Factors associated with infrainguinal bypass graft patency at 1-year; a retrospective analysis of a single centre experience

Supra-Inguinal Inflow for Distal Bypasses Have Acceptable Patency and Limb Salvage Rates

BACKGROUND

There is a paucity of data evaluating outcomes of lower extremity bypass (LEB) using supra-inguinal inflow for revascularization of infra-inguinal vessels. The purpose of this study is to report outcomes after LEB originating from aortoiliac arteries to infra-femoral targets.

METHODS

The Vascular Quality Initiative database (2003-2020) was queried for patients undergoing LEB from the aortoiliac arteries to the popliteal and tibial arteries. Patients were stratified into 3 cohorts based on outflow targets (above-knee [AK] popliteal, below-knee [BK] popliteal, and tibial arteries). Perioperative and 1-year outcomes including primary patency, amputation-free survival (AFS), and major adverse limb events (MALEs) were compared. A Cox proportional hazards model was used to estimate the independent prognostic factors of outcomes.

RESULTS

Of 403 LEBs, 389 (96.5%) originated from the external iliac artery, while the remaining used the aorta or common iliac artery as inflow. In terms of the distal target, the AK popliteal was used in 116 (28.8%), the BK popliteal in 151 (27.5%), and tibial vessels in 136 (43.7%) cases. BK popliteal and tibial bypasses, compared to AK popliteal bypasses, were more commonly performed in patients with chronic limb-threatening ischemia (69.5% and 69.9% vs. 48.3%; P < 0.001). Vein conduit was more often used for tibial bypass than for AK and BK popliteal bypasses (46.3% vs. 21.9% and 16.3%; P < 0.001). In the perioperative period, BK popliteal and tibial bypass patients had higher reoperation rates (16.9% and 13.2% vs. 5.2%; P = 0.02) and lower primary patency (89.4% and 89% vs. 95.7%; P = 0.04) than AK bypass patients. At 1 year, compared with AK popliteal bypasses, BK and tibial bypasses demonstrated lower primary patency (81.9% vs. 56.7% vs. 52.4%, P < 0.001) and freedom from MALE (77.6% vs. 70.2% vs. 63.1%, P = 0.04), although AFS was not significantly different (89.7% vs. 90.6% vs. 83.8%, P = 0.19).On multivariable analysis, compared with AK popliteal bypasses, tibial bypasses were independently associated with increased loss of primary patency (hazard ratio 1.9, 95% confidence interval, 1.03-3.51, P = 0.04). Subanalysis of patients with chronic limb-threatening ischemia demonstrated significantly higher primary patency in the AK popliteal cohort at discharge and 1 year, but no difference in AFS or freedom from MALE between the cohorts at follow-up.

CONCLUSIONS

LEB with supra-inguinal inflow appear to have acceptable rates of 1-year patency and limb salvage in patients at high risk of bypass failure. Tibial outflow target was independently associated with worse primary patency but not with MALE or AFS.

Effect of Direct Oral Anticoagulants versus Warfarin on Patency in High-Risk Bypass Patients

OBJECTIVES

The use of warfarin for anticoagulation in thromboembolic disease has been the mainstay of treatment. Direct oral anticoagulants (DOACs) have demonstrated equivalent anticoagulant effects, without increased bleeding risks or need for frequent monitoring. However, the role of DOACs remains unclear in the setting of replacing warfarin for high-risk peripheral artery disease (PAD) interventions. The purpose of this study is to evaluate the efficacy of DOACs compared to warfarin during the postoperative period in patients that underwent a lower extremity high risk bypass (HRB).

METHODS

The study is a single institution, retrospective review of all lower extremity HRBs be-tween January 2012 and June 2021, who were previously placed on or started on anticoagulation with a DOAC or warfarin. The HRB group included all patients undergoing femoral to above or below knee bypass with an adjunct procedure, or below knee bypass with synthetic or composite vein conduit. All demographics, preoperative factors, and complications were evaluated with respect to DOAC versus warfarin.

RESULTS

A total of 44 patients (28 males; average age 68.8 ± 10.9) underwent a HRB during the study period. There were no significant differences in demographics and preoperative characteristics between the two groups. Among patient comorbidities, coronary artery disease was found to be significantly higher in patients on DOACs (p=0.03). The 12-month primary patency rate was 83.3% vs 57.1%, for DOAC vs warfarin respectively (p=0.03). Multivariate analyses revealed that <30-day reinterventions contribute to 12-month patency (p=0.02).

CONCLUSION

Patients who underwent lower extremity HRB with postoperative DOAC appeared to exhibit higher graft patency rates than those who were placed on warfarin. Due to their low incidence of undesirable side effects and the lack of frequent monitoring, DOACs could be considered a safe alternative to warfarin in the postoperative period for patients with HRB.