Patients who were excluded from myocardial infarction (MI) in the emergency room but who still have moderate, highly sensitive cardiac troponin levels are three times more likely to develop coronary artery disease (CAD) than those who were excluded with low troponin levels, a new study shows .
The result suggests that highly sensitive cardiac troponin could help select patients who need coronary computed tomography angiography (CCTA) to find occult CAD and guide the use of preventive therapy to prevent future MI, they say Authors.
The study was published on September 27 in the Journal of the American College of Cardiology.
“The introduction of early myocardial infarction exclusion pathways has increased the proportion of patients discharged straight from the emergency room,” first author Kuan Ken Lee, MD, University of Edinburgh Center for Cardiovascular Sciences, Edinburgh, Scotland, told theheart. org | Medscape cardiology.
“Current guidelines are unclear on how to further evaluate patients without myocardial infarction, and there is little evidence of further testing in the highly sensitive cardiac troponin era. Therefore, most clinicians select patients for further testing and follow-up based on whether their symptoms are present sound.” like angina or not, “said Lee.
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 who had ruled out myocardial infarction.
Patients with medium (5 ng / l to the sex-specific 99th percentile threshold) and low (<5 ng / l) highly sensitive cardiac troponin concentrations were invited to an early outpatient CT coronary angiogram.
The mean age of the study participants was 61 ± 12 years, 31% were women.
Overall, 42.4% of the 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 moderate troponin concentrations were more than three times more likely to develop CAD than patients with low troponin concentrations (odds ratio 3.33; 95% confidence interval 1.92-5.78).
In contrast, the proportion of patients with typical or atypical angina who had CHD was the same as those who were thought to have nonanginal chest pain.
Most patients with CHD (53.2% or 83 of 156 patients) had no prior diagnosis and were not receiving antiplatelet drugs or statin therapy before undergoing CCTA.
“We know that patients with moderate cardiac troponin concentrations one year after admission to an index hospital are 10 times more likely to have a cardiovascular event than patients with low cardiac troponin concentrations,” writes senior author Nicholas L. Mills, MD, Professor, British Heart Foundation Chair in Cardiology, BHF Center for Cardiovascular Sciences & Usher Institute, Edinburgh, Scotland, opposite theheart.org | Medscape cardiology.
“Routine use of coronary computed tomographic angiography in patients with moderate troponin concentrations could help us identify patients with undetected coronary artery disease and target preventive therapy more effectively,” said Mills.
These data can influence patient selection for CCTA, but more studies are needed to see if this approach can improve outcomes, he said.
“We are currently investigating whether troponin-directed CTCA will reduce the risk of future myocardial infarction or cardiac death compared to standard treatment in TARGET-CTCA, a large, multicenter, randomized controlled trial funded by the British Heart Foundation.”
Take the troponin levels into account
“Rather than focusing entirely on the ‘cut-off’ threshold for highly sensitive troponin, it may be time to consider an individual patient’s actual troponin levels to determine the need for additional testing with CTA. to determine [computed tomography angiography], “write Kavitha Chinnaiyan, MD, Beaumont Health, Royal Oak, Michigan, and James L. Januzzi Jr, MD, Massachusetts General Hospital, Baim Institute for Clinical Research, Boston, Massachusetts, in an accompanying editorial.
“This study was very interesting,” Chinnaiyan told theheart.org | Medscape cardiology. “Usually you go to the hospital, get a highly sensitive troponin, if it’s less than the cut-off, then you’re sent home; it’s really not a heart attack so we don’t have to worry. But that might not be all Story, “she said.
“As these investigators show, when your troponin is in the higher range of the importance of the real value of the troponin, even within the normal range you have a higher burden of disease, your risk factors tend to be higher, and your risk of suffering an event is likely to be higher.” Looking at troponin instead of looking at it as positive or negative, “she added.
J. Am. Coll. Cardiol. 2021; 78: 1407-1417. Full text, editorial
The study was funded by the British Heart Foundation. Lee reports that he has received honoraria from Abbott Diagnostics. Mills reports that he has received honoraria from Abbott Diagnostics, Siemens Healthineers, Roche Diagnostics, and Lumira DX. Chinnaiyan does not report any relevant financial relationships.
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