Basilar Artery Vasospasm and Delayed Posterior Circulation Ischemia After Aneurysmal Subarachnoid Hemorrhage

Background and Purpose— The clinical and hemodynamic impacts of basilar artery (BA) vasospasm (VS) after aneurysmal subarachnoid hemorrhage (SAH) are ill-defined. The purpose of the present study was to evaluate the relationship between BA-VS and regional cerebral blood flow (rCBF) with posterior circulation after aneurysmal SAH. Methods— Daily transcranial Doppler (TCD) measurements of posterior and anterior circulation arteries were conducted in 162 patients with aneurysmal SAH. rCBF to the brain stem (BS) and other brain territories was assessed by multiple single-photon emission computed tomography with 99mTc ethyl cysteinate dimer single-photon emission computed tomography (ECD-SPECT) imaging during the course of VS. Results— SPECT imaging showed delayed BS hypoperfusion in 29 patients (17.9%). Of them, 23 patients (79.3%) were found to have BA-VS. Patients with very high BA flow velocities (FVs; >115 cm/s) had a 50% chance of developing delayed BS ischemia. BA-VS was found at a higher rate in patien...