Prospective Evaluation of the Effects of Neutrophil to Lymphocyte Ratio on Mortality After Elective Vascular Surgical Procedures

The neutrophil-lymphocyte ratio (NLR) is an inflammatory marker associated with vascular surgical outcomes in retrospective studies. This study prospectively evaluates the association of NLR with mortality after elective vascular surgical procedures. We prospectively collected data of patients who underwent elective open and endovascular vascular surgery for atherosclerotic diseases from January 2019 to December 2021. Patients who underwent elective carotid endarterectomy, endovascular and open aortic reconstruction, and lower extremity revascularization (including open and percutaneous revascularization) were included. Dialysis-related procedures, venous interventions, major amputations, or emergency procedures were excluded. Patients who had a normal preoperative complete blood count with differential leukocyte counts within 60 days of operation were included. NLR was computed by dividing the absolute neutrophil count by the absolute lymphocyte count. Logistic regression analysis was used to predict the odds for mortality. In this cohort of 344 patients, the mean age was 67.31 ± 13.10 years, with 56.4% male. The mean preoperative NLR for the study cohort was 2.98 ± 1.90. There were 222 patients with NLR <3 (64.5%), and 122 patients with NLR >3 (35.5%). Perioperative mortality rate was 8.4% and was not associated with NLR status. However, late mortality was significantly higher in patients with NLR >3. The 2-year Kaplan-Meier estimated survival rate was 74.6% in patients with NLR >3.0 compared to 90.1% in patients with NLR <3.0 (log-rank P < .001) (Figure). On univariate analysis, NLR >3.0 (hazard ratio [HR], 2.87; 95% confidence interval [CI], 1.66-4.96; P < .001), chronic obstructive pulmonary disease (HR, 2.92; 95% CI, 1.70-5.04, P < .001), and end-stage renal disease (HR, 2.46; 95% CI, 1.05-5.75, P = .038) were associated with increased mortality. On multivariable analysis, NLR >3.0 (HR, 2.98; 95% CI, 1.71-5.22, P < .001) and chronic obstructive pulmonary disease (HR, 3.13; 95% CI, 1.82-5.41, P < .001) were associated with mortality. In contrast, statin had a protective effect against mortality (HR, 0.539; 95% CI, 0.30-0.98, P = .042) (Table). When treated continuously, each 1 unit increase in NLR increased the odds of mortality by 1.48 (95% CI, 1.27-1.71). Preoperative NLR >3.0 is associated with higher mortality after elective vascular surgery. Future studies are warranted to define the underlying mechanism and develop inflammation and immunomodulation-targeted therapy.TableMultivariable Cox regression analysis of factors associated with mortalityVariableHR95% CIP valueNLR2.981.71-5.22<.001Chronic obstructive pulmonary disease3.131.82-5.41<.001End-stage renal disease1.980.84-4.69.120Statin0.5390.30-0.98.042CI, Confidence interval; HR, hazard ratio; NKR, neutrophil-lymphocyte ratio. Open table in a new tab