Intervenções Percutâneas em Cardiopatias Congênitas

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.

A new balloon catheter was developed which allows mitral commissurotomy without thoracotomy. The procedure has been successful in five of the six patients with mitral stenosis so treated. In the remaining patient, the procedure could not be performed because of technical difficulties. The balloon is reinforced with a nylon micromesh and its shape changes in three stages, depending on the extent of inflation. It is inserted from the saphenous vein into the mitral orifice transseptally, fixed across the mitral orifice with partial inflation, and finally inflated to full its extent, separating the fused commissures by its expansile force. After the procedure, catheterization revealed a significant reduction in the mean diastolic pressure gradient across the mitral valve without resultant mitral regurgitation in each patient. Two-dimensional echocardiograms showed a marked to moderate degree of dilatation of the mitral orifice in each patient. All five patients are well with remarkable clinical improvements 2 to 16 months after the procedure.