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Myocardial ischemia not tied to long-term risk for CV events in certain patients

Myocardial ischemia in patients with stable multivessel coronary artery disease is not tied to major cardiovascular events and is not a predictor of ventricular function changes, according to study results published in JAMA Internal Medicine.

“Previous studies suggested that the presence of myocardial ischemia during stress testing and ambulatory electrocardiographic monitoring indicated an increased risk of cardiac events,” Cibele Larrosa Garzillo, MD, PhD, of Instituto do Coração (InCor), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Brazil, and colleagues wrote.

To determine the long-term implications of myocardial ischemia detected during stress testing in patients with multivessel coronary artery disease, researchers conducted a prospective cohort study with data from a single-center randomized clinical trial, the Medicine, Angioplasty, or Surgery Study (MASS II).

Participants in the study had stable coronary artery disease and were randomly assigned to receive optimal medical therapy, percutaneous coronary intervention with bare metal stents, or coronary artery bypass grafting between May 1, 1995, and May 1, 2000.

Cardiovascular outcomes were tracked from randomization for a minimum of 10 years and up to 15 years. Exercise stress testing was performed at baseline and at 1-year intervals to assess the presence of myocardial ischemia, and echocardiography was performed at baseline and at the end of the 10-year follow-up period to assess ventricular function.

A total of 611 patients were enrolled in the study, 535 of whom underwent exercise stress testing at the baseline. During testing, 270 (50.5%) participants were identified with stress-induced ischemia and 265 (49.5%) were not. The mean age of those who underwent testing was 59.7 years.

Researchers determined that there was no association between ischemia during the baseline and cardiovascular events during follow-up (hazard ratio = 1; 95% CI, 0.8-1.27) after adjusting for baseline characteristics, including randomized treatment.

Patients who underwent echocardiograph evaluation (n = 320) experienced slight declines in left ventricular ejection fraction at the end of the follow-up period. The declines were similar in those who had documented ischemia (median = 4.9% [18.7%]) and in those who did not (median = 6.6% [20%]; P = .97).

“Although the presence of documented ischemia has been identified as a possible marker of a higher-risk population and an indication for myocardial revascularization procedures to protect the myocardium from the chronic, deleterious effects of ischemia over time, the present study’s findings do not support this assumption,” Garzillo and colleagues wrote. “The delicate imbalance between oxygen supply and demand at stress is a consequence and does not seem to be a factor for impairment of ventricular function or coronary events during a long-term follow-up.”– by Erin Michael

Disclosures: The authors report no relevant financial disclosures