[Therapeutic strategy for cerebral arteriovenous malformations. Proposal for classification of individual hemorrhagic risk].

Therapeutic strategy for the cerebral arteriovenous malformations (cAVM) is mainly based on the assessment of hemorrhage risk. This risk is estimated between 2 and 4% according to various series. However, this is a collective risk projected upon a given population. To improve therapeutic strategy for cAVM, we propose a grading of the individual hemorrhage risk based on 5 angiographic parameters: 4 are increasing risk factors and one is a favorable index.This grading system has been achieved by univariate then multivariate analysis by logistic regression from angiographic data of 250 consecutive patients with cAVM. Thirty angiographic parameters were studied.Grade I has no risk factors and has two subgrades: Ia with venous recruitment (which is the lonely favorable parameter), Ib without venous recruitment. Grade II is the presence of venous stenosis or venous reflux. Grade III is the presence of exclusive deep venous drainage. Grade IV is the presence of intra or juxta-nidal aneurysm. There were 13% of hemorrhage in grade Ia, 38% in grade Ib, 48% in grade II, 90% in grades III and IV.This model can be helpful for the treatment decision making and also contributes to a better understanding of the natural history of cAVM. It must be further confirmed by a prospective study.