was seen for oral contraceptive use, as smoking is such a powerful risk factor for mortality. The primary contributor to all-cause mortality appeared to be ischemic heart disease, the incidence of which was significantly lower in parous women (by 14%) and those who breastfed (by 20%) and was not related to oral contraceptive use.³⁵

Strengths of this study included the large sample size recruited from countries across Europe, with varying rates of breastfeeding and contraceptive use. However, as with all observational studies, it remains subject to the possibility of residual confounding.

What should we tell this patient?

After congratulating her for breastfeeding, we can reassure her about the safety of all available contraceptives. According to the US Centers for Disease Control and Prevention (CDC),³⁶ after 42 days postpartum most women can use combined hormonal contraception. All other methods can be used immediately postpartum, including progestin-only pills.

As lactational amenorrhea is only effective while mothers are exclusively breastfeeding, and short interpregnancy intervals have been associated with higher rates of adverse pregnancy outcomes,³⁷ this patient will likely benefit from promptly starting a prescription contraceptive.

HIGHLY EFFECTIVE REVERSIBLE CONTRACEPTION

This same 26-year-old patient is concerned that she will not remember to take an oral contraceptive every day, and expresses interest in a more convenient method of contraception. However, she is concerned about the potential risks.

Although intrauterine contraceptives (IUCs) are typically 20 times more effective than oral contraceptives³⁸ and have been used by millions of women worldwide, rates of use in the United States have been lower than in many other countries.³⁹

A study of intrauterine contraception

To clarify the safety of IUCs, researchers followed 61,448 women who underwent IUC placement in six European countries between 2006 and 2013.⁴⁰ Most participants received an IUC containing levonorgestrel, while 30% received a copper IUC.

Findings. Overall, rates of uterine perforation were low (approximately 1 per 1,000 insertions). The most significant risk factors for perforation were breastfeeding at the time of insertion and insertion less than 36 weeks after the last delivery. None of the perforations in the study led to serious illness or injury of intra-abdominal or pelvic structures. Interestingly, women using a levonorgestrel IUC were considerably less likely to experience a contraceptive failure than those using a copper IUC.⁴¹

Strengths of this study included the prospective data collection and power to examine rare clinical outcomes. However, it was industry-funded.

The risk of pelvic infection with an IUC is so low that the CDC does not recommend prophylactic antibiotics with the insertion procedure. If women have other indications for testing for sexually transmitted disease, an IUC can be placed the same day as testing, and before results are available.⁴² If a woman is found to have a sexually transmitted disease while she has an IUC in place, she should be treated with antibiotics, and there is no need to remove the IUC.⁴³

Subdermal implants

Another highly effective contraceptive option for this patient is the progestin-only subdermal contraceptive implant (marketed in the United States as Nexplanon). Implants have been well-studied and found to have no adverse effect on lactation.⁴⁴

Learning to place a subdermal contraceptive is far easier than learning to place an IUC, but it requires a few hours of FDA-mandated in-person training. Unfortunately, relatively few clinicians have obtained this training.⁴⁵ As placing a subdermal contraceptive is like placing an intravenous line without needing to hit the vein, this procedure can easily be incorporated into a primary care practice. Training from the manufacturer is available to providers who request it.

What should we tell this patient?

An IUC is a great option for many women. When pregnancy is desired, the device is easily removed. Of the three IUCs now available in the United States, those containing 52 mg of levonorgestrel (marketed in the United States as Mirena and Liletta) are the most effective.

The only option more effective than these IUCs is subdermal contraception.⁴⁶ These reversible contraceptives are typically more effective than permanent contraceptives (ie, tubal ligation)⁴⁷ and can be removed at any time if a patient wishes to switch to another method or to become pregnant.

Pregnancy rates following attempts at “sterilization” are higher than many realize. There are a variety of approaches to “tying tubes,” some of which may not result in complete tubal occlusion. The failure rate of the laparoscopic approach, according to the US Collaborative Review of Sterilization, ranges from 7.5 per 1,000 procedures for unipolar coagulation to a high of 36.5 per 1,000 for the spring clip.⁴⁸ The relatively commonly used Filshie clip was not included in this study, but its failure rate is reported to be between 1% and 2%.

Women's health encompasses a variety of topics relevant to the daily practice of internists. Staying up to date with the evidence in this wide field is a challenge.

This article reviews important studies published in 2015 and early 2016 on treatment of urinary tract infections, the optimal duration of bisphosphonate use, ovarian cancer screening, the impact of oral contraceptives and lactation on mortality rates, and the risks and benefits of intrauterine contraception. We critically appraised the studies and judged that their methodology was strong and appropriate for inclusion in this review.

IBUPROFEN FOR URINARY TRACT INFECTIONS

A 36-year-old woman reports 4 days of mild to moderate dysuria, frequency, and urgency. She denies fever, nausea, or back pain. Her last urinary tract infection was 2 years ago. Office urinalysis reveals leukocyte esterase and nitrites. She has read an article about antibiotic resistance and Clostridium difficile infection and asks you if antibiotics are truly necessary. What do you recommend?

Urinary tract infections are often self-limited

Uncomplicated urinary tract infections account for 25% of antibiotic prescriptions in primary care.¹

Several small studies have suggested that many of these infections are self-limited, resolving within 3 to 14 days without antibiotics (Table 1).^2–6 A potential disadvantage of withholding treatment is slower bacterial clearance and resolution of symptoms, but reducing the number of antibiotic prescriptions may help slow antibiotic resistance.^7,8 Surveys and qualitative studies have suggested that women are concerned about the harms of antibiotic treatment and so may be willing to avoid or postpone antibiotic use.^9–11

Ibuprofen vs fosfomycin

Gágyor et al⁶ conducted a double-blind, randomized multicenter trial in 42 general practices in Germany to assess whether treating the symptoms of uncomplicated urinary tract infection with ibuprofen would reduce antibiotic use without worsening outcomes.

Of the 779 eligible women with suspected urinary tract infection, 281 declined to participate in the study, 4 did not participate for reasons not specified, 246 received a single dose of fosfomycin 3 g, and 248 were treated with ibuprofen 400 mg three times a day for 3 days. Participants scored their daily symptoms and activity impairment, and safety data were collected for adverse events and relapses up to day 28 and within 6 and 12 months. In both groups, if symptoms worsened or persisted, antibiotic therapy was initiated at the discretion of the treating physician.

Exclusion criteria included fever, “loin” (back) tenderness, pregnancy, renal disease, a previous urinary tract infection within 2 weeks, urinary catheterization, and a contraindication to nonsteroidal anti-inflammatory medications.

Results. Within 28 days of symptom onset, women in the ibuprofen group had received 81 courses of antibiotics for symptoms of urinary tract infection (plus another 13 courses for other reasons), compared with 277 courses for urinary tract infection in the fosfomycin group (plus 6 courses for other reasons), for a relative rate reduction in antibiotic use of 66.5% (95% confidence interval [CI] 58.8%–74.4%, P < .001). The women who received ibuprofen were more likely to need antibiotics after initial treatment because of refractory symptoms but were still less likely to receive antibiotics overall (Table 1).

The mean duration of symptoms was slightly shorter in the fosfomycin group (4.6 vs 5.6 days, P < .001). However, the percentage of patients who had a recurrent urinary tract infection within 2 to 4 weeks was higher in the fosfomycin-treated patients (11% vs 6% P = .049).

Although the study was not powered to show significant differences in pyelonephritis, five patients in the ibuprofen group developed pyelonephritis compared with one in the antibiotic-treated group (P = .12).

An important limitation of the study was that nonparticipants had higher symptom scores, which may mean that the results are not generalizable to women who have recurrent urinary tract infections, longer duration of symptoms, or symptoms that are more severe. The strengths of the study were that more than half of all potentially eligible women were enrolled, and baseline data were collected from nonparticipants.

Can our patient avoid antibiotics?

Given the mild nature of her symptoms, the clinician should discuss with her the risks vs benefits of delaying antibiotics, once it has been determined that she has no risk factors for severe urinary tract infection. Her symptoms are likely to resolve within 1 week even if she declines antibiotic treatment, though they may last a day longer with ibuprofen alone than if she had received antibiotics. She should watch for symptoms of pyelonephritis (eg, flank pain, fever, chills, vomiting) and should seek prompt medical care if such symptoms occur.

DISCONTINUING BISPHOSPHONATES

A 64-year-old woman has taken alendronate for her osteoporosis for 5 years. She has no history of fractures. Her original bone density scans showed a T-score of –2.6 at the spine and –1.5 at the hip. Since she started to take alendronate, there has been no further loss in bone mineral density. She is tolerating the drug well and does not take any other medications. Should she continue the bisphosphonate?

Optimal duration of therapy unknown

The risks and benefits of long-term bisphosphonate use are debated.

In the Fracture Intervention Trial (FIT),¹² women with low bone mineral density of the femoral neck were randomized to receive alendronate or placebo and were followed for 36 months. The alendronate group had significantly fewer vertebral fractures and clinical fractures overall. Then, in the FIT Long-term Extension (FLEX) study,¹³ 1,009 alendronate-treated women in the FIT study were rerandomized to receive 5 years of additional treatment or to stop treatment. Bone density in the untreated women decreased, although not to the level it was before treatment. At the end of the study, there was no difference in hip fracture rate between the two groups (3% of each group had had a hip fracture), although women in the treated group had a lower rate of clinical vertebral fracture (2% vs 5%, relative risk 0.5, 95% CI 0.2–0.8).

In addition, rare but serious risks have been associated with bisphosphonate use, specifically atypical femoral fracture and osteonecrosis of the jaw. A US Food and Drug Administration (FDA) evaluation of long-term bisphosphonate use concluded that there was evidence of an increased risk of osteonecrosis of the jaw with longer duration of use, but causality was not established. The evaluation also noted conflicting results about the association with atypical femoral fracture.¹⁴

Based on this report and focusing on the absence of nonspine benefit after 5 years, the FDA suggested that bisphosphonates may be safely discontinued in some patients without compromising therapeutic gains, but no adequate clinical trial has yet delineated how long the benefits of treatment are maintained after cessation. A periodic reevaluation of continued need was recommended.¹⁴

New recommendations from the American Society for Bone and Mineral Research

Age is the greatest risk factor for fracture.¹⁵ Therefore, deciding whether to discontinue a bisphosphonate when a woman is older, and hence at higher risk, is a challenge.

A task force of the American Society for Bone and Mineral Research (ASBMR) has developed an evidence-based guideline on managing osteoporosis in patients on long-term bisphosphonate treatment.¹⁶ The goal was to provide guidance on the duration of bisphosphonate therapy from the perspective of risk vs benefit. The authors conducted a systematic review focusing on two randomized controlled trials (FLEX¹³ and the Health Outcomes and Reduced Incidence With Zoledronic Acid Once Yearly Pivotal Fracture Trial¹⁷) that provided data on long-term bisphosphonate use.

The task force recommended¹⁶ that after 5 years of oral bisphosphonates or 3 years of intravenous bisphosphonates, risk should be reassessed. In women at high fracture risk, they recommended continuing the oral bisphosphonate for 10 years or the intravenous bisphosphonate for 6 years. Factors that favored continuation of bisphosphonate therapy were as follows:

• An osteoporotic fracture before or during therapy
• A hip bone mineral density T-score ≤ –2.5
• High risk of fracture, defined as age older than 70 or 75, other strong risk factors for fracture, or a FRAX fracture risk score¹⁸ above a country-specific threshold.

(The FRAX score is based on age, sex, weight, height, previous fracture, hip fracture in a parent, current smoking, use of glucocorticoids, rheumatoid arthritis, secondary osteoporosis, alcohol use, and bone mineral density in the femoral neck. It gives an estimate of the 10-year risk of major osteoporotic fracture and hip fracture. High risk would be a 10-year risk of major osteoporotic fracture greater than 20% or a 10-year risk of hip fracture greater than 3%.)

For women at high risk, the risks of atypical femoral fracture and osteonecrosis of the jaw are outweighed by the benefit of a reduction in vertebral fracture risk. For women not at high risk of fracture, a drug holiday of 2 to 3 years can be considered after 3 to 5 years of treatment.

Although the task force recommended reassessment after 2 to 3 years of drug holiday, how best to do this is not clear. The task force did not recommend a specific approach to reassessment, so decisions about when to restart therapy after a drug holiday could potentially be informed by subsequent bone mineral density testing if it were to show persistent bone loss. Another option could be to restart bisphosphonates after a defined amount of time (eg, 3–5 years) for women who have previously experienced benefit.

The task force recommendations are in line with those of other societies, the FDA, and expert opinion.^19–23

The American Association of Clinical Endocrinologists recommends considering a drug holiday in low-risk patients after 4 to 5 years of treatment. For high-risk patients, they recommend 1 to 2 years of drug holiday after 10 years of treatment. They encourage restarting treatment if bone mineral density decreases, bone turnover markers rise, or fracture occurs.¹⁹ This is a grade C recommendation, meaning the advice is based on descriptive studies and expert opinion.

Although some clinicians restart bisphosphonates when markers of bone turnover such as NTX (N-telopeptide of type 1 collagen) rise to premenopausal levels, there is no evidence to support this strategy.²⁴

The task force recommendations are based on limited evidence that primarily comes from white postmenopausal women. Another important limitation is that the outcomes are primarily vertebral fractures. However, until additional evidence is available, these guidelines can be useful in guiding decision-making.

Should our patient continue therapy?

Our patient is relatively young and does not have any of the high-risk features noted within the task force recommendations. She has responded well to bisphosphonate treatment and so can consider a drug holiday at this time.

OVARIAN CANCER SCREENING

A 50-year-old woman requests screening for ovarian cancer. She is postmenopausal and has no personal or family history of cancer. She is concerned because a friend forwarded an e-mail stating, “Please tell all your female friends and relatives to insist on a cancer antigen (CA) 125 blood test every year as part of their annual exam. This is an inexpensive and simple blood test. Don’t take no for an answer. If I had known then what I know now, we would have caught my cancer much earlier, before it was stage III!” What should you tell the patient?

Ovarian cancer is the most deadly of female reproductive cancers, largely because in most patients the cancer has already spread beyond the ovary by the time of clinical detection. Death rates from ovarian cancer have decreased only slightly in the past 30 years.

Little benefit and considerable harm of screening

In 2011, the Prostate Lung Colorectal Ovarian (PLCO) Cancer Screening trial²⁵ randomized more than 68,000 women ages 55 to 74 from the general US population to annual screening with CA 125 testing and transvaginal ultrasonography compared with usual care. They were followed for a median of 12.4 years.

Screening did not affect stage at diagnosis (77%–78% were in stage III or IV in both the screening and usual care groups), nor did it reduce the rate of death from ovarian cancer. In addition, false-positive findings led to some harm: nearly one in three women who had a positive screening test underwent surgery. Of 3,285 women with false-positive results, 1,080 underwent surgery, and 15% of these had at least one serious complication. The trial was stopped early due to evidence of futility.

A new UK study also found no benefit from screening

In the PLCO study, a CA 125 result of 35 U/mL or greater was classified as abnormal. However, researchers in the United Kingdom postulated that instead of using a single cutoff for a normal or abnormal CA 125 level, it would be better to interpret the CA 125 result according to a somewhat complicated (and proprietary) algorithm called the Risk of Ovarian Cancer Algorithm (ROCA).^26,27 The ROCA takes into account a woman’s age, menopausal status, known genetic mutations (BRCA 1 or 2 or Lynch syndrome), Ashkenazi Jewish descent, and family history of ovarian or breast cancer, as well as any change in CA 125 level over time.

In a 2016 UK study,²⁶ 202,638 postmenopausal women ages 50 to 74 were randomized to no screening, annual screening with transvaginal ultrasonography, or multimodal screening with an annual CA 125 blood test interpreted with the ROCA algorithm, adding transvaginal ultrasonography as a second-line test when needed if the CA 125 level was abnormal based on the ROCA. Women with abnormal findings on multimodal screening or ultrasonography had repeat tests, and women with persistent abnormalities underwent clinical evaluation and, when appropriate, surgery.

Participants were at average risk of ovarian cancer; those with suspected familial ovarian cancer syndrome were excluded, as were those with a personal history of ovarian cancer or other active cancer.

Results. At a median follow-up of 11.1 years, the percentage of women who were diagnosed with ovarian cancer was 0.7% in the multimodal screening group, 0.6% in the screening ultrasonography group, and 0.6% in the no-screening group. Comparing either multimodal or screening ultrasonography with no screening, there was no statistically significant reduction in mortality rate over 14 years of follow-up.

Screening had significant costs and potential harms. For every ovarian or peritoneal cancer detected by screening, an additional 2 women in the multimodal screening group and 10 women in the ultrasonography group underwent needless surgery.

Strengths of this trial included its large size, allowing adequate power to detect differences in outcomes, its multicenter setting, its high compliance rate, and the low crossover rate in the no-screening group. However, the design of the study makes it difficult to anticipate the late effects of screening. Also, the patient must purchase ROCA testing online and must also pay a consultation fee. Insurance providers do not cover this test.

Should our patient proceed with ovarian cancer screening?

No. Current evidence shows no clear benefit to ovarian cancer screening for average-risk women, and we should not recommend yearly ultrasonography and CA 125 level testing, as they are likely to cause harm without providing benefit. The US Preventive Services Task Force recommends against screening for ovarian cancer.²⁸ For premenopausal women, pregnancy, hormonal contraception, and breastfeeding all significantly decrease ovarian cancer risk by suppressing ovulation.^29–31

REPRODUCTIVE FACTORS AND THE RISK OF DEATH

A 26-year-old woman comes in to discuss her contraceptive options. She has been breastfeeding since the birth of her first baby 6 months ago, and wonders how lactation and contraception may affect her long-term health.

Questions about the safety of contraceptive options are common, especially in breastfeeding mothers.

In 2010, the long-term Royal College of General Practitioners’ Oral Contraceptive Study reported that the all-cause mortality rate was actually lower in women who used oral contraceptives.³² Similarly, in 2013, an Oxford study that followed 17,032 women for over 30 years reported no association between oral contraceptives and breast cancer.³³

However, in 2014, results from the Nurses’ Health Study indicated that breast cancer rates were higher in oral contraceptive users, although reassuringly, the study found no difference in all-cause mortality rates in women who had used oral contraception.³⁴

The European Prospective Investigation Into Cancer and Nutrition

To further characterize relationships between reproductive characteristics and mortality rates, investigators analyzed data from the European Prospective Investigation Into Cancer and Nutrition,³⁵ which recruited 322,972 women from 10 countries between 1992 and 2000. Analyses were stratified by study center and participant age and were adjusted for body mass index, physical activity, education level, smoking, and menopausal status; alcohol intake was examined as a potential confounder but was excluded from final models.

Findings. Over an average 13 years of follow-up, the rate of all-cause mortality was 20% lower in parous than in nulliparous women. In parous women, the all-cause mortality rate was additionally 18% lower in those who had breastfed vs those who had never breastfed, although breastfeeding duration was not associated with mortality. Use of oral contraceptives lowered all-cause mortality by 10% among nonsmokers; in smokers, no association with all-cause mortality was seen for oral contraceptive use, as smoking is such a powerful risk factor for mortality. The primary contributor to all-cause mortality appeared to be ischemic heart disease, the incidence of which was significantly lower in parous women (by 14%) and those who breastfed (by 20%) and was not related to oral contraceptive use.³⁵

Strengths of this study included the large sample size recruited from countries across Europe, with varying rates of breastfeeding and contraceptive use. However, as with all observational studies, it remains subject to the possibility of residual confounding.

What should we tell this patient?

After congratulating her for breastfeeding, we can reassure her about the safety of all available contraceptives. According to the US Centers for Disease Control and Prevention (CDC),³⁶ after 42 days postpartum most women can use combined hormonal contraception. All other methods can be used immediately postpartum, including progestin-only pills.

As lactational amenorrhea is only effective while mothers are exclusively breastfeeding, and short interpregnancy intervals have been associated with higher rates of adverse pregnancy outcomes,³⁷ this patient will likely benefit from promptly starting a prescription contraceptive.

HIGHLY EFFECTIVE REVERSIBLE CONTRACEPTION

This same 26-year-old patient is concerned that she will not remember to take an oral contraceptive every day, and expresses interest in a more convenient method of contraception. However, she is concerned about the potential risks.

Although intrauterine contraceptives (IUCs) are typically 20 times more effective than oral contraceptives³⁸ and have been used by millions of women worldwide, rates of use in the United States have been lower than in many other countries.³⁹

A study of intrauterine contraception

To clarify the safety of IUCs, researchers followed 61,448 women who underwent IUC placement in six European countries between 2006 and 2013.⁴⁰ Most participants received an IUC containing levonorgestrel, while 30% received a copper IUC.

Findings. Overall, rates of uterine perforation were low (approximately 1 per 1,000 insertions). The most significant risk factors for perforation were breastfeeding at the time of insertion and insertion less than 36 weeks after the last delivery. None of the perforations in the study led to serious illness or injury of intra-abdominal or pelvic structures. Interestingly, women using a levonorgestrel IUC were considerably less likely to experience a contraceptive failure than those using a copper IUC.⁴¹

Strengths of this study included the prospective data collection and power to examine rare clinical outcomes. However, it was industry-funded.

The risk of pelvic infection with an IUC is so low that the CDC does not recommend prophylactic antibiotics with the insertion procedure. If women have other indications for testing for sexually transmitted disease, an IUC can be placed the same day as testing, and before results are available.⁴² If a woman is found to have a sexually transmitted disease while she has an IUC in place, she should be treated with antibiotics, and there is no need to remove the IUC.⁴³

Subdermal implants

Another highly effective contraceptive option for this patient is the progestin-only subdermal contraceptive implant (marketed in the United States as Nexplanon). Implants have been well-studied and found to have no adverse effect on lactation.⁴⁴

Learning to place a subdermal contraceptive is far easier than learning to place an IUC, but it requires a few hours of FDA-mandated in-person training. Unfortunately, relatively few clinicians have obtained this training.⁴⁵ As placing a subdermal contraceptive is like placing an intravenous line without needing to hit the vein, this procedure can easily be incorporated into a primary care practice. Training from the manufacturer is available to providers who request it.

What should we tell this patient?

An IUC is a great option for many women. When pregnancy is desired, the device is easily removed. Of the three IUCs now available in the United States, those containing 52 mg of levonorgestrel (marketed in the United States as Mirena and Liletta) are the most effective.

The only option more effective than these IUCs is subdermal contraception.⁴⁶ These reversible contraceptives are typically more effective than permanent contraceptives (ie, tubal ligation)⁴⁷ and can be removed at any time if a patient wishes to switch to another method or to become pregnant.

Pregnancy rates following attempts at “sterilization” are higher than many realize. There are a variety of approaches to “tying tubes,” some of which may not result in complete tubal occlusion. The failure rate of the laparoscopic approach, according to the US Collaborative Review of Sterilization, ranges from 7.5 per 1,000 procedures for unipolar coagulation to a high of 36.5 per 1,000 for the spring clip.⁴⁸ The relatively commonly used Filshie clip was not included in this study, but its failure rate is reported to be between 1% and 2%.

Women's health encompasses a variety of topics relevant to the daily practice of internists. Staying up to date with the evidence in this wide field is a challenge.

This article reviews important studies published in 2015 and early 2016 on treatment of urinary tract infections, the optimal duration of bisphosphonate use, ovarian cancer screening, the impact of oral contraceptives and lactation on mortality rates, and the risks and benefits of intrauterine contraception. We critically appraised the studies and judged that their methodology was strong and appropriate for inclusion in this review.

IBUPROFEN FOR URINARY TRACT INFECTIONS

A 36-year-old woman reports 4 days of mild to moderate dysuria, frequency, and urgency. She denies fever, nausea, or back pain. Her last urinary tract infection was 2 years ago. Office urinalysis reveals leukocyte esterase and nitrites. She has read an article about antibiotic resistance and Clostridium difficile infection and asks you if antibiotics are truly necessary. What do you recommend?

Urinary tract infections are often self-limited

Uncomplicated urinary tract infections account for 25% of antibiotic prescriptions in primary care.¹

Several small studies have suggested that many of these infections are self-limited, resolving within 3 to 14 days without antibiotics (Table 1).^2–6 A potential disadvantage of withholding treatment is slower bacterial clearance and resolution of symptoms, but reducing the number of antibiotic prescriptions may help slow antibiotic resistance.^7,8 Surveys and qualitative studies have suggested that women are concerned about the harms of antibiotic treatment and so may be willing to avoid or postpone antibiotic use.^9–11

Ibuprofen vs fosfomycin

Gágyor et al⁶ conducted a double-blind, randomized multicenter trial in 42 general practices in Germany to assess whether treating the symptoms of uncomplicated urinary tract infection with ibuprofen would reduce antibiotic use without worsening outcomes.

Of the 779 eligible women with suspected urinary tract infection, 281 declined to participate in the study, 4 did not participate for reasons not specified, 246 received a single dose of fosfomycin 3 g, and 248 were treated with ibuprofen 400 mg three times a day for 3 days. Participants scored their daily symptoms and activity impairment, and safety data were collected for adverse events and relapses up to day 28 and within 6 and 12 months. In both groups, if symptoms worsened or persisted, antibiotic therapy was initiated at the discretion of the treating physician.

Exclusion criteria included fever, “loin” (back) tenderness, pregnancy, renal disease, a previous urinary tract infection within 2 weeks, urinary catheterization, and a contraindication to nonsteroidal anti-inflammatory medications.

Results. Within 28 days of symptom onset, women in the ibuprofen group had received 81 courses of antibiotics for symptoms of urinary tract infection (plus another 13 courses for other reasons), compared with 277 courses for urinary tract infection in the fosfomycin group (plus 6 courses for other reasons), for a relative rate reduction in antibiotic use of 66.5% (95% confidence interval [CI] 58.8%–74.4%, P < .001). The women who received ibuprofen were more likely to need antibiotics after initial treatment because of refractory symptoms but were still less likely to receive antibiotics overall (Table 1).

The mean duration of symptoms was slightly shorter in the fosfomycin group (4.6 vs 5.6 days, P < .001). However, the percentage of patients who had a recurrent urinary tract infection within 2 to 4 weeks was higher in the fosfomycin-treated patients (11% vs 6% P = .049).

Although the study was not powered to show significant differences in pyelonephritis, five patients in the ibuprofen group developed pyelonephritis compared with one in the antibiotic-treated group (P = .12).

An important limitation of the study was that nonparticipants had higher symptom scores, which may mean that the results are not generalizable to women who have recurrent urinary tract infections, longer duration of symptoms, or symptoms that are more severe. The strengths of the study were that more than half of all potentially eligible women were enrolled, and baseline data were collected from nonparticipants.

Can our patient avoid antibiotics?

Given the mild nature of her symptoms, the clinician should discuss with her the risks vs benefits of delaying antibiotics, once it has been determined that she has no risk factors for severe urinary tract infection. Her symptoms are likely to resolve within 1 week even if she declines antibiotic treatment, though they may last a day longer with ibuprofen alone than if she had received antibiotics. She should watch for symptoms of pyelonephritis (eg, flank pain, fever, chills, vomiting) and should seek prompt medical care if such symptoms occur.

DISCONTINUING BISPHOSPHONATES

A 64-year-old woman has taken alendronate for her osteoporosis for 5 years. She has no history of fractures. Her original bone density scans showed a T-score of –2.6 at the spine and –1.5 at the hip. Since she started to take alendronate, there has been no further loss in bone mineral density. She is tolerating the drug well and does not take any other medications. Should she continue the bisphosphonate?

Optimal duration of therapy unknown

The risks and benefits of long-term bisphosphonate use are debated.

In the Fracture Intervention Trial (FIT),¹² women with low bone mineral density of the femoral neck were randomized to receive alendronate or placebo and were followed for 36 months. The alendronate group had significantly fewer vertebral fractures and clinical fractures overall. Then, in the FIT Long-term Extension (FLEX) study,¹³ 1,009 alendronate-treated women in the FIT study were rerandomized to receive 5 years of additional treatment or to stop treatment. Bone density in the untreated women decreased, although not to the level it was before treatment. At the end of the study, there was no difference in hip fracture rate between the two groups (3% of each group had had a hip fracture), although women in the treated group had a lower rate of clinical vertebral fracture (2% vs 5%, relative risk 0.5, 95% CI 0.2–0.8).

In addition, rare but serious risks have been associated with bisphosphonate use, specifically atypical femoral fracture and osteonecrosis of the jaw. A US Food and Drug Administration (FDA) evaluation of long-term bisphosphonate use concluded that there was evidence of an increased risk of osteonecrosis of the jaw with longer duration of use, but causality was not established. The evaluation also noted conflicting results about the association with atypical femoral fracture.¹⁴

Based on this report and focusing on the absence of nonspine benefit after 5 years, the FDA suggested that bisphosphonates may be safely discontinued in some patients without compromising therapeutic gains, but no adequate clinical trial has yet delineated how long the benefits of treatment are maintained after cessation. A periodic reevaluation of continued need was recommended.¹⁴

New recommendations from the American Society for Bone and Mineral Research

Age is the greatest risk factor for fracture.¹⁵ Therefore, deciding whether to discontinue a bisphosphonate when a woman is older, and hence at higher risk, is a challenge.

A task force of the American Society for Bone and Mineral Research (ASBMR) has developed an evidence-based guideline on managing osteoporosis in patients on long-term bisphosphonate treatment.¹⁶ The goal was to provide guidance on the duration of bisphosphonate therapy from the perspective of risk vs benefit. The authors conducted a systematic review focusing on two randomized controlled trials (FLEX¹³ and the Health Outcomes and Reduced Incidence With Zoledronic Acid Once Yearly Pivotal Fracture Trial¹⁷) that provided data on long-term bisphosphonate use.

The task force recommended¹⁶ that after 5 years of oral bisphosphonates or 3 years of intravenous bisphosphonates, risk should be reassessed. In women at high fracture risk, they recommended continuing the oral bisphosphonate for 10 years or the intravenous bisphosphonate for 6 years. Factors that favored continuation of bisphosphonate therapy were as follows:

• An osteoporotic fracture before or during therapy
• A hip bone mineral density T-score ≤ –2.5
• High risk of fracture, defined as age older than 70 or 75, other strong risk factors for fracture, or a FRAX fracture risk score¹⁸ above a country-specific threshold.

(The FRAX score is based on age, sex, weight, height, previous fracture, hip fracture in a parent, current smoking, use of glucocorticoids, rheumatoid arthritis, secondary osteoporosis, alcohol use, and bone mineral density in the femoral neck. It gives an estimate of the 10-year risk of major osteoporotic fracture and hip fracture. High risk would be a 10-year risk of major osteoporotic fracture greater than 20% or a 10-year risk of hip fracture greater than 3%.)

For women at high risk, the risks of atypical femoral fracture and osteonecrosis of the jaw are outweighed by the benefit of a reduction in vertebral fracture risk. For women not at high risk of fracture, a drug holiday of 2 to 3 years can be considered after 3 to 5 years of treatment.

Although the task force recommended reassessment after 2 to 3 years of drug holiday, how best to do this is not clear. The task force did not recommend a specific approach to reassessment, so decisions about when to restart therapy after a drug holiday could potentially be informed by subsequent bone mineral density testing if it were to show persistent bone loss. Another option could be to restart bisphosphonates after a defined amount of time (eg, 3–5 years) for women who have previously experienced benefit.

The task force recommendations are in line with those of other societies, the FDA, and expert opinion.^19–23

The American Association of Clinical Endocrinologists recommends considering a drug holiday in low-risk patients after 4 to 5 years of treatment. For high-risk patients, they recommend 1 to 2 years of drug holiday after 10 years of treatment. They encourage restarting treatment if bone mineral density decreases, bone turnover markers rise, or fracture occurs.¹⁹ This is a grade C recommendation, meaning the advice is based on descriptive studies and expert opinion.

Although some clinicians restart bisphosphonates when markers of bone turnover such as NTX (N-telopeptide of type 1 collagen) rise to premenopausal levels, there is no evidence to support this strategy.²⁴

The task force recommendations are based on limited evidence that primarily comes from white postmenopausal women. Another important limitation is that the outcomes are primarily vertebral fractures. However, until additional evidence is available, these guidelines can be useful in guiding decision-making.

Should our patient continue therapy?

Our patient is relatively young and does not have any of the high-risk features noted within the task force recommendations. She has responded well to bisphosphonate treatment and so can consider a drug holiday at this time.

OVARIAN CANCER SCREENING

A 50-year-old woman requests screening for ovarian cancer. She is postmenopausal and has no personal or family history of cancer. She is concerned because a friend forwarded an e-mail stating, “Please tell all your female friends and relatives to insist on a cancer antigen (CA) 125 blood test every year as part of their annual exam. This is an inexpensive and simple blood test. Don’t take no for an answer. If I had known then what I know now, we would have caught my cancer much earlier, before it was stage III!” What should you tell the patient?

Ovarian cancer is the most deadly of female reproductive cancers, largely because in most patients the cancer has already spread beyond the ovary by the time of clinical detection. Death rates from ovarian cancer have decreased only slightly in the past 30 years.

Little benefit and considerable harm of screening

In 2011, the Prostate Lung Colorectal Ovarian (PLCO) Cancer Screening trial²⁵ randomized more than 68,000 women ages 55 to 74 from the general US population to annual screening with CA 125 testing and transvaginal ultrasonography compared with usual care. They were followed for a median of 12.4 years.

Screening did not affect stage at diagnosis (77%–78% were in stage III or IV in both the screening and usual care groups), nor did it reduce the rate of death from ovarian cancer. In addition, false-positive findings led to some harm: nearly one in three women who had a positive screening test underwent surgery. Of 3,285 women with false-positive results, 1,080 underwent surgery, and 15% of these had at least one serious complication. The trial was stopped early due to evidence of futility.

A new UK study also found no benefit from screening

In the PLCO study, a CA 125 result of 35 U/mL or greater was classified as abnormal. However, researchers in the United Kingdom postulated that instead of using a single cutoff for a normal or abnormal CA 125 level, it would be better to interpret the CA 125 result according to a somewhat complicated (and proprietary) algorithm called the Risk of Ovarian Cancer Algorithm (ROCA).^26,27 The ROCA takes into account a woman’s age, menopausal status, known genetic mutations (BRCA 1 or 2 or Lynch syndrome), Ashkenazi Jewish descent, and family history of ovarian or breast cancer, as well as any change in CA 125 level over time.

In a 2016 UK study,²⁶ 202,638 postmenopausal women ages 50 to 74 were randomized to no screening, annual screening with transvaginal ultrasonography, or multimodal screening with an annual CA 125 blood test interpreted with the ROCA algorithm, adding transvaginal ultrasonography as a second-line test when needed if the CA 125 level was abnormal based on the ROCA. Women with abnormal findings on multimodal screening or ultrasonography had repeat tests, and women with persistent abnormalities underwent clinical evaluation and, when appropriate, surgery.

Participants were at average risk of ovarian cancer; those with suspected familial ovarian cancer syndrome were excluded, as were those with a personal history of ovarian cancer or other active cancer.

Results. At a median follow-up of 11.1 years, the percentage of women who were diagnosed with ovarian cancer was 0.7% in the multimodal screening group, 0.6% in the screening ultrasonography group, and 0.6% in the no-screening group. Comparing either multimodal or screening ultrasonography with no screening, there was no statistically significant reduction in mortality rate over 14 years of follow-up.

Screening had significant costs and potential harms. For every ovarian or peritoneal cancer detected by screening, an additional 2 women in the multimodal screening group and 10 women in the ultrasonography group underwent needless surgery.

Strengths of this trial included its large size, allowing adequate power to detect differences in outcomes, its multicenter setting, its high compliance rate, and the low crossover rate in the no-screening group. However, the design of the study makes it difficult to anticipate the late effects of screening. Also, the patient must purchase ROCA testing online and must also pay a consultation fee. Insurance providers do not cover this test.

Should our patient proceed with ovarian cancer screening?

No. Current evidence shows no clear benefit to ovarian cancer screening for average-risk women, and we should not recommend yearly ultrasonography and CA 125 level testing, as they are likely to cause harm without providing benefit. The US Preventive Services Task Force recommends against screening for ovarian cancer.²⁸ For premenopausal women, pregnancy, hormonal contraception, and breastfeeding all significantly decrease ovarian cancer risk by suppressing ovulation.^29–31

REPRODUCTIVE FACTORS AND THE RISK OF DEATH

A 26-year-old woman comes in to discuss her contraceptive options. She has been breastfeeding since the birth of her first baby 6 months ago, and wonders how lactation and contraception may affect her long-term health.

Questions about the safety of contraceptive options are common, especially in breastfeeding mothers.

In 2010, the long-term Royal College of General Practitioners’ Oral Contraceptive Study reported that the all-cause mortality rate was actually lower in women who used oral contraceptives.³² Similarly, in 2013, an Oxford study that followed 17,032 women for over 30 years reported no association between oral contraceptives and breast cancer.³³

However, in 2014, results from the Nurses’ Health Study indicated that breast cancer rates were higher in oral contraceptive users, although reassuringly, the study found no difference in all-cause mortality rates in women who had used oral contraception.³⁴

The European Prospective Investigation Into Cancer and Nutrition

To further characterize relationships between reproductive characteristics and mortality rates, investigators analyzed data from the European Prospective Investigation Into Cancer and Nutrition,³⁵ which recruited 322,972 women from 10 countries between 1992 and 2000. Analyses were stratified by study center and participant age and were adjusted for body mass index, physical activity, education level, smoking, and menopausal status; alcohol intake was examined as a potential confounder but was excluded from final models.

Findings. Over an average 13 years of follow-up, the rate of all-cause mortality was 20% lower in parous than in nulliparous women. In parous women, the all-cause mortality rate was additionally 18% lower in those who had breastfed vs those who had never breastfed, although breastfeeding duration was not associated with mortality. Use of oral contraceptives lowered all-cause mortality by 10% among nonsmokers; in smokers, no association with all-cause mortality was seen for oral contraceptive use, as smoking is such a powerful risk factor for mortality. The primary contributor to all-cause mortality appeared to be ischemic heart disease, the incidence of which was significantly lower in parous women (by 14%) and those who breastfed (by 20%) and was not related to oral contraceptive use.³⁵

Strengths of this study included the large sample size recruited from countries across Europe, with varying rates of breastfeeding and contraceptive use. However, as with all observational studies, it remains subject to the possibility of residual confounding.

What should we tell this patient?

After congratulating her for breastfeeding, we can reassure her about the safety of all available contraceptives. According to the US Centers for Disease Control and Prevention (CDC),³⁶ after 42 days postpartum most women can use combined hormonal contraception. All other methods can be used immediately postpartum, including progestin-only pills.

As lactational amenorrhea is only effective while mothers are exclusively breastfeeding, and short interpregnancy intervals have been associated with higher rates of adverse pregnancy outcomes,³⁷ this patient will likely benefit from promptly starting a prescription contraceptive.

HIGHLY EFFECTIVE REVERSIBLE CONTRACEPTION

This same 26-year-old patient is concerned that she will not remember to take an oral contraceptive every day, and expresses interest in a more convenient method of contraception. However, she is concerned about the potential risks.

Although intrauterine contraceptives (IUCs) are typically 20 times more effective than oral contraceptives³⁸ and have been used by millions of women worldwide, rates of use in the United States have been lower than in many other countries.³⁹

A study of intrauterine contraception

To clarify the safety of IUCs, researchers followed 61,448 women who underwent IUC placement in six European countries between 2006 and 2013.⁴⁰ Most participants received an IUC containing levonorgestrel, while 30% received a copper IUC.

Findings. Overall, rates of uterine perforation were low (approximately 1 per 1,000 insertions). The most significant risk factors for perforation were breastfeeding at the time of insertion and insertion less than 36 weeks after the last delivery. None of the perforations in the study led to serious illness or injury of intra-abdominal or pelvic structures. Interestingly, women using a levonorgestrel IUC were considerably less likely to experience a contraceptive failure than those using a copper IUC.⁴¹

Strengths of this study included the prospective data collection and power to examine rare clinical outcomes. However, it was industry-funded.

The risk of pelvic infection with an IUC is so low that the CDC does not recommend prophylactic antibiotics with the insertion procedure. If women have other indications for testing for sexually transmitted disease, an IUC can be placed the same day as testing, and before results are available.⁴² If a woman is found to have a sexually transmitted disease while she has an IUC in place, she should be treated with antibiotics, and there is no need to remove the IUC.⁴³

Subdermal implants

Another highly effective contraceptive option for this patient is the progestin-only subdermal contraceptive implant (marketed in the United States as Nexplanon). Implants have been well-studied and found to have no adverse effect on lactation.⁴⁴

Learning to place a subdermal contraceptive is far easier than learning to place an IUC, but it requires a few hours of FDA-mandated in-person training. Unfortunately, relatively few clinicians have obtained this training.⁴⁵ As placing a subdermal contraceptive is like placing an intravenous line without needing to hit the vein, this procedure can easily be incorporated into a primary care practice. Training from the manufacturer is available to providers who request it.

What should we tell this patient?

An IUC is a great option for many women. When pregnancy is desired, the device is easily removed. Of the three IUCs now available in the United States, those containing 52 mg of levonorgestrel (marketed in the United States as Mirena and Liletta) are the most effective.

The only option more effective than these IUCs is subdermal contraception.⁴⁶ These reversible contraceptives are typically more effective than permanent contraceptives (ie, tubal ligation)⁴⁷ and can be removed at any time if a patient wishes to switch to another method or to become pregnant.

Pregnancy rates following attempts at “sterilization” are higher than many realize. There are a variety of approaches to “tying tubes,” some of which may not result in complete tubal occlusion. The failure rate of the laparoscopic approach, according to the US Collaborative Review of Sterilization, ranges from 7.5 per 1,000 procedures for unipolar coagulation to a high of 36.5 per 1,000 for the spring clip.⁴⁸ The relatively commonly used Filshie clip was not included in this study, but its failure rate is reported to be between 1% and 2%.