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

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.