Faculty Bibliography

INTRODUCTION: Cerebral arterial vasospasm following aneurysmal subarachnoid hemorrhage (SAH) is an important cause of delayed neurologic deterioration. Vasospasm following isolated intraventricular hemorrhage (IVH) is less common. Accepted predictors of vasospasm following SAH include poor Hunt-Hess grade, elevated transcranial Doppler velocities, and the thickness of cisternal blood on neuroimaging [1, 2]. The role of intraventricular hemorrhage in vasospasm is more controversial. METHODS: Case report and review of the literature. RESULTS: A 41-year-old woman developed symptomatic delayed vasospasm 10 days following isolated IVH due to the rupture of an arteriovenous malformation (AVM). CONCLUSION: Intraventricular hemorrhage can independently cause significant delayed vasospasm. Possible mechanisms are described.

OBJECTIVE: We developed a modification of the Fisher computed tomographic rating scale and compared it with the original Fisher scale to determine which scale best predicts symptomatic vasospasm after subarachnoid hemorrhage. METHODS: We analyzed data from 1355 subarachnoid hemorrhage patients in the placebo arm of four randomized, double-blind, placebo-controlled studies of tirilazad. Modified Fisher computed tomographic grades were calculated on the basis of the presence of cisternal blood and intraventricular hemorrhage. Crude odds ratios (OR) reflecting the risk of developing symptomatic vasospasm were calculated for each scale level, and adjusted ORs expressing the incremental risk were calculated after controlling for known predictors of vasospasm. RESULTS: Of 1355 patients, 451 (33%) developed symptomatic vasospasm. For the modified Fisher scale, compared with Grade 0 to 1 patients, the crude OR for vasospasm was 1.6 (95% confidence interval [CI], 1.0-2.5) for Grade 2, 1.6 (95% CI, 1.1-2.2) for Grade 3, and 2.2 (95% CI, 1.6-3.1) for Grade 4. For the original Fisher scale, referenced to Grade 1, the OR for vasospasm was 1.3 (95% CI, 0.7-2.2) for Grade 2, 2.2 (95% CI, 1.4-3.5) for Grade 3, and 1.7 (95% CI, 1.0-3.0) for Grade 4. Early angiographic vasospasm, history of hypertension, neurological grade, and elevated admission mean arterial pressure were identified as risk factors for symptomatic vasospasm. After adjusting for these variables, the modified Fisher scale remained a significant predictor of vasospasm (adjusted OR, 1.28; 95% CI, 1.06-1.54), whereas the original Fisher scale was not. CONCLUSION: The modified Fisher scale, which accounts for thick cisternal and ventricular blood, predicts symptomatic vasospasm after subarachnoid hemorrhage more accurately than original Fisher scale.

The authors performed serial transcranial Doppler (TCD) and carbon dioxide reactivity (CO2R) testing in 20 aneurysmal subarachnoid hemorrhage patients to determine whether impaired cerebrovascular reactivity was associated with symptomatic vasospasm. Symptomatic vasospasm occurred in 9 of 14 patients with abnormal CO2R and in none of 6 patients with preserved reactivity (p = 0.011). Abnormal CO2R preceded the onset of vasospasm in 7 of 9 patients. Abnormal standard TCD testing was not associated with vasospasm.