Bassima Abdallah, MD

Background: There is an alarming trend toward overuse of computed tomographic pulmonary angiography (CTPA) for the rule-out of low clinical probability PE. The eight-item Pulmonary Embolism Rule-Out Criteria (PERC) rule was devised to be used in populations of patients with low clinical probability of PE to guide which patients would likely not benefit from CTPA imaging. Recent concerns have been raised that the use of the PERC rule could result in high false-negative rates.

Study design: Crossover cluster–randomized clinical noninferiority trial.

Setting: 14 EDs in France from August 2015 to September 2016.

Synopsis: 1,916 emergency department patients with low clinical probability of PE were cluster-randomized to usual care or to a PERC strategy where, if the PERC score was zero, PE was ruled out without additional testing. The primary outcome was diagnosis of a symptomatic PE within 3 months that had not been diagnosed initially. Primary outcome results met prespecified noninferiority criteria for the PERC group, compared with the usual-care group (0.1% in the PERC group, 0% in the control group). The PERC group had significantly lower median length of ED stay and lower likelihood of admission.

Limitations of this study include its younger average patient age (44 years) and its cluster, as opposed to per-patient, randomization design.

Bottom line: In patients for whom the clinical probability of PE is low, use of the PERC rule is noninferior to a conventional d-dimer and CTPA strategy for ruling out symptomatic PE.

Citation: Freund Y et al. Effect of the pulmonary embolism rule-out criteria on subsequent thromboembolic events among low-risk emergency department patients. JAMA. 2018;319(6):559-66.

Dr. Abdallah is a hospitalist at Beth Israel Deaconess Medical Center, and instructor in medicine, Harvard Medical School, Boston.

Background: There is an alarming trend toward overuse of computed tomographic pulmonary angiography (CTPA) for the rule-out of low clinical probability PE. The eight-item Pulmonary Embolism Rule-Out Criteria (PERC) rule was devised to be used in populations of patients with low clinical probability of PE to guide which patients would likely not benefit from CTPA imaging. Recent concerns have been raised that the use of the PERC rule could result in high false-negative rates.

Study design: Crossover cluster–randomized clinical noninferiority trial.

Setting: 14 EDs in France from August 2015 to September 2016.

Synopsis: 1,916 emergency department patients with low clinical probability of PE were cluster-randomized to usual care or to a PERC strategy where, if the PERC score was zero, PE was ruled out without additional testing. The primary outcome was diagnosis of a symptomatic PE within 3 months that had not been diagnosed initially. Primary outcome results met prespecified noninferiority criteria for the PERC group, compared with the usual-care group (0.1% in the PERC group, 0% in the control group). The PERC group had significantly lower median length of ED stay and lower likelihood of admission.

Limitations of this study include its younger average patient age (44 years) and its cluster, as opposed to per-patient, randomization design.

Bottom line: In patients for whom the clinical probability of PE is low, use of the PERC rule is noninferior to a conventional d-dimer and CTPA strategy for ruling out symptomatic PE.

Citation: Freund Y et al. Effect of the pulmonary embolism rule-out criteria on subsequent thromboembolic events among low-risk emergency department patients. JAMA. 2018;319(6):559-66.

Dr. Abdallah is a hospitalist at Beth Israel Deaconess Medical Center, and instructor in medicine, Harvard Medical School, Boston.

Background: There is an alarming trend toward overuse of computed tomographic pulmonary angiography (CTPA) for the rule-out of low clinical probability PE. The eight-item Pulmonary Embolism Rule-Out Criteria (PERC) rule was devised to be used in populations of patients with low clinical probability of PE to guide which patients would likely not benefit from CTPA imaging. Recent concerns have been raised that the use of the PERC rule could result in high false-negative rates.

Study design: Crossover cluster–randomized clinical noninferiority trial.

Setting: 14 EDs in France from August 2015 to September 2016.

Synopsis: 1,916 emergency department patients with low clinical probability of PE were cluster-randomized to usual care or to a PERC strategy where, if the PERC score was zero, PE was ruled out without additional testing. The primary outcome was diagnosis of a symptomatic PE within 3 months that had not been diagnosed initially. Primary outcome results met prespecified noninferiority criteria for the PERC group, compared with the usual-care group (0.1% in the PERC group, 0% in the control group). The PERC group had significantly lower median length of ED stay and lower likelihood of admission.

Limitations of this study include its younger average patient age (44 years) and its cluster, as opposed to per-patient, randomization design.

Bottom line: In patients for whom the clinical probability of PE is low, use of the PERC rule is noninferior to a conventional d-dimer and CTPA strategy for ruling out symptomatic PE.

Citation: Freund Y et al. Effect of the pulmonary embolism rule-out criteria on subsequent thromboembolic events among low-risk emergency department patients. JAMA. 2018;319(6):559-66.

Dr. Abdallah is a hospitalist at Beth Israel Deaconess Medical Center, and instructor in medicine, Harvard Medical School, Boston.

Background: While there is a consensus on the need for chemoprophylaxis to reduce the rates of postoperative VTE, there is wide variation in choice of agents recommended. Aspirin, while cheap and widely available, has never been directly compared with a direct oral anticoagulant in randomized, controlled trials.

Study design: Multicenter, double-­blind, randomized, controlled noninferiority trial.

Setting: 15 university-affiliated health centers in Canada from January 2013 through April 2016.

Synopsis: 3,224 patients who received daily rivaroxaban for 5 days following joint arthroplasty were randomized to either receive aspirin 81 mg daily or continue daily rivaroxaban. Duration of therapy was determined by type of surgery (9 days for knee, 17 days for hip). The primary effectiveness outcome was defined as symptomatic pulmonary embolism or proximal deep venous thrombosis diagnosed in the 90-day follow-up period. The primary outcome results met the predetermined criterion for noninferiority with similar rates of symptomatic VTE in the aspirin and rivaroxaban group (0.64% vs. 0.7%; P less than .001). There was no significant difference in bleeding rates between the groups. Given that patients with prior VTE, morbid obesity, or cancer were not well represented in this study, these results should not be extrapolated to those populations felt to be at highest risk for VTE.

Bottom line: For thromboprophylaxis after joint arthroplasty, rivaroxaban followed by aspirin may be noninferior to extended rivaroxaban.

Citation: Anderson D et al. Aspirin or rivaroxaban for VTE prophylaxis after hip or knee arthroplasty. N Eng J Med. 2018 Feb 22;378(8):699-707.

Dr. Abdallah is a hospitalist at Beth Israel Deaconess Medical Center, and instructor in medicine, Harvard Medical School, Boston.

Background: While there is a consensus on the need for chemoprophylaxis to reduce the rates of postoperative VTE, there is wide variation in choice of agents recommended. Aspirin, while cheap and widely available, has never been directly compared with a direct oral anticoagulant in randomized, controlled trials.

Study design: Multicenter, double-­blind, randomized, controlled noninferiority trial.

Setting: 15 university-affiliated health centers in Canada from January 2013 through April 2016.

Synopsis: 3,224 patients who received daily rivaroxaban for 5 days following joint arthroplasty were randomized to either receive aspirin 81 mg daily or continue daily rivaroxaban. Duration of therapy was determined by type of surgery (9 days for knee, 17 days for hip). The primary effectiveness outcome was defined as symptomatic pulmonary embolism or proximal deep venous thrombosis diagnosed in the 90-day follow-up period. The primary outcome results met the predetermined criterion for noninferiority with similar rates of symptomatic VTE in the aspirin and rivaroxaban group (0.64% vs. 0.7%; P less than .001). There was no significant difference in bleeding rates between the groups. Given that patients with prior VTE, morbid obesity, or cancer were not well represented in this study, these results should not be extrapolated to those populations felt to be at highest risk for VTE.

Bottom line: For thromboprophylaxis after joint arthroplasty, rivaroxaban followed by aspirin may be noninferior to extended rivaroxaban.

Citation: Anderson D et al. Aspirin or rivaroxaban for VTE prophylaxis after hip or knee arthroplasty. N Eng J Med. 2018 Feb 22;378(8):699-707.

Dr. Abdallah is a hospitalist at Beth Israel Deaconess Medical Center, and instructor in medicine, Harvard Medical School, Boston.

Background: While there is a consensus on the need for chemoprophylaxis to reduce the rates of postoperative VTE, there is wide variation in choice of agents recommended. Aspirin, while cheap and widely available, has never been directly compared with a direct oral anticoagulant in randomized, controlled trials.

Study design: Multicenter, double-­blind, randomized, controlled noninferiority trial.

Setting: 15 university-affiliated health centers in Canada from January 2013 through April 2016.

Synopsis: 3,224 patients who received daily rivaroxaban for 5 days following joint arthroplasty were randomized to either receive aspirin 81 mg daily or continue daily rivaroxaban. Duration of therapy was determined by type of surgery (9 days for knee, 17 days for hip). The primary effectiveness outcome was defined as symptomatic pulmonary embolism or proximal deep venous thrombosis diagnosed in the 90-day follow-up period. The primary outcome results met the predetermined criterion for noninferiority with similar rates of symptomatic VTE in the aspirin and rivaroxaban group (0.64% vs. 0.7%; P less than .001). There was no significant difference in bleeding rates between the groups. Given that patients with prior VTE, morbid obesity, or cancer were not well represented in this study, these results should not be extrapolated to those populations felt to be at highest risk for VTE.

Bottom line: For thromboprophylaxis after joint arthroplasty, rivaroxaban followed by aspirin may be noninferior to extended rivaroxaban.

Citation: Anderson D et al. Aspirin or rivaroxaban for VTE prophylaxis after hip or knee arthroplasty. N Eng J Med. 2018 Feb 22;378(8):699-707.

Dr. Abdallah is a hospitalist at Beth Israel Deaconess Medical Center, and instructor in medicine, Harvard Medical School, Boston.