Time course of cerebral hemodynamics in aneurysmal subarachnoid hemorrhage

Background: Vascular complications are important causes of neurologic sequelae among survivors of aneurysmal subarachnoid hemorrhage (SAH). However, little is known about the time course of cerebral hemodynamics and outcome in patients with and without angiographically confirmed cerebral vasospasm. Methods.: Serial transcranial color-coded sonography (TCCS), angiography, and MRI studies were performed to measure cerebrovascular hemodynamics and assess complications following aneurysmal SAH. Results: Eighteen aneurysmal SAH patients were enrolled. Angiographically confirmed cerebral vasospasm occurred in 14 patients (77.8%), 5 of whom (35.7%) were asymptomatic. The mean blood flow velocity (V _mean) of the middle cerebral artery increased significantly as compared with healthy volunteers from day 1 to day 15, and substantially decreased thereafter. The V _mean of middle cerebral artery was significantly higher in patients with than in patients without angiographically confirmed cerebral vasospasm from day 3 to day 12. Compared to angiography, TCCS detected cerebral vasospasm with 85.7% sensitivity, 100% specificity, 100% positive predictive value, and 66.7% negative predictive value. MRI-evidenced cerebral infarctions occurred in nine patients (50%), three of whom (33.3%) were asymptomatic. Conclusions: This study demonstrated that approximately one-third of acute phase aneurysmal SAH patients have asymptomatic delayed cerebral infarction, which was undetected by TCCS in one-third of them. This may explain why the accuracy of TCCS to predict clinical symptomatic cerebral vasospasm is suboptimal.