Disparity in outcomes of surgical revascularization for limb salvage: race and gender are synergistic determinants of vein graft failure and limb loss

Abstract

Background: Vein bypass surgery is an effective therapy for atherosclerotic occlusive disease in the coronary and peripheral circulations; however, long-term results are limited by progressive attrition of graft patency. Failure of vein bypass grafts in patients with critical limb ischemia results in morbidity, limb loss, and additional resource use. Although technical factors are known to be critical to the success of surgical revascularization, patient-specific risk factors are not well defined. In particular, the relationship of race/ethnicity and gender to the outcomes of peripheral bypass surgery has been controversial.

Methods and results: We analyzed the Project of Ex Vivo Vein Graft Engineering via Transfection III (PREVENT III) randomized trial database, which included 1404 lower extremity vein graft operations performed exclusively for critical limb ischemia at 83 North American centers. Trial design included intensive ultrasound surveillance of the bypass graft and clinical follow-up to 1 year. Multivariable modeling (Cox proportional hazards and propensity score) was used to examine the relationships of demographic variables to clinical end points, including perioperative (30-day) events and 1-year outcomes (vein graft patency, limb salvage, and patient survival). Final propensity score models adjusted for 16 covariates (including type of institution, technical factors, selected comorbidities, and adjunctive medications) to examine the associations between race, gender, and outcomes. Among the 249 black patients enrolled in PREVENT III, 118 were women and 131 were men. Black men were at increased risk for early graft failure (hazard ratio [HR], 2.832 for 30-day failure; 95% confidence interval [CI], 1.393 to 5.759; P=0.0004), even when the analysis was restricted to exclude high-risk venous conduits. Black patients experienced reduced secondary patency (HR, 1.49; 95% CI, 1.08 to 2.06; P=0.016) and limb salvage (HR, 2.02; 95% CI, 1.27 to 3.20; P=0.003) at 1 year. Propensity score models demonstrate that black women were the most disadvantaged, with an increased risk for loss of graft patency (HR, 2.02 for secondary patency; 95% CI, 1.27 to 3.20; P=0.003) and major amputation (HR, 2.38; 95% CI, 1.18 to 4.83; P=0.016) at 1 year. Perioperative mortality and 1-year mortality were similar across race/gender groups.

Conclusions: Black race and female gender are risk factors for adverse outcomes after vein bypass surgery for limb salvage. Graft failure and limb loss are more common events in black patients, with black women being a particularly high-risk group. These data suggest the possibility of an altered biological response to vein grafting in this population; however, further studies are needed to determine the mechanisms underlying these observed disparities in outcome.

Figure

Propensity score–adjusted multivariable Cox proportional-hazard analysis of race and gender combinations for PP (A), PAP (B), SP (C), limb salvage (D), and survival (E).