Durable Polymer-based Drug-eluting Stents Research Articles

P3393Comparison of intermediate-term vascular response to new-generation biodegradable polymer and durable polymer-based drug-eluting stents: optical coherence tomographic study

Abstract Background Over the last decade, drug-eluting stents (DES) have undergone substantial modifications with thinner struts and more biocompatible durable polymer (DP) or biodegradable polymer (BP). In DP-based DES, after drug elusion has been completed, DP remnants may trigger of local inflammatory vascular reactions and promote delayed healing, leading to accelerated neoatherosclerosis (NA). Thus, BPs have been developed to reduce the above-mentioned risks. Recently, poor strut coverage and in-stent NA are increasingly recognized the cause of late stent failure, but it is unclear whether BPs can reduce the incidence of NA and the poor stent coverage as compared to DPs. Objectives The purpose of this study was to compare the incidence of NA and the stent coverage using optical coherence tomography (OCT) between the DPs and the BPs. Methods Between July 2016 and April 2018, 127 consecutive patients with new-generation DES who underwent 8-month follow up OCT imaging were enrolled. Patients were divided into the two groups: DP group who had the new-generation durable polymer everolimus-eluting and zotarolimus-eluting stents and BP group who had the new-generation biodegradable polymer sirolimus-eluting and everolimus-eluting stents. We compared patient characteristics including hypertension, dyslipidemia and diabetes mellitus and 8-month follow up OCT findings including NA, uncovered struts and malapposed struts between the two groups. Results The DP group comprised 64 patients (50.4%. The incidence of NA, uncovered struts and malapposed struts were similar between the two groups (DPs vs BPs, 1.56% vs 7.94%, P=0.11; 7.80% vs 5.88%, P=0.16 and 2.76% vs 2.01%, P=0.43, respectively) (table). The other parameters were also similar between the two groups. Table 1 DP group (n=64) BP group (n=63) P value Hypertension 44 (68.8%) 50 (79.4%) 0.2251 Dyslipidemia 39 (60.9%) 37 (58.7%) 0.8573 Diabetes mellitus 25 (39.1%) 30 (47.6%) 0.3731 8 month OCT follow up findings Neoatherosclerosis 1 (1.6%) 5 (7.9%) 0.1147 Uncovered struts 7.8% (2.8–20.4) 5.9% (0.7–16.7) 0.1616 Malapposed struts 0.2% (0–2.8) 0% (0–2.8) 0.4392 Conclusions The new-generation DP based-DES may have similar effects on vascular response compared to the new-generation BP-based DES during 8-month follow-up period.

Comparisons of early vascular reactions in biodegradable and durable polymer-based drug-eluting stents in the porcine coronary artery

Current drug-eluting stents have abluminal polymer coating; however, thrombus formation in these compared with that in uniformly coated stents remains controversial. We evaluated thrombus formation and early endothelialization after using abluminal biodegradable polymer-coated sirolimus- (BP-SES), and everolimus-eluting stents (BP-EES) versus a durable polymer-coated everolimus-eluting stent (DP-EES) in an in vivo setting. BP-SES, BP-EES, and DP-EES (n = 6 each) were implanted in coronary arteries of 12 mini-pigs that were then sacrificed after 7 and 10 days. Stents were stained with hematoxylin and eosin, and a combined Verhoeff and Masson trichrome stain. Areas of fibrin deposition were digitally detected and measured with off-line morphometric software. Stents were investigated for re-endothelialization by transmission electron microscopy. At 7 days, histological analysis revealed the lowest area of fibrin deposition in BP-SES (BP-SES vs. BP-EES vs. DP-EES; 0.10 ± 0.06 mm2 vs. 0.15 ± 0.07 mm2 vs. 0.19 ± 0.06 mm2, p = 0.0004). At 10 days, the area of fibrin deposition was significantly greater in DP-EES (0.13 ± 0.04 mm2 vs. 0.14 ± 0.05 mm2 vs. 0.19 ± 0.08 mm2, p = 0.007). Endothelial cells in BP-SES demonstrated a significantly greater number of tight junctions than those in DP-EES according to by transmission electron microscopy for both days (p<0.05). Various parameters, including an inflammatory reaction and neointimal formation, were comparable among the groups at 7 and 10 days. An abluminal biodegradable polymer-coated SES showed the least fibrin deposition and greatest endothelial cell recovery at an early stage following implantation in the coronary arteries of mini-pigs.

2925Four-year clinical outcome following randomised use of zotarolimus-eluting stents versus everolimus-eluting stents in all-comers: insights from the DUTCH PEERS trial

Background: The DUTCH PEERS (TWENTE II) trial (clinicaltrials.gov NCT01331707) is a randomised, multicenter, single-blinded, investigator initiated all-comers trial. All coronary syndromes were permitted with no limit for lesion length, reference size, or number of lesions or diseased vessels to be treated. In total, 1811 patients were 1:1 randomised to cobalt chromium-based zotarolimuseluting stents (ZES) versus platinum chromium-based everolimus-eluting stents (EES). These durable polymer-based drug-eluting stents (DES) were developed to facilitate device deliverability and to improve stent apposition to the vessel wall. Purpose: We assessed the 4-year clinical outcome of the DUTCH PEERS trial in terms of safety and efficacy. Methods: Clinical outcome was assessed by means of follow-up data of the trial participants. The primary endpoint target vessel failure (TVF) is a composite of cardiac death, target vessel-related myocardial infarction (MI) or target vessel revascularization. Secondary endpoints included the individual components of the TVF and the incidence of definite-or-probable stent thrombosis. Endpoints were analyzed by the logrank test by comparing the time to the endpoint, using the Kaplan-Meier method. Independent contract research organizations performed the study monitoring and clinical event adjudication. Results: The 4-year clinical follow-up data were available in 1802 patients (99.5%; 4 patients were lost to follow-up and 5 withdrew consent). The ZES and EES groups showed favourable outcomes with a similar incidence of TVF (12.1% vs. 12.1%; Logrank p=0.95). The rates of the individual components of TVF were also similar for both stent arms: cardiac death (3.9% vs. 3.7%; Logrank p=0.78); target vessel-related MI (3.2% vs. 2.5%; Logrank p=0.38); and target vessel revascularization (6.8% vs. 7.5%; Logrank p=0.55), respectively. In addition, the incidence of definite-or-probable stent thrombosis was similar for patients treated with ZES versus EES (1.5% vs. 1.2%; Logrank p=0.67). Conclusion: At 4-year follow-up, ZES and EES showed similar and sustained results in terms of safety and efficacy for treating all-comer patients.

TCT-483 “Real world use of ultra-thin sirolimus-eluting stent with biodegradable polymers. 9-month results from the FLEX-registry.”

Durable polymer-based drug-eluting stents have been reported to adversely affect the safety profile and are also suspected to cause serious long-term complications. It has been proposed that the biodegradable polymer coatings may reduce such late-stage adverse effects. The purpose of this registry

Comparison of 3 biodegradable polymer and durable polymer-based drug-eluting stents in all-comers (BIO-RESORT): Rationale and study design of the randomized TWENTE III multicenter trial

To evaluate the safety and efficacy of 2 novel drug-eluting stents (DES) with biodegradable polymer-based coatings versus a durable coating DES. BIO-RESORT is an investigator-initiated, prospective, patient-blinded, randomized multicenter trial in 3540 Dutch all-comers with various clinical syndromes, requiring percutaneous coronary interventions (PCI) with DES implantation. Randomization (stratified for diabetes mellitus) is being performed in a 1:1:1 ratio between ORSIRO sirolimus-eluting stent with circumferential biodegradable coating, SYNERGY everolimus-eluting stent with abluminal biodegradable coating, and RESOLUTE INTEGRITY zotarolimus-eluting stent with durable coating. The primary endpoint is the incidence of the composite endpoint target vessel failure at 1 year, consisting of cardiac death, target vessel-related myocardial infarction, or clinically driven target vessel revascularization. Power calculation assumes a target vessel failure rate of 8.5% with a 3.5% non-inferiority margin, giving the study a power of 85% (α level .025 adjusted for multiple testing). The impact of diabetes mellitus on post-PCI outcome will be evaluated. The first patient was enrolled on December 21, 2012. BIO-RESORT is a large, prospective, randomized, multicenter trial with three arms, comparing two DES with biodegradable coatings versus a reference DES with a durable coating in 3540 all-comers. The trial will provide novel insights into the clinical outcome of modern DES and will address the impact of known and so far undetected diabetes mellitus on post-PCI outcome.

Scanning electron microscopic assessment of coating irregularities and their precursors in unexpanded durable polymer-based drug-eluting stents

To assess and quantify coating irregularities on unexpanded and expanded durable polymer-based drug-eluting stents (DES) to gain insights into the origin of coating irregularities. Previous scanning electron microscopy (SEM) studies in various expanded DES revealed differences in frequency and size of coating irregularities between DES types and specific distribution patterns, however, the origin of these irregularities is unclear. We assessed at bench side a total of 1,200 SEM images obtained in 30 DES samples (15 expanded and 15 unexpanded) of Cypher Select Plus, Taxus Liberté, Endeavor, Xience V, and resolute. For most coating irregularities seen on expanded DES (72%; 23/32), a matching irregularity (n = 18/23) and/or its precursor (n = 11/23) was observed in unexpanded DES. Unexpanded Cypher select showed (small) crater lesions and cracks together with precursors of "peeling." On unexpanded Taxus Liberté, thinning of polymer, small bare metal areas, wrinkles, and one precursor type were found. Unexpanded endeavor showed cracks, small bare metal areas, crater lesions, and precursors of the latter. Unexpanded Xience V and resolute mainly revealed crater lesions and their precursors. On unexpanded versus expanded DES, there was no difference in measured frequency of coating irregularities and precursors (P = ns) with the exception of more bare metal areas on expanded Taxus Liberte (P = 0.01). Most coating irregularities, or the potential to develop them, are inherent to the unexpanded DES. Important determinants of the formation of coating irregularities may be the stent geometry and the physical properties of the coating, while stent-balloon interaction plays no major role.

TCT-448: Scanning Electron Microscopic Observation of Coating Irregularities and Their Precursors in Unexpanded Durable Polymer-Based Drug-Eluting Stents

Background: Previous scanning electron microscopy (SEM) studies in expanded DES revealed differences in the frequency and size of coating irregularities between DES types and specific distribution patterns, however, the origin of these irregularities is unclear.The current study quantifies coating irregularities on unexpanded and expanded durable polymer-based drug-eluting stents (DES) to gain insights into the potential origin of coating irregularities. Methods:We assessed at bench side a total of 1200 SEM images obtained in 30 DES samples (15 expanded and 15 unexpanded) of Cypher Select, Taxus Liberte, Endeavor, Xience V, and Resolute. Results: For most types of coating irregularities seen on expanded DES (72%; 23/32), a matching irregularity (n=18/24) and/or its precursor (n=11/24) was observed in unexpanded corresponding DES. Only a few individual coating irregularities (13%; 4/32) could not be accessed in unexpanded samples, as these irregularities were located on the (invisible) luminal side. Unexpanded Cypher Select showed (small) crater lesions and cracks together with precursors of ‘peeling of polymer’. On unexpanded Taxus Liberte, thinning of polymer, small bare metal areas, wrinkles and one type of precursor was found. Unexpanded phosphorylcholine-based Endeavor stents showed cracks, small bare metal areas, and crater lesions as well as precursors of the latter. Unexpanded Xience V and Endeavor Resolute mainly revealed crater lesions and their precursors. Conclusion: SEM assessment demonstrated the presence of various coating irregularities and/or their precursors on unexpanded durable polymer-based DES. These findings provide evidence that coating irregularities arise during both DES manufacturing and stent expansion.

Effect of Oversized Partial Postdilatation on Coatings of Contemporary Durable Polymer-Based Drug-Eluting Stents: A Scanning Electron Microscopy Study

Oversized postdilation of drug-eluting stents (DES) is often performed to avoid stent malapposition. In stents implanted in long lesion or major bifurcations, extremely oversized partial postdilation may be required, which exposes DES coating to extreme forces. This study aims to assess shape and incidence of coating irregularities on durable polymer-based DES following extremely oversized partial postdilatation. Fifteen DES samples (3 3.5 mm stents of Cypher Select plus [Cordis Europa, Roden, the Netherlands], Taxus Liberté[Boston Scientific Corp., Natick, MA, USA], Endeavor Sprint [Medtronic Vascular, Santa Rosa, CA, USA], Endeavor Resolute [Medtronic Vascular, Santa Rosa, CA, USA], and Xience V [Abbott Vascular, Santa Clara, CA, USA]) were deployed in sterile water (37 °C) at 14 atm, followed by a proximal postdilation with noncompliant 5.0-mm balloons at 18 atm. Stents were then examined with scanning electron microscopy. Thorough examination of a total of 660 scanning electron microscopic images demonstrated that shape and incidence of coating irregularities in the postdilated and/or transitional DES regions differed only mildly from the nonpostdilated regions. Cypher Select plus showed more peeling without bare metal aspect in the postdilated and transitional regions, and cracks were wider (P < 0.001) in the postdilated and transitional regions; in Taxus Liberté one additional irregularity (torn webbing) and more wrinkles were observed (P < 0.05 for both); in Endeavor Resolute wider cracks were found in the extremely postdilated region only (P < 0.001). Endeavor Sprint and Xience V showed no differences in shape or incidence of coating irregularities between oversized and nonoversized stent regions. Bench side assessment of five contemporary durable polymer-based DES with scanning electron microscopy suggests that even very aggressive stent postdilatation results in no more than mild differences in coating irregularities between postdilated and nonpostdilated stent regions.

Coating irregularities of durable polymer-based drug-eluting stents as assessed by scanning electron microscopy

To classify and quantify post-expansion irregularities in durable polymer-based coatings of drug-eluting stents (DES). Taxus Liberté, Endeavor Sprint, Endeavor Resolute and Xience V DES (three samples of each) were explored by light microscopy and scanning electron microscopy (SEM) following expansion at 14 atm in water. Incidence and size of irregularities were measured during thorough quantitative examinations of a 360 SEM images. DES types examined showed a significant difference in the incidence of irregularities (p<0.0001; 6.6+/-4.2/image at 60-fold magnification) with typical patterns specific for each DES. All types showed areas with bare metal-aspects, but incidence, shape, and size differed largely: Sprint showed the largest areas. Cracks were only found in Sprint and Resolute, while wrinkles were seen exclusively in Taxus Liberté and Xience V (p<0.0001). The coating of each DES type showed some inhomogeneity of distribution, but the incidence differed (p<0.0001) and was least in Taxus Liberté, which, on the other hand, was the only DES that showed webbing with large bare-metal exposure. The incidence and size of various coating irregularities on different types of DES varied widely. These data may be considered in ongoing discussions on the differences between DES and may serve as reference to compare novel DES.

Overview of the 2007 Food and Drug Administration Circulatory System Devices Panel Meeting on the Endeavor Zotarolimus-Eluting Coronary Stent

Initial trials comparing stenting with balloon angioplasty demonstrated improved angiographic and clinical outcomes with the former.1–3 The main clinical problem with bare metal stents (BMS) became the development of in-stent restenosis.4–6 Early data suggested that drug-eluting stents (DES) could mitigate, if not abolish, this problem.7–9 Since the approval of DES, these devices have become the predominant stents used in percutaneous coronary interventions, regardless of indication. As of September 2007, the Cypher sirolimus-eluting stent (SES) (Cordis Johnson & Johnson, Miami Lakes, Fla) had been deployed in >3 million patients worldwide,10 and the millionth Taxus paclitaxel-eluting stent (PES) (Boston Scientific, Natick, Mass) was implanted as of January 2005.11 Over the past 2 years, numerous reports of very late stent thrombosis (ST) with first-generation DES have surfaced. This highly morbid complication and data suggesting that death and myocardial infarction (MI) may be more common with DES12,13 have altered the focus of trials and registries working to determine optimal DES use. There is a hope that second-generation DES will be less prone to ST as a result of differences in drug, stent design, and polymer. Medtronic, Inc (Minneapolis, Minn) presented safety and efficacy data to a public meeting of the US Food and Drug Administration (FDA) Circulatory System Devices Panel (CSDP) in October 2007 on its Endeavor zotarolimus-eluting stent (ZES), seeking approval for the indication of treating de novo native coronary lesions ≤27 mm with reference vessel diameters of 2.5 to 3.5 mm. The FDA asked the CSDP to determine whether the data presented demonstrated a reasonable level of safety and effectiveness, with clinical benefits clearly outweighing short- and long-term risks of ZES use. Important efficacy end points included ischemia-driven target lesion revascularization (TLR) or target vessel revascularization (TVR); safety end points included death, MI, and ST. The …