Angiographic study of cerebral vasospasm following rupture of intracranial aneurysms: Part I. Time of the appearance.

An investigation of the time of appearance of vasospasm as seen angiographically after the onset of subarachnoid hemorrhage was carried out on 797 cases of intracranial saccular aneurysm in which operations were performed. It has been reported that vasospasm often occurs early after the onset of subarachnoid hemorrhage. With only one subarachnoid hemorrhage, vasospasm occurred within three days after the hemorrhage in only 4.2% of the 120 cases in this study. The appearance of vasospasm was most frequently seen angiographically between ten and 17 days. During this period vasospasm was seen in 49.1% of 116 cases. In those cases with a subarachnoid hemorrhage one to 17 days before the last one, vasospasm within three days after the last hemorrhage was seen in 38.7% of 62 cases. During the period between ten and 17 days after the last hemorrhage, vasospasm was seen in only 20% of 25 cases. The preceding subarachnoid hemorrhage, which had occurred between one and 17 days before the last hemorrhage, seemed to be responsible for the high rate of vasospasm within three days after the last hemorrhage, and the low rate of vasospasm in the period between ten and 17 days after the last hemorrhage.