Heart bypass surgery outperforms stents in diabetics

LOS ANGELES – Bypass surgery may be a better option for diabetic patients with clogged arteries than a less invasive procedure to prop open blocked vessels from the inside, an international team reports. The finding could change how doctors treat many diabetic cardiac patients.

Bypass surgery requires taking healthy vessels from another part of the body and patching them onto the heart to restore blood flow around a clogged coronary artery. The surgery requires a longer recovery time than implanting stents, mesh cylinders coated with medication that doctors thread up into the arteries to improve blood flow.

Roughly 700,000 people in the United States undergo a coronary artery fix each year — whether by stenting or bypass surgery — and one in four has diabetes, says cardiologist Valentin Fuster of Mount Sinai Medical Center in New York City. 

To find the best treatment for these patients, Fuster and colleagues randomly assigned 1,900 people with diabetes who had blockages in more than one coronary branch to get either bypass surgery or stents. After five years, 26.6 percent of patients assigned to get stents had suffered a heart attack or a stroke, or had died. Only 18.7 percent of those getting bypass surgery met one of those fates. And although both groups also received the best medical care otherwise available, those getting stents were more than twice as likely to have to return to a hospital to fix repeat blockages, says Fuster, who presented the study results at a meeting of the American Heart Association on November 4. The report also appeared online the same day in the New England Journal of Medicine.

“I think the data are very convincing,” says Timothy Gardner, a heart surgeon at Christiana Hospital in Newark, Del., who wasn’t part of the study team. “Interventional cardiologists have been skeptical that the more invasive coronary artery bypass graft in patients — especially with the other morbidities such as diabetes — was worth it.”

People with diabetes tend to have different kinds of blockages than other heart patients: Plaques that obstruct blood flow are diffusely strung out inside of their coronary arteries. Why diabetes patients form such plaques is unknown, Gardner says.

The diffuse plaques make blockages harder to fix with a single stent, says Elliott Antman, a cardiologist at Harvard Medical School and Brigham and Women’s Hospital in Boston. The blockages exist “along the entire length of the blood vessel. If we concentrate on a point lesion [with a stent], we may not be covering all of the vessel adequately.”

Although patients getting bypass surgery had a somewhat higher risk of stroke, Fuster believes the overall thrust of the findings is clear. “These results are going to make a change in practice,” he says.