Arteriovenous malformation of the brain

Hartmann, A., Mast, H., Choi, J. H., Stapf, C. Mohr, J. P. (2007) Treatment of arteriovenous malformations of the brain. Current Neurology and Neuroscience... 

About 10% of people with HHT die prematurely or are disabled due to complications of their vascular malformations. These events are preventable by early diagnosis, treatment, and follow-up. Most patients are largely asymptomatic before their first serious complication. Approximately 50% of patients with HHT will have an arteriovenous malformation of the brain, lung, or liver, or a combination of two or three and will require therapy usually by a pluridisciplinary team consisting of internists and interventional radiologists with special expertise in this disorder. 

Arteriovenous malformations of the brain (brain AVMs) correspond to congenital cerebrovascular anomalies, also known as intracerebral or pial AVMs. First of all, it is important to stress the fact that this is not a neoplastic lesion and therefore not an angioma , which is obviously an inappropriate though commonly used term (Rosenblum et al. 1996). 

Aberfeld DC, Rao KR (1981) Familial arteriovenous malformation of the brain. Neurology 31 184-186 Aesch B, Lioret E, deToffel B et al. (1991) Multiple cerebral angiomas and Rendu-Osler-Weber disease case report. Neurosurgery 29 599-602... 

Al-Shahi R, Warlow C (2001) A systematic review of the frequency and prognosis of arteriovenous malformations of the brain in adults. Brain 124 1900-1926 Amin-Hanjani S, Robertzon R, Arginteanu MS, Scott RM (1998) Familial intracranial arteriovenous malformations. Case report and review of the literature. Pediatr Neurosurg 29 208-213... 

Andrews BT, Wilson CB (1987) Staged treatment of arteriovenous malformations of the brain. Neurosurgery 21 314-323... 

Fults D, Kelly DL (1984) Natural history of arteriovenous malformations of the brain a clinical study. Neurosurgery 15 658-662... 

Merland JJ, Rufenacht D, Laurent A et al. (1986) Endovascular treatment with isobutyl cyanoacrylate in patients with arteriovenous malformation of the brain indications, results and complications. Acta Radiol 369 621-622... 

Nakstad PH, Nornes H (1994) Superselective angiography, embolisation and surgery in treatment of arteriovenous malformations of the brain. Neuroradiology 36 410-413 Nakstad PH, Bakke SJ, Hald JK (1992) Embolization of intracranial arteriovenous malformations and fistulas with polyvinyl alcohol particles and platinum fibre coils. Neuroradiology 34 348-351... 

Taki W, Kikuchi H, Iwata H et al. (1990) Embolization of arteriovenous malformations using EVAL mixture (a new liquid embolization material). Neuroradiology 33 195-196 Terada T, Nakamura Y, Nakai K, Tsuura M et al. (1991) Embolization of arteriovenous malformations with peripheral aneurysms using ethylene vinyl alcohol copolymer report of three cases. J Neurosurg 75 655-660 The Arteriovenous Malformation Study Group (1999) Arteriovenous malformations of the brain in adults. N Engl J Med 340 1812-1818... 

Advances A. M. Landolt Progress in Pituitary Adenoma Biology. Results of Research and Clinical Applications. — J. Hildebrand and J. Brihaye Chemotherapy of Brain Tumours. — S. Mingrino Supratentorial Arteriovenous Malformations of the Brain. 

Cyanoacrylate (Histoacryl) is a tissue adhesive used in duraplasty. The sites at which it is used should be carefully chosen. Cyanoacrylates are also in use for embolization of arteriovenous malformations in the brain. The risk of this procedure is the creation of pulmonary emboli after acrylate glue injection, particularly when delivery systems without flow arrest are used in high-flow vascular brain lesions. Techniques using acetic acid to delay polymerization time and sandwich techniques, in which glue is pushed with dextrose, appear to be more likely to cause this complication (1). 

Meyer B, Stangl AP, Schramm J (1995) Association of venous and true arteriovenous malformation a rare entity among mixed vascular malformations of the brain. J Neurosurg 83 141-144... 

Vascular malformations of the brain are usually divided into arteriovenous malformations, capillary telangiectasias, venous malformations, and cavernous malformations. However, for a long time, the term angiographically occult vascular malformation or cryptic (Cohen et al. 1982 Dillon 1997 Wilson 1992) has been used to describe those vascular malformations that could not be visualized angiographically, but obviously were able to cause intracerebral hemorrhage. 

Moyamoya seems to be mainly confined to the Japanese and other Asians, and in most cases the cause is unknown (Bruno et al. 1988 Chiu et al. 1998). Some cases are familial (Kitahara et al. 1979) others appear to be caused by a generalized fibrous disorder of arteries (Aoyagi et al. 1996), and a few may result from a congenital hypoplastic anomaly affecting arteries at the base of the brain, or associated with Down s syndrome (Cramer et al. 1996). The syndrome may present in infancy with recurrent episodes of cerebral ischemia and infarction, mental retardation, headache, epileptic seizures and, occasionally, involuntary movements. In adults, subarachnoid or primary intracerebral hemorrhage are also common owing to rupture of collateral vessels. There have also been a few reports of associated intracranial aneurysms (Iwama et al. 1997) and also of cerebral arteriovenous malformations. 

For subarachnoid hemorrhage surgical clipping of the causative aneurysm or resection of the arteriovenous malformation is the mainstay of treatment. Endovascular coiling of the aneurysm can also be performed. Post-operative infection (either brain or respiratory) is an uncommon complication and not believed to be any more common than after other invasive surgical procedures. Hypervolemic-hemodilution and hypertensive (HHH) therapy is used to prevent spasm. There may be a role for anti-inflammatory measures for the prevention of vasospasm and delayed cerebral ischemia, as shown in a recent pilot study of patients treated with statins (Lynch et al., 2005). 

One simple but smart example of a fibrous implantable medical device that uses the high surface ratio feature of fibers is embolization coil. Such devices are intended for many endovascular treatments of aneurysms, hemorrhages of peripheral lesions, and arteriovenous malformations. The procedure involves the threading of thin coils through a catheter into the affected area of the brain, filling the weakened portion of the vessel. Once in place, the body responds by forming a clot around the coil, further reducing the pressure and risk of rupmre. 

Hemorrhagic strokes account for 12% of strokes and include subarachnoid hemorrhage, intracerebral hemorrhage, and subdural hematomas. Subarachnoid hemorrhage may result from trauma or rupture of an intracranial aneurysm or arteriovenous malformation. Intracerebral hemorrhage occurs when a ruptured blood vessel within the brain parenchyma causes formation of a hematoma. Subdural hematomas are most often caused by trauma. 

Arteriovenous malformations present most commonly with signs consistent with a space-occupying lesion or seizures and consist of an abnormal fistulous connection(s) between one or more hypertrophied feeding arteries and dilated draining veins (Clatterbuck et al. 2005) (Fig. 7.5). The blood supply is derived from one cerebral artery or, more often, several, sometimes with a contribution from branches of the external carotid artery. Arteriovenous malformations vary from a few millimeters to several centimeters in diameter. Approximately 15% are associated with aneurysms on their feeding arteries. Some grow during life but a few shrink or even disappear, and some are multiple. These fistulae occur in or on the brain, or in the dura of the intracranial sinuses. 

Telangiectasias are collections of dilated capillaries that are usually of no clinical significance (Milandre et al. 1987). They may be associated with hereditary hemorrhagic telangiectasia (the Osler-Weber-Rendu syndrome), but this is more likely to be associated with neurological complications from a pulmonary arteriovenous malformation with right-to-left shunting, such as cerebral hypoxia, brain abscess, paradoxical and septic embolism, or from an associated intracranial arteriovenous malformation or aneurysm (McDonald et al. 1998). 

Arteriovenous malformations—A tangle of blood vessels, both arterial and venous, that can rupture and cause hemorrhage in the brain. 

Debrun (1997) Embolization of the nidus of brain arteriovenous malformations with n-butyl cyanoacrylate. Neurosurgery, 40, 112-121. 

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