For severe heart disease, bypass surgery slightly better than stenting — with caveats, study finds

Patients with severe coronary artery disease generally fared better with bypass surgery than with stents to open blocked arteries, according to a major new multinational study led by Stanford Medicine investigators.

However, some patients benefited more from stents, particularly if their disease wasn’t complex, the researchers found.

“The good news for patients is that both groups did better than what was found in previous studies, and the differences between the two strategies has lessened,” said William Fearon, MD, professor of cardiovascular medicine and principal investigator of the trial. He said the trial, the largest of its kind, will serve as a guide for determining which approach is best for individual patients.

“I think it will have an immediate impact on how patients and physicians choose treatment,” said Fearon, who is also the director of interventional cardiology at Stanford.

A paper describing the study, called the FAME 3 trial, was published online Nov. 4 in The New England Journal of Medicine. Fearon shares lead authorship on the paper with Frederick Zimmermann, MD, of Catharina Hospital in the Netherlands. Nico Pijls, MD, PhD, of Catharina Hospital, was the paper’s senior author.

Most previous studies of the two heart procedures have shown that bypass surgery produces better results than stents, tiny mesh tubes used to prop open an artery, Fearon noted. But these studies didn’t take into consideration a number of recent advances in stent technology, he said. The goal of the latest trial, which involved 1,500 patients in 24 countries, was to determine if these advances have shifted the balance and prove stents to be as good, or better, than bypass.

Testing a diagnostic tool

As many as 40% of Americans older than 60 experience some narrowing of their coronary arteries caused by the buildup up of plaque in the walls of the blood vessels, according to the American Heart Association. Most cases aren’t serious enough to limit oxygen supply to the heart and can be treated with statins or aspirin. But significant blockages can cause chest pain and increase the risk of heart attack or death.

For years, clinicians relied exclusively on angiograms — an X-ray of the coronary arteries — to determine whether the vessels were sufficiently narrowed to warrant intervention. But angiograms can be misleading, showing a tight space within a vessel when none exists, Fearon said.

A better diagnostic tool, known as fractional flow reserve, or FFR, can measure whether blood flow has been reduced to a dangerous level. Doctors thread a wire with a small sensor on the tip into the artery to measure the pressure of the flow. In a significantly narrowed vessel, the blood pressure will drop in that segment of the vessel beyond the narrowing, signaling the need for intervention.

In the FAME 1 study, whose results were published in 2009, Fearon and his colleague found that use of FFR led to fewer stent placements and fewer complications when compared with stenting based on angiogram images alone. Among patients with FFR-guided stents, the rates of death, heart attack and the need for repeat procedures were significantly less, they found.

The good news for patients is that both groups did better.

Today, clinicians also are using second-generation stents with thinner struts that are less likely to lead to blood clots or re-narrowing, common complications of earlier-generation stents, Fearon said. In addition, today’s stents are coated with a bio-friendly polymer that doesn’t cause inflammation, as previous ones did, he said. The stents are designed to slowly release a drug that helps prevent re-narrowing of the artery.

In the latest study, the researchers compared these new stents, guided by FFR, with bypass surgery in patients who had three blocked coronary vessels. The patients, whose average age was 65, were randomly assigned to two groups, with 757 receiving the stents and 743 undergoing surgery. In the bypass procedure, doctors take a healthy blood vessel from the patient’s leg, arm or chest and stitch it above and below the blocked artery to create a clear channel.

Among the stent group, the incidence of a major complication — death, heart attack, stroke or the need for a repeat procedure — was 10.6% after a year. Among bypass patients, the rate was 6.9%. However, when the need for a repeat procedure was excluded from the equation, the figures were more aligned: 7.3% for stents versus 5.2% for bypass. The difference is not statistically significant, Fearon said.

Considering complexity of heart disease

The researchers looked at results based on the patients’ underlying coronary disease. They found that patients with less complex coronary artery disease did better with stents, as physicians could limit the number of the mesh tubes they had to place. (Complex coronary artery disease includes conditions such as plaque buildup that is calcified, causes complete blockage of a blood vessel, occurs at branching points or is very extensive.)

“I think the study results will guide both physicians and patients on the best strategy for their circumstances,” Fearon said. “If patients have very complex disease that would require numerous stents, then bypass might be a better option. If they have less complex disease, they can feel reassured that by receiving the latest generation of drug-eluting stents guided by FFR, their outcomes would be just as good as they would be with surgery.”

He said stents also have an advantage in that they entail shorter hospital stays and faster recoveries. Patients who receive stents generally go home the same day and recover quickly. Bypass patients, on the other hand, may remain in the hospital for as many as five days or longer, with a recovery time of six to eight weeks. In the study, bypass patients also had a higher incidence of major bleeding, arrythmia, acute kidney injury and rehospitalization within 30 days.

Overall, Fearon said the study shows just how much care for these patients has improved over the years. In a major 2009 trial, known as the SYNTAX study, the rate of complications among patients was significantly higher: 17.8% among stent patients, and 12.4% among bypass patients. Fearon said he believes improved surgical techniques and more consistent use of drug therapy are among the factors that have led to better results. Some 90% of patients in the current study took a heart drug — typically a statin or beta-blocker — to help prevent heart attacks and stroke.

The FAME 3 trial was initiated by Fearon and two of the other investigators and was sponsored by Stanford Medicine. Medtronic Inc. and Abbott Vascular Inc. provided research grants for the study but were not involved in its design or implementation.

Other Stanford co-authors of the study are Mark Hlatky, MD, professor of health policy and medicine; Kenneth Mahaffey, MD, professor of medicine; Manisha Desai, PhD, professor of medicine and of biomedical data science; Joseph Woo, MD, professor and chair of cardiothoracic surgery and the Norman E. Shumway Professor; and Alan C. Yeung, MD, professor of medicine and the Li Ka Shing Professor in Cardiology.

Researchers from 47 other institutions in the United States and abroad also contributed to the work.