Factors associated with intracranial hemorrhage in cases of cerebral arteriovenous malformation

OBJECTIVE: The standard categorization of arteriovenous malformations (AVMs) involves the Spetzler-Martin grading system, which uses a simple analysis of size, location (superficial or deep), and the presence of deep or superficial drainage. Hemodynamic risk factors are also thought to play important roles in the pathogenesis of these lesions and to be associated with the intracranial hemorrhage (ICH) rate. The actual hemodynamic factors for AVMs cannot be easily measured, but angioarchitectural features can be assessed and used as surrogate parameters. METHODS: The AVM angioarchitectural features for 662 patients were analyzed, and their associations with ICH as a presenting sign were studied. A cross-sectional analysis was used to qualify the strength of associations among clinical features, angioarchitectural characteristics, and ICH before treatment. RESULTS: The multivariate analysis indicated that arterial stenosis and arterial ectasia were associated with lower ICH rates, whereas venous stenosis increased the rate of ICH. The presence of angiogenesis modified the effects of arterial and venous stenosis. Furthermore, the effect of venous stenosis depended on the location of the nidus. The presented data do not support a direct positive association between associated aneurysms and ICH. CONCLUSION: Certain angiographic features seem to have prognostic potential with respect to the occurrence of ICH among patients with AVMs. A discriminatory prognostic index is proposed; its relevance must be proven in a future prospective study.