Failure-to-Salvage After Femoropopliteal Bypass Surgery is Associated With Nonmodifiable Risk Factors.

Introduction: Bypass graft failure and major amputation are among the worst complications after femoropopliteal bypass surgery. In this large multicenter analysis, we examined our incidence and risk factors for failure-to-salvage (FTS) following either bypass surgery or bypass graft failure.

Methods: A regional multicenter database was retrospectively queried for all femoropopliteal bypass procedures performed between 2002 and 2021. Re-do bypasses were excluded. The primary outcome was FTS, defined as major ipsilateral limb amputation within 90 d following index bypass surgery or bypass graft failure. Bypass graft failure was defined as critical stenosis or occlusion of the bypass graft requiring reintervention. Graft rescue was defined as bypass graft failure without subsequent major ipsilateral limb amputation within 90 d. Multivariable logistic regression analysis was utilized to identify factors associated with bypass graft failure and FTS.

Results: Over the study period, 1315 femoropopliteal bypass procedures were performed across five hospitals. There were 25 major amputations within 90 d of initial bypass. Bypass graft failure was diagnosed in an additional 503 (38.3%) patients. Mean time to graft failure was 619 d. On multivariable analysis, bypass for tissue loss (adjusted odds ratio [aOR] 1.38 [95% confidence interval (CI) 1.03-1.83], P = 0.03) was associated with graft failure. Of patients with graft failure, 33 had major amputation, leading to an overall FTS incidence of 4.4% (n = 58) over a mean follow-up period of 3.4 y. Patient demographics, medical comorbidities, and bypass conduits were similar between the FTS and graft rescue groups (n = NS each). The FTS group more frequently underwent bypass for tissue loss (51.7% versus 29.8%, P = 0.002), and an infrageniculate bypass target was more frequently utilized in FTS compared to graft rescue patients (81.0% versus 60.4%, P = 0.002). Anticoagulation (34.5% in FTS versus 37.7% in rescue) and dual antiplatelet therapy (15.5% versus 22.1%, respectively) were similar between groups (P = NS each). On multivariable analysis, factors associated with FTS included infrageniculate target (aOR 2.42 [95% CI 1.22-4.08], P = 0.01), black race (aOR 2.47 [95% CI 1.04-5.84], P = 0.04), and bypass for tissue loss (aOR 4.75 [95% CI 1.41-16.0], P = 0.01). Anticoagulation and dual antiplatelet therapy were not associated with loss of graft patency or FTS.

Conclusions: Failure-to-salvage after femoropopliteal bypass surgery is associated with nonmodifiable factors, and may represent 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 likelihood of graft salvage may be warranted.