The Role of ABO Blood Group in Cerebral Vasospasm, Associated Intracranial Hemorrhage, and Delayed Cerebral Ischemia in 470 Patients with Subarachnoid Hemorrhage

OBJECTIVE: Rupture of an intracranial aneurysm usually presents with an acute onset and requires multidisciplinary intensive care treatment and the overall death and disability rates are high. The ABO blood type is known to play an important role in hemostasis, thrombosis, and vascular NO response. The aspect of ABO blood type in onset, clinical progress, and outcome after subarachnoid hemorrhage (SAH) is largely unexplored. We conducted this study to elucidate the association of ABO blood type with the occurrence and outcome of aneurysmal SAH. METHODS: In our retrospective study, 470 patients with aneurysmal SAH treated at our institution were included. We performed a chi(2) test for comparison between blood types and World Federation of Neurosurgical Societies admission status, cerebral vasospasm, delayed infarction, associated intracerebral hemorrhage and Fisher grade for analysis for their association with SAH. RESULTS: No significant difference between blood type and the reviewed variables for SAH outcome were identified: World Federation of Neurosurgical Societies admission status (odds ratio, 1.12; 95% confidence interval [CI], 0.7-1.6; P = 0.56); SAH-associated intracerebral hemorrhage (odds ratio, 0.81; 95% CI, 0.5-1.3; P = 0.36); cerebral vasospasm (odds ratio, 1.08; 95% CI, 0.7-1.6; P = 0.71); DCI (odds ratio, 1.23; 95% CI, 0.8-1.8; P = 0.30); Fisher grade (odds ratio, 1.13; 95% CI, 0.7-1.6; P = 0.19). CONCLUSIONS: Although a possible relationship between the ABO blood group and the clinical course of patients with SAH was hypothesized, our study showed no significant influence of patient's ABO blood type on cerebral vasospasm onset, SAH-associated intracerebral hemorrhage, or delayed infarction.