Bypass surgery on a beating heart is an excellent option for many patients with blocked heart arteries

Nov 24 2004

Bypass surgery on a beating heart is an excellent option for many patients with blocked heart arteries, according to a study in Circulation: Journal of the American Heart Association.

“Our data shows that operating on a beating heart is as safe and effective as the traditional method of placing patients on a heart-lung machine during surgery,” said study author Petr Widimsky, M.D., Dr.Sc., a professor of cardiology at the University Hospital Vinohrady in Prague, Czech Republic.

The study, known as PRAGUE-4, does not prove that one method is better than the other – just that the surgeon and his or her patient now have two equally effective options, he said. “The decision of which option to choose should be made on an individual basis and depends on a number of factors, such as age, how sick the patient is, and co-existing illnesses.”

Off-pump bypass surgery is not new; in fact, surgeons have been using the technique for more than eight years, Widimsky said. “But until now, we did not have a long-term study directly comparing the newer off-pump method with classic on-pump surgery, so we did not really know which was best.”

Each year in the United States, 500,000 coronary artery bypass surgery procedures are performed after coronary arteries become clogged with fatty tissue or blood clots, Widimsky said. During the surgery, surgeons make a detour around the blocked part of a coronary artery using a blood vessel from another part of the body, usually an artery from the chest wall or vein from the leg. A key to success of the procedure has been the use of a cardiopulmonary bypass pump oxygenator – or heart-lung machine – that lets surgeons stop the heart but keep blood flowing to the rest of the body. In this setting, the surgeon is operating on a still heart.

In off-pump bypass surgery, surgeons operate on a beating heart rather than shifting the heart’s work to a mechanical pump. Since the heart is moving during the procedure, the operation is technically more demanding for the surgeon, Widimsky said.

But use of the heart-lung machine carries risks as well, he said, including an increased risk of stroke, heart attack, and in rare cases, death.

Many of the complications after bypass surgery occur when the bypass graft reclogs, he said. The goal of the new study, was to investigate how bypass grafts done on the beating heart keep their function after one year, Widimsky said. In the study, 400 patients with clogged bypass grafts were randomly assigned to on-pump or off-pump surgery.

One year later, doctors examined all the patients’ grafts using coronary angiography, an X-ray examination of the blood vessels and bypass grafts of the heart.

The study showed that both methods were equally effective, with chest arteries reclogging in only 9 percent of patients in both groups.

The reclogging of leg bypass grafts did not vary significantly between the groups – 41 percent in the on-pump group versus 51 percent in the off-pump group.

“The higher rates [of leg graft reblockage] most likely reflect the fact that the patients in the study had extensive, advanced disease, as is the case in the current era of prevailing coronary stenting, when only patients with very advanced disease are referred to bypass graft surgery,” he added.

A previous analysis of the PRAGUE-4 study showed that 30 days after the procedure, death, heart attack, stroke, and severe kidney disease rates were also basically equivalent between the two groups: 2.9 percent in the on-pump group versus 3.8 percent in the off-pump group, Widimsky said.

“We believe this study will have two big implications,” he concluded. “First, off-pump bypass surgery is used in about one-quarter of patients nationwide, but that number will increase steadily. Secondly, the problem of venous bypass graft reclogging is currently more frequent than in older studies due to the changed spectrum of cardiac surgery patients – who are older with more extensive coronary artery narrowing and calcification.”

Co-authors are Straka Zbynek, M.D., Ph.D.; Petr Stros, M.D.; Jirasek Karel, M.D.; Dvorak Jaroslav M.D.; Votava Jan, M.D.; Lisa Libor, M.D.; Budesinsky Tomas, M.D.; Kolesar Miroslav, M.D.; Vanek Tomas, M.D., Ph.D.; and Petr Brucek M.D.