Principal Investigator: Guy McKhann, M.D.
Over 400,000 persons undergo Coronary Artery Bypass Graft (CABG) each year in the United States. While CABG is very effective in relieving angina, there are both shorter term and longer term cognitive and neurologic adverse outcomes associated with this procedure. In the immediate postoperative period the major complications are postoperative stroke and encephalopathy. Cognitive changes, especially in memory, also occur in the postoperative period. These difficulties typically return to baseline performance by 3 months. Of greater interest is the question of longer term cognitive change. Studies of only surgical populations suggest that there is a “late decline”, between 1 and 5 years after surgery as indicated by decline on specific neuropsychological tests, primarily of what is referred to as “executive function” (planning, following complex commands, and certain aspects of judgment). These observed progressive changes are often accompanied by the patient’s complaints of being “not quite the same”.
We are involved in a prospective four-arm study comparing the cognitive outcomes in - Those undergoing CABG;
- Those with a newer form of cardiac surgery, “off-pump surgery,” in which no cardiopulmonary bypass pump is used;
- Those with proven coronary artery disease, but without surgery; and
- Those without the risk factors for coronary artery disease - a healthy control group.
We are in the process of evaluating the 3 year date from this study, and are actively collecting data on subjects 5 years after entry or surgery. Our preliminary analyses indicate that those with coronary artery disease, with or without surgery, do not perform as well as the healthy controls. This suggests to us that the progressive cognitive decline attributed to CABG may be the effects of progression of pre-existing cerebrovascular disease rather than an effect of surgery.
As part of this study, in collaboration with the Alzheimer Disease Research Center (ADRC), we are obtaining autopsies on these carefully evaluated patients to determine the correlation between cerebrovascular disease and cognitive change.
For more information, please contact Dr. Guy M. McKhann, at (410) 516-8640
or guy.mckhann@jhu.edu
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