Results and value of immediate postoperative angiography after operations for arteriovenous malformations.

Postoperative angiograms show immediate haemodynamic changes in large vessels, with a decrease in the diameter of the internal carotid artery and filling of vascular territories not previously injected. In 90% of the feeding vessels there is a disproportion between vessel lumen and flow after removal of the angioma. Mechanisms for adaptation exist, but they are inadequate in the immediate postoperative period. There is an increased risk of postoperative bleeding and brain swelling in patients with long feeding vessels, which are visible for longer than ten seconds in the angiogram.