Gastrointestinal Arterio-venous malformations: Clinical and endoscopic experience with 124 patients and analysis of risk factors

Arterio-venous malformations (AVMs) of the gastrointestinal tract despite being uncommon are a significant cause of morbidity due to hemorrhage and anemia. Little is known however of their natural history, mode of presentation and risk factors. The aim of this study was to (1) analyze our clinical and endoscopic experience in a large cohort of patients with AVMs and (2) to look for risk factors. Methods: A computerized database for endoscopic procedures was reviewed for the last four years. Patients with findings of AVMs were selected and their medical records were reviewed for demographics, presentation of gastrointestinal bleeds, medication usage, reasons for endoscopy, and co-morbid conditions in comparison to age matched control. Results: 124 patients out of 14,367 (0.86%) patients who were endoscoped had findings of AVMs in their gastrointestinal (GI) tract. Bleeding AVMs constituted 4.06% of all causes of gastrointestinal bleeding during this four year period. The average age of patients was 58.8 years with no gender bias. 23.4% of patients presented with iron deficiency anemia, 7.3% with hemetamesis, 16.1% with heme positive stools, and 21.7% with symptoms unrelated to GI bleed. On endoscopy, 52.8% of the patients had multiple AVMs, and 47.2% had a single AVMs. By location, 19.4% of the patients had AVMs in the stomach, 24.5% in the duodenum, 1.6% in the small bowel, 18.5% in the right colon, 4% in the transverse colon, and 16.9% in the left colon. 15.4% had AVMs at multiple sites. There was no significant difference in frequency of co-morbid conditions such as hypertension, diabetes, and renal failure between patients with AVMs and aged matched non-AVMs GI bleed patients. In 32 patients (27.6%), the findings of AVMs were incidental. Multiple AVMs were less likely to be an incidental finding when compared to patients with single AVMs (p<0.0002). In addition, patients with multiple AVMs presented with significantly lower hemoglobin when compared to single AVMs patients (Hb 7.8 vs HB 9.0). Conclusions: Arterio-venous malformations are an uncommon cause of gastrointestinal bleed. No clinical risk factors can be identified that predict the presence of AVMs or the severity of bleeding. However, patients with multiple AVMs are more likely to be symptomatic and pose a more serious clinical problem.