Embolic effects of transcatheter mesenteric arterial embolization with microspheres on the small bowel in a dog model

To determine the arterial distribution and ischemic effects of various particle sizes after transcatheter embolization of the small bowel in a dog model.

In 10 dogs, selective microsphere embolization was performed in six branches of the superior mesenteric artery. Microspheres were allocated into three size ranges (100-300 μm, 300-500 μm, and 500-700 μm) and four volume concentrations (0.625%, 1.25%, 2.5%, and 5%). For each size and volume concentration, embolization was performed of five branches at the origin of the last arcade. The distribution of microspheres and the range of ischemic changes of mucosa were evaluated histologically. Angiograms were categorized into two groups: group A, only the vasa recta nonopacified; group B, the last arcade or more proximal branches nonopacified.

Microspheres sized 100-300 μm penetrated into intramural arteries and 500-700 μm microspheres mainly blocked arteries in the mesentery. There was a significant difference among three sizes in terms of the locations within the vasculature (P < .0001). The larger volume and the smaller size resulted in more ischemia. The range of ischemic changes among three sizes and among four volume concentrations was significantly different (P = .004 and P < .0001, respectively). The range of ischemic changes with 500-700 μm microspheres in group B was significantly greater than in group A (0% in group A vs 83% in group B, P = .001).

In a dog model, embolization of the small bowel limited to the vasa recta with the use if 500-700 μm microspheres reduced the range of ischemic changes.