Association of Platelet Indices with Cardiac Enzymes and Left Ventricular Function in Patients with Acute Myocardial Infarction: A Cross-sectional Study

Introduction: Myocardial Infarction (MI) is a leading cause of mortality worldwide. Platelet activation has been implicated in its pathogenesis, and platelet indices, which measure platelet hyperactivity, have been suggested as biomarkers of Coronary Artery Disease (CAD). However, the association of platelet indices with cardiac enzymes and Left Ventricular (LV) function in patients with Acute Myocardial Infarction (AMI) remains unexplored. Aim: To determine the association between platelet indices, cardiac enzymes, and LV function in patients with AMI. Materials and Methods: This hospital-based cross-sectional study was conducted at the Department of Medicine, Regional Institute of Medical Sciences (RIMS), Imphal, Manipur, India from May 2022 to July 2024. The study included 55 patients with AMI, aged 18 years and above, who were admitted to the medicine ward and Intensive Cardiac Care Unit (ICCU) of RIMS. Data were collected on demographics, clinical history, vital parameters, lipid profiles, Electrocardiogram (ECG) findings, cardiac enzymes (Creatine Kinase Myocardial Band (CK-MB), hs Troponin I), and 2D echocardiographic findings. The platelet indices measured included Mean Platelet Volume (MPV), Platelet Distribution Width (PDW), Plateletcrit (PCT), and Platelet-large Cell Ratio (P-LCR). The data were analysed using the Statistical Package for Social Sciences (SPSS) version 26.0 and expressed as descriptive and inferential statistics. Results: The study population had a mean age of 65.14±13.38 years, with a male-to-female ratio of 1.8:1. The most common complaints were chest pain (90.3%) and shortness of breath (56.4%). The risk factors included smoking (78.2%) and hypertension (50.9%). The mean and standard deviation of MPV (fL) was 10.995±1.592, PDW was 16.107±0.436, PCT (%) was 0.255±0.082, and P-LCR (%) was 32.836±10.920, respectively. Key correlations observed included PDW, which was negatively correlated with the LV internal diameter in diastole (r-value=-0.286, p-value=0.034) and the LV internal diameter in systole (r-value=- 0.314, p-value=0.020). Furthermore, MPV showed a possible negative correlation with Left Ventricular Ejection Fraction (LVEF) (r-value=-0.247, p-value=0.069). No significant correlation was observed between platelet indices and cardiac enzymes. Conclusion: The findings from present study highlight that elevated platelet indices, particularly MPV and PDW, play a crucial role in the prothrombotic environment seen in AMI and are linked to LV dysfunction and remodeling. These indices, when integrated into routine diagnostics, could improve the assessment of AMI severity, predict outcomes, and provide insights into post-AMI LV changes.