A follow-up of surgical and medical treatment for congestive heart failure and coronary artery disease (STICH) showed that there’s no association between myocardial viability and the long-term mortality benefit of coronary artery bypass grafting (CABG) in patients with ischemic cardiomyopathy.

The study, published yesterday in the New England Journal of Medicine, followed 601 patients with coronary artery disease amenable to CABG who had a left ventricular ejection fraction of 35% or lower.

Patients were randomly assigned to undergo CABG or medical therapy. Researchers reported that the CABG treatment had no mortality benefit in the 318 surviving patients observed after 10.4 years. The findings mirror the conclusions made at the five-year mark of the study.

CABG plus medical therapy had the lowest incidence of death in the study. Among 298 patients in the CABG group, there were 182 deaths, compared to 209 deaths among 303 patients in the medical therapy group. There was no significant interaction between the presence or absence of myocardial viability and the beneficial effect of CABG plus medical therapy over medical therapy alone. Patients with viable myocardium had a mortality risk of 64%, which was not significantly lower than patients without (68%).

The study found improvement in left ventricular systolic function, regardless of which treatment the patient underwent, but it was not related to long-term survival.

“This is a very high-risk population of patients and bypass surgery is a high-risk proposition, so ideally, if you had a test to identify what patients would benefit from the surgery, that would be great,” lead author Julio Panza, MD, chief of cardiology at Westchester Medical Center in Valhalla, New York, told Medscape. “For years, based on results of retro studies, we have believed tests of [myocardial] viability can be a differentiator of patients who do vs. those who don’t benefit from that surgery, but our results do not prove that hypothesis.”