Factors in the Mortality and Morbidity Associated with Surgical Treatment of Cerebrovascular Insufficiency

The mortality and morbidity associated with 267 surgical procedures for cerebrovascular insufficiency carried out over a 5-year period are reviewed. Patients with marked intracranial arterial disease on angiogram, with completed strokes, over 70 years old or who required continuous nursing care are identified as the highest surgical risks. The introduction of monitoring of the oxygen saturation of lateral sinus venous blood has reduced the incidence of intra-operative new neurological deficit during general anesthesia from 9.1 to 4.4%. Episodes of hypotension occurred in 27% of patients but were associated with 48% of grave complications. The occurrence of hypotension is related to diabetes, preoperative hypertension, and to the extent of the operative procedure. Evidence is presented that hypotension is due to abnormal circulatory reflexes and may best be prevented by careful maintenance of intravascular volume.