The purpose of this trial is to determine whether aortic manipulation in patients undergoing coronary bypass graft surgery leads to increased incidence of microemboli and subsequent impairment of neurobehavioral function.
Patients who have coronary artery bypass graft (CABG) surgery must have their aorta (the large blood vessel that is attached to the heart) clamped with an instrument. There are two basic ways of manipulating the aorta during surgery. One way is to place a single clamp across the aorta. The other way is to place more than one clamp on the aorta in several places. Both methods are used, but it is not known if one way is better than the other.
The purpose of this study is to compare the two methods of clamping to see if one way is better than the other, and to determine whether patients who undergo reduced manipulation of the aorta have fewer microemboli delivered to the brain during CABG surgery and have a lower incidence of neurobehavioral problems following surgery. Microemboli are tiny fat particles that enter the bloodstream during surgery, circulate to the brain, and block tiny blood vessels, causing brain deficits.
Participants in this trial will be randomly classified into one of two groups: the experimental group will undergo cross clamping of the aorta with a single clamp and be given retrograde cardioplegia for heart protection, and the control group will undergo cross clamping of the aorta with multiple clamps and be given antegrade cardioplegia for heart protection. Neurobehavioral assessments will be accomplished with a comprehensive battery of neurological and neuropsychological tests.