Current status of intracoronary stents

Abstract

Although a decade of experience has resulted in improved initial success of percutaneous transluminal coronary angioplasty (PTCA) even in the presence of more difficult anatomic problems (1, 2), the technique fails to yield lasting results in a significant percentage of patients. Early failures occur due to abrupt coronary artery closure in approximately 5%–7% of all patients (3, 4), and it is in these patients that most of the procedure related morbidity is encountered (3, 5). Restenosis appears in approximately a quarter of all patients within six months and in over one half of the patients undergoing vein graft PTCA (7, 8). Although a number of clinical, angiographic and procedural factors have been identified which appear to be associated with an increased risk of acute occlusion (3, 4, 9, 10, 11) and restenosis (6, 7, 8), the occurrence of these events in individual patients remains unpredictable. If one assumes that the results obtained in 14 experienced American centers participating in the 1985–86 NHLBI registry are similar to those in current practice, performance of 250 000 procedures annually world-wide would be expected to result in 19 000 acute closures (a 7.7% incidence) and 2 750 in-hospital deaths (a 1.1% incidence). Restenosis would be expected in at least 75 000 patients (assuming a 30% incidence). The enormous cost and morbidity related to these major limitations of PTCA have fostered innovative new invasive approaches aimed at maintenance of coronary luminal integrity. Placement of intracoronary stenting devices, a concept introduced by Dotter two decades ago (12), has been performed in several animal models and a number of different stent designs are currently undergoing clinical trials. Although still in an embryonic stage with respect to design features, determination of clinical utility and indications, and optimal adjunctive therapy, these new techniques have stimulated intense interest and may provide a method for treatment of patients who are now failures of PTCA or they may even become a routine component of angioplasty in some specific patient subgroups. The place of intravascular stenting in our therapeutic armamentarium will be determined by critical analysis of ongoing laboratory and clinical evaluations and technological improvements.