The clinical significance of cardiac troponins in medical practice

Abstract

Troponins are regulatory proteins that form the cornerstone of muscle contraction. The amino acid sequences of cardiac troponins differentiate them from that of skeletal muscles, allowing for the development of monoclonal antibody-based assay of troponin I (TnI) and troponin T (TnT). Along with the patient history, physical examination and electrocardiography, the measurement of highly sensitive and specific cardiac troponin has supplanted the former gold standard biomarker (creatine kinase-MB) to detect myocardial damage and estimate the prognosis of patients with ischemic heart disease. The current guidelines for the diagnosis of non-ST segment elevation myocardial infarction are largely based on an elevated troponin level. The implementation of these new guidelines in clinical practice has led to a substantial increase in the frequency of myocardial infarction diagnosis. Automated assays using cardiac-specific monoclonal antibodies to cardiac TnI and TnT are commercially available. They play a major role in the evaluation of myocardial injury and prediction of cardiovascular outcome in cardiac and non-cardiac causes. In this review we discuss the clinical applications of cardiac troponins and the interpretation of elevated levels in the context of various clinical settings.

The Relationship Between Smoking Intensity and Subclinical Cardiovascular Injury: The Multi-Ethnic Study of Atherosclerosis (MESA)

“…Smoking is known to cause temporary coronary vasospasm, 12 and microvascular ischemia, 60 which may result in troponin elevation. The lack of association between smoking intensity and subclinical myocardial injury in our study could be explained by the fact that high-sensitivity troponin assays were not performed in MESA, 61 and participants were instructed to abstain from smoking on the morning of the MESA visit. Therefore it is possible that micro elevations in troponin related to acute smoking exposure may have dissipated by the time of the assessment in this study.…”

Correlation between Acute Stroke and Concentration of Creatine Kinase Myocardial Band, Troponin T, Hemoglobin, and Electroyltes

“…A concentration of 0.07-0.5 mg/mL was presumed to be consistent with probability of cardiac damage and probability of increase in clinical risk, while concentration >0.5 mg/mL was consistent with cardiac damage and increase in clinical risk (Singh et al, 2011;Abdi et al, 2015). Elevated troponin concentration was found in other clinical condition such as sepsis, hypovolemia, atrial fibrillation, congestive heart failure, myocarditis, and stroke (Alcalai et al, 2007;Wells et al, 2008;Al-otaiby et al, 2011). Mechanism of troponin T increase could be attributed to imbalance of autonomous nervous system which cause excessive sympathetic activity and increase in cathecolamine influence towards cardiac cell (Hasirci et al, 2013).…”

“…Troponin T has a half time of 90 minutes. Persistent increase in the third or fourth day shows degradation of contractile element as marker of irreversible cell damage (Wells et al, 2008;Jagannadharao et al, 2010;Al-otaiby et al, 2011).…”

Factors influencing troponin T concentration in patients with obstructive sleep apnea syndrome

“…The damage is directly proportional to their increase. Regardless the underlying reason of troponin T (TnT) elevation, its increase is considered strong and independent predictor of cardiac injury and worse prognosis [6]. Only a few studies have assessed relation between the troponin level and severity of sleep apnea and their findings are often inconsistent [7].…”