MORBIDITY OF INTRACRANIAL HEMORRHAGE IN PATIENTS WITH CEREBRAL ARTERIOVENOUS MALFORMATION

Background and Purpose-Decisions on invasive arteriovenous malformatio n (AVM) treatment are currently based on natural-course risk estimates of AVM bleeding and assumptions on morbidity from cerebral hemorrhage in general. However, morbidity of AVM hemorrhage has rarely been repo rted. We sought to assess the morbidity of intracranial hemorrhage in patients with cerebral AVMs. Methods-From a prospective AVM database, 119 patients were analyzed: 115 had a hemorrhage as the diagnostic eve nt, and 27 of them suffered a second hemorrhage during follow-up; an a dditional 4 patients had other diagnostic symptoms but bled during fol low-up. The type (parenchymal, subarachnoid, intraventricular) and loc ation of AVM hemorrhage were determined by CT/MR brain imaging. Disabi lity and neurological impairment were assessed with the Barthel Index, the Rankin Scale, and the National Institutes of Health Stroke Scale, with a mean follow-up time of 16.2 months. Results-Of the 115 inciden t hemorrhages, 34 (30%) were subarachnoid, 27 (23%) parenchymal, 18 (1 6%) intraventricular, and 36 (31%) in combined locations. In 54 patien ts (47%; 95% confidence interval [CI], 38% to 56%) the incident hemorr hage resulted in no neurological deficit, and an additional 43 patient s (37%; 95% CI, 28% to 46%) were independent in their daily activities (Rankin 1). Fifteen patients (13%; 95% CI, 7% to 19%) were moderately disabled (Rankin 2 or 3), and 3 (3%; 95% CI, 0% to 6%) were severely disabled (Rankin greater than or equal to 4). Parenchymal hemorrhages were most likely to result in a neurological deficit (52%). Type and m orbidity of hemorrhage during follow-up were similar to incident event s. Twenty (74%) of 27 patients with both incident and follow-up hemorr hages were normal or independent (Rankin 0 or 1), None of the patients with a hemorrhage during follow-up died during the observation period . Conclusions-Hemorrhage from cerebral AVMs appears to have a lower mo rbidity than currently assumed. This finding encourages a reevaluation of the risks and benefits of invasive AVM treatment.