Association of Serum Cardiac Troponin in the Outcome of Acute Myocardial Infarction

Background The diagnosis of acute myocardial infarction (AMI) relies on a comprehensive clinical framework that integrates patient presentation, electrocardiographic findings, and cardiac biomarkers, including highly sensitive troponins. While cardiac biomarkers such as highly sensitive troponins have traditionally served as a cornerstone for the diagnosis of acute myocardial infarction, they also hold significant clinical value in risk stratification and prognosis. Highly sensitive troponins may have prognostic value for predicting the course of a patient's hospital stay, including complications and mortality. Objective This study aimed to evaluate the association between elevated cardiac troponin levels and clinical outcomes, including hypotension requiring inotropes (indicative of early cardiogenic shock), reinfarction, Wall Motion Score Index (WMSI), and in-hospital mortality, among patients admitted with acute myocardial infarction. Methods This prospective observational cohort study was conducted from October 2022 to April 2024 in the department of general medicine at a tertiary care center. A total of 148 patients with acute myocardial infarction were selected using consecutive sampling. Clinical data, including highly sensitive cardiac troponin I (hs-cTnI) and transthoracic echocardiography findings, were collected along with patient demographics, medical histories, and course in the hospital. Blood samples were obtained on admission under aseptic conditions to measure highly sensitive cardiac troponin I. A transthoracic echocardiogram was performed by the same skilled technician to calculate the left ventricular ejection fraction (LVEF) and Wall Motion Score Index (WMSI) using a standard 16-segment model. The course in the hospital was monitored. Statistical analysis was performed using SPSS version 26 (IBM Corp., Armonk, NY), employing descriptive statistics, Spearman correlation coefficients, and the Mann-Whitney test. Results The study included 148 patients (66.9% male; mean age: 64.53 years). Median admission hs-cTnI was 1832 ng/L (IQR: 253.2-5887), mean WMSI was 2.04, and mean LVEF was 39.22%. During hospitalization, incidence rates of hypotension, reinfarction, and mortality were 40.5% (n = 60), 8.1% (n = 12), and 18.9% (n = 28), respectively. Admission hs-cTnI positively correlated with WMSI (Spearman's rho = 0.280; 95% CI: 0.124-0.422; p = 0.0006). On ROC analysis, higher values of hs-cTnI were associated with hypotension (AUC = 0.605 (95% CI: 0.508-0.702), p = 0.035; cut-off: 9116 ng/L; sensitivity: 35.0% (95% CI: 23.1%-48.4%), specificity: 93.2% (95% CI: 85.8%-97.4%), PPV: 77.8% (95% CI: 57.7%-91.4%), NPV: 67.8% (95% CI: 58.7%-76.0%)) and reinfarction (AUC = 0.678 (95% CI: 0.511-0.845), p = 0.035; sensitivity: 58.3% (95% CI: 27.7%-84.8%), specificity: 86.8% (95% CI: 80.0%-92.0%), PPV: 28.0% (95% CI: 12.1%-49.4%), NPV: 95.9% (95% CI: 90.8%-98.7%)). Baseline hs-cTnI did not correlate with in-hospital mortality (AUC = 0.513 (95% CI: 0.395-0.631), p = 0.814). Conclusion This study supports the potential role of hs-cTnI as an early marker associated with selected in-hospital complications after acute myocardial infarction. This study supports the potential role of highly sensitive cardiac troponin levels as an early marker to assess the risk of myocardial infarction-related complications. Further multicenter, prospective studies and serial measurements of troponin levels are required to validate these findings.