Preoperative evaluation of hemodynamic factors in cerebral arteriovenous malformations for selection of a radical surgery tactic with special reference to vascular autoregulation disorders.

After reviewing the literature with respect to hemodynamic factors in AVM the authors describe their experience monitoring the blood volume under induced arterial hypotension. They have been able to select cases which presented disorders of the vascular autoregulation of the brain and represent, for this reason, a challenge to a radical excision; in such cases they advise to remove the AVM in several programmed stages. In addition it was possible to predict the efficiency of the hypotension on AVM vessels pressure during operation enabling the surgeon in case of positive effect of the hypotension to realize more securely the haemostasis. Moreover, the authors present the first data regarding the mean circulatory time the knowledge of which seems very promising. The last 33 cases of a series of 179 radical removals have been monitored before and in some cases after operation; the knowledge of these hemodynamic factors allowed the surgical team of La Pitié to extend the surgical indications for radical removal to AVM recently considered as inoperable.