Chest pain patients ruled out for MI with intermediate troponin levels at risk of CAD: JACC
intermediate hs-cTnI concentrations compared with low hs-cTnI concentrations.
UK: Patients with chest pain who were ruled out for myocardial infarction but had troponin levels into the intermediate range compared with low troponin levels were more likely to have coronary artery disease (CAD), shows a recent study. Also, the burden of atherosclerosis was higher in such patients. The study findings are published in the Journal of the American College of Cardiology.
"CAD was 3 times more likely in those with intermediate high-sensitivity cardiac troponin (hs-cTnI) concentrations compared with low hs-cTnI concentrations. CTTA could help identify those with occult CAD and to target preventive treatments thereby improves clinical outcomes," wrote the authors.
Coronary artery disease is the most common cause of death worldwide. Most of the time, CAD remains undiagnosed until they present to the hospital with acute chest pain. Current strategies focus on ruling in or ruling out heart attack through electrocardiography, bedside clinical assessment, and serial cardiac troponin testing. However, even after ruling out myocardial infarction, a significant proportion of patients may still have CAD and may be at risk for future adverse cardiac events. The optimal approach to select such patients for a further investigation remains uncertain.
In search of an optimal approach, Kuan Ken Lee, BHF Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, United Kingdom, and colleagues aimed to evaluate the usefulness of high-sensitivity cardiac troponin I to select patients for further investigation after myocardial infarction has been excluded in a prospective cohort study.
The study included patients presenting to the emergency department with the suspected acute coronary syndrome and hs-cTnI concentrations below the sex-specific 99th percentile. They were recruited in a 2:1 fashion, stratified by peak hs-cTnI concentration above and below the risk stratification threshold of 5 ng/L. After hospital discharge, coronary computed tomography angiography (CCTA) was performed in all the patients.
Overall, 250 patients were recruited (61.4 ± 12.2 years 31% women) in whom 62.4% (156 of 250 patients) had coronary artery disease (CAD).
Key findings include:
- Patients with intermediate hs-cTnI concentrations (between 5 ng/L and the sex-specific 99th percentile) were more likely to have CAD than those with hs-cTnI concentrations <5 ng/L (71.9% [120 of 167 patients] vs 43.4% [36 of 83 patients]; odds ratio: 3.33).
- Conversely, there was no association between anginal symptoms and CAD (63.2% [67 of 106 patients] vs 61.8% [89 of 144 patients]; odds ratio: 0.92).
- Most patients with CAD did not have a previous diagnosis (53.2%; 83 of 156 patients) and were not on antiplatelet and statin therapies (63.5%; 99 of 156 patients) before they underwent CCTA.
"In patients who had myocardial infarction excluded, CAD was 3× more likely in those with intermediate hs-cTnI concentrations compared with low hs-cTnI concentrations," wrote the authors. "In such patients, CCTA could help to identify those with occult CAD and to target preventative treatments, thereby improving clinical outcomes."
This approach to using cardiac troponin to select patients for downstream investigation after myocardial infarction has been ruled out has major potential to improve patient outcomes, they concluded.
The study titled, "Troponin-Guided Coronary Computed Tomographic Angiography After Exclusion of Myocardial Infarction," is published in the Journal of the American College of Cardiology.