Assessment of Severity of ST-Elevation Myocardial Infarction Using Neutrophil-to-Lymphocyte Ratio and Its Correlation With Thrombolysis in Myocardial Infarction Risk Score

Abstract

Introduction ST-segment elevation myocardial infarction (STEMI) is an acute presentation of myocardial infarction (MI). It is caused by the complete occlusion of coronary arteries by a thrombus secondary to atherosclerotic plaque formation within these vessels. The Thrombolysis in Myocardial Infarction (TIMI) risk score is a seven-item scale used to categorize patients based on risk and to predict mortality in acute MI patients. The neutrophil-to-lymphocyte ratio (NLR) is an independent assessor of prognosis in cardiovascular diseases; it holds a pivotal role in inflammation and atherosclerotic plaque formation. Methodology A hospital-based cross-sectional study was undertaken among 76 patients who had acute MI, out of which 50 patients who had STEMI were included and 26 patients were excluded (13 patients had non-ST-segment elevation myocardial infarction (NSTEMI), four patients had unstable angina, nine patients had arrhythmias). After detailed clinical and laboratory evaluation, NLR was calculated for all 50 patients, and they were distributed into low NLR, intermediate NLR and high NLR groups based on the ratio. Patients then underwent coronary angiography, and their TIMI-STEMI score was calculated and compared with their NLR score. Using SPSS software (IBM Corp., Armonk, NY, USA), the collected data was statistically analyzed. Results Fifty patients with acute coronary syndrome (ACS) based on their NLR were distributed into three categories: Category A with low NLR of <1.7 (n=2), Category B with intermediate NLR of 1.7-3 (n=10), and Category C with high NLR of >3 (n=38). In this study, there were more male patients (two in Category A, six in Category B, 28 in Category C), mean age group was 55 +/- 10 (one in Category A, five in Category B, 32 in Category C), the most common presentation was chest pain (two in Category A, nine in Category B, 37 in Category C), the most common risk factor was smoking (two in Category A, six in Category B, 15 in Category C), the angiographic TIMI-STEMI score was calculated and two, six, and two patients in Category A, Category B, Category C respectively had a low score of <4, four and 36 patients in Category B and C respectively had a high score of >4, and there was a significant correlation between high NLR and high TIMI-STEMI score (P = 0.001). Conclusion This study infers that a simple bedside parameter like the NLR, which is easily available and affordable, can predict the outcome in STEMI patients and stands on par with conventional angiographic scores.

Keywords: angiographic management; angiographic score; myocardial infarction; primary percutaneous coronary intervention (pci); total leucocyte count.

Figure 1. Patient distribution based on Neutrophil-to-Lymphocyte Ratio (NLR)