Patients who have myocardial infarction (MI) ruled out in the emergency department but still have intermediate high-sensitivity cardiac troponin concentrations are three times more likely to have coronary artery disease (CAD) than patients who are ruled out with low troponin concentrations, a new study shows.

The finding suggests that high-sensitivity cardiac troponin could help select which patients need coronary computed tomography angiography (CCTA) to find occult CAD and guide the use of preventive therapy to prevent future MI, the authors say.

The study was published September 27 in the Journal of the American College of Cardiology.

Dr Kuan Ken Lee

“The introduction of early rule-out pathways for myocardial infarction have increased the proportion of patients directly discharged from the Emergency Department,” first author, Kuan Ken Lee, MD, University of Edinburgh Centre for Cardiovascular Sciences, Edinburgh, Scotland, told theheart.org | Medscape Cardiology.

“Current guidelines are unclear how to further evaluate patients without myocardial infarction and there is little evidence to guide further testing in the high-sensitivity cardiac troponin era. As such, most clinicians select patients for further testing and follow up based on whether their symptoms sound like angina or not,” Lee said.

PRECISE-CTCA (Troponin to Risk Stratify Patients with Acute Chest Pain for Computed Tomography Coronary Angiography) was a prospective cohort study that enrolled 250 patients from the emergency department in whom myocardial infarction was excluded.

Patients with intermediate (5 ng/L to the sex-specific 99th percentile threshold) and low (< 5 ng/L) high-sensitivity cardiac troponin concentrations were invited for an early outpatient CT coronary angiogram.

The mean age of the study participants was 61 ± 12 years, and 31% were women.

Overall, 42.4% of patients had angina symptoms, 12.8% had typical angina, and 29.6% had atypical angina. The remainder were classified as having nonanginal chest pain.

Patients with intermediate troponin concentrations were more than three times more likely to have CAD than those with low troponin concentrations (odds ratio, 3.33; 95% confidence interval, 1.92 – 5.78).