Seven hundred and seven carotid angiograms of 305 patients with ruptured intracranial aneurysms were analyzed to investigate the sequential changes of the type and severity of vasospasm. Furthermore, the study was undertaken to analyze the effect of vasospasm upon clinical states, cerebral circulation, the development of cerebral infarction and prognosis of the patients.
Vasospasms were simply classified according to their extents into four types; diffuse (narrowing intraarterial diameter over 2cm in length in the proximal parts), peripheral (narrowing over 2cm in length in the distal parts), multi-local and local. The diffuse type of vasospasm was further divided into two grades of severity; diffuse severe (reduction of the caliber by more than 50%) and diffuse mild (reduction of the caliber by 25 to 50%). Measurements of the rCBF were undertaken by the intra-arterial Xe-133 injection method.
The results were as follows: 1) Vasospasm which occurred within 3 days after the onset was seen in only 3 of 79 cases. However, the incidence of vasospasm increased as time passed and reached its peak at the period between 8th and 15th day, when vasospasm was seen in 83 of 106 cases. The type of narrowing was diffuse in most of these cases. Thereafter, the occurrence of vasospasm gradually decreased and the type of narrowing tended to change from diffuse to local or multi-local types. Only a few cases showed vasospasm after 50th day. 2) Most of the patients with the diffuse type of vasospasm, especially with the diffuse severe type, showed decreases of mean CBF, while mean CBF of the patients with the multi-local or the local type of vasospasm showed no meaningful decrease when compared with the patients without vasospasms. 3) Twenty out of 38 patients with the diffuse type of vasospasm developed cerebral infarctions, while none of the 14 patients with no vasospasm or the local and multi-local types of vasospasm developed cerebral infarctions. 4) The diffuse type of vasospasm tended to have some effects on the clinical state and outcome of the patients.
It was concluded that the present method of classifying the degree of vasospasms was useful in determining a clinical significance of vasospasms.
