Off-Pump Bypass Surgery Not for Everyone
Study finds fewer grafts remain open under procedure
WEDNESDAY, Dec. 31, 2003 (HealthDayNews) -- Off-pump cardiac surgery has become increasingly popular over the last decade and has compared favorably with traditional on-pump surgery, but new research finds fewer grafts remain open in patients who have the off-pump procedure.
"Our study is the only one that has shown a major difference between patients who undergo off-pump procedures compared with those who undergo on-pump procedures," says co-researcher Dr. Anthony De Souza, a consultant cardiac surgeon at the Royal Brompton Hospital in London.
The "pump" is a heart-lung bypass machine. Until recently, all coronary bypass operations -- about 500,000 will be done in the United States this year -- were done by stopping the heart and having the machine support the body's circulation.
But many patients having such surgery have complained about mental confusion, memory loss and other neurological problems afterwards. Some have suffered strokes. So in recent years, more and more of these operations have been done while the heart is still beating.
While the quality of the cardiac bypass grafts is equal between on- and off-pump procedures, the off-pump operation is more complicated and requires more training, De Souza adds. It is more difficult to operate on a beating heart than one that is still, he notes.
Off-pump surgery lets patients receive coronary bypass grafts without using the heart-lung machine. This is a minimally invasive technique that lets surgeons operate on multiple heart vessels while the heart continues to beat.
During the operation, a surgeon cuts a small vertical incision in the chest. A mechanical stabilizing device is inserted to restrict movement of the heart so the doctor can operate on the heart while it is beating. As the operation progresses, the heart maintains its own rhythm without the assistance of the machine.
In their study, De Souza's team randomly assigned 50 patients to on-pump coronary artery bypass grafting and 54 to off-pump surgery. Three months later, the researchers evaluated the patients with coronary angiography.
Patients in the on-pump group received a mean of three grafts, as did the patients in the off-pump group. There were no deaths, according to the report in the Jan. 1 issue of the New England Journal of Medicine.
Although both groups fared well at the three-month checkup, one significant difference was found, De Souza says. Among patients in the on-pump group, 98 percent of the grafts remained open compared with 88 percent of the grafts in the off-pump group.
"Off-pump surgery may not be the nirvana everyone professes it to be," De Souza says. "It is a good technique, but it may not completely replace on-pump surgery."
"Every surgeon does the operation differently, both operations are safe, but there are benefits and disadvantages to off-pump surgery. Patients should not demand off-pump surgery. The surgeon needs to make the decision on the basis of what is best for the individual patient," he notes.
Dr. Gus J. Vlahakes, from the Division of Cardiac Surgery at Massachusetts General Hospital and author of an accompanying perspective article, says he reserves off-pump surgery for high-risk patients.
However, he finds the difference between the techniques surprising. "This study has raised the question that graft patency might not be as good in patients done off-pump," Vlahakes says.
"The ability to do surgery off-pump is another tool in the box." For those who do only off-pump procedures, they need to ask themselves if they are getting the same results they would get with on-pump surgery, he says.
Another expert takes issue with one aspect of the study.
"This paper does not really make any sense, because it is done by surgeons who are not experienced at doing off-pump surgery," says Dr. Nirav Patel, a cardiac surgeon at Lenox Hill Hospital in New York City, where 98 percent of the operations are done off-pump.
Patel notes that De Souza's group had only two years experience and only 98 patients who had off-pump surgery before the start of their study.
"Two years and small numbers of selected patients is not enough experience to complete the learning curve," he says. "Before we started doing most of our operations off-pump, we had done more than 800 procedures on selected patients before we went on to operate on unselected patients."
Patel says he has not seen these problems. Today, he is seeing more high-risk patients undergo off-pump surgery because lower-risk patients are being treated with angioplasty and stents, he adds.