Antithrombotic therapy for left ventricular assist devices in adults: a systematic review

BackgroundLeft ventricular assist devices (LVADs) have dramatically increased the survival of adults with end-stage systolic heart failure. However, rates of bleeding and thromboembolism remain high. ObjectivesWe completed a systematic review to evaluate outcomes of adults with LVADs treated with various anticoagulant and antiplatelet strategies. MethodsDatabases were searched using the terms assist device', thrombosis', and anticoagulant' or platelet aggregation inhibitor' with appropriate synonyms, device names and manufacturers. Results and ConclusionsOf 977 manuscripts, 24 articles met the inclusion criteria of adults with implanted LVADs where clinical outcomes were defined based on anticoagulant and/or antiplatelet regimen. Most studies reported treatment with unfractionated heparin post-operatively which was transitioned to a vitamin K antagonist (VKA). Goal INR varied between 1.5-3.5. Antiplatelet regimens ranged from no treatment to dual therapy. Definition of major bleeding differed between trials and incidence varied between 0% and 58%. The available evidence could not demonstrate a clear benefit of aspirin compared with VKA therapy alone [stroke RR 1.02 (95% CI 0.49-2.1)]. There was a suggestion that treatment with aspirin and dipyridamole decreased the risk of thromboembolism compared to aspirin [RR 0.50 (0.36-0.68)], but the comparison is limited by differences in demographics, devices, and INR goals among studies. Additionally, most studies did not blind investigators to outcomes thus contributing to an increased risk for bias. Clinical equipoise exists as to the most appropriate antithrombotic therapy in LVAD patients. Randomization between regimens within a prospective trial is needed to define the treatment regimen that minimizes both bleeding and thrombotic complications.