New Predictors of Infarct Size: The Neutrophil/Lymphocyte Index

Introduction: The neutrophil/lymphocyte (N/L) index has been proposed as a new indicator of the patient`s systemic inflammatory status and has been related to prognosis in different cardiovascular pathologies. The aim of this study was to evaluate whether N/L predicts the extent of myocardial infarction in patients with acute coronary syndrome with ST elevation (STEMI).
Material and methods: Retrospective study, which included 220 patients (P) with STEMI, successfully treated with primary angioplasty (TIMI 3 final flow). The N/L index was obtained from a blood sample upon hospital arrival. Patients were classified according to infarct size, that was calculated according to peak troponin level (extensive infarct, above median value vs non extensive infarct, below median value).
Results: Of the 220 P included, 180 (81.8%) were males. Risk factors included 24.5% diabetes, 45.5% hypertension, 39.1% dyslipidemia, 62.3% smokers, 3.2% renal failure, 3.6% peripheral arterial disease and 1.8% previous stroke. Previous acute myocardial infarction (AMI) was present in 16.9% of the cases and 11.8% had a previous angioplasty. Patients with extensive AMI had higher N/L index compared to those with non-extensive AMI [3.96 (2.31-7.09) vs 2.31 (1.4- 4.65), p <0.001). After adjusting for cardiovascular risk factors, age, sex and door to balloon time, the N/L index was the unique predictor of extensive AMI (OR: 2.6; 95% CI: 1.5-4.5 ;P=0.01).
Conclusions: The N/L index is a predictor of infarct size, regardless of the presence of cardiovascular risk factors. It is a cheap and widely available test that allows us to identify patients at greater risk who could benefit from more aggressive management.