Arteriovenous malformation associated with occluded middle cerebral artery

The authors present a rare case of a frontal arteriovenous malformation (AVM) associated with an occlusion of the ipsilateral middle cerebral artery. The association of the AVM and the occlusion of the afferent vessels is not only rare but also presents unique radiological features and difficulty for treatment. The patient. 48 year-old-male, was admitted because of the sudden onset of the right hemiparesis and aphasia. CT scan showed a left frontal intracerebral hematoma with vascular enhanced lesion. Angiography showed an occlusion of the left middle cerebral artery at its origin and AVM in the left frontal area with numerous surrounding moyamoya vessels. Immediately after an uneventfull excision of the AVM, massive brain swelling and multiple arterial bleeding from the brain occured. The hemostasis was impossible and high dose barbiturate coma therapy was started. Postoperative CT showed a massive left frontoparietal hematoma with ventricular rupture. Angiography showed no residual AVM but many stagnant arteries and hyperemia of the surrounding brain. The left middle cerebral artery was well filled via the moyamoya vesel at base. On the 5th postoperaive day, the cranitomy was reopened and the hemotoma was evacuated. No abnormal bleeding or brain swelling was encountered at this time. The patient regained his consciousness after the second surgery and he could walk at the time of discharge. Repeated angiography showed disappearance of the moyamoya vessle resulting in poor filling of the left middle cerebral artery. There are only two well described reported cases of the association of the AVM and the afferent vessel occulsion in the literature. Both of the cases suffered from intraoperative or postoperative normal perfusion pressure breakthrough bleeding (NPPB). There are many factors explaining high risk of NPPB in this combination of the disease. The occlusion of the major afferent cerebral artery causes further ischemia of the chronicaly hypoperfused surrounding brain rendering more loss of the autoregulation of the vessels in it. Moyamoya vessels developed for collateralls are so vulnerable and easily torn by hemodynamic stress. Athough it is rare, the association of the occlusion of the afferent vessels with AVM is not coincidental phenomenon, because there is no episode of acute occlusion of the vessel in the reported cases and gradual occlusion with the development of moyamoya collateral was oberved in many cases. This gradual stenosis and occlusio