Colonic Angiodysplasia

Colonic angiodysplasia is the second most common cause colonic arterial bleeding in patients over 50 years of age (later than diverticulosis). They are found most commonly on the right and are characterized by clusters of dilated thin-walled veins in the submucosa.

Hemorrhage from angiodysplasia is episodic, making specific localization by extravasation of contrast media the exception rather than the rule. Angiography will show a cluster of small arteries during the arterial phase along the antimesenteric border of the colon. There will be accumulation of contrast material in vascular spaces and intense opacification of the bowel wall during the capillary phase followed by early opacification of dilated draining veins that persists late into the venous phase.

For some reason, bleeding from angiodysplasia is associated with aortic stenosis, a complex referred to as Heyde syndrome. More strange still, bleeding usually stops after aortic valve replacement. It has been suggested that this has to do with acquired type IIA von Willebrand syndrome, a deficiency of high-molecular-weight multimers of von Willebrand factor.

References

• Baum S, Athanasoulis CA, Waltman AC, Galdabini J, Schapiro RH, Warshaw AL, Ottinger LW. Angiodysplasia of the right colon: a cause of gastrointestinal bleeding. AJR Am J Roentgenol. 1977 Nov;129(5):789-94.
• Warkentin TE, Moore JC, Morgan DG. Gastrointestinal angiodysplasia and aortic stenosis. N Engl J Med. 2002 Sep 12;347(11):858-9.