Development in Intracoronary Stents

I n 1964, Dotter et al used the term “stent” to describe wire tubular implants that could be placed in femoral arteries of animals with non-surgical techniques for the first time. The first reports on the use of intravascular stents were made much later, in 1983, by Dotter et al and Gragg et al who placed a wire spring of nitinol in arteries of dogs using a catheter. These reports served as a catalyst for the conduction of experimental research in order to develop such novel devices. In 1985, Gianturco et al published their conclusions on implantation of self-expanding intravascular wire stents in animals. In the same year, Palmaz et al introduced the concept of transferring the intravascular stent in a non-deployed balloon and placing it exactly at the lesion site. In 1987, Roussau, Roubin and Schatz reported placements of various types of intravascular stents in animals in their publications. A common finding of all researchers, was the severe problem of acute or subacute thrombosis despite intensive anticoagulative treatment. These reports in cardiology, but not radiology reviews, signaled a change of orientation for the intravascular stent technique from the vascular radiology field towards the interventional cardiology domain. In 1986, the first implantation in a human subject was carried out by Jacques Puel (Toulouse, France) and soon after that, Ulrich Sigwart announced the implantation of 24 self-expanding, intracoronary mesh type stents in 19 patients. The initial indications of intracoronary stent placement were: a) restenosis of prior angioplasty, b) stenosis of aortocoronary grafts, and c) acute artery occlusion, due to dissection during balloon angioplasty. The first favorable results came from a new, so called “Giantourco-Roubin”, stent. In 1991, Schatz announced the results of a multi-center study on 229 intracoronary stent placements in 230 lesions, on 213 patients, using a new, so called “Palmaz-Schatz” stent. Subacute thrombosis reached a rate of 14%, and restenosis 40% in 6 months, i.e. the rates of conventional angioplasty, despite the use of a high-dosage anticoagulative treatment that caused bleeding disorders and prolonged hospitalization. High thrombosis rates convinced cardiologists that intracoronary stents, being foreign bodies, exhibited high thrombogenicity. Using high pressure balloons, Antonio Colombo achieved the best, most symmetrical deployment of intracoronary stents, improving blood flow through them. This resulted in lower thrombosis rates and reduction of anticoagulative treatment. Using high-dosage antiplatelet treatment and without using anticoagulative drugs, subacute and acute thrombosis have been restricted today to acceptable levels. The Benestent and Stress studies established intracoronary stent implantation as a method that reduces restenosis rates at least in one lesion class, and allowed researchers to focus on the enhancement of intracoronary stent features and concomitant medication, in Development in Intracoronary Stents