What Is It, Causes, Symptoms, and More

Author: Lily Guo

Editors: Alyssa Haag, Józia McGowan, DO, Kelsey LaFayette, DNP, RN

Illustrator: Jessica Reynolds, MS

Copyeditor: Sadia Zaman, MBBS, BSc

What is angiodysplasia?

Angiodysplasia, also known as angioectasia or arteriovenous malformation, refers to a tortuous (twisted) and swollen blood vessel in the mucosal and submucosal layers of the gastrointestinal (GI) tract. It is the most frequent etiology of small bowel bleeding in individuals older than 60 years of age. The segments of the GI tract are divided into four layers: the mucosa (epithelium, lamina propria, and muscularis mucosa), the submucosa, the muscularis propria (inner circular muscle layer, intermuscular space, and outer longitudinal muscle layer), and the serosa. With angiodysplasia, the vessels found directly adjacent to the lumen, or opening, of the GI tract can become fragile and can burst leading to blood loss. It is the most common vascular malformation in the GI tract and most frequently occurs in the colon. It can also affect the large intestine, small intestine, or stomach. 

What causes angiodysplasia?

While the exact mechanism of angiodysplasia is unknown, it is thought that the muscularis propria, or the thick muscular layer of the GI tract, may increase in contractility, thereby obstructing the submucosal veins. These veins drain the mucosal and submucosal layers as they course through the muscularis propria. Over time, the obstruction may cause the submucosal veins to dilate, or widen, and become tortuous, along with all the the venules and capillaries that subsequently drain them. 

Age-related degeneration of small blood vessels and cardiovascular and pulmonary disease are also risk factors. These conditions may cause hypoperfusion of vessels, thereby causing abnormal lesions and ischemic necrosis. Heyde syndrome refers to the triad of aortic stenosis (a condition that occurs when the heart valve controlling the aorta narrows and becomes constricted), an acquired coagulopathy, and anemia due to bleeding from intestinal angiodysplasia. Heyde syndrome is thought to be due to alterations in the blood’s coagulation factors, such as Von Willebrand factor (VWF). Additionally, when VWF is absent or deficient, it can cause Von Willebrand disease (VWD), a blood disorder in which the blood does not clot properly, and can lead to bleeding from upper and lower GI angiodysplasia lesions. 

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What are the signs and symptoms of angiodysplasia?

Individuals with angiodysplasia may be asymptomatic or have mild to moderate occult lower GI bleeding without abdominal pain. Occult bleeding is defined as gastrointestinal bleeding that is not visible to the person or clinician, but stool samples are positive for blood. If angiodysplasia bleeds, the appearance can vary based on the source and location of the bleed. For example, slow bleeding from the stomach or small intestine may present as melena, which refers to dark and sticky feces. If the bleeding is from the colon, it may present as bright, red blood. If there is excessive bleeding, or slow occult bleeding over a longer period of time, one can show symptoms of iron-deficiency anemia. This includes excess fatigue, shortness of breath, or a heart murmur. The prevalence of angiodysplasia increases with age and mainly occurs in individuals over 60 years of age. If there is underlying aortic stenosis associated with the angiodysplasia, cardiac examination may show a systolic ejection murmur. In cases of acute and heavy bleeding from the abnormal vessel, orthostasis and hypotension may occur.

How is angiodysplasia diagnosed?

Angiodysplasia is typically diagnosed on incidental finding during a colonoscopy for colorectal cancer screening exams, or when evaluating the patient for acute or chronic blood loss related anemia. For these diagnoses, a medical history is typically obtained, assessing for the presence of weakness, dizziness, or hematemesis (i.e., blood present in vomit). A physical exam is also usually conducted to evaluate an individual’s vitals to ensure they are hemodynamically stable. Various lab tests, including a complete blood count, liver function test, coagulation studies, and renal function tests may be ordered to assess for anemia and diagnose underlying medical conditions associated with the rectal bleeding (e.g., end-stage renal disease or congenital or acquired coagulation disorders). Upper endoscopy, a non-surgical procedure where a flexible tube with a light and camera attached are placed through the mouth to visualize the GI tract, may also be performed to visualize angiodysplasia. Since angiodysplasia can occur further along the GI tract, an upper endoscopy may not be able to visualize the lesion; in these cases, a capsule endoscopy may be used. During this procedure a pill-sized capsule is swallowed and as it travels through the digestive tract, it takes images. Other diagnostic methods include radionuclide scanning images (i.e., an imaging technique that uses a small dose of a radioactive chemical), CT mesenteric angiography, and magnetic resonance angiography (i.e., procedures that use a dye and x-rays to see how blood flows through the arteries). 

How is angiodysplasia treated?

Incidental angiodysplasias found during routine examination do not require treatment if there is no history of GI bleeding or unexplained iron-deficiency anemia. If symptomatic, however, management will often include hemodynamic resuscitation, restoring proper tissue perfusion, complete blood count monitoring, and blood transfusion, if needed. To manage the source of bleeding, argon plasma coagulation (APC) ablation is the most commonly used intervention. APC is a medical endoscopic procedure used to control bleeding from certain lesions in the GI tract. Other interventions include electrocoagulation, which is a procedure that uses heat from an electric current to destroy abnormal tissue, as well as endoscopic clips and band ligation, both of which are mechanical methods used to treat angiodysplasia. Injection sclerotherapy, which involves injecting a sclerosant (i.e., a medicine causing vessels to shrink) to obliterate angiodysplasia, can be used as well. If the cause of bleeding is due to Heyde syndrome, an aortic valve replacement can offer long term resolution of the bleeding.

Can angiodysplasia be cured?

Angiodysplasia may be cured through surgical resection of the part of the GI tract where angiodysplasia is present, or by other treatment options including APC, electrocoagulation, ligation and sclerotherapy. However, if there are no adverse symptoms of angiodysplasia, it is very likely that it does not have to be treated or cured. In fact, most bleeding angiodysplasias will cease spontaneously. Overall, a conservative approach is recommended especially for those who are hemodynamically stable. 

What are the most important facts to know about angiodysplasia?

Angiodysplasia are swollen and tortuous blood vessels found in the mucosal and submucosal walls of the GI tract. Most common are angiodysplasias of the colon, followed by the small intestine, and the stomach. It is not clear what the cause is, however, it may be due to increased contractility of the muscles lining the GI tract. Diagnosis relies on a thorough medical history and physical exam, as well as lab studies, endoscopy, and imaging. Treatment is not always indicated, especially if the bleeding stops on its own. If there is profuse bleeding, the goal is to restore any blood lost and stop the bleeding. This can be done through APC ablation, electrocoagulation, endoscopic clips, or sclerotherapy. If the angiodysplasia persists despite conservative management, surgery may be indicated and is curative. 

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Related links

Gastrointestinal bleeding: Pathology review
Gastrointestinal system anatomy and physiology

Resources for research and reference

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