Postoperative Direct Oral Anticoagulants Are Associated with Improved Amputation-Free Survival in Infra-Geniculate Bypasses Performed by Prosthetic Grafts in Patients with Chronic Limb-Threatening Ischemia.

Abstract

Objectives: Autogenous single-segment great saphenous vein graft is the conduit of choice in infra-inguinal bypasses particularly when the distal target of bypass is infra-geniculate. However, use of prosthetic grafts for infra-geniculate bypass (IGB) is required in certain patients. Different measures have been used to increase the durability of prosthetic grafts in IGB. We aimed to investigate the effect of postoperative anticoagulation on outcomes of IGBs performed by prosthetic conduits in patients with chronic limb-threatening ischemia (CLTI).

Methods: The Vascular Quality Initiative-Medicare-linked database was queried for IGBs performed for CLTI (rest pain or tissue loss) between May 2014 to December 2019. All included patients underwent IGB by polytetrafluoroethylene (PTFE) grafts. The patients were stratified based on postoperative anticoagulation status: no discharge anticoagulation, warfarin, and direct oral anticoagulants (DOACs). DOACs included rivaroxaban or dabigatran. The primary outcome was amputation-free survival (AFS). Secondary outcomes were overall survival, limb salvage, and freedom from reintervention. Kaplan-Meier survival estimates, and Cox regression were used for statistical analysis.

Results: The study included three cohorts: No discharge anticoagulation (N=1,170, 63.5%), warfarin (N=482, 26.2%), and DOAC (N=189, 10.3%). After adjusting for potential confounders, discharge warfarin and DOAC were associated with lower risk of death in one-year (aHR, 0.60 [95% CI:0.46-0.78], P<.001 and aHR, 0.63 [95% CI:0.43-0.93], P=0.021, respectively) and three-year (aHR, 0.72 [95% CI:0.59-0.89], P=0.002 and aHR, 0.64 [95% CI:0.45-0.90], P=0.011, respectively) compared to no anticoagulation. Patients receiving warfarin were at greater risk of major amputation at three years postoperatively (aHR, 1.33 [95% CI:1.03-1.72], P=0.029) compared to the non-anticoagulated patients, while patients receiving DOACs did not have a greater risk of major amputation. At three years, DOAC was associated with improved AFS compared to warfarin (aHR, 0.76 [95% CI:0.58-0.99], P=0.045). Neither warfarin nor DOAC was associated with reintervention at three-year follow-up compared to no anticoagulation.

Conclusions: We found that postoperative anticoagulation use was associated with improved survival in patients undergoing IGB with PTFE graft for CLTI. Moreover, patients receiving DOACs were associated with greater AFS at three years postoperatively compared to warfarin. This study supports the use of anticoagulants, DOAC preferably to achieve favorable outcomes in IGBs when a prosthetic graft is being used. However, further prospective studies are necessary to confirm our findings.