Dataset Information

Cardiac troponins: from myocardial infarction to chronic disease.

ABSTRACT: Elucidation of the physiologically distinct subunits of troponin in 1973 greatly facilitated our understanding of cardiac contraction. Although troponins are expressed in both skeletal and cardiac muscle, there are isoforms of troponin I/T expressed selectively in the heart. By exploiting cardiac-restricted epitopes within these proteins, one of the most successful diagnostic tests to date has been developed: cardiac troponin (cTn) assays. For the past decade, cTn has been regarded as the gold-standard marker for acute myocardial necrosis: the pathological hallmark of acute myocardial infarction (AMI). Whilst cTn is the cornerstone for ruling-out AMI in patients presenting with a suspected acute coronary syndrome (ACS), elevated cTn is frequently observed in those without clinical signs indicative of AMI, often reflecting myocardial injury of 'unknown origin'. cTn is commonly elevated in acute non-ACS conditions, as well as in chronic diseases. It is unclear why these elevations occur; yet they cannot be ignored as cTn levels in chronically unwell patients are directly correlated to prognosis. Paradoxically, improvements in assay sensitivity have meant more differential diagnoses have to be considered due to decreased specificity, since cTn is now more easily detected in these non-ACS conditions. It is important to be aware cTn is highly specific for myocardial injury, which could be attributable to a myriad of underlying causes, emphasizing the notion that cTn is an organ-specific, not disease-specific biomarker. Furthermore, the ability to detect increased cTn using high-sensitivity assays following extreme exercise is disconcerting. It has been suggested troponin release can occur without cardiomyocyte necrosis, contradicting conventional dogma, emphasizing a need to understand the mechanisms of such release. This review discusses basic troponin biology, the physiology behind its detection in serum, its use in the diagnosis of AMI, and some key concepts and experimental evidence as to why cTn can be elevated in chronic diseases.

SUBMITTER: Park KC

PROVIDER: S-EPMC5852618 | biostudies-literature | 2017 Dec

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Cardiac troponins: from myocardial infarction to chronic disease.

Park Kyung Chan KC Gaze David C DC Collinson Paul O PO Marber Michael S MS

Cardiovascular research 20171201 14

Elucidation of the physiologically distinct subunits of troponin in 1973 greatly facilitated our understanding of cardiac contraction. Although troponins are expressed in both skeletal and cardiac muscle, there are isoforms of troponin I/T expressed selectively in the heart. By exploiting cardiac-restricted epitopes within these proteins, one of the most successful diagnostic tests to date has been developed: cardiac troponin (cTn) assays. For the past decade, cTn has been regarded as the gold-s ...[more]

PMID: 29016754

Similar Datasets

Project description:Little is known about patients with cancer presenting with acute chest discomfort to the emergency department (ED). The aim of this study was to assess the prevalence of acute myocardial infarction (AMI), outcomes, and the diagnostic utility of recommended diagnostic tools in this population. Patients presenting with chest pain to the ED were prospectively enrolled in an international multicenter diagnostic study with central adjudication. Cancer status was assessed prospectively and additional cancer details retrospectively. Findings were externally validated in an independent multicenter cohort. Among 8,267 patients, 711 (8.6%) had cancer. Patients with cancer had a higher burden of cardiovascular risk factors and pre-existing cardiac disease. Total length of stay in the ED (5.2 hours vs 4.3 hours) and hospitalization rate (49.8% vs 34.3%) were both increased in patients with cancer (P < 0.001 for both). Among 8,093 patients eligible for the AMI analyses, those with cancer more often had final diagnoses of AMI (184 of 686 with cancer [26.8%] vs 1,561 of 7,407 without cancer [21.1%]; P < 0.001). In patients with cancer, high-sensitivity cardiac troponin T (hs-cTnT) but not high sensitivity cardiac troponin I (hs-cTnI) concentration had lower diagnostic accuracy for non-ST-segment elevation myocardial infarction (for hs-cTnT, area under the curve: 0.89 [95% CI: 0.86-0.92] vs 0.94 [95% CI: 0.93-0.94] [P < 0.001]; for hs-cTnI, area under the curve: 0.93 [95% CI: 0.91-0.95] vs 0.95 [95% CI: 0.94-0.95] [P = 0.10]). In patients with cancer, the European Society of Cardiology 0/1-hour hs-cTnT and hs-cTnI algorithms maintained very high safety but had lower efficacy, with twice the number of patients remaining in the observe zone. Similar findings were obtained in the external validation cohort. Patients with cancer have a substantially higher prevalence of AMI as the cause of chest pain. Length of ED stay and hospitalization rates are increased. The diagnostic performance of hs-cTnT and the efficacy of both the European Society of Cardiology 0/1-hour hs-cTnT and hs-cTnI algorithms is reduced. (Advantageous Predictors of Acute Coronary Syndromes Evaluation [APACE] Study; NCT00470587).

Project description:BACKGROUND:Cardiac myosin-binding protein C (cMyC) is a cardiac-restricted protein that is more abundant than cardiac troponins (cTn) and is released more rapidly after acute myocardial infarction (AMI). We evaluated cMyC as an adjunct or alternative to cTn in the early diagnosis of AMI. METHODS:Unselected patients (N=1954) presenting to the emergency department with symptoms suggestive of AMI, concentrations of cMyC, and high-sensitivity (hs) and standard-sensitivity cTn were measured at presentation. The final diagnosis of AMI was independently adjudicated using all available clinical and biochemical information without knowledge of cMyC. The prognostic end point was long-term mortality. RESULTS:Final diagnosis was AMI in 340 patients (17%). Concentrations of cMyC at presentation were significantly higher in those with versus without AMI (median, 237 ng/L versus 13 ng/L, P<0.001). Discriminatory power for AMI, as quantified by the area under the receiver-operating characteristic curve (AUC), was comparable for cMyC (AUC, 0.924), hs-cTnT (AUC, 0.927), and hs-cTnI (AUC, 0.922) and superior to cTnI measured by a contemporary sensitivity assay (AUC, 0.909). The combination of cMyC with hs-cTnT or standard-sensitivity cTnI (but not hs-cTnI) led to an increase in AUC to 0.931 (P<0.0001) and 0.926 (P=0.003), respectively. Use of cMyC more accurately classified patients with a single blood test into rule-out or rule-in categories: Net Reclassification Improvement +0.149 versus hs-cTnT, +0.235 versus hs-cTnI (P<0.001). In early presenters (chest pain <3 h), the improvement in rule-in/rule-out classification with cMyC was larger compared with hs-cTnT (Net Reclassification Improvement +0.256) and hs-cTnI (Net Reclassification Improvement +0.308; both P<0.001). Comparing the C statistics, cMyC was superior to hs-cTnI and standard sensitivity cTnI (P<0.05 for both) and similar to hs-cTnT at predicting death at 3 years. CONCLUSIONS:cMyC at presentation provides discriminatory power comparable to hs-cTnT and hs-cTnI in the diagnosis of AMI and may perform favorably in patients presenting early after symptom onset. CLINICAL TRIAL REGISTRATION:URL: https://www.clinicaltrials.gov. Unique identifier: NCT00470587.

Dataset Information

Cardiac troponins: from myocardial infarction to chronic disease.

Publications

Cardiac troponins: from myocardial infarction to chronic disease.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets