Rivaroxaban Prophylaxis in Noncirrhotic Portal Vein Thrombosis.

BACKGROUND: In patients with noncirrhotic chronic portal vein thrombosis (PVT), the benefit of long-term anticoagulation is unknown. We assessed the effects of rivaroxaban on the risk of venous thromboembolism and portal hypertension-related bleeding in such patients. METHODS: In this multicenter, controlled trial, we randomly assigned patients with noncirrhotic chronic PVT without major risk factors for thrombosis to receive either rivaroxaban 15 mg/day or no anticoagulation. The primary end point was 2-year thrombosis-free survival. Secondary end points included the occurrence of site-specific thromboses and major bleeding events. RESULTS: A total of 111 participants were enrolled in the trial, with a mean age of 50.4±13.2 years; 58% of participants were men. An unplanned interim analysis was requested by the independent data safety monitoring board (DSMB) after 10 thrombotic events occurred. The thrombosis incidence rate was 0 per 100 person-years in the rivaroxaban group and 19.71 per 100 person-years (95% confidence interval, 7.49 to 31.92) in the no anticoagulation group (log-rank P=0.0008) after a median follow-up of 11.8 months. Based on the interim analysis, the DSMB recommended switching patients from the no anticoagulation group to anticoagulation. After a median follow-up of 30.3 months (intraquartile range, 24.3 to 47.8), major bleeding occurred in two patients receiving rivaroxaban and in one patient not receiving anticoagulation. No deaths occurred. CONCLUSIONS: After a median follow-up of 11.8 months, among patients with noncirrhotic chronic PVT without major risk factors for thrombosis, daily rivaroxaban reduced the incidence of venous thromboembolism and did not increase major bleeding events. (Funded by grants from the French Ministry of Health and the Association de Malades des Vaisseaux du foie; ClinicalTrials.gov number, NCT02555111.)