The aim of this study was to compare the results of lower limb bypass surgery with those of endovascular treatment (EVT) in patients with chronic limb threatening ischemia (CLTI).

This retrospective multicentre study involved 808 patients with CLTI. In this series, between January 2016 and January 2019, 368 patients underwent lower limb bypass surgery, and 440 patients underwent EVT. The primary endpoint was amputation-free survival (AFS), and the secondary endpoint was ischemic wound healing. The hemodynamic criteria and severity of foot lesions were ordered according to the WIfI classification. Grades of femoropopliteal and infrapopliteal arterial lesions were used to determine the GLASS stage. Data were analysed by the Student's t-test or Mann-Whitney for continuous variables and by Fisher's exact test for categorical variables. AFS was expressed using the Kaplan-Meier method. The log rank was used to test the difference between survival curves. The Cox proportional-hazards regression model was used to evaluate the prognostic effect of factors on AFS. The statistical analyses were performed with SPSS 28.0 (Chicago, IL, USA). The MatchIt ® package of the R software version 4.1.1 ® was used to perform 1:1 propensity score matching (PSM) with a caliper value set to 0.02 to compare the results of the two techniques on comparable groups of patients (1).

In the whole group, before pairing, AFS (Fig.1) did not significantly differ at 3-year between the bypass group (69 ± 2%) and the endovascular group (68 ± 2%), log rank: p =. 53), HR 1.06 (95% CI 0.86 -1.31). The univariate analysis found 7 variables whose distribution significantly differed between the two groups (Table 1) and independently associated with a risk of death or major amputation. Five variables were confirmed by Cox proportional hazard regression model as factors associated with a risk of death or major amputation, including WIfI stages 3-4 vs. 1-2 (HR 1.32, 95%CI 1.07-1.62, p=.008), GLASS 3 stage vs. 1-2 (HR 1.46, 95%CI 1.17-1.81, p<.001), diabetes (HR 2.79, 95%CI 2.23-3.51, p<.001), severe chronic kidney disease (HR 2.38, 95%CI 1.93-2.94, p=.001), and left ventricular ejection fraction <40% (HR 1.61, 95%CI 1.30-2.00, p=.001). After matching the two groups by entering these 5 variables in the propensity score, we obtained two groups of 166 patients whose distributions of variables were comparable (Table 1). In these matched groups, 3-year amputation-free survival (Fig.2) was found to be significantly higher in the bypass group compared to the EVT group (73 ± 3% vs. 64 ± 4%, log rank: p =.001), HR 1.82 (95% CI 1.32 - 2.50). The secondary endpoint (Fig.3) compared healing in 564 patients with ischemic wounds (bypass, n=283; endovascular, n=281). Complete healing at 3-month was significantly more frequent among patients in the bypass group (44 ± 3%) compared to 24 ± 3% of patients in the EVT group (log rank p=.001).

This multicentre cohort study showed that patients with CLTI receiving bypass surgery had more severe ischemic wounds (WIfI) and more severe arterial lesions (GLASS) than those receiving an endovascular technique, with comparable results regardless of the revascularization technique. PSM allowed us to obtain two comparable groups for the main variables and showed the superiority of the bypass group compared to the endovascular group for the primary outcome (AFS). Despite limitations due to the retrospective nature of the study, and pending the results of ongoing randomized studies, these results suggest that after considering the cardiovascular status of the patient, the choice of revascularization in patients with CLTI must be adapted according to the WIfI and GLASS stages and not decided a priori with an endovascular-first or a bypass-first position.

(1) Ho DE, Imai K, King G, Stuart EA. MatchIt: Nonparametric Preprocessing for Parametric Causal Inference." Journal of Statistical Software, 2011;42:1-28. doi: 10.18637/jss.