Recurrent splanchnic and extrasplanchnic thrombotic events in patients with non-cirrhotic portal vein thrombosis associated with local factors.

Background & Aims: One-third of non-cirrhotic portal vein thrombosis (NCPVT) cases are associated with local factors. The risk of rethrombosis after anticoagulation withdrawal is unknown. We aimed to determine factors associated with new splanchnic or extrasplanchnic thrombotic events in this setting.

Methods: We performed a retrospective study including cases of recent NCPVT associated with local factors. High- and low-risk prothrombotic factors, prespecified according to RIPORT study criteria, were assessed. Univariate and multivariate Cox models assessed the influence of different variables on the occurrence of new thrombotic events.

Results: At baseline, 83/154 (53.9%) patients had at least one prothrombotic factor including 50 (32.5%) with a high-risk and 33 (21.4%) with a low-risk prothrombotic factor. Oestrogen-containing contraception was discontinued in all patients. During follow-up, 63/140 (45%) patients had at least one prothrombotic factor, including 47 (33.6%) with a high-risk and 16 (11.4%) with a low-risk prothrombotic factor. Seventeen new thrombotic events occurred after a median follow-up of 52 (IQR 14-62) (min-max 3.0-69.0) months. New thromboses were associated with high-risk factors (hazard ratio [HR] 3.817, 95% CI 1.303-11.180, p = 0.015), but were inversely related to recanalization (HR 0.222, 95% CI 0.078-0.635, p = 0.005) and anticoagulation (HR 0.976, 95% CI 0.956-0.995, p = 0.016). When a high-risk factor was present a new thrombotic event occurred in 7.4%, 14.6%, 14.6% and 28.8% of patients at 1, 3, 5 and 7 years under anticoagulants, respectively, compared to 21.2%, 21.2%, 58% and 58% without anticoagulants, respectively.

Conclusions: In cases of recent NCPVT associated with local factors, high-risk factors for thrombosis are associated with new thrombotic events. Permanent anticoagulation appears beneficial in this high-risk situation.

Impact And Implications: In non-cirrhotic portal vein thrombosis (NCPVT) associated with local factors, systematic screening for prothrombotic factors is recommended, but the prevalence of the latter is not clearly established, and the risk of recurrent intra or extrasplanchnic thromboembolism is poorly described. Thus, interest in permanent anticoagulation remains. NCPVT associated with local factors is a matter of concern for hepatologists, gastroenterologists and digestive surgeons. Due to a lack of knowledge, practices are heterogeneous. Our findings highlight that systematic screening for prothrombotic factors in NCPVT is needed even when associated with local factors, as it may justify long-term anticoagulation for the prevention of new intra or extrasplanchnic thrombotic events in at least one-third of cases. The interest in long-term anticoagulation should be investigated prospectively in the absence of high-risk prothrombotic factors.

Clinical Trial Number: NCT0536064.