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Study Backs Bypass Operations Without Pumps

They're as effective as surgeries that use heart-lung machines

TUESDAY, April 20, 2004 (HealthDayNews) -- Since the advent of coronary bypass operations four decades ago, surgeons have temporarily stilled the hearts of their patients during surgery by hooking them up to heart-lung machines.

Now, new research suggests patients do just as well -- and at a lower cost -- when cardiologists let the heart keep beating on its own during the procedure.

According to an Emory University study, patients who had "off-pump" coronary artery operations were just as likely as traditional patients to experience the same results a year after their bypasses. Some experts think the off-pump operations are more tolerable, too.

"This operation is more challenging for the surgeon but easier on the patient," said study co-author Dr. John D. Puskas, an associate professor of surgery at Emory.

The study findings appear in the April 21 issue of the Journal of the American Medical Association. The research was partially funded by Medtronic Inc., a medical device company that employs Puskas as a consultant.

Off-pump coronary operations aren't quite routine in American hospitals yet, however. In 2002, only an estimated 21 percent of bypass operations were done without the use of a heart-and-lung machine.

That number may go up as surgeons learn about the procedure and become more experienced with it, Puskas said. "This study will help to give surgeons the confidence that the operation can yield patients the benefits of the old operation."

Bypass operations have become quite common in the United States. An estimated 500,000 Americans have the procedures each year, and former patients include David Letterman and Vice President Dick Cheney. "It's a very frequently performed operation with great results," Puskas said.

In the operations, surgeons act like police officers sending traffic around an accident. Using grafts, they reroute arteries past blockages so blood can flow easily in and out of the heart.

Typically, surgeons hook patients up to heart-lung machines that oxygenate blood and return it to the body. Both the heart and the lungs are temporarily stilled as the surgeon works. "The heart-lung machine basically serves the surgeon," Puskas said. "It makes the heart lay still. The heart-lung machine provides no benefit to the patient."

Unfortunately, the blood's contact with artificial surfaces can cause the immune system to kick in, causing inflammation throughout the body, Puskas said. In some patients, especially those who are older and sicker, that inflammation can spell trouble.

Operations using a heart-lung pump also require more transfused blood and could impair brain activity after surgery, added Dr. Eric Eichhorn, a cardiologist at the Dallas Heart Group in Texas.

During the past several years, more surgeons have turned to off-pump procedures. The percentage of off-pump bypasses has jumped by seven times since the late 1990s, Puskas said.

Surgeons avoid the need for the heart-lung machines by using mechanical devices to hold part of the heart steady during the operations.

From 2000 to 2001, Puskas and colleagues studied 197 patients 30 days after their bypass operations and followed up with 185 of them a year later.

The grafts of the patients held up at about the same level in both groups, as were the rates of death, stroke, angina and heart attack. "We think that their ability to think will be better, but that's not been proven," Eichhorn added.

The new study also reports that initial hospitalization costs for off-pump patients were $2,272 lower than for pump patients. The average costs for pump and off-pump patients were $21,068 and $18,796, respectively.

Other cardiologists caution the ultimate worth of the off-pump procedure still needs to be confirmed. In an editorial accompanying the study, two Duke University doctors suggest that researchers need to launch a large, extensive study on the subject. Among other things, the doctors said researchers could examine whether the benefits of off-pump operations are actually greater, as suspected, in older patients and those with kidney problems or cardiovascular disease.

Last winter, a study in the New England Journal of Medicine reported patients actually did worse after having off-pump surgeries. A critic, however, pointed out the doctors in the study lacked experience with the procedure.

More information

The American Heart Association and the National Library of Medicine offer more information on bypass operations.

SOURCES: John D. Puskas, M.D., associate professor, surgery, Emory University School of Medicine, Atlanta; Eric Eichhorn, M.D., staff cardiologist, Dallas Heart Group, and medical director, Cardiopulmonary Research Science and Technology Institute, Dallas; April 21, 2004, Journal of the American Medical Association
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