A large, federally funded study found bypass surgeries and stents are not more effective than cholesterol-lowering drugs or healthy habits at preventing heart attacks and deaths, researchers announced Saturday at the American Heart Association (AHA) annual meeting—findings that call into question the care of thousands of patients with blocked coronary arteries, the New York Times reports.

Coronary artery disease affects about 9.4 million Americans, according to the Wall Street Journal. For years, providers and researchers have debated how to treat patients with narrowed coronary arteries who are not experiencing acute symptoms. Currently, bypass surgeries, which redirect blood around a blockage, and stents, which are small mesh cages used to prop open blocked arteries, are both standard treatments for coronary artery disease. They are common even among patients who have no symptoms or who only feel chest pain when they exert themselves, according to the Journal.

Study details

For the latest study, which the Journal reports is the most rigorous to date, researchers conducted a clinical trial over a four-year period involving 5,179 participants from 37 countries with moderate or severe ischemia, a condition in which there is not enough blood flow to the heart muscle.

Judith Hochman, the study's chair and the senior associate dean for clinical sciences at the New York University Grossman School of Medicine, said the researchers excluded patients from the study if they either did not have narrowing in their arteries or had a blockage in their main artery, which supplies blood to a large portion of the heart. The researchers did not focus on patients admitted to the hospital with a heart attack, as these patients typically receive a bypass, angioplasty, or stenting to quickly open a blocked artery, according to HealthDay.

Researchers randomly assigned participants to undergo a procedural intervention—either bypass surgery or a stent procedure—in combination with intensive medical therapy, or the medical therapy alone. The medical therapy included drugs to lower cholesterol and blood pressure, as well as lifestyle therapy including dietary changes, and smoking cessation.  

Following treatment, the researchers monitored whether the patients experienced a:

• Cardiovascular-related death;
• Heart attack;
• Heart failure;
• Hospitalization for unstable chest pain; or
• Resuscitation after cardiac arrest.

The researchers are seeking funding to follow the participants for a longer period of time.

Findings

The researchers found no difference in the overall rate of the five disease-related events between the groups. Hochman said the invasive procedures "did not demonstrate a reduced risk over a median 3.3 years" when compared with medical and lifestyle therapy.

However, the researchers noted the groups began to show differences at various points in time. For instance, Hochman said the researchers found the group who underwent bypass surgeries and stents experienced heart attacks or other events at a higher rate six months into their treatment—5.3% vs. 3.4% for the medical therapy group—which suggests participants might have experienced complications from the procedures, according to Hochman.

However, the researchers found the group of participants who underwent invasive procedures fared better after four years. Participants who had bypass surgeries and stent procedures experienced heart attacks and other events at a rate of 13.3% after four years, while participants who received intensive medical and lifestyle therapy experienced heart attacks and other events at a rate of 15.5%. Hochman said these differences will receive further study.

The researchers also found 50% of patients who underwent invasive treatment for frequent chest pain no longer had symptoms a year after their treatment, while 20% of patients who received intensive medical and lifestyle therapy did not experience symptoms. Therefore, researchers said bypass surgery and stents are likely better than medical treatments at relieving the symptoms of patients with frequent angina, or chest pain, but they do not change their odds of death or other events.

Discussion

Hochman said the findings should encourage patients to have more discussions about their treatment options with providers. She said, "Statins and aspirin are critically important. We need to understand better how to get people to modify their risk factors." She noted lifestyle changes are difficult to make and sustain.

Some cardiologists have said the findings will likely change medical practice.

Alice Jacobs, director of the Cardiac Catheterization Laboratory and Interventional Cardiology at Boston Medical Center, said, "Based on the trial results to date, I as a clinician would feel comfortable advising my patient not to undergo the invasive strategy if their angina was absent or controlled or it was tolerated."

Glenn Levine, director of cardiac care at Baylor College of Medicine and a member of the AHA's guidelines committee, said the study's results will be incorporated into treatment guidelines.

William Boden, scientific director of the clinical trials network at VA Boston Healthcare System, who was a member of the study's leadership committee, said, "We have to finally get past the whining about how hard optimal medical therapy is and begin in earnest to educate our patients as to what works and is effective and what isn't" (McKay, Wall Street Journal, 11/16; Thompson, HealthDay/U.S. News & World Report, 11/18; Kolata, New York Times, 11/16; Marchione, AP/PBS News Hour, 11/17).