Spatial clustering of simultaneous nonhereditary gastrointestinal angiodysplasia. Small but significant correlation between nonhereditary colonic and upper gastrointestinal angiodysplasia.

Simultaneous nonhereditary colonic and upper gastrointestinal angiodysplasia were spatially clustered in an endoscopic study of 46 consecutive patients. For example, clustering of colonic angiodysplasia was demonstrated using a nonparametric test of clustering (Kruskal-Wallis statistic with 29 degrees of freedom = 76.2, P less than 0.0005), and a parametric test of clustering (F test statistic with 29 and 101 degrees of freedom = 6.91, P less than 0.0005). In accord with spatial clustering, only two of 13 patients (15%) with colonic angiodysplasia who underwent panendoscopy had upper gastrointestinal angiodysplasia. Two of nine patients (22%) with upper gastrointestinal angiodysplasia who underwent colonoscopy had colonic angiodysplasia. These findings suggest that local factors may be important in the pathogenesis of simultaneous nonhereditary angiodysplasia. Possible local factors include intermittent venous obstruction, increased intraluminal pressure, intermittent abnormal arterial flow, and local vascular degeneration. Due to the approximately 20% correlation between upper and lower nonhereditary gastrointestinal angiodysplasia, the upper and lower tract should be examined by endoscopy prior to elective local resection for bleeding from gastrointestinal angiodysplasia.