Intra- and perioperative aspects of the hemodynamics of supratentorial AV-malformations.

The risks which result from hemodynamic changes after surgery of 35 patients with supratentorial arterio-venous angiomas were investigated. With the help of a miniaturized 20 MHz Doppler probe flow and resistance were measured before, during, and after operations. The Doppler findings were compared with pre- and postoperative angiograms and intraoperative surgical findings. Postoperative angiograms were performed immediately after operation. The risk of haemorrhage and oedema was found to be high in cases of large vessels with slow flow and high resistance, in high flow angiomas, in stagnating arteries visible longer than 10 s and a length more than 6 cm, and in cases of pre-operative steal. These hemodynamic risky angiomas must be treated either by multiple step-operation or hypotension.