Intellectual function late after open-heart operation.

Cerebral emboli are not uncommon complications after valve replacements. We investigated the hypothesis that there are emboli that are clinically unnoticeable but that may affect the intellectual function of the brain. One hundred sixty-five patients were studied with a battery of psychometric tests before and after operation, two months postoperatively, and 2 to 8 years after operation. Ten patients sustained late cerebral infarction or hemorrhage. Their late intellectual function was low, indicating an impairment in brain performance. The remaining 155 patients had had no cerebral complications postoperatively. Eighty-three had had valve replacement (Björk-Shiley valves); 51, aortocoronary bypass operations; and 21, closure of an atrial septal defect (all adult patients). Late intellectual function was significantly lower in the patients with a valve prosthesis than in the other two groups. However, this difference could be traced back to the operation. Thus, we have not been able to confirm our hypothesis that late intellectual function in patients with a heart valve prosthesis deteriorates as a result of clinically silent emboli. On the contrary, patients who have undergone aortocoronary bypass operation sustain more deterioration in late intellectual function than the other groups. Late intellectual function in this study population clearly was influenced by events during the operation. Because cerebral injury can be shown almost regularly after open-heart operation, this investigation provides an incentive for further efforts to improve the quality of open-heart surgery with the aim of keeping brain function as intact as possible.