Treatment of venous thromboembolism in acute leukemia: A systematic review

Background: The safety and efficacy of venous thromboembolism (VTE) treatment in patients with acute leukemia (AL) are not well understood and the optimal treatment strategy is unclear. Methods: We conducted a systematic review of the literature aiming to identify observational studies and randomized trials describing treatment of VTE in the setting of AL including, acute myeloid leukemia (AML), acute promyelocytic leukemia (APL), and acute lymphoblastic leukemia (ALL). Due to the heterogeneity of findings, no meta-analysis was attempted. Results: A total of 13 observational studies (11 cohorts and 2 case-control) totaling 5359 participants were included. The number of patients with VTE among the total population was 304 (5.7%; 95% CI 5.1-6.3). In patients with VTE, 221 patients received treatment with anticoagulation using either of low-molecular-weight heparin, unfractionated heparin, and/or vitamin K antagonists. Most studies adjusted the anticoagulant dose based on platelet count. The reported recurrence rate ranged from 0 to 29% among different studies and varied according to the duration of anticoagulant treatment and follow up. Bleeding events were not uniformly reported but the total number was low among anti-coagulated patients. Conclusion: There is a significant lack of data in this area with a high degree of heterogeneity in the choice of anticoagulant, dose adjustments for thrombocytopenia, and duration of anticoagulation. Further studies are required to develop guidelines and suggestions for treatment of VTE in AL.