The cerebral arteriovenous malformations correspond to the formation of an entanglement of morphologically abnormal vessels called nidus, which shunt the blood circulation directly from the arterial circulation to the venous circulation.

The cerebral arteriovenous malformations are an important cause of hemorrhagic stroke.

The hypothesis is that cerebral haemorrhage associated with a cerebral arteriovenous malformations would come from peri-nidal micro-vessels, in connection with infiltration of leucocytes and / or defective maintenance of microvascular integrity by platelets.

Inclusion Criteria:

• Patient over 18 years old
• Patient with a cerebral AVM for which an intervention (endovascular treatment or surgery) or only clinical monitoring
• Express consent to participate in the study

And

• children
• Free informed and express consent of both holders of the minor patient's parental authority, or, by way of derogation and only if the other holder of parental authority cannot give his or her consent within a time limit compatible with the methodological requirements specific to the conduct of the research with regard to its purposes, of one of the two holders of parental authority

Exclusion Criteria:

• Patient benefiting from a legal protection measure
• Pregnant or breast feeding woman

Patient with a cerebral arterioveinus malformation for which an intervention (endovascular treatment or surgery) or only clinical monitoring is planned