Bioresorbable Scaffold

Abstract

T he invention of balloon angioplasty as a percutaneous treatment for obstructive coronary disease by Andreas Gruntzig in 1977 was a huge leap forward in cardiovascular medicine and undoubtedly will always be remembered as a revolution in the field of revascularization. However, this technique was plagued by multiple problems, including the risk of acute vessel closure secondary to occlusive coronary dissection, sometimes necessitating emergency coronary artery bypass surgery. 1-3 Although late luminal enlargement and vascular remodeling could take place, more often restenosis 4 -8 would occur instead. The restenosis would essentially be caused by constrictive remodeling 9 -13 and, to a lesser extent, by elastic recoil 14 or the neointimal hyperplastic healing response. [15][16][17] The advent of bare metal stenting (BMS) and the landmark Belgian-Netherlands Stent Study (BENESTENT) and Stent Restenosis Study (STRESS) trials have established BMS as the second revolution in interventional cardiology. 18,19 This technology provided a solution to acute vessel occlusion by sealing the dissection flaps and preventing recoil. The rate of subacute occlusion was reduced to 1.5%, making emergency bypass surgery a rare occurrence. Restenosis rates were further reduced from 32% to 22% at 7 months, but this rate was still high, and neointimal hyperplasia inside the stent was even more prominent than with angioplasty, necessitating repeat treatment in numerous patients. 18 Because the vessel was now caged with metal, late luminal enlargement and advantageous vascular remodeling could no longer occur. Another problem, namely late stent thrombosis (ST), was also first described. 20 To solve the problem of in-stent restenosis, after the historic failure of brachytherapy to resolve this problem, 21,22 drug-eluting stents (DES) were introduced. The first 45 patients implanted with the sirolimuseluting Bx velocity stent (Cordis, Johnson & Johnson, Warren, NJ) were found to have negligible neointimal hyperplasia at follow-up. 23,24 This was confirmed in the randomized comparison of a sirolimus-eluting stent with a standard stent for coronary revascularization (RAVEL) study. 25,26 The introduction of DES was thus dubbed the third revolution in interventional cardiology. Both large-scale randomized trials and all-comer registries showed excellent results in terms of the need for repeat revascularization. However, the early enthusiasm has been tempered in recent years after widespread concerns about the increased risk of late and very late ST. [27][28][29][30][31] Registries of all comers treated with DES showed late ST rates of 0.53%/y, with a continued increase to 3% over 4 years. 32,33 In the Arterial Revascularization Therapies Study II (ARTS II) trial, which enrolled patients with complex multivessel disease, the rate of combined definite, probable, and possible ST was as high as 9.4% at 5 years, accounting for 32% of major adverse cardiovascular events (MACEs). 34 In addition, postmortem pathological specimens of DES revealed sig...

Mechanical, rheological, fatigue, and degradation behavior of PLLA, PGLA and PDGLA as materials for vascular implants

“…At the 10-year clinical follow up, stent showed impressive results. There were only 7 deaths during 10 years, whilst cumulative rates of target lesion revascularization (TLR) were 16 % at 1 year, 18 % at 5 years and 28 % at 10 years [2,3]. Igaki-Tamai stent didn't cause changes in external elastic membrane area and was mostly degraded within 3 years.…”

“…70°C which was supposed to be the burden to surrounding tissues. For low-risk patients these concerns were not substantiated but the stent is available in Europe only for peripheral use [2]. The AMS-1 (Biotronik, Berlin, Germany) was the first metallic, magnesium biodegradable stent.…”

“…Unfortunately, inflammation caused by REVA stent was higher compared to patients with bare metal stents (BMS). Redesigned, drug-eluting stent ReZolve showed good initial results in preclinical trials [2,6], clinical trials are in progress. The BVS stent backbone was made of poly(l-lactide) (PLLA) core and poly D,L-lactide acid (PDLLA) coating, containing antiproliferative drug everolimus.…”

Comparison of a Drug‐Free Early Programmed Dismantling PDLLA Bioresorbable Scaffold and a Metallic Stent in a Porcine Coronary Artery Model at 3‐Year Follow‐Up

“…Bioresorbable scaffolds (BRS) have been emerged as an alternative to metallic stents for the percutaneous treatment of obstructive atherosclerotic coronary lesions 1, 2. In the 1‐year result of the ABSORB III randomized clinical trial, everolimus‐eluting bioresorbable vascular scaffold (Absorb BVS, Abbott Vascular, Santa Clara, CA) showed noninferiority for target lesion failure compared with the everolimus‐eluting Xience drug‐eluting stent (Abbott Vascular, Santa Clara, CA) 3.…”

“…The dismantling of ART‐BRS began at 3 months after implantation, which allowed for rapid vascular restoration with progressive lumen enlargement up to 6 months 2, 8, 9. The aim of the current study was to characterize the vascular response following implantation of a novel ART‐BRS in comparison to bare metal stents (BMS) by angiography, histopathology, and biochemical analysis of molecular weight up to 36 months in a healthy porcine coronary artery model.…”