Cardiac troponin (cTn) elevation is an important major adverse event (MAE) risk predictor in patients admitted to the hospital with suspected acute coronary syndrome (ACS) despite lack of a specific diagnosis, according to a study recently published in the Journal of the American College of Cardiology.

A large retrospective cohort study was undertaken utilizing data from the TOTAL-AMI (Tailoring Of Treatment in All comers with Acute Myocardial Infarction) project. Investigators collected data on first-time patients who had been admitted to Swedish coronary care units or other specialized facilities due to suspected ACS between January 2005 and August 2013 (N=48,872).

Patients were discharged without a specified diagnosis according to the diagnostic classification used within the SWEDEHEART (Swedish Web-system for Enhancement and Development of Evidence-based care in Heart disease Evaluated According to Recommended Therapies) registry framework.


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Data included >100 variables, including clinical findings such as risk factors, electrocardiogram findings, medications, medical histories, echocardiography and angiography findings, and the highest level of biomarkers of myocardial damage recorded during the hospitalization.

Investigators grouped patients into 4 strata. One included those with cTn levels less than or equal to the assay-specific (30 ng/L) cTn 99th percentile (n=39,072). The remaining patients were separated by tertiles: tertile 1 (n=5137), tertile 2 (n=2490), and tertile 3 (n=2173) were calculated separately for each assay.

MAEs were experienced by 7529 patients (15.4%) during a median follow-up of 4.9 years. MAE incidence rates and assessed single outcomes increased in a stepwise fashion in patients with higher cTn levels.

Hazard ratios for MAE across increasing assay-specific cTn tertiles were 1.25 (95% CI, 1.18-1.34) in tertile 1, 1.53 (95% CI, 1.40-1.67) in tertile 2, and 2.59 (95% CI, 2.39-2.80) in tertile 3, compared with patients with cTn ≤99th percentile.

Risks for cardiovascular mortality, myocardial infarction, and readmission for heart failure were the primary drivers for MAE in the total cohort.

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Analysis showed that older, male patients as well as patients with diabetes, renal dysfunction, lower body mass index, with previous manifestations of cardiovascular disease, chronic obstructive pulmonary disease, or malignancies were at higher risk of experiencing an MAE.

This study was limited by inconsistent quantification of cTn levels below the 99th percentile by some hospitals participating in the SWEDEHEART registry. Erroneous registrations of cTn results of misdiagnoses may have contributed to the relatively high proportion of patients who underwent coronary intervention during their hospitalization, despite an unspecified diagnosis.

The authors advise that “the term troponinemia, sometimes used to label this scenario, is trivializing and should be avoided. Instead, careful work-up is required in these patients.”

Disclosures: Multiple authors declare affiliations with the pharmaceutical industry. Please refer to original reference for a complete list of disclosures.

Reference

Eggers KM, Jernberg T, Lindahl B. Cardiac troponin elevation in patients without a specific diagnosisJ Am Coll Cardiol. 2019; 73(1):1-9. doi:10.1016/j.jacc.2018.09.082