Study Shows Bypass Safer than Stents for Diabetics

As doctors worldwide voice concerns about the overuse of stenting, a new study concludes that diabetics with heart disease live longer if treated with coronary bypass surgery rather than stents.

An analysis conducted by researchers at St. Michael’s Hospital in Toronto, Canada, and published in Lancet Diabetes and Endocrinology found that mortality rates are 30 percent lower for diabetics treated with bypass than for those treated with stents. The research team pooled clinical data from more than 30 years of trials and examined results from 3,612 diabetics with heart disease to reach its conclusion.

The discovery is significant and could have wide-ranging public health implications due to the sizable difference in outcomes. Heart disease is the top killer of diabetics; those with the disease represent roughly 25 percent of all patients who undergo coronary artery procedures, according to the hospital. “Although bypass surgery is more invasive than stenting, it is imperative that physicians and patients realize that long-term mortality reduction is best achieved with bypass surgery,” said Subodh Verma, M.D., a cardiac surgeon and principal author of the Lancet analysis. “Physicians must disclose this benefit to the patient to truly obtain informed consent.”

Verma and St. Michael’s intensivist Jan Friedrich, M.D., were inspired to compare the two cardiovascular treatments by the intense debate currently raging in the scientific and medical communities. Over the summer, the American Medical Association placed stenting on its list of the five most overused medical interventions, claiming that roughly 10 percent of elective angioplasty-stent procedures (also known as percutaneous coronary intervention) performed nationwide are performed with almost no chance of benefiting patients.

Researchers could not explain the improved life expectancy of diabetics treated with coronary bypass surgery (CABG), though Verma suspects it may be tied to the extensive and diffuse blockages that are best treated through bypass. They did, however, learn that CABG procedures carry an increased risk of non-fatal strokes in diabetics, a “side effect” that could be could be caused by the heart’s stoppage during the procedure.

Verma noted the decision between CABG and stenting rests with cardiologists, who generally performing stenting (bypass surgeries are performed by cardiac sugeons). “Despite guidelines from the American Heart Association and the American College of Cardiology advocating for bypasses over stents, until joint decision-making between a cardiologist and cardiac surgeon is facilitated, these findings will be difficult to translate into clinical practice.”

The European Society of Cardiology supports the concept of a Heart Team, wherein a surgeon, interventionalist, cardiologist and other specialties work together to decide on a course of treatment.

The study was funded by the Canadian Institutes of Health Research, the Heart and Stroke Foundation of Canada, and the Canada Research Chairs program.