Abstract WP531: Nontraumatic Convexal Subarachnoid Hemorrhage Concomitants with Hyperacute Ischemic Stroke

Abstract

Background and Purpose: Nontraumatic convexal subarachnoid hemorrhage (cSAH) rarely occurs concomitant with acute ischemic stroke. The purpose of this study was to investigate the incidence, imaging findings, clinical backgrounds, and outcomes of hyperacute ischemic stroke with cSAH. Methods: Patients were selected from a comprehensive stroke center with ≤4.5 h from onset to door with symptomatic ischemic stroke between October 2012 and May 2018. All patients underwent CT and/or MRI on admission and we reviewed them to identify cSAH. Follow-up CT and/or MRI were also reviewed. cSAH caused by trauma, detected after thrombolysis or endovascular treatment, and accompanied with intracerebral hemorrhage was excluded. Retrospective review of cSAH incidence, imaging findings, clinical backgrounds, and outcomes was performed. Results: We screened 1249 consecutive symptomatic ischemic stroke patients, including 466 patients with ≤4.5 h from onset to door (342 (73%) male, median age 68 years). Of 466 hyperacute ischemic stroke patients, cSAH was observed in 5 (1.1%) patients (5 male, median age 49 years): 3 were detected on admission and the other was detected at follow-up. None had any meningeal irritation signs, and all were detected incidentally. Four patients (case 1-4) were diagnosed as arterial infarction, and 1 as venous infarction. Of the 4 arterial infarction patients, arterial stenosis or occlusion was observed ipsilaterally to the cSAH (Figure). In addition, of the 4 arterial infarction patients, hyperintense vessel signs were observed on FLAIR imaging on admission suggesting retrograde flow via collateral vessels, or slow flow (Figure). In all, cSAH disappeared gradually, and outcomes were favorable (modified Rankin Scale 0-1 at 3 months from the onset). Conclusions: cSAH was accompanied with approximately 1% of hyperacute ischemic stroke. Patients with arterial infarction and cSAH had arterial stenosis or occlusion ipsilaterally to cSAH.