A simplified arteriovenous malformation model in sheep: Feasibility study

BACKGROUND AND PURPOSE: Recently, a swine model of a cerebral arteriovenous malformation (AVM) has been developed that closely resembles a human AVM o f the brain. The creation of such a model requires sophisticated neurointer ventional techniques. The purpose of this study was to develop a simple and cost-effective AVM animal model that does not require additional endovascu lar techniques. METHODS: A surgical anastomosis was created in seven sheep between the comm on carotid artery and the ipsilateral jugular vein, followed by ligation of the jugular vein above the anastomosis and of the proximal common carotid artery below the anastomosis. The anastomosis was created on the left side in four animals and on the right side in three. Cerebral angiography from t he contralateral carotid artery was performed before and immediately after surgery to delineate the relevant cerebral vascular anatomy and to determin e the direction of blood flow. RESULTS: An angiographic appearance simulating an AVM was found in all the animals. The ramus anastomoticus and arteria anastomotica functioned as the feeding vessels to the rete mirabile, which represented the nidus in our m odel, and to the jugular vein, which represented the draining vein from the malformation. Extensive collateral flow through the rete mirabile into the distal segment of the external carotid artery above the Ligature was obser ved angiographically, with retrograde flow through the surgical anastomosis into the jugular vein. CONCLUSION: A simple surgically created experimental model for cerebral AVM s was developed in sheep without the need for additional complex endovascul ar catheter manipulations of intracranial branches. Such an animal model ca n substantially reduce the cost of research and training in the neurointerv entional or radiosurgical management of AVMs.