VESS02 - A Microvascular Risk Score Predicts Limb Outcomes After Infrainguinal Revascularization for Chronic Limb-Threatening Ischemia: A Vascular Quality Initiative Analysis

Objectives: Patients with chronic limb-threatening ischemia (CLTI) remain at high risk for major adverse limb events (MALE) despite contemporary revascularization strategies, suggesting that factors beyond local arterial patency influence outcomes. We evaluated whether a Microvascular Risk Score (MRS) reflecting cardiac, renal, and diabetic disease predicts 1-year MALE after infrainguinal revascularization.

Methods: We conducted a retrospective cohort study using the Vascular Quality Initiative Peripheral Vascular Intervention and Infra-Inguinal Bypass registries (2018-2024). Adults aged ≥ 18 years undergoing infrainguinal revascularization for CLTI were included. Patients with prior ipsilateral revascularization, index major amputation, or missing score components were excluded. The MRS (range 0-6) was a cumulative measure of renal dysfunction (creatinine ≥ 2mg/dL and/or dialysis), cardiac disease (coronary artery disease with prior MI/PCI/CABG), and diabetes severity (none, non-insulin treated, insulin-treated). Patients were categorized as low (0-1), moderate (2-3), or high risk (4-6). The primary outcome was 1-year MALE (ipsilateral major amputation or major reintervention). Secondary outcomes included individual MALE components and 1-year all-cause mortality. Kaplan-Meier methods and multivariable Cox models adjusted for procedure type, age, sex, race/ethnicity, smoking status, COPD, congestive heart failure, and ambulatory status were used.

Results: Among 94,228 patients (mean age 70; 63% male) undergoing first infrainguinal revascularization for CLTI, 79,323 (84%) underwent endovascular intervention. Baseline characteristics varied across MRS strata (Table I).
Increasing MRS was associated with progressively lower 1-year freedom from MALE (Figure 1). Compared with low-risk patients, moderate- and high-risk patients had higher MALE hazards (HR 1.22 and 1.34; both p < 0.001), driven predominantly by major amputation (HR 1.60 and 2.12; both p < 0.001). Overall, MRS was not associated with major reintervention.
MRS demonstrated a strong association with 1-year all-cause mortality, with higher mortality hazards among moderate- and high-risk patients (HR 1.40 and 3.04, respectively; both p < 0.001). Procedure type did not modify MALE hazard in low- or moderate-risk patients; however, among high-risk patients, infrainguinal bypass was associated with a 21% lower MALE hazard compared with endovascular intervention (HR 0.79, 95% CI 0.63-0.98), highlighting a subgroup in which procedural choice meaningfully influenced limb outcomes.

Conclusions: Systemic microvascular disease burden strongly predicts limb loss and mortality after infrainguinal revascularization for CLTI and identifies a high-risk microvascular disease pattern that may derive a preferential limb-salvage benefit from surgical bypass over endovascular intervention. Incorporating MRS may improve risk stratification, patient selection, and counseling regarding the likelihood of successful limb salvage.