Segmental Infrapopliteal Scoring Shows Stronger Associations than Global Assessment in Diabetic CLTI

Background: Peripheral artery disease (PAD) progressing to chronic limb-threatening ischemia (CLTI) is associated with high morbidity and limb loss. Diabetes mellitus (DM) is a major modifier of disease distribution and outcomes. The Bollinger score, GLASS classification, and WIfI staging are complementary tools for assessing anatomical burden and limb threat. The aim of this study was to analyze the associations between these scoring systems in diabetic CLTI, with Bollinger and GLASS assessed on digital subtraction angiography, and with a focus on segmental infra-popliteal versus global anatomical evaluation. Methods: This single-center, retrospective observational study included 136 patients with CLTI who underwent endovascular revascularization between May 2021 and May 2023. Baseline demographics and comorbidities, angiographic severity, WIfI stage, Bollinger score (whole leg; above- and below-knee), GLASS staging (global; femoropopliteal/infra-popliteal segments), and outcomes (technical success, bypass conversion, major amputation, and one-year mortality) were analyzed. Results: Patients were classified into a diabetic group (DM; n = 85) and a non-diabetic group (NDM; n = 51). Diabetic patients more frequently presented with infra-inguinal stenoses >50% (55.3% vs. 35.3%, p = 0.024) but fewer complete occlusions (83.5% vs. 96.1%, p = 0.028). WIfI stage 1 tended to be more frequent in diabetics (54.1% vs. 33.3%, p ≈ 0.08). Bollinger scores were lower in the DM group for the whole leg (30.07 ± 16.34 vs. 36.78 ± 16.09, p = 0.018) and for the below-knee segment (20.53 ± 15.88 vs. 26.86 ± 13.93, p = 0.015). Conclusions: In this cohort, diabetic patients with CLTI exhibited a distinct distal angiographic pattern characterized by prevalent infra-popliteal stenoses and lower additive Bollinger scores. Segmental infra-popliteal assessment showed stronger clinical relevance than global evaluation, with below-knee Bollinger scores and GLASS infra-popliteal stages demonstrating the closest association with WIfI severity. These findings highlight the dominant role of distal disease in diabetic arteriopathy and support a segment-focused approach to endovascular planning.