Neutrophil-Lymphocyte Ratio: Prognostic Impact in Heart Surgery. Early Outcomes and Late Survival.

BACKGROUND: The neutrophil-lymphocyte ratio (NLR) is a recognized marker of inflammation associated with poor outcomes in various clinical situations. We analyzed the prognostic significance of preoperative elevated NLR in patients undergoing cardiac surgery.

METHODS: We performed a retrospective review of 3,027 consecutive patients undergoing cardiac surgery. Receiver-operating-characteristic was used to determine the cutoff value for elevated NLR. Multivariate regression was used to determine the predictive value of preoperative NLR on clinical outcomes. Cox proportional hazards functions were used to determine predictors of late events. Late survival data to 16 years was obtained from the Ministry of Interior.

RESULTS: The cutoff value for elevated NLR was 2.6. Patients with elevated NLR were older (p < 0.0001), had a higher incidence of cardiac comorbidity (p < 0.0001), and higher European System for Cardiac Operative Risk Evaluation score (p < 0.0001). An elevated NLR emerged as an independent predictor of operative mortality (hazard ratio [HR] 2.15, 95% confidence interval [CI]: 1.51 to 3.08, p < 0.0001); pleural effusion (HR 1.42, 95% CI: 1.13 to 1.80, p = 0.003); low output syndrome (HR 1.54, 95% CI: 1.23 to 1.93, p = 0.0002); prolonged ventilation (HR 1.49, 95% CI: 1.23 to 1.82, p = 0.0001); or composite outcomes (HR 1.61, 95% CI: 1.36 to 1.91, p < 0.0001). The NLR emerged as an independent predictor of late mortality (HR 1.19, 95% CI: 1.11 to 1.28; p < 0.0001).

CONCLUSIONS: Elevated NLR is associated with a higher incidence of adverse outcomes after cardiac surgery. It is a predictor of operative as well as late mortality. Further studies are warranted to determine whether prophylactic treatment with antiinflammatory agents can prevent such outcomes. It may be warranted to include the baseline NLR as another variable in risk stratification of patients about to undergo cardiac surgery.