Neutrophil to Lymphocyte Ratio Predicts Long-Term Clinical Outcomes in Patients with ST-Segment Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention

Background and Objectives: A higher neutrophil to lymphocyte ratio (NLR) has been associated with poor clinical outcomes in various cardiac diseases. However, the clinical availability of NLR in patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI) has not been known. We evaluated the availability of NLR to predict clinical outcomes in patients with STEMI undergoing primary PCI. Subjects and Methods: We analyzed 326 consecutive STEMI patients treated with primary PCI. The patients were divided into tertiles according to NLR: NLR${\leq}3.30(n=108)$, 3.31 and NLR>6.53 (n=110). We evaluated the incidence of major adverse cardiac events (MACE), a composite of all causes of death, non-fatal MI, and ischemic stroke at the 12-month follow-up. Results: The high NLR group was associated with a significantly higher rate of 12-month MACE (19.1% vs. 3.7%, p<0.001), 12-month death (18.2% vs. 2.8%, p<0.001), in-hospital MACE (12.7% vs. 2.8%, p=0.010) and in-hospital death (12.7% vs. 1.9%, p=0.003) compared to the low NLR group. In the multivariable model, high NLR was an independent predictor of 12-month MACE {hazard ratio (HR) 3.33 (1.09-10.16), p=0.035} and death {HR 4.10 (1.17-14.46), p=0.028} after adjustment for gender, left ventricular ejection fraction, creatinine clearance, angiographic parameters and factors included in the Thrombolysis in Myocardial Infarction risk score for STEMI. There was a significant gradient of 12-month MACE across the NLR tertiles with a markedly increased MACE hazard in the high NLR group (log rank test p=0.002). Conclusion: The NLR is a useful marker to predict 12-month MACE and death in patients with STEMI who have undergone primary PCI.