Abstract
Non-ST segment elevation myocardial infarction (NSTEMI) is an acute coronary syndrome event where myocardial ischemia is present, with an increase of cardiac troponins without an elevation of the ST segment. One of the fundamental measures used to diagnose or rule out acute coronary syndrome (ACS) is troponin levels in the blood. Troponin is a broad term used for the category of muscle contraction regulatory proteins and is commonly measured during ACS evaluation. Troponin I is only released by cardiac tissue, while some assay measurements will also pick up troponin released by skeletal muscle injury. This retrospective observational study was performed investigating troponin assays and how they relate to patient's outcomes. The troponin assays used in this Miami hospital where the database of patients was collected between 2018 and 2023 were troponin I (cTnI), the conventional troponin assay, and the newer high-sensitivity troponin I assay (hs-cTn). In this observational study patients who received an admitting diagnosis of NSTEMI corroborated by an independent cardiologist had their respective troponin assay levels included. Patients found to have ECG changes significant for non-ischemic pathologies, or echocardiogram findings suggestive of myocardial dysfunction not clinically correlated to an ACS were excluded from the study. A total of 75 patients were included in this study and the mean age was 75.97 ±14.72 years, with a presentation of chest pain, dyspnea and general weakness recorded in 59% (n = 45) of patients. The median time between troponin samples was 6.63 hours across both assays and hs-cTn showed a 4.99% increase in variation between samples while cTnI had a decrease of 2.53%. The study objective is to support whether there is a difference in rates of cardiac catheterization or mortality based on the type of troponin testing. There was no significant association found between, the type of troponin assay used during hospital admission, and the outcomes of catheterization and death (p > 0.009).