The heart is a hard worker, pumping all day and night. The coronary arteries keep it supplied with the oxygen it needs to maintain its activity. In coronary artery disease, those vital blood vessels become clogged; in severe cases, this blockage can cause a heart attack. There are two major physical ways to restore blood flow. One is grafting another piece of blood vessel onto the artery as a bypass around the clogged spot. The other is threading a tiny catheter up through the circulatory system to the problem spot to deal with it directly. In recent years, doctors have also been able to leave a tiny device called a stent at the problem spot to hold it open. A study in this week's New England Journal of Medicine compared bypass surgery with stents.

What the researchers wanted to know: Do bypasses or stents work better in the long run for people with coronary artery disease?

What they did: New York state has registries of heart surgery and the group of interventions that include stenting, known as percutaneous coronary interventions. For this study, the researchers looked at people in those databases who had serious narrowing of two or three of the three main arteries that feed the heart. Between 1997 and 2000, 37,212 patients had bypass surgery and 22,102 patients had stents inserted. The researchers were interested in whether patients died or had to go back for revascularization—an additional attempt to restore blood supply—by the end of 2000.

What they found: Patients who had bypass surgery were sicker than those who just had stents inserted, so the researchers adjusted their results to account for the severity of the patient's illness. They found that people who had bypasses done were more likely to survive than those who had stents. People who had coronary artery bypass surgery were also significantly less likely to have to undergo revascularization than people who had stents put in, regardless of how sick they were.

What the study means to you: Previous studies on bypass surgery and stents were small, and they found conflicting results. This study suggests a long-term benefit for coronary artery bypass surgery. That doesn't mean bypass surgery is for everyone; having a stent put in is a much less invasive procedure, and the researchers say patients might prefer to try that first in hopes of avoiding bypass surgery.

Caveats: The technology for bypass surgery and stents is constantly involving; for example, doctors now have the option of using stents that contain drugs meant to prevent the artery from closing up again. These might work better than the stents that were in use in the time period covered by this study, the late 1990s and 2000.

Find out more: Information about coronary artery disease from the National Heart, Lung, and Blood Institute

An explanation of coronary artery bypass surgery from the American Heart Association

Read the article: Hannan, E.L., et al. "Long-Term Outcomes of Coronary-Artery Bypass Grafting Versus Stent Implantation." New England Journal of Medicine. May 26, 2005, Vol. 352, No. 21, pp. 2174-2183.

Abstract online: http://content.nejm.org