The relevance of hemodynamic factors to perioperative ischemic complications in childhood moyamoya disease.

Of 124 children younger than 15 years who underwent surgery for moyamoya disease, 21 (16.9%) experienced perioperative ischemic complications that could not be unequivocally attributed to the surgery. Eleven of the 21 patients experienced infarctions, and 10 experienced reversible ischemic neurological deficits without new lesions, as revealed by computed tomographic scans. An examination of the patients' perioperative clinical and laboratory data revealed that the mean values of intra- and postoperative minimum arterial carbon dioxide pressure, maximum arterial carbon dioxide pressure, and mean arterial pressure were similar in patients with and without ischemic complications. However, in patients with perioperative complications, the incidence of preoperative transient ischemic attacks (TIAs) and intra- and postoperative hypercapnia (maximum arterial carbon dioxide pressure > 45 mm Hg) was significantly higher. In addition, 7 of the 11 perioperative infarctions occurred in patients with frequent preoperative TIAs and intra- and postoperative hypercapnia. Cerebral blood flow studies with preoperative acetazolamide loading showed that the new infarctions were located in areas in which the cerebral blood flow had been compromised. Our results suggest that the occurrence of frequent preoperative TIA is an important indicator of the instability of the cerebral hemodynamics and of the risk of perioperative ischemic complications. To prevent these complications, preoperative management aimed at stabilizing the hemodynamic status is very important. Children who have moyamoya disease and who experience frequent preoperative TIAs are at risk for ischemic brain damage caused by hypercapnia as well as hypocapnia and hypotension. The establishment and maintenance of normocapnia with normotension are highly desirable for the perioperative management of moyamoya disease in children.