Prolonged Experimental Cerebral Vasospasm

Abstract

HE visualization of constricted cerebral vessels by angiographie studies of patients suffering from ruptured intracranial aneurysms is now accepted by neurosurgeons and radiologists. The fact that this cerebral vasoconstriction, or vasospasm, has often disappeared by the time of follow-up studies indicates that the phenomenon was not due to a permanent pathological change in the vessel walls. Narrowing of cerebral arteries has been reported in a high percentage of patients with ruptured intracranial aneurysms, particularly when the patients are studied shortly after the hemorrhage. Several retrospective studies have indicated a significant correlation between mortality or morbidity and the presence of cerebral vasospasm. 14,1~,~S Fletcher, et al., S found that the incidence of coma or stupor, seizures, hemiparesis, and papilledema increased two- to fivefold when spasm was present in the angiogram. Other clinical studies have demonstrated that spasm may occur postoperatively following successful intracranial obliteration of any aneurysm. Allcock and Drake 1 noted vasospasm postoperatively in 27% of the patients who recovered satisfactorily from intracranial surgery for aneurysms, whereas 71% of their patients with unsatisfactory results demonstrated postoperative vasospasm. Smith/~ and Birse and Tom ~ have demonstrated ischemia of the cortex and edema of the white matter in the territory supplied by the aneurysm-bearing vessel, suggesting that the vasospasm led to cerebral infarction. The phenomenon of cerebral vasospasm is respected to the extent that neurosurgeons feel that, when demonstrated, it is a definite