Contemporary Outcomes in Chronic Limb-Threatening Ischemia: The Role of the Social Vulnerability Index

Health disparities have been shown to influence the outcomes of vascular surgery interventions. This study aimed to analyze the association of the Social Vulnerability Index (SVI) with the outcomes of patients undergoing a lower extremity intervention for chronic limb-threatening ischemia (CLTI).

This is a retrospective cohort study. Between 2018 and 2023, all patients undergoing a primary intervention (bypass, BYP; endovascular interventions, EVs; or major amputation, AMP) for CLTI presenting with wound ischemia foot infection (WIfI) stages 1-5 were analyzed. Patients presenting acutely and/or with prior vascular procedures on the limb in question were excluded. Patient addresses were geocoded, and estimated SVI scores were assigned. The cutoff for high-risk versus low-risk social vulnerability was an SVI >75th percentile. SVI consists of 4 distinct disparity domains that allow for subgroup analysis: socioeconomic status, minority status and language, household composition and disability, and housing and transportation. Short-term objective performance goals, amputation-free survival (AFS; survival without major amputation), and freedom from major adverse limb events (MALE; above ankle amputation of the index limb or major reintervention (new bypass graft, jump/interposition graft revision) were evaluated.

A total of 1,974 patients (55% male, age 64 ± 12 years, mean ± SD) underwent either EV (57%), a BYP (29%), or AMP (14%). The median follow-up of 4.1 years. Patient distribution by SVI quartiles (from less social disparity to greater social disparity) was as follows: Q1 (11%), Q2 (21%), Q3 (32%), and Q4 (37%). The incidence of diabetes, obesity, and end-stage renal disease increased as SVI increased (P = 0.03). Access to primary care also diminished as the SVI quartile increased. When dichotomized into low-risk (n = 1,263) and high-risk SVI (n = 711) groups, 30-day major adverse cardiac event (5% vs. 11%; low-risk vs. high-risk SVI, respectively; P = 0.03, 30-day MALE (7% vs. 18%; P = 0.01), and 30-day amputation (4% vs. 9%; P = 0.01) were significantly increased in the high-risk SVI group. Patients in high SVI group had significantly lower survival (55 ± 9% vs. 31 ± 8%, low vs. high SVI respectively, mean ± SEM; P = 0.003), lower freedom from MALE (61 ± 7% vs. 31 ± 8%; P = 0.001) and lower AFS at 5 years (49 ± 5% vs. 21 ± 6%; P = 0.001).

Social vulnerability as measured by socioeconomic status, minority status and language, household composition, disability, housing, and transportation influences short-term and long-term outcomes after intervention for CLTI. Assessing and addressing domains in social disparity risk may improve outcomes before major lower extremity intervention.