Selective Use of Anticoagulation or Dual Antiplatelet Therapy for Patients with Extra-anatomic Bypasses

Abstract

The benefit of long-term anticoagulation or dual antiplatelet therapy (DAPT) for patients with extra-anatomic bypasses to the lower extremity remains poorly defined. Our study analyzed the real-world use of antithrombotic therapy in patients with extra-anatomic bypass grafts to the lower extremity and compared graft and patient outcomes by antithrombotic regimen. We studied patients who underwent axillofemoral or femoral-femoral bypass within the Vascular Quality Initiative with one-year follow-up data. Primary exposures were anticoagulation and DAPT, at the time of index procedure and one-year follow-up. Primary outcomes were major adverse limb events (MALE) defined as reintervention or above-ankle amputation, and primary patency. Secondary outcomes included perioperative blood transfusion requirements and the need for reoperation specifically for bleeding. We analyzed outcomes using the Kaplan-Meier estimation and examined factors associated with choice of antithrombotic therapy via logistic regression. Our cohort included 2,760 patients (axillofemoral bypass, n=857; femoral-femoral bypass, n=1,903) across 168 centers from 2009 to 2018. Mean age was 66.5±10.5years and 59% were male. Patients were infrequently prescribed long-term anticoagulation (19%) or DAPT (22%). One-year primary patency was 86% and was similar by anticoagulation (log-rank P=0.12) and DAPT status (log-rank P=0.26). Freedom from MALE was 87% at 1year and was slightly inferior for patients on anticoagulation (88 vs. 83%, log-rank P=0.001) but was similar by DAPT (log-rank P=0.19). Transfusion was more common in patients who were anticoagulated than those who were not (30 vs. 25%, P<0.01), but there was no increase in reoperation because of bleeding (anticoagulation 0.8 vs. 0.8, P=0.98). Anticoagulation was more commonly prescribed according to disease severity, such as rest pain (adjusted odds ratio (OR): 1.6 (95% confidence interval (CI): 1.20-2.20), tissue loss (OR: 1.9, CI: 1.28-2.73), or acute limb ischemia (OR: 1.9, CI: 1.35-2.71) or prior bypass graft (OR: 2.6, CI: 2.07-3.35). Patients were more commonly prescribed DAPT according to comorbidities, including hypertension (OR: 1.4, CI: 1.04-1.94) and coronary artery disease (OR: 1.6, CI 1.26-1.95). Antithrombotics are selectively used in patients with extra-anatomic bypass to the lower extremity, the selection of which appears associated with disease severity for anticoagulants and patient comorbidities for DAPT. Primary patency and MALE rates are similar with focused utilization of anticoagulants or DAPT. Blood transfusions are more common among patients on antithrombotics without a difference in the need for reoperation for bleeding.