Posted by Henry Alken on January 04, 2004 at 13:27:07:
January 2, 2004 7:17 a.m. EST
Study Rethinks 'Off-Pump' SurgeryBypasses Done While Heart
Beats Lead to More Blockage
Than Does Old Procedure
An increasingly popular type of bypass surgery on a beating heart leads to more blockage in grafted arteries than does the conventional technique of keeping patients on a heart-lung pump, according to a study in the New England Journal of Medicine.The British study is one of the first to cast doubt on what is commonly called off-pump surgery. During these procedures, a device stabilizes the small area on the surface of the heart where surgeons are stitching while the rest of the organ continues to function normally.
The report contradicts earlier findings that the new technique is as effective as the traditional method, in which the heart is stopped and a heart-lung machine keeps the patient alive during the operation.
Conducted at Royal Brompton and Harefield National Health Service Trust in London, the study of 104 patients found that 98% of those placed on heart-lung pumps still had blood flowing through their grafted arteries three months later, compared with only 88% of patients undergoing the off-pump surgery. In both surgeries, doctors attach blood vessels taken from other parts of the body to the heart to replace coronary arteries obstructed by disease.
"There is a huge pressure on cardiac surgeons to try this new technique, when the conventional method is extremely effective and has extremely good results," said Natasha E. Kahn, lead author of the study. The findings, she said, "will allow surgeons to continue using a technique they trust." She said the higher failure rate for the off-pump technique was unexpected, and that the explanation remains unclear.
By some estimates, nearly one-fourth of the 400,000 coronary-artery bypass procedures in the U.S. each year are performed off-pump. The off-pump method has become popular in the past five years because it tends to be easier on patients than the conventional technique, requiring fewer transfusions and shorter recovery times. Also, although less than 3% of patients die during traditional bypass surgery, risks of brain damage and kidney failure are associated with exposure to the heart-lung machine.
Timothy Gardner, a professor of heart surgery at the University of Pennsylvania, said the study suggests "a little bit of caution" is warranted toward the off-pump procedure. He said off-pump operations may be less successful because they are more technically difficult for surgeons than the standard approach. "The heart may be moving a little bit; there may be blood in the field," he said. As surgeons master the technique, he said, the frequency of occluded arteries may drop.
Dr. Kahn, who ran the trial and didn't perform any of the surgeries herself, said the two surgeons who conducted the operations each had about three years' experience with the off-pump technique. According to the article, the surgeons performed 13% of their bypass operations off-pump in the prior two years.
Dr. Kahn acknowledged that the procedure "may need a longer learning curve. That's one of the big issues."
Jodi Harpstead, general manager of cardiac surgery technology business for Medtronic Inc., Minneapolis, which makes the off-pump device used in the British study, attributed the higher failure rate to what she called the surgeons' relative lack of experience with that technique, and criticized the journal for publishing the study. "I know of beating-heart surgeons who have submitted to New England Journal with more experience and longer follow-up, whose papers were not accepted," she said.
Ms. Harpstead predicted the study won't hurt sales and that, in five years, half of all coronary-artery bypasses in the U.S. will be done off-pump. Revenue for Medtronic's cardiac business was $557 million in the fiscal year ended April 25, 2003.