CHICAGO — Any detectable plasma cardiac troponin T level in ambulatory patients with stable coronary artery disease is an independent predictor of future cardiovascular events.
“[Troponin T] testing may have potential as a risk-stratifying tool in the management of stable CAD,” said Dr. Bill Pei-Chin Hsieh at the annual meeting of the American College of Cardiology. “A positive troponin T [TnT] could be a reason to pursue a more aggressive management strategy.”
An elevated cardiac TnT, defined as any measurable level using the commercially available third-generation Roche immunoassay, is not uncommon in stable CAD. Levels of 0.01–0.72 mcg/mL were identified in 6% of 988 patients in the Heart and Soul Study, a National Institutes of Health-sponsored study whose primary aim was to examine psychosocial factors in CAD. Subjects had to have a history of MI or coronary revascularization, angiographic evidence of greater than 50% stenosis in at least one coronary artery, or demonstration of exercise-induced ischemia. Prevalence of the latter, diastolic dysfunction, regional wall motion abnormalities, elevated C-reactive protein, and other high-risk CAD features was significantly greater in those with detectable TnT, suggesting multiple potential mechanisms for the raised rate of cardiovascular events in TnT-positive patients, Dr. Hsieh of the University of California, San Francisco, said in an interview.
During a mean follow-up of 4.3 years, the combined cardiovascular end point of coronary heart disease death, nonfatal MI, severe arrhythmia, heart failure, and coronary revascularization occurred in nearly 60% of the TnT-positive group, 3.6-fold greater than in those without detectable TnT. After adjusting for creatinine clearance, baseline exercise-induced myocardial ischemia, and other potential confounders, a positive TnT assay was still associated with a twofold increased risk of the combined end point.
The next step is a confirmatory study in a different cohort with the highly sensitive Roche TnT assay expected to become commercially available soon, Dr. Hsieh said.