Factors Associated With Limb Failure to Rescue After Infrainguinal Bypass Surgery

Abstract

Bypass graft failure and major amputation are among the most dreaded complications of infrainguinal bypass surgery. In this large multicenter analysis, we examined the incidence and risk factors for limb failure to rescue (FTR) after either bypass surgery or bypass graft failure. A prospectively maintained, multicenter database was retrospectively queried for all infrainguinal bypass procedures performed between 2002 and 2021. Redo bypasses were excluded. The primary outcome was limb FTR, defined as major ipsilateral limb amputation within 90 days after index bypass surgery or bypass graft failure. Bypass graft failure was defined as requiring reintervention for critical stenosis or occlusion of the bypass graft. Graft rescue was defined as bypass graft failure without subsequent major ipsilateral limb amputation within 90 days. Multivariable logistic regression analysis was used to identify risk factors for bypass graft failure and for limb FTR. Over the study period, 1315 infrainguinal bypass procedures were performed across five hospitals. There were 25 major amputations within 90 days of initial bypass. Bypass graft failure was diagnosed in an additional 503 (38.3%) patients. The median time to graft failure was 239 days (interquartile range: 90-667 days). On multivariable analysis, bypass for tissue loss (odds ratio [OR]: 1.38, 95% confidence interval [CI]: 1.03-1.83; P = .03) was the only risk factor identified for graft failure. Of patients with graft failure, 33 had major amputation, leading to an overall limb FTR incidence of 4.4% (n = 58) over a median follow-up period of 1.7 years (Fig). Patient demographics, medical comorbidities, and bypass conduits were similar between the FTR and graft rescue groups (n = NS each). The FTR group more frequently underwent bypass for tissue loss (51.7% vs 29.8%, P = .002), and an infrageniculate bypass target was more frequently used in FTR compared with graft rescue patients (81.0% vs 60.4%, P = .002). Anticoagulation (34.5% in FTR vs 37.7% in rescue) and dual antiplatelet therapy (15.5% vs 22.1%, respectively) were similar between the groups (P = NS each). Risk factors for FTR included infrageniculate target (OR: 2.42, 95% CI: 1.22-4.08; P = .01), Black race (OR: 2.47, 95% CI: 1.04-5.84; P = .04), and bypass for tissue loss (OR: 4.75, 95% CI: 1.41-16.0; P = .01). Anticoagulation and dual antiplatelet therapy were not associated with loss of graft patency or FTR. Limb FTR after infrainguinal bypass surgery is associated with nonmodifiable risk factors and may represent the progression of underlying disease. These data may help inform vascular surgeons in counseling patients with failing bypass grafts. Further investigation of care delivery factors improving the likelihood of graft salvage may be warranted.