Anticoagulation for splanchnic vein thrombosis in myeloproliferative neoplasms: a systematic review and meta-analysis

Background: Optimal anticoagulation management in patients with myeloproliferative neoplasms (MPN) experiencing splanchnic vein thrombosis (SpVT) requires balancing risks of bleeding and recurrent thrombosis. Objectives: We conducted a systematic review and meta-analysis to assess the incidence of bleeding and thrombosis recurrence in patients with MPN-SpVT. Methods: We included retrospective or prospective studies in English with ≥10 adult patients with MPN-SpVT. Outcomes included recurrent venous thrombosis (SpVT and non-SpVT), arterial thrombosis, and major bleeding. Pooled rates per 100 patient years with 95% CIs were calculated by DerSimonian–Laird method using random-effects model. Results: Out of 4624 studies screened, 9 studies with a total of 443 patients were included in the meta-analysis with median follow-up of 3.5 years. In the 364 patients with MPN-SpVT treated with anticoagulation, pooled event rate for major bleeding was 2.8 (95% CI, 1.5-5.1; I² = 95%), for recurrent venous thrombosis was 1.4 (95% CI, 0.8–2.2; I² = 72%), and for arterial thrombosis was 1.4 (95% CI, 0.6-3.3; I² = 92%) per 100 patient years. Among 79 patients (n = 4 studies) who did not receive anticoagulation, pooled event rate for major bleeding was 3.2 (95% CI, 0.7-12.7; I² = 97%), for recurrent venous thrombosis 3.5 (95% CI, 1.8-6.4; I² = 88%), and for arterial thrombosis rate 1.6 (95% CI, 0.4-6.6; I² = 95%) per 100 patient years. Conclusion: Patients with MPN-SpVT treated with anticoagulation have significant risks for both major bleeding and thrombosis recurrence. Further studies are necessary to determine the optimal anticoagulation approach in patients with MPN-SpVT.