Delayed hemorrhage following resection of an arteriovenous malformation in the brain

Between 1989 and 2002 the authors treated 416 cases of angiographically confirmed arteriovenous malformations (AVMs) of the brain.

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.

In selected cases an aggressive postoperative blood pressure protocol is likely to reduce delayed hemorrhage following AVM resection.