II. Definitions
- Arteriovenous Malformation
- Abnormal blood vessel configuration in which blood is shunted directly from arteries to veins, bypassing capillaries
- Either a single dilated artery or arteriole, or clusters of dilated arteries and arterioles join and connect directly to a vein
- Cerebral AV Malformations are the most common Clinically Significant AVMs, and risk Intracerebral Hemorrhage
- Arteriovenous Fistula
- Subtype of AV Malformation, in which a single dilated artery connects to a single vein
- Angiodysplasia
- Acquired dilation or ectasia of blood vessels, that develops with aging
- Results in single, tortuous, thin walled vessels (esp. capillaries) prone to bleeding
- Most commonly affects the Gastrointestinal Tract, presenting with GI Bleeding
III. Background
- Vascular Malformations are a subset of vascular anomalies (vascular tumors and Vascular Malformations)
- Vascular tumors include Hemangiomas (infantile or Congenital Hemangiomas)
- Vascular Malformation Types (vascular proliferation)
- Slow flow (venous)
- Capillary malformation
- Venous malformation
- Lymphatic malformation
- Fast flow (arterial)
- Arterial malformation
- Arteriovenous Fistula
- Arteriovenous Malformation
- Slow flow (venous)
IV. Causes: Genetic AV Malformation
-
Hereditary Hemorrhagic Telangiectasia (HHT, or Osler-Weber-Rendu Syndrome)
- Spontaneous Epistaxis
- Mucocutaneous Telangiectasia
- Visceral Arteriovenous Malformations
- HHT Family History
- Capillary Malformation - Arteriovenous Malformation (CM-AVM)
- Cerebral Cavernous Malformation (CCM)
- Cutaneous Venous Malformation (VMCM)
V. References
- Zyck and Sampath (2021) Arteriovenous Malformations, Stat Pearls, Treasure Island, accessed 3/30/2022
- Whitehead (2013) Cold Spring Harb Persp Med 3:a006635 [PubMed]