Neutrophil to lymphocyte ratio predicts short- and long-term mortality following revascularization therapy for ST elevation myocardial infarction

Abstract

Background: Several inflammation biomarkers have been implicated in the pathogenesis and prognosis of acute coronary syndromes. However, the prognostic role of the neutrophil-lymphocyte white cell interactive response to myocardial injury in predicting short- and long-term mortality after ST elevation myocardial infarction (STEMI) remains poorly defined.

Methods: We evaluated 250 consecutive STEMI patients presenting acutely for revascularization to our tertiary care center over 1 year. Patients with acute sepsis, trauma, recent surgery, autoimmune diseases, or underlying malignancy were excluded. Data gathered included demographics, clinical presentation, leukocyte markers, electrocardiograms, evaluations, therapy,major adverse cardiac events, and all-cause mortality.

Results: Mean age was 62 ± 15 years, 70.4% of subjects were males while majority (49.4%) were Caucasians. Mean duration of follow-up was 571 ± 291 days (median 730 days). Univariate analysis of several inflammatory biomarkers including C-reactive protein, revealed white cell count (OR = 1.09, p < 0.001) and neutrophil to lymphocyte ratio (NLR) (OR = 1.05, p = 0.011) as predictors of short- and long-term mortality; but not mean neutrophil count (OR = 1.04, p = 0.055) or lymphocyte count alone (OR = 0.96, p = 0.551). Multivariate analysis using backward stepwise regression revealed NLR (OR = 2.64, p = 0.026), female gender (OR = 5.35, p < 0.001), cerebrovascular accident history (OR = 3.36, p = 0.023), low glomerular filtration rate (OR = 0.98, p = 0.012) and cardiac arrest on admission (OR = 17.43, p < 0.001) as robust independent predictors of long-term mortality. NLR was divided into two sub-groups based on an optimal cut off value of 7.4. This provided the best discriminatory cut off point for predicting adverse mortality outcome. Both short-term (≤ 30 days) and long-term (≤ 2 years) mortality were predicted with Kaplan-Meier survival curve separation best stratified by a NLR cut off value of 7.4.

Conclusions: NLR based on an optimal cut off value of 7.4, was an excellent predictor of short- and long-term survival in patients with revascularized STEMI and warrants larger scale multi-center prospective evaluation, as a prognostic indicator. NLR offers improved prognostic capacity when combined with conventional clinical scoring systems, such as the Thrombolysis In Myocardial Infarction risk score.