This study was designed to assess the efficacy of a metallic, rigid, balloon-expandable stent (Palmaz-Schatz) for occlusion of an aneurysm. First, a glass model of two types of aneurysms was constructed, one simple lateral aneurysm and one lateral aneurysm with a side branch. After placement of the stent, the flow towards the distal, post-aneurysmal part of the glass tube was increased with immediate reduction of the flow towards the aneurysm. Beside some turbulences around the struts of the stent there was some inflow of dye into the aneurysm with partial and delayed filling of the aneurysm and delayed washout of the dye from the aneurysm. The same observations could be made with the side-branch aneurysm model. Although parts of the struts involved the ostium of the side branch, there was no flow alteration towards this branch. Second, 10 experimentally constructed aneurysms of the carotid artery in beagles were treated with stents. These stents were placed transfemorally and, since the stents were barely visible under fluoroscopy, angioscopy was performed before and after stenting in order to improve positioning of the stent. In 8 out of 10 cases placement of the stent resulted in an immediate complete occlusion of the aneurysm with remaining patency of the carotid artery. In the other 2 cases, a delayed, but complete occlusion was achieved. In one case, the carotid artery was completely occluded at a follow-up angiography after two weeks, probably induced by intimal damage during insertion of the stent. In two other cases, there was considerable stenosis of the carotid artery due to intimal proliferation.(ABSTRACT TRUNCATED AT 250 WORDS)