Cognition Before Heart Surgery Predicts Decline After

Up to 50 percent of people who undergo heart bypass surgery experience a drop in their mental abilities after the operation. The best predictor of this decline in cognitive function seems to be their thinking ability before surgery, new research shows.

Up to 50 percent of people who undergo heart bypass surgery experience a drop in their mental abilities after the operation. The best predictor of this decline in cognitive function seems to be their thinking ability before surgery, new research shows. In the study, cognitive problems before surgery were a strong predictor of cognitive decline postoperatively, according to findings presented this week at the annual scientific meeting of the American Geriatrics Society in Las Vegas. To assess cognitive function, the researchers used a computerized test they developed called CogState. Unlike conventional thinking tests, CogState can assess cognitive function in just a few minutes, making it suitable for use immediately before surgery. “In our study, the best predictor of postoperative cognitive decline was the preoperative cognitive state of the patient,” lead author Dr. David Darby, chief medical officer of CogState Ltd. in Carlton, Australia, told Reuters Health. “Greater impairment preoperatively raises the risk of cognitive decline afterward. This is a novel finding.” In contrast to past research, Darby’s team found no evidence that operative factors, such as whether the heart was beating or was stopped during surgery, had a major impact on cognitive function after the operation. The new findings are based on a study of 112 patients who were tested with CogState before and after undergoing heart bypass surgery. Postoperative cognitive function was evaluated at several points up to 90 days. “We were able to identify three groups of patients based on preoperative cognitive scores,” Darby said. “Patients with the highest preoperative scores had a transient drop in cognition that resolved by 30 days, patients with intermediate scores showed a delayed recovery in cognition, and patients with the lowest scores were the ones that showed a continual decline in cognitive function.” So what should doctors do differently if preoperative testing indicates a high risk of cognitive decline after surgery? Darby said that at-risk patients could possibly be candidates for experimental drugs that may protect the brain from damage. At the very least, they should probably be followed more closely in consultation with a geriatrician, he added.(Source: American Geriatrics Society: Reuters Health News: Anthony J. Brown, MD: May 2004)