Coronary artery disease occurs when plaque clogs the blood vessels that branch off the aorta, depriving the heart of oxygen-rich blood. The leading cause of death and disability worldwide, coronary artery disease affects 17.6 million Americans, killing 450,000 annually. Each year, more than a million patients in the U.S. have stents placed to treat coronary blockages; 200,000 have bypass surgery. These invasive measures can save lives after a heart attack. But experts have long debated whether they’re more effective than medication alone at preventing heart attacks or death in patients whose disease is stable—that is, those who haven’t had recent cardiac events or changes in symptoms.

A clinical trial led by Judith S. Hochman, MD, the Harold Snyder Family Professor of Cardiology and senior associate dean for clinical science, may have finally settled that question. The International Study of Comparative Health Effectiveness with Medical and Invasive Approaches (ISCHEMIA) was funded by an $84 million grant from the National Heart, Lung, and Blood Institute, the largest award in NYU Langone Health’s history. The study randomly assigned 5,179 patients with stable ischemic coronary disease—enrolled at 320 sites in 37 countries—to either a conservative or an invasive treatment strategy. The conservative group initially received only medications and counseling in heart-healthy habits. If conservative therapy failed, patients underwent an exploratory cardiac catheterization procedure, which in some cases resulted in stenting or bypass surgery. The invasive group received similar types of medications and counseling, but underwent stenting or surgery, if feasible, soon after diagnosis. Patients were followed for a median of 3.2 years.

The results, presented last November at the meeting of the American Heart Association, were unequivocal: although the invasive strategy significantly outperformed the conservative approach in controlling chest pain (angina), it offered no advantage in preventing cardiovascular-related death, heart attack, hospitalization for unstable angina or heart failure, or resuscitation after cardiac arrest.

“Individuals with stable coronary heart disease should know that if they have no angina, or if it’s well controlled by medication, there is no added benefit from an invasive strategy,” Dr. Hochman says. “This trial provides important information for patients as they discuss treatment decisions with their doctors.”

It could also lead to changes in medical guidelines. The researchers estimate that 20 percent of stent procedures performed in the U.S. each year are for patients with stable heart disease. Of those, 24 percent—about 23,000—are performed on patients without symptoms. If those procedures were avoided, the team concludes, the cost savings could be at least $570 million annually.