Marcelo Gomes, MD

Managing anticoagulation in patients with infectious endocarditis requires an individualized approach, using a careful risk-benefit assessment on a case-by-case basis. There is a dearth of high-quality evidence; consequently, the recommendations also vary according to the clinical situation.

Newly diagnosed native valve infectious endocarditis in itself is not an indication for anticoagulation.^1–3 The question of whether to anticoagulate arises in patients who have a preexisting or coexisting indication for anticoagulation such as atrial fibrillation, deep vein thrombosis, pulmonary embolism, or a mechanical prosthetic heart valve. The question becomes yet more complex in patients with cerebrovascular complications and a coexistent strong indication for anticoagulation, creating what is often a very thorny dilemma.

Based on a review of available evidence, recommendations for anticoagulation in patients with infectious endocarditis are summarized below.

AVAILABLE EVIDENCE IS SCARCE AND MIXED

Earlier observational studies suggested a significant risk of cerebral hemorrhage with anticoagulation in patients with native valve endocarditis, although none of these studies were recent (some of them took place in the 1940s), and none are methodologically compelling.^4–8 Consequently, some experts have expressed skepticism regarding their findings, particularly in recent years.

In part, this skepticism arises from studies that showed a lower incidence of cerebrovascular complications and smaller vegetation size in patients with prosthetic valve infectious endocarditis, studies in which many of the patients received anticoagulation therapy.^9,10 The mechanism responsible for this effect is theorized to be that the vegetation is an amalgam of destroyed cells, platelets, and fibrin, with anticoagulation preventing this aggregation from further growth and propagation.

How great is the benefit or the potential harm?

Some experts argue that the incidence of ischemic stroke with hemorrhagic transformation in patients with infectious endocarditis receiving anticoagulation is overestimated. According to this view, the beneficial effects of anticoagulation at least counterbalance the potential harmful effects.

In addition to the studies cited above, recent studies have shown that patients on anticoagulation tend to have smaller vegetations and fewer cerebrovascular complications.^11–13 Snygg-Martin et al¹¹ and Rasmussen et al¹² found not only that cerebrovascular complications were less common in patients already on anticoagulation at the time infectious endocarditis was diagnosed, but also that no increase in the rate of hemorrhagic lesions was reported.

These were all nonrandomized studies, and most of the patients in them had native valve infectious endocarditis diagnosed at an early stage. Importantly, these studies found that the beneficial effects of anticoagulation were only present if the patient was receiving warfarin before infectious endocarditis was diagnosed and antibiotic therapy was initiated. No benefits from anticoagulation were demonstrated once antimicrobial therapy was begun.

Similarly, Anavekar et al¹⁴ showed that embolic events occurred significantly less often in those who were currently on continuous daily antiplatelet therapy, suggesting that receiving antiplatelet agents at baseline protects against cardioembolic events in patients who develop infective endocarditis. However, the only randomized trial examining the initiation of antiplatelet therapy in patients diagnosed with infectious endocarditis receiving antibiotic treatment showed that adding aspirin did not reduce the risk of embolic events and was associated with a trend toward increased risk of bleeding.¹⁵

A recent large cohort study suggested that infectious endocarditis patients who receive anticoagulation therapy may have a higher incidence of cerebrovascular complications (hazard ratio 1.31, 95% confidence interval 1.00–1.72, P = .048), with a particular association of anticoagulation therapy with intracranial bleeding (hazard ratio 2.71, 95% confidence interval 1.54–4.76, P = .001).¹⁶

Another provocative link supported by the same study was a higher incidence of hemorrhagic complications with anticoagulation in patients with infectious endocarditis caused by Staphylococcus aureus, an association also suggested by older data from Tornos et al,⁸ but not seen in a study by Rasmussen et al.¹²

Continuing anticoagulation is an individualized decision

The benefit or harm of anticoagulation in patients with infectious endocarditis may be determined at least in part by a complex mix of factors including the valve involved (embolic events are more common with mitral valve vegetations than with aortic valve vegetations), vegetation size (higher risk if > 1 cm), mobility of vegetations, and perhaps the virulence of the causative organism.^16,17 The fact that antimicrobial therapy obviates any beneficial effect of anticoagulation speaks strongly against starting anticoagulation therapy in infectious endocarditis patients with the sole purpose of reducing stroke risk.

Without large randomized trials to better delineate the risks and benefits of continuing preexisting anticoagulation in all patients with infectious endocarditis, patients already receiving anticoagulants need a careful, individualized risk-benefit assessment. Current guidelines agree that newly diagnosed infectious endocarditis per se is not an indication for anticoagulation or aspirin therapy (Table 1).^1–3

TAKE-HOME POINTS

• Starting antiplatelet and anticoagulation therapy for the sole purpose of stroke prevention is not recommended in patients with newly diagnosed infectious endocarditis.
• In most cases, anticoagulation and antiplatelet therapy should be temporarily discontinued in patients with infectious endocarditis and stroke or suspected stroke.
• Patients need careful assessment on a case-by-case basis, and the presence of risk factors predisposing patients to cerebrovascular complications (eg, large or very mobile vegetations, causative pathogens such as S aureus or Candida spp) may prompt temporary suspension of anticoagulation and antiplatelet therapy.
• If there is a clear preexisting or coexisting indication for these agents and surgery is not anticipated, consider continuing antiplatelet and anticoagulant therapy in patients with infectious endocarditis, provided they lack the risk factors described above and stroke has been excluded.
• If there is a clear preexisting or coexisting indication for these agents and surgery is being considered, consider using a short-acting anticoagulant such as intravenous or low-molecular weight heparin as a bridge to surgery.

Managing anticoagulation in patients with infectious endocarditis requires an individualized approach, using a careful risk-benefit assessment on a case-by-case basis. There is a dearth of high-quality evidence; consequently, the recommendations also vary according to the clinical situation.

Newly diagnosed native valve infectious endocarditis in itself is not an indication for anticoagulation.^1–3 The question of whether to anticoagulate arises in patients who have a preexisting or coexisting indication for anticoagulation such as atrial fibrillation, deep vein thrombosis, pulmonary embolism, or a mechanical prosthetic heart valve. The question becomes yet more complex in patients with cerebrovascular complications and a coexistent strong indication for anticoagulation, creating what is often a very thorny dilemma.

Based on a review of available evidence, recommendations for anticoagulation in patients with infectious endocarditis are summarized below.

AVAILABLE EVIDENCE IS SCARCE AND MIXED

Earlier observational studies suggested a significant risk of cerebral hemorrhage with anticoagulation in patients with native valve endocarditis, although none of these studies were recent (some of them took place in the 1940s), and none are methodologically compelling.^4–8 Consequently, some experts have expressed skepticism regarding their findings, particularly in recent years.

In part, this skepticism arises from studies that showed a lower incidence of cerebrovascular complications and smaller vegetation size in patients with prosthetic valve infectious endocarditis, studies in which many of the patients received anticoagulation therapy.^9,10 The mechanism responsible for this effect is theorized to be that the vegetation is an amalgam of destroyed cells, platelets, and fibrin, with anticoagulation preventing this aggregation from further growth and propagation.

How great is the benefit or the potential harm?

Some experts argue that the incidence of ischemic stroke with hemorrhagic transformation in patients with infectious endocarditis receiving anticoagulation is overestimated. According to this view, the beneficial effects of anticoagulation at least counterbalance the potential harmful effects.

In addition to the studies cited above, recent studies have shown that patients on anticoagulation tend to have smaller vegetations and fewer cerebrovascular complications.^11–13 Snygg-Martin et al¹¹ and Rasmussen et al¹² found not only that cerebrovascular complications were less common in patients already on anticoagulation at the time infectious endocarditis was diagnosed, but also that no increase in the rate of hemorrhagic lesions was reported.

These were all nonrandomized studies, and most of the patients in them had native valve infectious endocarditis diagnosed at an early stage. Importantly, these studies found that the beneficial effects of anticoagulation were only present if the patient was receiving warfarin before infectious endocarditis was diagnosed and antibiotic therapy was initiated. No benefits from anticoagulation were demonstrated once antimicrobial therapy was begun.

Similarly, Anavekar et al¹⁴ showed that embolic events occurred significantly less often in those who were currently on continuous daily antiplatelet therapy, suggesting that receiving antiplatelet agents at baseline protects against cardioembolic events in patients who develop infective endocarditis. However, the only randomized trial examining the initiation of antiplatelet therapy in patients diagnosed with infectious endocarditis receiving antibiotic treatment showed that adding aspirin did not reduce the risk of embolic events and was associated with a trend toward increased risk of bleeding.¹⁵

A recent large cohort study suggested that infectious endocarditis patients who receive anticoagulation therapy may have a higher incidence of cerebrovascular complications (hazard ratio 1.31, 95% confidence interval 1.00–1.72, P = .048), with a particular association of anticoagulation therapy with intracranial bleeding (hazard ratio 2.71, 95% confidence interval 1.54–4.76, P = .001).¹⁶

Another provocative link supported by the same study was a higher incidence of hemorrhagic complications with anticoagulation in patients with infectious endocarditis caused by Staphylococcus aureus, an association also suggested by older data from Tornos et al,⁸ but not seen in a study by Rasmussen et al.¹²

Continuing anticoagulation is an individualized decision

The benefit or harm of anticoagulation in patients with infectious endocarditis may be determined at least in part by a complex mix of factors including the valve involved (embolic events are more common with mitral valve vegetations than with aortic valve vegetations), vegetation size (higher risk if > 1 cm), mobility of vegetations, and perhaps the virulence of the causative organism.^16,17 The fact that antimicrobial therapy obviates any beneficial effect of anticoagulation speaks strongly against starting anticoagulation therapy in infectious endocarditis patients with the sole purpose of reducing stroke risk.

Without large randomized trials to better delineate the risks and benefits of continuing preexisting anticoagulation in all patients with infectious endocarditis, patients already receiving anticoagulants need a careful, individualized risk-benefit assessment. Current guidelines agree that newly diagnosed infectious endocarditis per se is not an indication for anticoagulation or aspirin therapy (Table 1).^1–3

TAKE-HOME POINTS

• Starting antiplatelet and anticoagulation therapy for the sole purpose of stroke prevention is not recommended in patients with newly diagnosed infectious endocarditis.
• In most cases, anticoagulation and antiplatelet therapy should be temporarily discontinued in patients with infectious endocarditis and stroke or suspected stroke.
• Patients need careful assessment on a case-by-case basis, and the presence of risk factors predisposing patients to cerebrovascular complications (eg, large or very mobile vegetations, causative pathogens such as S aureus or Candida spp) may prompt temporary suspension of anticoagulation and antiplatelet therapy.
• If there is a clear preexisting or coexisting indication for these agents and surgery is not anticipated, consider continuing antiplatelet and anticoagulant therapy in patients with infectious endocarditis, provided they lack the risk factors described above and stroke has been excluded.
• If there is a clear preexisting or coexisting indication for these agents and surgery is being considered, consider using a short-acting anticoagulant such as intravenous or low-molecular weight heparin as a bridge to surgery.

Managing anticoagulation in patients with infectious endocarditis requires an individualized approach, using a careful risk-benefit assessment on a case-by-case basis. There is a dearth of high-quality evidence; consequently, the recommendations also vary according to the clinical situation.

Newly diagnosed native valve infectious endocarditis in itself is not an indication for anticoagulation.^1–3 The question of whether to anticoagulate arises in patients who have a preexisting or coexisting indication for anticoagulation such as atrial fibrillation, deep vein thrombosis, pulmonary embolism, or a mechanical prosthetic heart valve. The question becomes yet more complex in patients with cerebrovascular complications and a coexistent strong indication for anticoagulation, creating what is often a very thorny dilemma.

Based on a review of available evidence, recommendations for anticoagulation in patients with infectious endocarditis are summarized below.

AVAILABLE EVIDENCE IS SCARCE AND MIXED

Earlier observational studies suggested a significant risk of cerebral hemorrhage with anticoagulation in patients with native valve endocarditis, although none of these studies were recent (some of them took place in the 1940s), and none are methodologically compelling.^4–8 Consequently, some experts have expressed skepticism regarding their findings, particularly in recent years.

In part, this skepticism arises from studies that showed a lower incidence of cerebrovascular complications and smaller vegetation size in patients with prosthetic valve infectious endocarditis, studies in which many of the patients received anticoagulation therapy.^9,10 The mechanism responsible for this effect is theorized to be that the vegetation is an amalgam of destroyed cells, platelets, and fibrin, with anticoagulation preventing this aggregation from further growth and propagation.

How great is the benefit or the potential harm?

Some experts argue that the incidence of ischemic stroke with hemorrhagic transformation in patients with infectious endocarditis receiving anticoagulation is overestimated. According to this view, the beneficial effects of anticoagulation at least counterbalance the potential harmful effects.

In addition to the studies cited above, recent studies have shown that patients on anticoagulation tend to have smaller vegetations and fewer cerebrovascular complications.^11–13 Snygg-Martin et al¹¹ and Rasmussen et al¹² found not only that cerebrovascular complications were less common in patients already on anticoagulation at the time infectious endocarditis was diagnosed, but also that no increase in the rate of hemorrhagic lesions was reported.

These were all nonrandomized studies, and most of the patients in them had native valve infectious endocarditis diagnosed at an early stage. Importantly, these studies found that the beneficial effects of anticoagulation were only present if the patient was receiving warfarin before infectious endocarditis was diagnosed and antibiotic therapy was initiated. No benefits from anticoagulation were demonstrated once antimicrobial therapy was begun.

Similarly, Anavekar et al¹⁴ showed that embolic events occurred significantly less often in those who were currently on continuous daily antiplatelet therapy, suggesting that receiving antiplatelet agents at baseline protects against cardioembolic events in patients who develop infective endocarditis. However, the only randomized trial examining the initiation of antiplatelet therapy in patients diagnosed with infectious endocarditis receiving antibiotic treatment showed that adding aspirin did not reduce the risk of embolic events and was associated with a trend toward increased risk of bleeding.¹⁵

A recent large cohort study suggested that infectious endocarditis patients who receive anticoagulation therapy may have a higher incidence of cerebrovascular complications (hazard ratio 1.31, 95% confidence interval 1.00–1.72, P = .048), with a particular association of anticoagulation therapy with intracranial bleeding (hazard ratio 2.71, 95% confidence interval 1.54–4.76, P = .001).¹⁶

Another provocative link supported by the same study was a higher incidence of hemorrhagic complications with anticoagulation in patients with infectious endocarditis caused by Staphylococcus aureus, an association also suggested by older data from Tornos et al,⁸ but not seen in a study by Rasmussen et al.¹²

Continuing anticoagulation is an individualized decision

The benefit or harm of anticoagulation in patients with infectious endocarditis may be determined at least in part by a complex mix of factors including the valve involved (embolic events are more common with mitral valve vegetations than with aortic valve vegetations), vegetation size (higher risk if > 1 cm), mobility of vegetations, and perhaps the virulence of the causative organism.^16,17 The fact that antimicrobial therapy obviates any beneficial effect of anticoagulation speaks strongly against starting anticoagulation therapy in infectious endocarditis patients with the sole purpose of reducing stroke risk.

Without large randomized trials to better delineate the risks and benefits of continuing preexisting anticoagulation in all patients with infectious endocarditis, patients already receiving anticoagulants need a careful, individualized risk-benefit assessment. Current guidelines agree that newly diagnosed infectious endocarditis per se is not an indication for anticoagulation or aspirin therapy (Table 1).^1–3

TAKE-HOME POINTS

• Starting antiplatelet and anticoagulation therapy for the sole purpose of stroke prevention is not recommended in patients with newly diagnosed infectious endocarditis.
• In most cases, anticoagulation and antiplatelet therapy should be temporarily discontinued in patients with infectious endocarditis and stroke or suspected stroke.
• Patients need careful assessment on a case-by-case basis, and the presence of risk factors predisposing patients to cerebrovascular complications (eg, large or very mobile vegetations, causative pathogens such as S aureus or Candida spp) may prompt temporary suspension of anticoagulation and antiplatelet therapy.
• If there is a clear preexisting or coexisting indication for these agents and surgery is not anticipated, consider continuing antiplatelet and anticoagulant therapy in patients with infectious endocarditis, provided they lack the risk factors described above and stroke has been excluded.
• If there is a clear preexisting or coexisting indication for these agents and surgery is being considered, consider using a short-acting anticoagulant such as intravenous or low-molecular weight heparin as a bridge to surgery.

No. in general, the decision to treat portal vein thrombosis with anticoagulant drugs is complex and depends on whether the thrombosis is acute or chronic, and whether the cause is a local factor, cirrhosis of the liver, or a systemic condition (Table 1). A “one-size-fits-all” approach should be avoided (Figure 1).

ACUTE PORTAL VEIN THROMBOSIS WITHOUT CIRRHOSIS

No randomized controlled trial has yet evaluated anticoagulation in acute portal vein thrombosis. But a prospective study published in 2010 showed that the portal vein and its left or right branch were patent in 39% of anticoagulated patients (vs 13% initially), the splenic vein in 80% (vs 57% initially), and the superior mesenteric vein in 73% (vs 42% initially).¹ Further, there appears to be a 20% reduction in the overall mortality rate associated with anticoagulation for acute portal vein thrombosis in retrospective studies.²

In the absence of contraindications, anticoagulation with heparin or low-molecular-weight heparin is recommended, with complete bridging to oral anticoagulation with a vitamin K antagonist. Anticoagulation should be continued for at least 3 months, and indefinitely in patients with permanent hypercoaguable risk factors.³

CHRONIC PORTAL VEIN THROMBOSIS WITHOUT CIRRHOSIS

All patients with chronic portal vein thrombosis should undergo esophagogastroduodenoscopy to evaluate for varices. Patients with large varices should be treated orally with a nonselective beta-adrenergic blocker or endoscopically. Though no prospective study has validated this practice, a retrospective analysis showed a decreased risk of first or recurrent bleeding.⁴

In 2007, a retrospective study showed a lower rate of death in patients with portomesenteric venous thrombosis treated with an oral vitamin K antagonist.⁵ Patients with chronic portal vein thrombosis with ongoing thrombotic risk factors should be treated with long-term anticoagulation after screening for varices, and if varices are present, primary prophylaxis should be started.³ With this approach, less than 5% of patients died from classic complications of portal vein thrombosis at 5 years of follow-up.⁴

ACUTE OR CHRONIC PORTAL VEIN THROMBOSIS WITH CIRRHOSIS

Portal vein thrombosis is common in patients with underlying cirrhosis. The risk in patients with cirrhosis significantly increases as liver function worsens. In patients with well-compensated cirrhosis, the risk is less than 1% vs 8% to 25% in those with advanced cirrhosis.⁶

In patients awaiting liver transplantation, a large retrospective study⁷ showed that the rate of partial or complete recanalization of the splanchnic veins was significantly higher in those who received anticoagulation (8 of 19) than in those who did not (0 of 10, P = .002). The rate of survival was significantly lower in those who had complete thrombotic obstruction of the portal vein at the time of surgery (P = .04). However, there was no difference in survival rates between those with partial obstruction who received anticoagulation and those with a patent portal vein.⁷

A later retrospective study⁸ showed no significant benefit in the rate of transplantation-free survival or survival after liver transplantation in patients with or without chronic portal vein thrombosis.⁸

Unfortunately, we have no data from prospective controlled trials and only limited data from retrospective studies to make a strong recommendation for or against anticoagulation in either acute and chronic portal vein thrombosis associated with cirrhosis. As such, each case must be evaluated on an individual basis in association with expert consultation.

In our experience, the risk of bleeding in patients with liver cirrhosis is substantial because of the decreased synthesis of coagulation factors and the presence of varices, whereas the efficacy and the benefits of recanalizing the portal vein in asymptomatic patients with liver cirrhosis and portal vein thrombosis are unknown. Therefore, unless the thrombosis extends into the mesenteric vein, thus posing a risk of mesenteric ischemia, we do not generally recommend anticoagulation in asymptomatic portal vein thrombosis in patients with cirrhosis.

No. in general, the decision to treat portal vein thrombosis with anticoagulant drugs is complex and depends on whether the thrombosis is acute or chronic, and whether the cause is a local factor, cirrhosis of the liver, or a systemic condition (Table 1). A “one-size-fits-all” approach should be avoided (Figure 1).

ACUTE PORTAL VEIN THROMBOSIS WITHOUT CIRRHOSIS

No randomized controlled trial has yet evaluated anticoagulation in acute portal vein thrombosis. But a prospective study published in 2010 showed that the portal vein and its left or right branch were patent in 39% of anticoagulated patients (vs 13% initially), the splenic vein in 80% (vs 57% initially), and the superior mesenteric vein in 73% (vs 42% initially).¹ Further, there appears to be a 20% reduction in the overall mortality rate associated with anticoagulation for acute portal vein thrombosis in retrospective studies.²

In the absence of contraindications, anticoagulation with heparin or low-molecular-weight heparin is recommended, with complete bridging to oral anticoagulation with a vitamin K antagonist. Anticoagulation should be continued for at least 3 months, and indefinitely in patients with permanent hypercoaguable risk factors.³

CHRONIC PORTAL VEIN THROMBOSIS WITHOUT CIRRHOSIS

All patients with chronic portal vein thrombosis should undergo esophagogastroduodenoscopy to evaluate for varices. Patients with large varices should be treated orally with a nonselective beta-adrenergic blocker or endoscopically. Though no prospective study has validated this practice, a retrospective analysis showed a decreased risk of first or recurrent bleeding.⁴

In 2007, a retrospective study showed a lower rate of death in patients with portomesenteric venous thrombosis treated with an oral vitamin K antagonist.⁵ Patients with chronic portal vein thrombosis with ongoing thrombotic risk factors should be treated with long-term anticoagulation after screening for varices, and if varices are present, primary prophylaxis should be started.³ With this approach, less than 5% of patients died from classic complications of portal vein thrombosis at 5 years of follow-up.⁴

ACUTE OR CHRONIC PORTAL VEIN THROMBOSIS WITH CIRRHOSIS

Portal vein thrombosis is common in patients with underlying cirrhosis. The risk in patients with cirrhosis significantly increases as liver function worsens. In patients with well-compensated cirrhosis, the risk is less than 1% vs 8% to 25% in those with advanced cirrhosis.⁶

In patients awaiting liver transplantation, a large retrospective study⁷ showed that the rate of partial or complete recanalization of the splanchnic veins was significantly higher in those who received anticoagulation (8 of 19) than in those who did not (0 of 10, P = .002). The rate of survival was significantly lower in those who had complete thrombotic obstruction of the portal vein at the time of surgery (P = .04). However, there was no difference in survival rates between those with partial obstruction who received anticoagulation and those with a patent portal vein.⁷

A later retrospective study⁸ showed no significant benefit in the rate of transplantation-free survival or survival after liver transplantation in patients with or without chronic portal vein thrombosis.⁸

Unfortunately, we have no data from prospective controlled trials and only limited data from retrospective studies to make a strong recommendation for or against anticoagulation in either acute and chronic portal vein thrombosis associated with cirrhosis. As such, each case must be evaluated on an individual basis in association with expert consultation.

In our experience, the risk of bleeding in patients with liver cirrhosis is substantial because of the decreased synthesis of coagulation factors and the presence of varices, whereas the efficacy and the benefits of recanalizing the portal vein in asymptomatic patients with liver cirrhosis and portal vein thrombosis are unknown. Therefore, unless the thrombosis extends into the mesenteric vein, thus posing a risk of mesenteric ischemia, we do not generally recommend anticoagulation in asymptomatic portal vein thrombosis in patients with cirrhosis.

No. in general, the decision to treat portal vein thrombosis with anticoagulant drugs is complex and depends on whether the thrombosis is acute or chronic, and whether the cause is a local factor, cirrhosis of the liver, or a systemic condition (Table 1). A “one-size-fits-all” approach should be avoided (Figure 1).

ACUTE PORTAL VEIN THROMBOSIS WITHOUT CIRRHOSIS

No randomized controlled trial has yet evaluated anticoagulation in acute portal vein thrombosis. But a prospective study published in 2010 showed that the portal vein and its left or right branch were patent in 39% of anticoagulated patients (vs 13% initially), the splenic vein in 80% (vs 57% initially), and the superior mesenteric vein in 73% (vs 42% initially).¹ Further, there appears to be a 20% reduction in the overall mortality rate associated with anticoagulation for acute portal vein thrombosis in retrospective studies.²

In the absence of contraindications, anticoagulation with heparin or low-molecular-weight heparin is recommended, with complete bridging to oral anticoagulation with a vitamin K antagonist. Anticoagulation should be continued for at least 3 months, and indefinitely in patients with permanent hypercoaguable risk factors.³

CHRONIC PORTAL VEIN THROMBOSIS WITHOUT CIRRHOSIS

All patients with chronic portal vein thrombosis should undergo esophagogastroduodenoscopy to evaluate for varices. Patients with large varices should be treated orally with a nonselective beta-adrenergic blocker or endoscopically. Though no prospective study has validated this practice, a retrospective analysis showed a decreased risk of first or recurrent bleeding.⁴

In 2007, a retrospective study showed a lower rate of death in patients with portomesenteric venous thrombosis treated with an oral vitamin K antagonist.⁵ Patients with chronic portal vein thrombosis with ongoing thrombotic risk factors should be treated with long-term anticoagulation after screening for varices, and if varices are present, primary prophylaxis should be started.³ With this approach, less than 5% of patients died from classic complications of portal vein thrombosis at 5 years of follow-up.⁴

ACUTE OR CHRONIC PORTAL VEIN THROMBOSIS WITH CIRRHOSIS

Portal vein thrombosis is common in patients with underlying cirrhosis. The risk in patients with cirrhosis significantly increases as liver function worsens. In patients with well-compensated cirrhosis, the risk is less than 1% vs 8% to 25% in those with advanced cirrhosis.⁶

In patients awaiting liver transplantation, a large retrospective study⁷ showed that the rate of partial or complete recanalization of the splanchnic veins was significantly higher in those who received anticoagulation (8 of 19) than in those who did not (0 of 10, P = .002). The rate of survival was significantly lower in those who had complete thrombotic obstruction of the portal vein at the time of surgery (P = .04). However, there was no difference in survival rates between those with partial obstruction who received anticoagulation and those with a patent portal vein.⁷

A later retrospective study⁸ showed no significant benefit in the rate of transplantation-free survival or survival after liver transplantation in patients with or without chronic portal vein thrombosis.⁸

Unfortunately, we have no data from prospective controlled trials and only limited data from retrospective studies to make a strong recommendation for or against anticoagulation in either acute and chronic portal vein thrombosis associated with cirrhosis. As such, each case must be evaluated on an individual basis in association with expert consultation.

In our experience, the risk of bleeding in patients with liver cirrhosis is substantial because of the decreased synthesis of coagulation factors and the presence of varices, whereas the efficacy and the benefits of recanalizing the portal vein in asymptomatic patients with liver cirrhosis and portal vein thrombosis are unknown. Therefore, unless the thrombosis extends into the mesenteric vein, thus posing a risk of mesenteric ischemia, we do not generally recommend anticoagulation in asymptomatic portal vein thrombosis in patients with cirrhosis.