Splanchnic vein thrombosis with and without myeloproliferative neoplasms: a comparative cohort study

BACKGROUND: Splanchnic vein thrombosis (SVT) is a rare type of venous thromboembolism, but relatively common in patients with myeloproliferative neoplasms (MPN). Studies on management and outcomes for patients with MPN-SVT, including comparisons with non-MPN-SVT, are scarce. We assessed anticoagulant management and recurrent thrombosis, bleeding and survival outcomes in SVT patients with and without MPN. METHODS: We conducted a multicenter comparative cohort study in adults with SVT using individual patient-data from three published studies and two hospital cohorts. Anticoagulant management after SVT diagnosis was evaluated. 6-months cumulative incidences of recurrent thrombosis, bleeding and death were calculated. We used propensity-score weighting to compare outcomes between patients with and without MPN. A subanalysis excluding patients with cirrhosis or solid cancer was performed. RESULTS: We investigated 1189 SVT patients, 187 with underlying MPN. Anticoagulation was started in 76.1% of patients within 30 days after SVT diagnosis, 78.6% were still anticoagulated at 6 months; this was similar between patients with and without MPN. 6-month cumulative incidence of recurrent thrombosis and bleeding was 2.5% and 4.5%, respectively. Overall survival was 93.7% at 6-months follow-up. No significant differences were observed in clinical outcomes between patients with and without MPN, also confirmed by subanalyses. CONCLUSIONS: In this large cohort, incidences of recurrent thrombosis, bleeding and survival 6 months after SVT were similar in patients with and without MPN. This suggests that MPN-related SVT could be regarded similarly to non-cirrhotic, non-malignant SVT for anticoagulant management and outcomes. Prospective studies with long-term follow-up are still needed for MPN-related SVT patients.