Coronary stenting using Xience v des: general problems, perspectives (a review)

1 Address for correspondence: Dr. Mohammad Matini, Russia, 101000, Moscow, Sverchkov per., 5 Moscow City Center of Interventional Cardioangiology Tel . 007 (495) 624 96 36 Fax 007 (495) 624 67 33 e-mail: zoliz@mail.ru Manuscript received on June 20, 2011. Accepted for publication of September 15, 2001 Endovascular methods of diagnostics and treatment have emerged already in mid-20th century, but only by the end of this century they rose to prominence in modern cardioangiology. With the advent of interventional methods of myocardial revascularization the possibilities of treatment of different forms of coronary artery disease were significantly extended (1). The development and the perfection of endovascular techniques allowed to replace one method of treatment by another due to the extension of indications for non-surgical treatment. From 1991 through 2001, the amount of interventional procedures for coronary artery disease in the USA has increased by 7 times, while of direct surgical interventions — by only 1,5 times(2). Andreas R. Gruentzig can be named pioneer of angioplasty. In 1974 he was the first to invent a polymer balloon catheter with a fixed inflated diameter, and already by mid-1977 he has performed to first successful transluminal balloon angioplasty of a human coronary artery (3). With the accumulation of experience, during the last decades, certain disadvantages of balloon angioplasty have been revealed. These disadvantages significantly influence the clinical course of the underlying disease. In the last decade of the 20th century the leading place among all endovascular interventions on the coronary arteries went to coronary stenting. The first implantation of an intracoronary stent in man was described by Sigwart et al. in 1987 (4). The use of high pressure during stent implantation in combination with antithrombotic pharmacological support has contributed to adequate blood flow restoration in the coronary arteries. Herewith the procedure of stenting was associated with low complication rate. Initially stenting was applied in cases with threatening coronary artery occlusion during transluminal balloon angioplasty (5). According to Garas S.M. et al. (6), the use of intracoronary stenting significantly decreased the rate of restenosis — from 50% to 20-30% — in comparison with balloon angioplasty. However it did not completely solve the problem of restenosis. Stent insertion has provided a high rate of immediate success and has allowed to avoid some serious complications proper to PTCA: marked dissections, acute coronary occlusions (7, 8, 9, 10). But the main advantage of stenting in comparison with balloon angioplasty consisted in a significant reduction of the rate of restenosis — recurrent narrowing of the lumen of a vessel previously subjected to angioplasty (11, 12). The reduction of restenosis rate by 10-15% after stenting as compared with balloon angioplasty was firstly proved in 1993-1994 in the STRESS (13) and BENESTENT (7) trials, that investigated the results of coronary stenting and balloon angioplasty. The trials have demonstrated an improvement of the results after stenting in comparison with balloon angioplasty. The authors concluded that after the procedure the diameter of a stented vessel was increased in a far greater degree than after PTCA, and in the long-term the stented coronary arteries preserved a bigger internal lumen; herewith the extension of their angiographic restenosis was decreased (31,6% vs. 42,1%, р=0,046 in the work of Fishman D., et al., and 26% р=0,02 — in the work of Serruys P. et al) (7, 13, 14). Similar results were obtained by Rodriguez A. et al. (15), Versacci F. et al. (16) and Antoniocci D. et al. (17). The authors have demonstrated a decrease of the rate of late restenosis in the stented group, which, in its turn has contributed to a significant reduction of the need of repeated endovascular interventions (15, 16, 17). Today coronary stenting is the most frequently used method of heart revascularization. However the damage of vascular endothelium and subsequent hyperplasia of the neointima developing mainly within the first 6 months after stent insertion often causes in-stent restenosis (18,19). According to most authors, a restenosis is considered hemodynamically significant if the vessel lumen in the site of dilatation is reduced by > 50% of the reference diameter or 75% of its surface area (20, 21, 22, 23). In 1999, late in-stent stenosis was revealed in over 250.000 stented patients. For this reason worldwide trials are being conducted with the aim to study the causes of in-stent stenosis, the possibilities of its prevention and the development of an optimal tactics of treatment for the improvement of clinical prognosis (24, 25). The mechanism of restenosis is well known: it occurs due to a multitude of factors, such elastic recoil of the vessels, thrombosis, neointimal hyperplasia and negative remodeling of the vessels (26). Elastic recoil is caused to natural elastic properties of