The Prevalence of Cerebral Vascular Abnormalities Detected in Various Diagnostic Subgroups of Spontaneous Subarachnoid Hemorrhage in the Modern Era

OBJECTIVE: To determine the prevalence of cerebral vascular abnormalities in various diagnostic subgroups of spontaneous subarachnoid hemorrhage (SAH) in a regional neurosurgical center in the modern era. METHODS: Prospective data collection of 609 consecutive patients with spontaneous SAH in a 3-year period (August 2010 to August 2013) was carried out. Patients were divided into three diagnostic subgroups: computed tomography (CT) positive for SAH; CT negative but positive cerebrospinal fluid (CSF) examination by spectrophotometry for SAH; CT negative for SAH and inconclusive CSF examination. All patients fit for intervention then underwent computed tomography angiography (CTA), with or without digital subtraction angiography (DSA) to identify vascular abnormalities for subsequent treatment. RESULTS: Of the 609 identified patients, 554 were fit for further investigation and consideration of further intervention. 514 patients had confirmed SAH. 61.5% of patients were female. The mean age was 54.0 years. 390 patients (75.9%) showed vascular abnormalities on angiography. 438 patients (85.2%) with confirmed SAH were diagnosed on CT scan (Group 1) and 81.1% had detectable vascular abnormalities. 18.9% of patients with a positive CT scan had no identifiable cause of SAH. 76 patients (14.8%) with confirmed SAH had negative CT but positive LP (Group 2) and 46.1% of patients in this group had vascular abnormalities. 3 patients with inconclusive CSF examination had lesions requiring treatment. The median length of hospital stay in Group 1 patients was longer than the median length of hospital stay in Group 2 patients. CONCLUSIONS: The frequency of vascular abnormalities in spontaneous SAH is lower than the traditionally quoted figure, which would have diagnostic and prognostic implications for patient management.