Histology and angiography in a bifurcation aneurysm model.

Laser-sealed arteriotomy has recently been shown to produce a reliable saccular aneurysm model. By applying this method to the rat abdominal aorta and performing serial angiography, the behavior of this aneurysm model at an arterial bifurcation has been studied for the first time. Three days after laser-sealed arteriotomy, no aneurysms were found, but in animals studied 7, 14, 21, and 28 days after laser-sealed arteriotomy, a 100% (17/17) aneurysm formation rate was achieved. Serial angiography did not demonstrate significant changes in size when performed at 2-week intervals, but angiography significantly underestimated true aneurysm size (p less than 0.001) as a function of increasing aneurysm diameter (p less than 0.001). By light-microscopic analysis, these aneurysms were similar to human cerebral saccular aneurysms. This saccular aneurysm model could be used to study various surgical and interventional radiology techniques in experimental animals.