National Organization for Rare Disorders, Inc.
It is possible that the main title of the report Arteriovenous Malformation is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.
Arteriovenous malformation (AVM) is a vascular lesion that is a tangle of vessels of varying sizes in which there is one or more direct connections between the arterial and venous circulations. In the lesion there is no capillary bed, which is part of normal tissue. Brain AVMs are often presumed to be congenital, but there is no direct evidence that they form in utero. The distribution of age at detection for brain AVMs is normally-distributed with the mean age in the mid-30's. Although a small number of AVMs manifest themselves at or shortly after birth, most of them present later in life, and just as likely, form and progress during the later years of life. The lack of capillaries allows blood traveling through the abnormal fistulous connections to flow rapidly. The low resistance of the direct A-V connections, termed fistulas, results in very high flow rates in the vessels leading to and within the AVM. These high flow rates can lower the pressure in the arteries leading to the AVM and to surrounding relatively normal brain tissue. Further, because of the direct A-V connections, the pressure in the arteries, even if somewhat reduced, are transmitted to the veins draining the AVM and surrounding brain, which normally operate at very low pressures. AVM can occur in many different parts of the body, but those located in the central nervous system (brain and spinal cord) can cause problems that affect the brain like other forms of stroke.
HHT Foundation International, Inc.
P.O. Box 329
Monkton, MD 21111
NIH/National Institute of Neurological Disorders and Stroke
P.O. Box 5801
Bethesda, MD 20824
Vascular Disease Foundation
550 M Ritchie Highway
Severna Park, MD 21146
Genetic and Rare Diseases (GARD) Information Center
PO Box 8126
Gaithersburg, MD 20898-8126
National Organization of Vascular Anomalies
PO Box 38216
Greensboro, NC 27438-8216
Venous Disease Coalition
1075 S. Yukon Street, Suite 320
Lakewood, CO 80226
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It is possible that the title of this topic is not the name you selected. Please check the Synonyms listing to find the alternate name(s) and Disorder Subdivision(s) covered by this report
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Last Updated: 2/7/2013
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