Aneurysm Location as a Prognostic Outcome Factor After Subarachnoid Hemorrhage From Internal Carotid Artery Aneurysms and Potential Impact for Further Experimental Subarachnoid Hemorrhage Models

Abstract

Prognostic factors of favorable and unfavorable clinical outcome after aneurysmal subarachnoid hemorrhage (SAH) are still not completely known. We retrospectively analyzed the aneurysm location as a factor for patients' outcome after aneurysmal SAH. We retrospectively selected patients from our prospectively collected database with aneurysm at the carotid bifurcation artery (n= 23) and posterior communicating artery (n= 170). Outcome was assessed using the modified Rankin Scale (mRS) (favorable [mRS score, 0-2] vs. unfavorable [mRS score, 3-6]) 6 months after SAH. A good clinical admission status (World Federation of Neurological Surgery grade I-III) has a significant influence on mRS score after SAH. In univariate analysis, advanced age, Fisher grade 3, early hydrocephalus, severity of cerebral vasospasm (CVS), longer stay on the intensive care unit, and posterior communicating artery aneurysms were associated with an unfavorable outcome. Multivariate analysis showed 4 prognostic factors for a favorable outcome: good admission status (odds ratio [OR], 10.8); aneurysms of carotid bifurcation artery (OR, 4.3); absence of mild or severe CVS (OR, 3.4); and patients age less than 55 years (OR, 2.1). Despite the usual prognostic factors (good admission status, younger age, absence of CVS) for a favorable outcome after SAH, the aneurysm location (carotidbifurcation artery) itself seems to be a prognostic factor. Also, aneurysms of the carotid bifurcation artery showed less occurrence of an early hydrocephalus, which is an indicator for the presence of an early brain injury. According to these results, we question if experimental animal models (especially the endovascular model using the perforation of the carotid bifurcation artery) have to be re-evaluated.