Angiodysplasia

Angiodysplasias are acquired vascular ectasias of the GI mucosa and submucosa, characterized by dilated, thin-walled veins and capillaries with reduced smooth muscle support. They are the second most common cause of lower GI bleeding in adults over 60 and a major cause of obscure GI bleeding. The right colon is the most common location, but lesions can occur anywhere from the stomach to the rectum.

Endoscopically, angiodysplasias appear as small (typically 2–10 mm), red, fern-like or stellate vascular patterns flat against or slightly raised above the mucosal surface. They can be subtle, particularly in the right colon, and may be missed when the colonic mucosa is poorly distended. Bleeding is usually intermittent and chronic, presenting as iron-deficiency anemia or recurrent hematochezia.

Heyde syndrome describes the association of aortic stenosis with GI angiodysplasia bleeding, mediated by acquired type 2A von Willebrand syndrome from shearing of vWF multimers across the stenotic valve. Aortic valve replacement often resolves the bleeding diathesis.

Argon plasma coagulation is the workhorse endoscopic treatment, with band ligation, clipping, and bipolar coagulation as alternatives. Pharmacologic adjuncts (octreotide, thalidomide, hormonal therapy) can be considered for diffuse or refractory disease.