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"Off-pump" Bypass Surgery Associated with Reduced Occurrence of Stroke and Other Complications

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Press Release Date: October 25, 2006

Performing a common heart surgery without bypassing the cardiopulmonary system may cut down on the number of surgery-related strokes and other short-term complications, according to a new report by the U.S. Department of Health & Human Services' (HHS) Agency for Healthcare Research and Quality (AHRQ).

Traditionally, coronary artery bypass graft (CABG) surgery has depended heavily on cardiopulmonary bypass (CPB), particularly as its harmful effects have been reduced. However, many cardiac surgeons have in the past few years become interested in avoiding CPB altogether, a procedure known as "off-pump" CABG surgery. The findings of this study, released in the November issue of the journal Stroke, indicate that off-pump CABG is associated with lower incidence of stroke, atrial fibrillation, and health care-associated infection.

The report, authored by a team of researchers led by Artyom Sedrakyan, M.D., Ph.D., a cardiothoracic surgeon and health services researcher at AHRQ, is the first to document significant benefits of off-pump CABG in randomized trials. Specifically, they found that the off-pump procedure could prevent approximately 10 strokes per 1,000 CABGs, a 50-percent reduction in the risk faced by patients undergoing the surgery. Approximately 280,000 CABGs are performed in the United States each year.

"These findings represent a significant piece of new information regarding a common surgery," said AHRQ Director Carolyn M. Clancy, M.D. "Evidence emerging from this report will give physicians and, ultimately, patients a great deal more information upon which they can base decisions about care."

CABG, which was pioneered in 1967, is the nation's most common cardiac surgery. CABG surgery creates new paths around blocked arteries to improve blood flow to the heart. CPB stops the heart to allow surgeons to create the new pathways. The surgery was originally conceived as requiring CPB; however, CPB carries risks of adverse effects on heart, brain, lungs, kidney and other organs, and some surgeons believed that CPB is not required for a surgery aiming to restore blood supply to the heart—leading them to consider off-pump CABG as a less-invasive alternative that has a potential to be less costly.

The report, which analyzed data from 41 randomized clinical trials that included 3,996 patients whose procedures took place after 1999, is the first systematic analysis based on randomized clinical trials to report substantial stroke reduction associated with off-pump CABG. In addition, the researchers noted that off-pump CABG was associated with:

  • 30-percent reduction in atrial fibrillation (abnormal heart rhythm), translating to avoidance of 80 cases of atrial fibrillation per 1,000 off-pump CABGs.
  • 48-percent reduction in wound infection, translating to avoidance of 40 infections per 1,000 off-pump CABGs.

The study also found that off-pump surgery often involves fewer grafts to bypass coronary lesions as compared with traditional surgery. Fewer grafts could lead to re-interventions, such as repeat angioplasties or surgeries, and have unknown long-term effects. However, researchers found evidence that the difference between off-pump and traditional surgery in the number of bypass grafts used seemed to be small in studies in which more surgeries were performed. This indicates a relationship between the volume of procedures and their outcome. In other words, off-pump surgeries are more successfully performed at facilities that perform many of them.

Dr. Sedrakyan cautioned that this report provides limited evidence of off-pump CABG's benefits, and that traditional CABG may still be warranted in many cases. "Off-pump CABG carries its own risks, and requires substantial training to learn and perform comfortably," he said. "We look forward to more research on long-term outcomes and in settings outside trials to learn more about this important surgery."

For more information, please contact AHRQ Public Affairs: (301) 427-1998 or (301) 427-1965.


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