Effect of postoperative antithrombotic therapy on lower extremity outcomes after infrapopliteal bypass for chronic limb-threatening ischemia

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.

Comparison of lower extremity bypass and peripheral vascular intervention for chronic limb-threatening ischemia in the Medicare-linked Vascular Quality Initiative

OBJECTIVE

There is a relative lack of comparative effectiveness research on revascularization for patients with chronic limb-threatening ischemia (CLTI). We examined the association between lower extremity bypass (LEB) vs peripheral vascular intervention (PVI) for CLTI and 30-day and 5-year all-cause mortality and 30-day and 5-year amputation.

METHODS

Patients undergoing LEB and PVI of the below-the-knee popliteal and infrapopliteal arteries between 2014 and 2019 were queried from the Vascular Quality Initiative, and outcomes data were obtained from the Medicare claims-linked Vascular Implant Surveillance and Interventional Outcomes Network database. Propensity scores were calculated on 15 variables using a logistic regression model to control for imbalances between treatment groups. A 1:1 matching method was used. Kaplan-Meier survival curves and hierarchical Cox proportional hazards regression with a random intercept for site and operator nested in site to account for clustered data compared 30-day and 5-year all-cause mortality between groups. Thirty-day and 5-year amputation were subsequently compared using competing risk analysis to account for the competing risk of death.

RESULTS

There was a total of 2075 patients in each group. The overall mean age was 71 ± 11 years, 69% were male, and 76% were white, 18% were black, and 6% were of Hispanic ethnicity. Baseline clinical and demographic characteristics in the matched cohort were balanced between groups. There was no association between all-cause mortality over 30 days and LEB vs PVI (cumulative incidence, 2.3% vs 2.3% by Kaplan Meier; log-rank P-value = .906; hazard ratio [HR], 0.95; 95% confidence interval [CI], 0.62-1.44; P-value = .80). All-cause mortality over 5 years was lower for LEB vs PVI (cumulative incidence, 55.9% vs 60.1% by Kaplan Meier; log-rank P-value < .001; HR, 0.77; 95% CI, 0.70-0.86; P-value < .001). Accounting for competing risk of death, amputation over 30 days was also lower in LEB vs PVI (cumulative incidence function, 1.9% vs 3.0%; Fine and Gray P-value = .025; subHR, 0.63; 95% CI, 0.42-0.95; P-value = .025). There was no association between amputation over 5 years and LEB vs PVI (cumulative incidence function, 22.6% vs 23.4%; Fine and Gray P-value = .184; subHR, 0.91; 95% CI, 0.79-1.05; P-value = .184).

CONCLUSIONS

In the Vascular Quality Initiative-linked Medicare registry, LEB vs PVI for CLTI was associated with a lower risk of 30-day amputation and 5-year all-cause mortality. These results will serve as a foundation to validate recently published randomized controlled trial data, and to broaden the comparative effectiveness evidence base for CLTI.

Racial and ethnic disparities in 3-year outcomes following infrainguinal bypass for chronic limb-threatening ischemia

OBJECTIVE

Black and Hispanic patients have had higher rates of chronic limb-threatening ischemia (CLTI) and experienced worse perioperative outcomes after lower extremity bypass compared with White patients. The underlying reasons for these disparities have remained unclear, and data on 3-year outcomes are limited. Therefore, we examined the differences in 3-year outcomes after open infrainguinal bypass for CLTI stratified by race/ethnicity and explored the potential factors contributing to these differences.

METHODS

We identified all CLTI patients who had undergone primary open infrainguinal bypass in the Vascular Quality Initiative registry from 2003 to 2017 with linkage to Medicare claims through 2018 for the 3-year outcomes. Our primary outcomes were the 3-year rates of major amputation, reintervention, and mortality. We also recorded the 30-day major adverse limb events (MALE) defined as major amputation or reintervention. We used Kaplan-Meier estimation methods and multivariable Cox regression analyses to evaluate the outcomes stratified by race/ethnicity and identify contributing factors.

RESULTS

Of the 7108 patients with CLTI, 5599 (79%) were non-Hispanic White, 1053 (15%) were Black, 48 (1%) were Asian, and 408 (6%) were Hispanic patients. Compared with White patients, Black patients had higher rates of 3-year major amputation (Black vs White, 32% vs 19%; hazard ratio [HR], 1.9; 95% confidence interval [CI], 1.7-2.2), reintervention (Black vs White, 61% vs 57%; HR, 1.2; 95% CI, 1.1-1.3), and 30-day MALE (Black vs White, 8.1% vs 4.9%; HR, 1.3; 95% CI, 1.2-1.4) but lower mortality (Black vs White, 38% vs 42%; HR, 0.9; 95% CI, 0.8-0.99). Hispanic patients also experienced higher rates of amputation (Hispanic vs White, 27% vs 19%; HR, 1.6; 95% CI, 1.3-2.0), reintervention (Hispanic vs White, 70% vs 57%; HR, 1.4; 95% CI, 1.2-1.6), and MALE (Hispanic vs White, 8.7% vs 4.9%; HR, 1.5; 95% CI, 1.3-1.7. However, mortality was similar between the two groups (Hispanic vs White, 38% vs 42%; HR, 0.88; 95% CI, 0.76-1.0). The low number of Asian patients prevented a meaningful assessment of amputation (Asian vs White, 20% vs 19%; HR, 0.93; 95% CI, 0.44-2.0), reintervention (Asian vs White, 55% vs 57%; HR, 0.79; 95% CI, 0.51-1.2), MALE (Asian vs White, 8.5% vs 4.9%; HR, 0.71; 95% CI, 0.46-1.1), or mortality (Asian vs White, 36% vs 42%; HR, 0.83; 95% CI, 0.52-1.3). In the adjusted analyses, the association of Black race and Hispanic ethnicity with amputation and reintervention was explained by differences in the demographic characteristics (ie, age, sex) and baseline comorbidities (ie, tobacco use, diabetes, renal disease).

CONCLUSIONS

Compared with White patients, Black and Hispanic patients had higher 3-year major amputation and reintervention rates. However, mortality was lower for Black patients than for the White patients and similar between Hispanic and White patients. Disparities in amputation and reintervention were partly attributable to differences in demographic characteristics and the higher prevalence of comorbidities in Black and Hispanic patients with CLTI. Future work is necessary to determine whether interventions to improve access to care and reduce the burden of comorbidities in these populations will confer limb salvage benefits.