AN EXPERIMENTAL-STUDY OF ENDOVASCULAR STENTING WITH SPECIAL REFERENCETO THE EFFECTS ON THE AORTIC VASA VASORUM

Purpose: To evaluate the effects of bare stents and covered stents on the aortic wall, especially the vasa vasorum. Methods: Eight bare sten ts and nine covered stents were placed in the infrarenal aorta of nine dogs. The dogs were euthanized at 4-45 weeks after stent placement, T he vasa vasorum was evaluated by microstereoscopy with vascular castin g, and the histopathology of the aortic wall was examined by light mic roscopy.Results: In the unstented normal aorta, vasa vasorum nourished the adventitia and the outer media, and the intima and inner media we re avascular. In the stented segment, vascular dilatation and prolifer ation of vasa vasorum, medial atrophy, and intimal hyperplasia were ob served, more prominent for covered stents than for bare stents. Conclu sion: Intravascular stent placement caused not only medial atrophy and intimal hyperplasia but also proliferation of the vasa vasorum, proba bly due to hypoxia in the aortic wall.