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

Background: 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 neutrophil-lymphocyte-ratio in patients undergoing cardiac surgery.
Methods: We performed a retrospective review of 3027 consecutive patients undergoing cardiac surgery. Receiver-operating-characteristic was used to determine the cutoff value for elevated neutrophil-lymphocyte-ratio. Multivariate regression was used to determine the predictive value of preoperative neutrophil-lymphocyte-ratio on clinical outcomes. Cox proportional hazard functions were used to determine predictors of late events. Late survival data up to 16 years was obtained from the ministry of interior.
Results: The cutoff value for elevated neutrophil-lymphocyte-ratio was 2.6. Patients with elevated neutrophil-lymphocyte-ratio were older (p<0.0001), had a higher incidence of cardiac co-morbidity (p<0.0001), and higher EuroSCORE (p<0.0001). Elevated neutrophil-lymphocyte-ratio emerged as an independent predictor of operative mortality (HR 2.15, CI 1.51-3.08, p<0.0001); pleural effusion (HR 1.42, CI 1.13-1.80, p=0.003); low output syndrome (HR 1.54, CI 1.23-1.93, p=0.0002); prolonged ventilation (HR 1.49, CI 1.23-1.82, p=0.0001) or composite outcomes (HR 1.61, CI 1.36-1.91, p<0.0001). Neutrophil-lymphocyte-ratio emerged as an independent predictor of late mortality (HR 1.19; CI 1.11-1.28; p<0.0001).
Conclusions: Elevated neutrophil-lymphocyte-ratio 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 in order to determine whether prophylactic treatment with anti-inflammatory agents can prevent such outcomes. It may be warranted to include the baseline NLR as another parameter in risk stratification of patients about to undergo cardiac surgery.