PB0061 - Evaluating the Safety and Effectiveness of Anticoagulation after Lower Extremity Bypass Surgery for Peripheral Artery Disease – A Systematic Review and Meta-Analysis

Background: Patients with peripheral artery disease benefit from anticoagulation (AC) following open or endovascular lower extremity revascularization. Surgical bypass has also recently been established as the preferred method of revascularization; however, the specific benefit of AC in this population remains debated.

Aims: To evaluate the safety and effectiveness of AC in addition to antiplatelets compared to antiplatelets alone after lower extremity bypass.

Methods: Medline, EMBASE, and CENTRAL were searched for randomized and non-randomized cohort studies evaluating the role of oral anticoagulation following infrainguinal bypass surgery. The primary endpoints were major adverse limb events (MALE, defined as either major amputation and/or reintervention on the revascularized segment) and ISTH major bleeding. Secondary endpoints included amputation and graft thrombosis. Outcomes were stratified based on the type of AC used alongside the type of conduit used for bypass. Studies assessing the role of anticoagulation following an endovascular or hybrid primary procedure were excluded. Meta-analysis was done using Mantel-Haenszel random effects model.

Results: A total of three randomized (n=2303 participants) and eight non-randomized (n=23237 participants) studies were included for analysis. Characteristics of included studies and study endpoints are summarized in Tables 1 and 2 respectively. Anticoagulation with direct oral anticoagulants (DOACs) or vitamin-k antagonists (VKAs) were not associated with any significant reduction in MALE or amputation. DOACs were associated with an increased risk of bleeding and graft thrombosis. The risk of amputation after anticoagulation with a VKA did not change regardless of the type of graft conduit used.

Conclusion(s): The role of oral anticoagulation is supported by level-one evidence, however, real-world non-randomized evidence does not appear to share a similar therapeutic profile. This may be due to use of surrogate outcomes in large trials or clinical tendencies to reserve anticoagulation for high-risk patients leading to selection bias in non-randomized evidence.