Prevalence, timing, risk factors, and mechanisms of anterior cerebral artery infarctions following subarachnoid hemorrhage.

Anterior cerebral artery (ACA) ischemia may be underdiagnosed following subarachnoid hemorrhage (SAH). The purpose of this study is to characterize the prevalence, timing, and risk factors for ACA infarction, following primary spontaneous SAH. This was a retrospective study of consecutive SAH patients. Final admission CT scans were reviewed for the presence of ACA infarction, and prior scans serially reviewed to determine timing of infarct. Infarctions were categorized as any, early (days 0-3), late (days 4-15), or perioperative (2 days after aneurysm treatment). Demographic and clinical variables were statistically interrogated to identify predictors of infarct types. Of the 474 study patients, ACA infarctions occurred in 8 % of patients, with 42 % occurring during the early period. Multivariate logistic regression identified H/H grade 4/5 (p < 0.001), ACA/ACom aneurysm location (p < 0.001), and surgical clipping (p = 0.011) as independent predictors of any ACA infarct. In Cox hazards analysis, H/H grade 4/5 (p < 0.001), CT score 3/4 (p = 0.042), ACA/ACom aneurysm location (p < 0.001), and surgical clipping (p = 0.012) independently predicted any ACA infarct. Bivariate logistic regression identified non-Caucasian race (p = 0.032), H/H grade 3/4 (p < 0.001), CT score 3/4 (p = 0.006), IVH (p = 0.027), and ACA/ACom aneurysm (p = 0.001) as predictors of early infarct (EI). Late infarct (LI) was predicted by H/H grade 4/5 (p = 0.040), ACA/ACom aneurysm (p < 0.001), and vasospasm (p = 0.027), while postoperative infarct (PI) was predicted by surgical clipping (p = 0.044). Log-rank analyses confirmed non-Caucasian race (p = 0.024), H/H grade 3/4 (p < 0.001), CT score 3/4 (p = 0.003), IVH (p = 0.010), and ACA/ACom aneurysm (p < 0.001) as predictors of EI. LI was predicted by ACA/ACom aneurysm (p < 0.001) while surgical clipping (p = 0.046) again predicted PI. Clinical severity/grade and ACA/ACom aneurysm location are the most consistent predictors of ACA infarctions. Vasospastic and non-vasospastic processes may concurrently contribute to ACA infarcts.