Occlusion and restenosis are the most common reasons that transluminal balloon angioplasty may fail to provide long-term benefit. An intravascular mechanical support was therefore developed with the aim of preventing restenosis and sudden closure of diseased arteries after angioplasty. The endoprosthesis consists of a self-expandable stainless-steel mesh that can be implanted nonsurgically in the coronary or peripheral arteries. Experiments in animals showed complete intimal coverage within weeks and no late thrombosis during a follow-up period of up to one year. We performed 10 implantations in 6 patients for iliac or femoral arterial disease; 24 coronary-artery stents were implanted in 19 patients who presented with coronary-artery restenoses (n = 17) or abrupt closure (n = 4) after transluminal angioplasty or deterioration of coronary-bypass grafts (n = 3). We observed three complications in the group with coronary disease. One thrombotic occlusion of a stent resulted in asymptomatic closure, a second acute thrombosis was managed successfully with thrombolysis, and one patient died after bypass surgery for a suspected but unfound occlusion. Follow-up in the patients has continued for nine months without evidence of any further restenoses within the stented segments. Our preliminary experience suggests that this vascular endoprosthesis may offer a useful way to prevent occlusion and restenosis after transluminal angioplasty. Long-term follow-up will be required to validate the early success of this procedure.