Coronary stenting as an adjunct to balloon angioplasty

Andreas Gruentzig initiated the era of interventional cardiology in 19n with the introduction of percutaneous transluminal coronary angioplasty (PTCA) (1). The acceptance of coronary angioplasty is obvious by the widespread use of the procedure (>300,000 cases in the United States in 1990), the growing list of patient indications and the existence of an extensive infrastructure to support the procedure Qncluding the expansion of catheterization laboratories, fellowship trainee programmes, and substantial involvement by industry that has dedicated itself to continued improvement in advanced x-ray imaging systems, and angiop!asty hardware equipment). Yet despite the growth and success of PTCA, the first human coronary stent implantations were performed in 1986 in Lausanne, Switzerland by Ulrich Sigwart and in Toulouse, France by Jacques Puel (2). In fact, in the past fwe years several other devices have been clinically tested as alternatives or adjuncts to PTCA including directional atherectomy, rotational abrasion, and different types of laser therapy. These devices have been introduced due to the limitations of balloon angioplasty, namely early occlusion and restenosis within the first 6 months following angioplasty, which have persisted despite extensive attempts to find pharmacological solutions to these problems (3-5). $tents are devices that are implanted intraluminally to provide mechanical support. A number of devices have been developed that differ in composition. design, and mechanical behavior. According to Dr. Philip Urban of Geneva, the initial attempts to implant tubes inside vessels, are described in an article published by Alexis Carrel from New York in September 1912 in the American monthly ~surgery, Gynaeco!ogy and Obstetrics· (6). In these early experiments. 7 dogs were implanted with short glass tubes into the thoracic aorta, 3 animals received aluminium tubes and in 1 animal a gold plated alluminium tube was inserted through a surgical incision inside the thoracic aorta. Thrombosis of the tube occurred in 5 cases between 5 and 97 days after the implantation. Two animals died from hemorrhage 8 and 11 days following the operation. In 1969, Charles Dotter revived the concept when he implanted impervious plastic tube grafts in the normal canine femoral and popliteal arteries (7). His initial attempts failed due to thrombosis within the first 24 hours but patency rates improved when he substituted stainless steel coils instead of tubes and included heparin infusions for 4 days after implantation {8). In 1991, a variety of endovascular stent designs are under cHnical and experimental evaluation. Changes in design, the use of metal alloys and miniaturization of the endoprostheses has resulted in the availability of several type of stents for experimental and clinical evaluation.