Impact of nutrition on outcomes of limb salvage for chronic limb-threatening ischemia.

Abstract

Poor nutrition and decreased immunocompetency are identified frequently among vascular patients and predict poor surgical outcomes. The intent of this study was to quantify the impact of varying degrees of malnutrition and immunocompetence on the outcomes of subjects undergoing lower extremity intervention for chronic limb-threatening ischemia (CLTI). Between 2018 and 2022, all patients undergoing a primary intervention for CLTI (bypass or endovascular intervention, EV) were included. Nutritional state and immune-competency status was measured by use of the prognostic nutritional index (PNI = 10 × serum albumin [g/dL] + 0.005 × total lymphocyte count [per mm³]). Patients were designated as having a normal PNI (PNI value >50), mild malnutrition (PNI value 50-46), moderate malnutrition (PNI value 45-40), or severe malnutrition (PNI value< 40) for stratification. Amputation-free survival (survival without major amputation) and avoidance of major adverse limb events (MALEs; above-ankle amputation of the index limb or major reintervention [new bypass graft, jump/interposition graft revision]) were evaluated. We included 1207 patients (64% male; mean age, 65 ± 11 years) who underwent either endovascular intervention (66%) or bypass (34%). Of these patients, 17% were grouped based on the PNI as having normal, 25% as mild, 34% as moderate, and 24% as severe scores. Advancing age and increasing Charlson Comorbidity Index were positively associated with increasing severity on the PNI. Increasing severity on the PNI impacts 30-day major adverse cardiac event (3% vs 3% vs 10% vs 15%, normal vs mild vs moderate vs severe PNI; P = .002 compared with a normal PNI), 30-day MALE (4% vs 7% vs 11% vs 19%) and 30-day amputation (3% vs 5% vs 7% vs 11%; P = .001 compared with a normal PNI), wound healing at 3 months decreased as a worsened PNI (83% vs 71% vs 53% vs 40%; P =.001 compared with a normal PNI). At 5 years, both freedom from MALE (Mean ± SEM, 63 ± 5% vs 54 ± 4% vs 38 ± 5% vs 23 ± 4%; P =.001 compared with a normal PNI) and amputation-free survival (59 ± 5% vs 45 ± 6% vs 36 ± 5% vs 25 ± 4% [P = .001] compared with a normal PNI) were significantly worse as PNI severity increased. More than 50% of patients who present with CLTI have evidence of poor nutrition and decreased immunocompetence as defined by the PNI. An increasing severity of PNI leads to poorer short-term and long-term outcomes. Identifying patients with poor nutrition and decreased immunocompetence may further stratify risks attributed to CLTI interventions.