Even though coronary artery bypass graft surgery with use of cardiopulmonary bypass (on-pump CABG) is associated with cognitive decline, avoiding cardiopulmonary bypass (off-pump CABG) had no effect on cognitive or cardiac outcomes at five years in low-risk patients, according to a study in the February 21 issue of JAMA.
The incidence of cognitive decline in the first year after CABG surgery ranges from less than 5 percent to more than 30 percent. The desire to avoid the perceived ill effects of cardiopulmonary bypass has led to a renewed interest in bypass surgery on the beating heart (off-pump CABG surgery), in part prompted by the development of cardiac stabilizers, according to background information in the article. The off-pump procedure, however, is technically more demanding, and it is unknown whether off-pump surgery can match the long-term cardiac benefits of on-pump surgery or improve cognitive outcomes.
Diederik van Dijk, M.D., Ph.D., of the University Medical Center Utrecht, the Netherlands and colleagues assessed the 5-year cognitive and cardiac outcomes of 281 patients who were randomized to off-pump (n = 142) or on-pump (n = 139) CABG surgery. After 5 years, 130 patients were alive in each group.
Cognitive outcomes could be determined in 123 and 117 patients in the off-pump and on-pump groups, respectively. When applying the standard definition of cognitive decline (20 percent decline in 20 percent of the main test variables), 62 (50.4 percent) of 123 patients in the off-pump group and 59 (50.4 percent) of 117 patients in the on-pump group had cognitive decline. Using the alternative, more conservative definition of cognitive decline, 41 patients in the off-pump group (33.3 percent) and 41 patients in the on-pump group (35.0 percent) had cognitive decline.
Thirty patients assigned to undergo off-pump surgery (21.1 percent) and 25 patients assigned to undergo on-pump surgery (18.0 percent) had experienced a cardiovascular event. There were no differences between the 2 groups in the overall measure of quality of life or in angina status.
"We conclude that in low-risk patients undergoing CABG surgery, avoiding the use of cardiopulmonary bypass had no effect on cognitive or cardiac outcome 5 years after the procedure," the authors write.
"The present results suggest that factors other than cardiopulmonary bypass may be responsible for cognitive decline, such as anesthesia and the generalized inflammatory response that is associated with major surgical procedures. It is also possible that the cognitive decline observed at 5-year follow-up is not caused by the operation but reflects natural aging."
(JAMA. 2007;297:701-708. Available pre-embargo to the media at www.jamamedia.org)
Editor's Note: This study was supported by a grant from the International Anesthesia Research Society (IARS). Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc.
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