Practice of GIM

Angiodysplasia of the Gastrointestinal Tract and Bleeding: An Overview

Narmin Kassam, MD, Anca Tapardal, MD, Alan Thomson, MD

About the Authors

Narmin Kassam and Alan Thomson are members of the Division of General Internal Medicine, University of Alberta, Edmonton, Alberta. Anca Tapardal is a fourth-year internal medicine resident.

Angiodysplasia is the most common vascular abnormality of the gastrointestinal (GI) tract and the second leading cause of lower GI bleeding in patients older than 60 years, after diverticulosis.1 Phillips first described a vascular abnormality that caused bleeding from the large bowel in a letter to the London Medical Gazette in 1839. Galdabini first used the name angiodysplasia in 1974. However, confusion about the exact nature of these lesions resulted in a multitude of terms that included arteriovenous malformation, hemangioma, telangiectasia, and vascular ectasia. These terms have varying pathophysiologies that all present with GI bleeding.

Pathophysiology

Angiodysplasia is a degenerative lesion of previously healthy blood vessels found most commonly in the cecum and proximal ascending colon. Lesions typically are nonpalpable and small (<5 mm). Seventy-seven percent of angiodysplasias are located in the cecum and ascending colon, 15% are located in the jejunum and ileum, and the remainder are distributed throughout the alimentary tract. Angiodysplasia may present as an isolated lesion but more commonly as multiple vascular lesions. It is not associated with angiomatous lesions of the skin or other viscera.

The exact mechanism of development of angiodysplasia is not known. Chronic venous obstruction may play a role. This hypothesis accounts for the high prevalence of these lesions in the right colon and is based on the Law of Laplace. Wall tension is highest in bowel segments with the greatest diameter, such as the right colon. Dilated submucosal veins are the most consistent histological findings and may represent the earliest abnormality in colonic angiodysplasia, supporting the theory of chronic venous obstruction in the genesis of lesions.

Epidemiology

Angiodysplasia may account for approximately 6% of cases of lower GI bleeding. It may be observed incidentally at colonoscopy in as many as 0.8% of patients older than 50 years.2 Small bowel angiodysplasia may account for 30–40% of cases of GI bleeding of obscure origin. Most patients found to have angiodysplasia are older than 60 years; many are over 70. However, case reports exist of angiodysplasia in young people. Angiodysplasia occurs with equal frequency in men and women, and there is no racial predilection.

Diagnosis

Clinical Presentation

The clinical presentation of angiodysplasia is related to GI bleeding or its consequences. However, because these lesions may be located throughout the GI tract and because the rate of bleeding may be variable, presentations range from hematemesis or hematochezia to occult anemia. Bleeding is usually chronic or recurrent and, in most cases, low grade and painless because of the venous source. The estimated incidence of active, ongoing GI bleeding in patients with angiodysplasia is less than 10%.

Patients with colonic angiodysplasia may present with hematochezia (0–60%), melena (0–26%), hemoccult-positive stool (4–47%), or iron-deficiency anemia (0–51%). Ninety percent of angiodysplastic lesions stop the bleeding spontaneously. Hematemesis is frequently observed in patients with angiodysplasia of the upper GI tract: the presentation of hemodynamically well-compensated, chronic bleeding is typical and often suggests the diagnosis.

Hemodynamic instability may occur if bleeding is massive. This is observed in 15% of cases. Vital signs may demonstrate tachycardia, hypotension, and postural changes based on the amount of blood loss. In most cases, bleeding presents as bright red blood per the rectum but can also be maroon or melena. Stool typically is guaiac positive. Since bleeding may be intermittent, alternating positive and negative guaiac stools can be found. In 40–60% of patients with gastric and duodenal angiodysplasia, multiple lesions are observed at endoscopy, and 15–20% have accompanying colonic lesions that also tend to multiple rather than single.

Associated Conditions

Angiodysplasia has been reported to be associated with a number of other conditions. In 1958, Heyde first reported the combination of calcific aortic stenosis and GI bleeding due to angiodysplasia of the colon.3 A month later, Schwartz suggested a similar association.4 Studies using echocardiography have indicated that only a few patients with angiodysplastic lesions have significant valvular heart disease, with more patients having aortic sclerosis than aortic stenosis.5 Bleeding from angiodysplastic lesions in the upper and lower GI tracts has been reported in patients with von Willebrand’s disease.6 Because factor VIII complex is synthesized partly in vascular endothelial cells, patients with von Willebrand’s disease and angiodysplasia have been proposed to have an underlying endothelial defect that may be related to the subsequent development of the two disorders. Finally, bleeding angiodysplastic lesions in the upper GI tract have been found with a high prevalence in patients with chronic renal failure requiring dialysis.7  

Differential Diagnosis

The differential diagnosis for patients presenting with GI bleeding in a pattern similar to that expected in angiodysplasia includes colon and rectal cancers, colonic polyps, ischemic colitis, diverticulosis, hemorrhoids, metastatic cancer with an unknown primary, portal hypertension, enterocolitis, and other rare conditions. Figure 1 outlines an algorithm for approaching the work-up of patients presenting with GI bleeding.

Figure 1. Approach to acute gastrointestinal bleeding. CBC = complete blood count; EKG = electrocardiogram; GI = gastrointestinal; IVF = intravenous fluids; NG = nasogastric.

Assessment

Approximately 10% of patients who bleed from angiodysplasia present with anemia and iron deficiency only. As many as 15% of patients with bleeding angiodysplasia have stool that is intermittently positive for occult blood.

A number of imaging studies may be useful in the work-up for angiodysplasia. Radionuclide scanning using technetium Tc 99m–labelled red blood cells or 99mTc sulphur colloid can detect bleeding with rates as low as 0.1 mL/min. However, due to the intermittent bleeding nature of angiodysplasia, radionuclide studies are of limited use. Technetium has a long half-life, and repeat imaging may detect bleeding up to 72 hours after a single injection. Technetium Tc 99m sulphur colloid has a half-life of only 3 minutes; therefore, this tracer is helpful only in patients with active bleeding. Although nuclear scans are noninvasive and relatively easy to perform, they lack the specificity of an angiogram in differentiating the nature of bleeding lesions. Nuclear scans also do not have the therapeutic potential of angiography. Selective mesenteric angiography is a useful diagnostic technique, especially in patients with massive bleeding. Active bleeding is detected in 6–20% of patients, depending on the rate of bleeding (as low as 0.5 mL/min), the technique, and timing of angiography in relation to the period of bleeding. The sensitivity of detecting ectatic changes in vascular lesions is 58–86%, but this abnormality may also be observed in other disorders, such as malignancy. Helical computed tomography (CT) angiography can detect extravasation from angiodysplasia and may potentially be an important noninvasive test in patients with obscure, actively bleeding sites. Capsule endoscopy has been reported to detect cecal angiodysplasias in selected cases and is particularly useful to demonstrate actively bleeding in small intestinal lesions, but its role as a diagnostic test for the colon is still experimental.8 Finally, air contrast barium enema is not recommended during acute lower GI bleeding because the lesions are too small to be detected and the contrast can obscure other diagnostic studies.

Endoscopy is the most common and reliable method of diagnosing angiodysplasia in both the upper and lower GI tracts. The endoscopic appearance of lesions typically has been described as discrete, flat, or slightly raised (2–10 mm) and bright red with a stellate configuration (Figure 2).9 A surrounding pale rim or halo may also characterize the lesion. Angiodysplastic lesions encountered as incidental findings generally are small lesions with a pale colouration compared with lesions with recent hemorrhage, which are bright with elevated centres. The endoscopic appearance of angiodysplasia can be confused with the ectasias associated with systemic diseases, such as hereditary hemorrhagic telangiectasia, as well as the CREST (calcinosis cutis, Raynaud’s phenomenon, esophageal dysfunction, sclerodactyly, and telangiectasia) and Ehlers-Danlos syndromes. The lack of systemic manifestations distinguishes angiodysplasia from these syndromes.

Figure 2. Angiodysplasia identified on cecum wall during colonoscopy.

Comparative studies using selective angiography and colonoscopy indicate that the sensitivity of colonoscopy exceeds 80% when the lesions are located in the area examined by colonoscopy. Most angiodysplastic lesions are located in the right colon, so the entire colon must be examined. It goes without saying that the colon must be very well prepared in order for these tiny lesions to be seen. Angiography has the advantage of detecting additional non-colonic angiodysplastic lesions not detected by colonoscopy. Of course, upper endoscopy is preferable to establish a diagnosis of gastric and duodenal angiodysplasia. Push enteroscopy and double-balloon endoscopy are useful to identify small bowel lesions, and retrograde double-balloon endoscopy may allow for careful inspection of the cecum and ileocecal valve.10 Angiodysplasia can be detected very infrequently by visual inspection of the serosal side of the bowel during laparotomy; however, intraoperative enteroscopy can help in the localization of distal small bowel lesions.10

Endoscopic mucosal biopsy for the purpose of diagnosis generally is not recommended because of the low diagnostic yield and the risk of provoking hemorrhage. Biopsy may help to differentiate angiodysplasia from vascular tumours, lesions associated with congenital or systemic disease, or radiation damage.

Treatment

All patients need to be assessed for hemodynamic stability, with volume support and correction of any coagulation abnormality, as required. Gastroenterologists or surgeons may provide specific intervention to control hemorrhage, namely endoscopic obliteration, particularly for angiodysplasia of the colon, stomach, or duodenum. Rebleeding after these techniques may be due to bleeding at other sites rather than a failure of the procedure. The techniques include monopolar electrocautery, heater probe, sclerotherapy, band ligation, and argon and neodymium:yttrium-aluminum-garnet (Nd:YAG) lasers. Argon plasma coagulation is now the treatment of choice for most angiodysplastic lesions. Fifty percent of patients with distal small bowel lesions and no other defined GI bleeding sites benefit from enteroscopy and lesion obliteration.

Angiodysplasia rarely presents with acute, massive hemorrhage; this can be controlled effectively with angiographic therapy. Angiography is appropriate in severely ill patients who are not candidates for surgical intervention. In these patients, transcatheter embolization of selected mesenteric arteries has been effective.11 Angiography also plays an important role in preoperative localization.

Right hemicolectomy for angiodysplasia is second-line therapy after endoscopic ablation, if repeated endoscopic coagulation has failed. The mortality rate associated with surgical resection ranges from 10–50%, depending upon the patient’s comorbidities. Surgical resection is preferred for the acute management of severe hemorrhage or for the management of recurrent hemorrhage over a relatively short period accompanied by a large transfusion requirement. The risk of the left colon becoming a source of future bleeding if left behind is relatively low compared with the increased morbidity and mortality of subtotal colectomy. Partial or complete gastrectomy for the management of gastric angiodysplasia, on the other hand, is followed by rebleeding from other lesions in as many as 50% of patients.

Presently, no medical therapy has been proven to be effective in the management of active bleeding from angiodysplasia. Regularly scheduled octreotide infusion has been reported to decrease the rate of chronic bleeding and is usually well tolerated. It should be the first choice in patients with portal hypertension. Other agents, such as estrogen and progesterone, thalidomide, and desmopressin, are considered experimental, with controversial results in studies, and are used only on the basis of case reports. In the patient with chronic bleeding from angiodysplasia despite endoscopic obliteration, the patient may be maintained on oral iron therapy, their hemoglobin monitored regularly, and blood transfusions given as appropriate.

Prognosis and Follow-Up

Mortality is related to the severity of bleeding, hemodynamic instability, age, and the presence of comorbid medical conditions. Richter et al. reviewed the clinical course of 101 patients with colonic angiodysplasia.12 Fifteen asymptomatic individuals who had never bled were followed up for as long as 68 months (mean 23 months), and no patient experienced bleeding. Thirty-one patients with overt bleeding or anemia managed with blood transfusions alone had rebleeding rates at 1 and 3 years of 26% and 46%, respectively. The high rate of rebleeding justifies treatment for angiodysplasia in symptomatic individuals.

If a patient has asymptomatic angiodysplasia, a repeat colonoscopy is not recommended. Outpatient monitoring of hemoglobin and repeated tests for occult blood can be performed. Patients with chronic GI bleeding may need repeated colonoscopies. No preventive methods have been definitely identified at this time. Avoidance of nonsteroidal anti-inflammatory drugs is recommended in patients with chronic bleeding.

References

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2.         Foutch PG, Rex DK, Lieberman DA. Prevalence and natural history of colonic angiodysplasia among healthy asymptomatic people. Am J Gastroenterol 1995;90:564–7.

3.         Heyde EC. Gastrointestinal bleeding in aortic stenosis. N Engl J Med 1958;259:196.

4.         Schwartz J, Rozenfeld V, Habot B. Cessation of recurrent bleeding from gastrointestinal angiodysplasia, after beta blocker treatment in a patient with hypertrophic subaortic stenosis – a case history. Angiology 1992;43(3 Pt 1):244–8.

5.         Imperiale TF, Ransohoff DF. Aortic stenosis, idiopathic gastrointestinal bleeding, and angiodysplasia: is there an association? A methodologic critique of the literature. Gastroenterology 1988;95:1670–6. 

6.         Fressinaud E, Meyer D. International survey of patients with von Willebrand disease and angiodysplasia. Thromb Haemost 1993;70:546.

7.         Kaaroud H, Fatma LB, Beji S, et al. Gastrointestinal angiodysplasia in chronic renal failure. Saudi J Kidney Dis Transpl 2008;19:809–12.

8.         Kovacs M, Pak P, Pak G, et al. Multiple angiodysplasias diagnosed by capsule endoscopy. Orv Hetil 2007;148:2435–40.

9.         Skibba RM, Hartong WA, Mantz FA, et al. Angiodysplasia of the cecum: colonoscopic diagnosis. Gastrointest Endosc 1976;22:177–9. 

10.       Suzuki N, Arebi N, Saunders BP. A novel method of treating colonic angiodysplasia. Gastrointest Endosc 2006;64:424–7.

11.       Polese L, Angriman I, Pagano D, et al. Laser therapy and surgical treatment in transfusion-dependent patients with upper-gastrointestinal vascular ectasia. Lasers Med Sci 2006;21:140–6.

12.       Richter JM, Hedberg SE, Athanasonlis CA, Schapiro RH. Angiodysplasia clinical presentation and colonoscopic diagnosis. Dig Dis Sci 1984;29:481–5. 

Article Citation: Kassam N, Tapardal A, Thomson A. Angiodysplasia of the Gastrointestinal Tract and Bleeding: An Overview. Can J Gen Intern Med 2009;2(4):64-68