Poorer Outcomes After 'Off-Pump' Bypass Surgery
Keeping patients on the heart-lung machine improved survival, study found
WEDNESDAY, Nov. 4, 2009 (HealthDay News) -- Longer-term outcomes for people who had coronary bypass surgery "off-pump," meaning without the use of a heart-lung machine, were worse than for those undergoing the conventional procedure, a major study finds.
One year after surgery, about one in 10 patients getting the off-pump procedure had died, suffered major complications, had heart attacks or required repeat bypasses, compared to 7.4 percent of those who underwent operations using heart-lung machines, researchers report in the Nov. 5 issue of the New England Journal of Medicine.
And the hoped-for advantage of off-pump bypass in other areas, such as less effect on mental function, did not show up, said study co-author Dr. Frederick L. Grover, chair of surgery at the University of Colorado, Denver.
"We thought they would end up doing better neurologically, or that other organs would do better, or they would get out of the hospital faster -- and that did not pan out," Grover said.
Follow-up scans also showed that fewer of the off-pump grafts remained open after a year (82.6 percent vs. 87.8 percent). The percentage of grafted blood vessels that became narrower and less able to supply the heart with blood was also higher in the off-pump group, the researchers reported.
The study included more than 2,200 adults, almost all of them men, who had bypass surgeries at 18 Veterans Administration medical centers across the country. The research was needed because initial enthusiasm for the off-pump procedure has since been "tempered by concern" about the long-term effectiveness of the operation, the report's authors explained.
About 20 percent of bypass operations in the United States are done off-pump, Grover estimated.
There still is a role for off-pump bypass surgery, he said, based on individual surgeon's expertise and patient characteristics, but the study indicates that the procedure's role will be limited.
"Some surgeons around the country do off-pump bypass and they are very accomplished at it," he said. "Most haven't done the long-term follow-up that we have done, but they have pretty good results, and I would doubt they would change their practice. But those who haven't taken it on are less likely to take it on."
Grover said he would continue to do off-pump bypass surgery for some patients -- those who are elderly, who have major disabilities or have suffered previous strokes. "I would do it for Jehovah's Witnesses, who can't take [donated] blood," he said.
Another expert agreed. Off-pump bypass surgery will continue to be done, said Dr. Eric David Peterson, a professor of medicine at Duke University, even though the newly reported study, which he noted is larger than any done before, does not show the expected benefits.
"Surgeons who use it would say the results are about the same, and in their hands it would be an attractive alternative," Peterson said. "But for the physician who has not yet mastered it, this [off-pump surgery] would not be necessary because conventional means are at least as good, if not better."
The verdict in the study for bypass surgery in general was favorable, Peterson said. "Both methods look remarkably good, with very little effect on neurocognitive function," he said.
The study does not disprove the possible benefits of off-pump surgery for older, sicker people, Peterson said. The men who had bypass operations in the study were "a bit younger than average, and their risks are a little lower than what you see in the general bypass population," he noted.
"Those populations thought to be at most risk for complications probably were not enrolled in this study," Peterson said. "Off-pump bypass may have a role there."
The basics of coronary bypass surgery are explained at the U.S. National Library of Medicine.