Convexity Subarachnoid Hemorrhage Accompanied by Hyperacute Ischemic Stroke.

Introduction and Objectives: The clinical characteristics of convexity subarachnoid hemorrhage (cSAH) accompanying hyperacute ischemic stroke are unknown. We aimed to investigate the incidence and clinical characteristics of cSAH with hyperacute ischemic stroke. Methods: Participants comprised symptomatic ischemic stroke patients with <= 4.5 h from onset to door who also underwent initial MRI <= 4.5 h from onset. We reviewed initial and follow-up MRI during admission to identify cSAH. Retrospective reviews of cSAH incidence and clinical characteristics were performed. Results: We screened 1,249 consecutive symptomatic ischemic stroke patients, including 384 patients (279 males [73%]; median age, 67 years). Of the 384 patients, arterial ischemic stroke was seen in 382 patients, and venous ischemic stroke in 2 patients. Of the hyperacute arterial ischemic stroke, cSAH was identified within 4.5 h of ischemic stroke onset in 2 patients (0.5%) and around 6 days from ischemic stroke onset in 2 patients (0.5%). Of the hyperacute venous ischemic stroke, cSAH was observed in 1 patient on initial MRI. Comparing the clinical characteristics of hyperacute arterial ischemic stroke with and without cSAH, patients with cSAH were more likely to have arterial stenosis or occlusion ipsilateral to the cSAH (100 vs. 47%, p = 0.048), and the ischemic lesion only in the right hemisphere (100 vs. 33%, p = 0.013). In all cases, outcomes were favorable (modified Rankin Scale 0-1 at 3 months from onset). Conclusions: Convexity SAH was observed in 0.5% of hyperacute ischemic patients within 4.5 h of ischemic stroke onset and in 0.5% around 6 days from ischemic stroke onset.