No reports have focused on neurological outcomes after open heart surgery of patients with infective endocarditis (IE) and neurological complications. We evaluated parameters related to anesthetic management and neurological outcomes. The subjects analyzed were 24 patients who had undergone valvular surgeries under hypothermic cardiopulmonary bypass from April 1978 to December 1990. The patients were divided into two groups according to the interval between onset of neurological complication and the time of operation: 1) acute group (within one month before the surgery: n = 11, 9.4 +/- 9 days; means +/- SD) and 2) chronic group (more than one month before the surgery: n = 13, 120 +/- 80 days). After heart surgery, 5 patients in the acute group showed newly developed neurological abnormality including death from hemorrhagic transformation, hemiplegia or aphasia. No patients in the chronic group had newly developed neurological abnormality related to the surgery. In the neurologically deteriorated patients of the acute group, interval from the onset of neurological complication to surgery was 3.5 +/- 4.5 days, whereas that of the remainders of the acute group was significantly longer (14.4 +/- 9.0 days). Intraoperative events and anesthetic management of these patients were also analyzed. However, there were no significant differences in the parameters such as cerebral perfusion pressure, arterial PaCO2, doses of anesthetics and use of vasopressors. Our results suggest that the most important factor which may influence neurological outcome was the interval between the onset of neurological abnormality and the time of operation.(ABSTRACT TRUNCATED AT 250 WORDS)