What happens to blood pressure during coronary artery bypass surgery may have implications far beyond the end of the operation.
Specifically, researchers find people who experience an increase in arterial blood pressure — a measure related to how well the heart is pumping blood to the various organs in the body — are at higher risk for having memory and learning problems after the surgery is over.
Overall, those who experienced a drop in arterial blood pressure of 27 millimeters of mercury or more from pre-surgery levels ended up scoring worse on standard mental exams than they did before the operation.
Patients who underwent an MRI after their surgery may help explain what happened. Researchers found about half the group had suffered a stroke, and those with evidence of stroke were significantly more likely to be among those with an arterial blood pressure drop of 27 millimeters of mercury or more.
The researchers emphasize these results come from a relatively small sample of patients — 15 were included in the study overall, with 13 undergoing the MRIs — but believe they do point to arterial blood pressure as a key risk factor for memory problems following bypass surgery.
Future prospective studies are needed to further define the relationship between change in blood pressure and postoperative stroke as well as change in blood pressure and postoperative cognitive performance, they conclude.
SOURCE: Archives of Neurology, published online June 11, 2007
