Object: Between 1989 and 2002 the authors treated 416 cases of angiographically confirmed arteriovenous malformations (AVMs) of the brain.
Methods: Three hundred fifty-five patients underwent resection of an AVM; 2% died and 12% experienced a permanent morbidity (1.7% experienced a deterioration of modified Rankin Scale [mRS] score of 3-5). Patient outcomes in this series were based on the Spetzler-Martin grade. For patients with Grade I and II AVMs the rate of permanent morbidity was 1% and the rate of mortality was 0.5%. For patients with Grade III AVMs the morbidity rate was 18.9% (2.7% experienced a deterioration of mRS score of 3-5) and the mortality rate was 2.7%. For patients with Grade IV and V AVMs the morbidity rate was 25.6% (5.1% experienced a deterioration of mRS score of 3-5) and the mortality rate was 7.7%. No patient with a Spetzler-Martin Grade I or II lesion had a worsened outcome due to delayed hemorrhage, whereas 3.6% of patients with a Grade III and 12.8% of patients with Grade IV and V AVMs experienced delayed hemorrhage that led to a permanent downgrade in function. With the introduction of an aggressive postoperative blood pressure protocol (for AVMs with grades > II and sizes > 3.5 cm in diameter) the incidence of delayed postoperative hemorrhage leading to mortality or permanent morbidity decreased from 4.4 to 1%. This difference was significant. Neither case selection nor complications other than delayed hemorrhage changed between these two periods.
Conclusions: In selected cases an aggressive postoperative blood pressure protocol is likely to reduce delayed hemorrhage following AVM resection.