Elevated neutrophil to lymphocyte ratio is associated with decreased amputation-free survival after femoropopliteal percutaneous revascularization.

Abstract

An elevated neutrophil-lymphocyte ratio (NLR) is a biomarker associated with adverse outcomes after cardiovascular surgery. This study evaluates the association of preoperative NLR with clinical outcomes after peripheral vascular intervention (PVI) of the femoropopliteal segments. A retrospective review identified 488 patients who underwent percutaneous interventions of femoropopliteal arteries between 2011 and 2018 and had a pre-procedural complete blood count with differential with normal white blood cell count within 30 days prior to intervention. Amputation-free survival (AFS), survival, and freedom from major amputation were assessed using Kaplan-Meier methods. Cohorts of patients with NLR <3 (Low), 3-4 (Mid), and >4 (High) were compared using univariate and multivariable statistical models. In these analyses NLR was analyzed as a continuous variable to correlate with clinical outcomes. Mean age was 71.7±12.8 years and males constituted 55.5%. The majority of patients presented with chronic limb threatening ischemia (CLTI, 78.5%). Increasing NLR was correlated with increasing rates of comorbidities, except for smoking history. The 30-day mortality rates increased with increasing NLR: 1.4%, 4.3%, and 7.0% for low (<3), mid (3-4) and high (>4) NLR groups, respectively (P=0.005). Patients with a lower pre-operative NLR achieved significantly greater amputation-free survival at 4-year follow-up: low NLR, 65.5%; mid NLR, 37.5%; and high NLR, 17.6% (P<0.0001). By multivariable analysis, increasing NLR, advanced age, CLTI, and dialysis-dependent renal failure reduced AFS. Elevated NLR is an independent predictor of decreased AFS following percutaneous interventions of femoropopliteal segments. Further research on identification and modulation of risk factors for high NLR are warranted.