Polymer-free Drug-eluting Stents Research Articles

ELLIS Study: Comparative Analysis of Excimer Laser Coronary Angioplasty and Intravascular Lithotripsy on Drug-Eluting Stent as Assessed by Scanning Electron Microscopy.

Stent underexpansion is a significant challenge in percutaneous coronary intervention, critically impacting patient outcomes. While excimer laser coronary angioplasty (ELCA) and intravascular lithotripsy (IVL) are increasingly used to address this issue, their full impact on the integrity of drug-eluting stents remains unclear, raising concerns about their safety and efficacy. This in vitro study assessed the effects of ELCA and IVL on the structural integrity of drug-eluting stents using scanning electron microscopy. Nine stents, 5 Onyx Frontier (with durable circumferential polymer coating) and 4 Cre8 (polymer-free), were implanted in a 3-dimensional coronary artery simulator following standardized protocols. After implantation, treatments with saline-ELCA, contrast-ELCA, IVL, and high-pressure balloon dilatation were applied. A comprehensive evaluation of the stent surface was performed at 60-fold magnification. Scanning electron microscopy analysis revealed significant differences in polymer damage between the techniques. High-pressure balloon dilatation and contrast-ELCA exhibited substantial polymer fragmentation and detachment compared with IVL, saline-ELCA, and conventional dilatation. High-pressure balloon dilatation demonstrated the highest incidence of polymer shaving and overcoating. No significant alterations were observed in polymer-free stents, regardless of the technique used. IVL and saline-ELCA applied immediately after stent implantation produce minimal polymer damage, whereas high-pressure balloon dilatation and contrast-ELCA cause significant damage to the polymer coating. The integrity of polymer-free drug-eluting stent appears stable regardless of the technique used. Further research is needed to validate these findings and explore their clinical implications.

First-in-Human Evaluation of a Polymer-Free Everolimus-Eluting Stent Using a Titanium Dioxide Film.

In patients with coronary artery disease treated with permanent polymer-coated drug-eluting stents (DES), the persistent presence of a less biocompatible polymer might delay arterial healing. Thin strut polymer-free DES have the potential to improve clinical outcomes and reduce the duration of dual antiplatelet therapy (DAPT). The purpose of this first-in-human study was to assess the safety and effectiveness of a novel polymer-free DES in patients with de novo coronary lesions. The TIGERevolutioN® stent (CG Bio Co., Ltd., Seoul, Korea) consists of a cobalt chromium platform with a strut thickness of 70 μm and a surface treated with titanium dioxide onto which everolimus-eluting stent (EES) is applied abluminally (6 µg/mm of stent length) without utilization of a polymer. A total of 20 patients were enrolled, with de novo coronary lesions (stable or unstable angina) and > 50% diameter stenosis in a vessel 2.25 to 4.00 mm in diameter and ≤ 40 mm in length for angiographic, optical coherence tomography (OCT), and clinical assessment at 8 months. All patients received DAPT after stent implantation. The primary endpoint was angiographic in-stent late lumen loss (LLL) at 8 months. Twenty patients with 20 lesions were treated with TIGERevolutioN®. At 8 months, in-stent LLL was 0.7 ± 0.4 mm. On OCT, percent area stenosis was 29.2 ± 9.4% and stent strut coverage was complete in all lesions. No adverse cardiovascular event occurred at 8 months. The new polymer-free EES was safe and effective with low LLL and excellent strut coverage at 8 months of follow-up. Trial Registration: Clinical Research Information Service Identifier: KCT0005699.

Rationale and design of the PARTHENOPE trial: A two-by-two factorial comparison of polymer-free vs biodegradable-polymer drug-eluting stents and personalized vs standard duration of dual antiplatelet therapy in all-comers undergoing PCI

BackgroundOver the past few decades, percutaneous coronary intervention (PCI) has undergone significant advancements as a result of the combination of device-based and drug-based therapies. These iterations have led to the development of polymer-free drug-eluting stents. However, there is a scarcity of data regarding their clinical performance. Furthermore, while various risk scores have been proposed to determine the optimal duration of dual antiplatelet therapy (DAPT), none of them have undergone prospective validation within the context of randomized trials. DesignThe PARTHENOPE trial is a phase IV, prospective, randomized, multicenter, investigator-initiated, assessor-blind study being conducted at 14 centers in Italy (NCT04135989). It includes 2,107 all-comers patients with minimal exclusion criteria, randomly assigned in a 2-by-2 design to receive either the Cre8 amphilimus-eluting stent or the SYNERGY everolimus-eluting stent, along with either a personalized or standard duration of DAPT. Personalized DAPT duration is determined by the DAPT score, which accounts for both bleeding and ischemic risks. Patients with a DAPT score <2 (indicating higher bleeding than ischemic risk) receive DAPT for 3 or 6 months for chronic or acute coronary syndrome, respectively, while patients with a DAPT score ≥2 (indicating higher ischemic than bleeding risk) receive DAPT for 24 months. Patients in the standard DAPT group receive DAPT for 12 months. The trial aims to establish the noninferiority between stents with respect to a device-oriented composite end point of cardiovascular death, target-vessel myocardial infarction, or clinically-driven target-lesion revascularization at 12 months after PCI. Additionally, the trial aims to demonstrate the superiority of personalized DAPT compared to a standard approach with respect to a net clinical composite of all-cause death, any myocardial infarction, stroke, urgent target-vessel revascularization, or type 2 to 5 bleeding according to the Bleeding Academic Research Consortium criteria at 24-months after PCI. SummaryThe PARTHENOPE trial is the largest randomized trial investigating the efficacy and safety of a polymer-free DES with a reservoir technology for drug-release and the first trial evaluating a personalized duration of DAPT based on the DAPT score. The study results will provide novel insights into the optimizing the use of drug-eluting stents and DAPT in patients undergoing PCI.

Clinical Outcomes of Polymer-Free Versus Polymer-Coated Drug-Eluting Stents in Patients With Coronary Artery Disease: A Systematic Review and Meta-Analysis.

Drug-eluting stents have transformed the treatment of coronary artery disease (CAD), and there are two types: polymer-free and polymer-coated stents. Polymer-free stents have a coating that is quickly absorbed by the body, whereas polymer-coated stents have a coating that remains on the stent surface. This meta-analysis and systematic review aimed to compare the clinical outcomes of these two stent types in patients with coronary artery disease. The literature and abstracts from significant databases were reviewed to compare polymer-free drug-eluting stents (PF-DES) and polymer-coated drug-eluting stents (PC-DES) for the treatment of coronary artery disease (CAD). The primary efficacy endpoints of the study were all-cause mortality and deaths from cardiovascular and non-cardiovascular causes. Among the secondary outcomes were incidences of myocardial infarction (MI), target lesion revascularization (TLR), target vessel revascularization (TVR), stent thrombosis, stroke, and major adverse cardiovascular events (MACEs). In terms of the primary outcomes, the combined analysis revealed a marginally lower risk of all-cause mortality (relative risk, RR (95% CI) = 0.92 (0.85, 1.00), p = 0.05, I2 = 0%) with the use of PF-DESversus PC-DES. Nonetheless, there was no significant difference in cardiovascular mortality (RR (95% CI) = 0.97 (0.87, 1.08)) or non-cardiovascular mortality (RR (95% CI) = 0.87 (0.69, 1.10), p = 0.25, I2 = 9%) between the groups. Furthermore, univariate meta-regression revealed that male gender and prior myocardial infarction were independently associated with an increased risk of all-cause mortality and cardiovascular disease. According to the current meta-analysis, no statistically significant differences existed in PF-DES and PC-DES outcomes. More extensive research is needed to investigate these findings further and establish their validity.

Flexible 3D Nanonetworked Silica Film as a Polymer-Free Drug-Eluting Stent Platform to Effectively Suppress Tissue Hyperplasia in Rat Esophagus.

Loading and eluting drugs on self-expandable metallic stents (SEMSs) can be challenging in terms of fabrication, mechanical stability, and therapeutic effects. In this study, a flexible 3D nanonetworked silica film (NSF) capable of withstanding mechanical stress during dynamic expansion is constructed to function as a drug delivery platform on an entire SEMS surface. Despite covering a broad curved area, the synthesized NSF is defect-free and thin enough to increase the stent strut diameter (110µm) by only 0.4 percent (110.45µm). The hydrophobic modification of the surface enables loading of 4.7 times the sirolimus (SRL) concentration in NSF than Cypher, polymer-coated commercial stent, which is based on the same thickness of coating layer. Furthermore, SRL-loaded NSF exhibits a twofold delay in release compared to the control group without NSF. The SRL-loaded NSF SEMS significantly suppresses stent-induced tissue hyperplasia than the control SEMS in the rat esophagus (all variables, p <0.05). Thus, the developed NSF is a promising polymer-free drug delivery platform to efficiently treat esophageal stricture.

Ten-Year Clinical Outcomes in Patients With Acute Coronary Syndrome Treated With Biodegradable, Permanent-Polymer or Polymer-Free Drug-Eluting Stents.

This study aimed to compare 10-year clinical outcomes in patients with acute coronary syndrome (ACS) treated with new-generation biodegradable-polymer (BP-DES), polymer-free (PF-DES), and permanent-polymer drug-eluting stents (PPDES). We analyzed 10-year clinical outcomes for 2042 patients with ACS enrolled in the ISAR-TEST 4 and ISAR-TEST 5 randomized controlled trials. Patients were divided into 3 groups: new-generation PP-DES, BP-DES, and PF-DES. Endpoints of interest included a device-oriented composite endpoint (DOCE) and a patient-oriented composite endpoint (POCE) at 10 years. BP-DES as compared with PP-DES demonstrated a lower DOCE frequency, but this did not meet statistical significance (BP-DES vs PP-DES, 35.4% vs 41.5%, respectively; adjusted hazard ratio (HR), 0.83; 95% confidence interval [CI], 0.68-1.00; P=.05). There was a significantly lower POCE frequency in patients treated with BP-DES compared with PP-DES (65.3% vs 69.0%, respectively; HR, 0.86; 95% CI, 0.75-0.99; P=.04). The relative frequency of the DOCE (41.4% vs 41.5%; HR, 0.97; 95% CI, 0.83-1.15; P=.76) and the POCE (66.8% vs 69.0%; HR, 0.99; 0.87-1.12; P=.82) were comparable in patients treated with PF-DES and PP-DES. In patients with ACS, BP-DES were associated with a lower relative frequency of a POCE compared with new-generation PP-DES at 10 years. The relative frequencies of both device- and patient-related outcomes were comparable in patients treated with PF-DES and PP-DES at 10 years.

Real-World Clinical Outcomes of Indigenous Biodegradable Polymer Drug-Eluting Stents.

IntroductionThe durable polymer has been shown to cause neoatherosclerosis, and chronic local inflammation, predisposing individuals to in-stent restenosis and stent thrombosis (ST). The biodegradable polymer stents, which degrade after the desired function of drug release is achieved, allow for endothelial healing. Indigenous coronary stent manufacturing and its use are on the rise nowadays, and their safety and efficacy have been studied in well-structured clinical trials. However, data are scarce on their safety and efficacy in the real-world clinical setting. In this study, we examine the real-world one-year performance of bioresorbable or polymer-free stents manufactured in India.Materials and methodsThis was a single-center, single-arm prospective observational study involving 210 patients undergoing intracoronary stenting using bioabsorbable or polymer-free drug-eluting stents (DES) from Indian manufacturers. All patients were followed up for 12 months prospectively for any major clinical events.ResultsThe mean age of the enrolled patients was 57.04 years (IQR: 34-84 years), among which 159 (75.7%) were male; 99 (43.8%) patients had presented with acute myocardial infarction (MI). A total of 294 stents were deployed with a mean diameter of 3.1 ±0.4 mm, and a mean length of 29.4 ±9.1 mm. Two patients had experienced major adverse cardiovascular events (MACE). After three months of follow-up, one patient developed ST, and the same patient developed a cerebrovascular accident (CVA) after six months. After one year of follow-up, one patient died of cardiac causes.ConclusionBased on our findings, in the real-world clinical setting, the indigenously made biodegradable polymer DES are both safe and effective.

Ten-year clinical outcomes of polymer-free versus durable polymer new-generation drug-eluting stent in patients with coronary artery disease with and without diabetes mellitus

BackgroundVery long-term outcomes according to diabetic status of patients with coronary artery disease (CAD) undergoing percutaneous coronary intervention (PCI) with new-generation drug-eluting stents (DES) are scant. Both, the durable polymer zotarolimus-eluting stent (DP-ZES), the first DES to gain FDA-approval for specific use in patients with diabetes mellitus, and the polymer-free sirolimus- and probucol-eluting stent (PF-SES), with a unique design that enables effective drug release without the need of a polymer offer the potential to enhance clinical long-term outcomes especially in patients with diabetes mellitus.MethodsWe investigate 10-year clinical outcomes of the prespecified subgroups of patients with and without diabetes mellitus, randomly assigned to treatment with PF-SES versus DP-ZES in the ISAR-TEST 5 trial. The primary endpoint of interest was major adverse cardiac events (MACE), defined as the composite of all-cause death, any myocardial infarction or any revascularization. Further endpoints of interest were cardiac death, myocardial infarction related to the target vessel and target lesion revascularization as well as the individual components of the primary composite endpoint and the incidence of definite or probable stent thrombosis at 10 years.ResultsThis analysis includes a total of 3002 patients randomly assigned to PF-SES (n = 2002) or DP-ZES (n = 1000). Prevalence of diabetes mellitus was high and comparable, 575 Patients (28.7%) in PF-SES group and 295 patients (29.5%) in DP-ZES group (P = 0.66). At 10 years 53.5% of patients with diabetes mellitus and 68.5% of patients without diabetes mellitus were alive. Regarding major adverse cardiac events, PF-SES as compared to DP-ZES showed comparable event rates in patients with diabetes mellitus (74.8% vs. 79.6%; hazard ratio 0.86; 95% CI 0.73–1.02; P = 0.08) and in patients without diabetes (PF-SES 62.5% vs. DP-ZES 62.2%; hazard ratio 0.99; 95% CI 0.88–1.11; P = 0.88).ConclusionAt 10 years, both new-generation DES show comparable clinical outcome irrespective of diabetic status or polymer strategy. Event rates after PCI in patients with diabetes mellitus are considerable higher than in patients without diabetes mellitus and continue to accrue over time.Trial registrationClinicalTrials.gov, NCT00598533, Registered 10 January 2008, https://clinicaltrials.gov/ct2/show/NCT00598533?term=NCT00598533Graphic abstractKaplan-Meier estimates of endpoints of interest for patients with vs. without diabetes mellitus treated with PF-SES vs. DP-ZES. Bar graphs: Kaplan-Meier estimates as percentages. PF-SES: polymer-free sirolimus-eluting stent; DP-ZES: durable polymer zotarolimus-eluting stent; DM: diabetes mellitus. Comparison of event rates of individual endpoints in patients with and without diabetes mellitus treated with PF-SES vs. DP-ZES all without statistically significant differences. Comparison of event rates of individual endpoints in overall patients with vs. without diabetes mellitus significantly different (P ≤ 0.01 for all comparisons).

Optimal Stent Design for High Bleeding Risk Patients: Evidence From a Network Meta-Analysis.

To determine the best stent design for high bleeding risk (HBR) patients. Polymer-free (PF) drug eluting stent (DES) devices have a proven benefit over bare-metal stent (BMS) devices in previous trials. It is unknown, however, whether polymer-based (PB)-DES devices are as safe as PF-DES devices. A network meta-analysis including all randomized controlled trials (RCTs) that compared different stent technology in HBR patients with a 1-month course of dual-antiplatelet therapy (DAPT) was performed. The main efficacy outcome was major adverse cardiac event (MACE) rate, defined as the composite of all-cause mortality, myocardial infarction (MI), and target-lesion revascularization (TLR). Secondary efficacy events included all-cause and cardiac mortality, MI, stroke, TLR, and target-vessel revascularization (TVR). Safety outcomes included all bleeding, major bleeding, and stent thrombosis (ST). A total of 4 RCTs with 6456 patients were included. PF-DES and PB-DES yielded a reduced rate of MACE, MI, TLR, and TVR events compared with BMS (all P<.05). ST events were reduced in PB-DES compared with BMS (P=.01). No differences were found in all-cause death, cardiac death, or stroke events in PF-DES and PB-DES compared with BMS. Furthermore, no differences were found between PF-DES and PB-DES regarding any of the outcomes. DES devices were associated with lower MACE and TVR rates compared with BMS, whereas there were no statistical differences in other efficacy endpoints. Also, PB-DES were associated with fewer ST events compared with BMS. There were no statistical differences between PB-DES and PF-DES with regard to any of the endpoints.

Thromboresistance and endothelial healing in polymer-coated versus polymer-free drug-eluting stents: Implications for short-term dual anti-platelet therapy

BackgroundShort-term dual antiplatelet therapy (DAPT) is a suitable strategy after stent implantation especially in patients at high risk for bleeding. The thromboresistant characteristics and the healing profile permanent polymer stents such as the Resolute Onyx- drug-eluting stent (DES) has never been tested against the current approved stents for short-term DAPT, the polymer free (PF) biolimus-eluting stent (PF-BES) and bare metal stents (BMS) in dedicated preclinical models. MethodsAn ex-vivo porcine arteriovenous shunt and in-vivo flow loop model were used to evaluate thromboresistance. The healing profile was assessed in the rabbit model at 28 days by confocal microscopy (CM), scanning electron microscopy (SEM) and histology. Onyx-DES was separately compared with Onyx-BMS in first experiment and PF-BES in second experiment. ResultsIn an ex-vivo shunt model, CM and SEM showed significantly less platelet adhesion for Onyx-DES relative to Onyx-BMS and PF-BES. In a flow loop model using human blood, platelet adhesion was also significantly less in Onyx-DES as compared to PF-BES and Onyx-BMS. In the healing study, Onyx-BMS showed significantly greater healing profile relative to Onyx-DES as expected, whereas Onyx-DES showed equivalent endothelial coverage by SEM and significantly less Evan's blue uptake and comparable colocalization of p120 and vascular endothelial-cadherin when compared with PF-BES. ConclusionsOnyx-DES showed qualities of thomboresistance and healing which appear to be compatible with short-term DAPT. Thromboresistance was superior to PF-BES and healing was equivalent to PF-BES in this pre-clinical study. Onyx-DES might provide advantages when considering short-term DAPT especially in patients at high risk of bleeding.

10-Year Outcomes From a Randomized Trial of Polymer-Free Versus Durable Polymer Drug-Eluting Coronary Stents

BackgroundOutcome data after extended long-term follow-up of patients with coronary artery disease treated with drug-eluting stents (DES) in randomized clinical trials are scant. ObjectivesPerformance differences among devices may be expected to emerge over time depending on whether stenting is done with polymer-free or durable polymer DES. This study assessed the 10-year outcomes of patients enrolled in the ISAR-TEST-5 (Test Efficacy of Sirolimus- and Probucol-Eluting Versus Zotarolimus-Eluting Stents) trial. MethodsA total of 3,002 patients were randomized to treatment with either polymer-free sirolimus- and probucol-eluting stents (n = 2,002) or durable polymer zotarolimus-eluting stents (n = 1,000). The primary endpoint was the composite of cardiac death, target vessel–related myocardial infarction, or target lesion revascularization (a device-oriented composite endpoint [DOCE]). Additional endpoints of interest were the patient-oriented composite endpoint (POCE), including all-cause death, any myocardial infarction, or any revascularization; individual components of the composite endpoints; and definite or probable stent thrombosis. ResultsThe median age of the patients at randomization was 67.8 years. At 10 years, 63.9% of patients were alive. The rates of DOCE and POCE were high in both groups with no difference in the incidence between polymer-free sirolimus- and probucol-eluting stents and durable polymer zotarolimus-eluting stents (DOCE: 43.8% vs. 43.0%, respectively; hazard ratio: 1.01; 95% confidence interval [CI]: 0.89 to 1.14; p = 0.90; POCE: 66.2% vs. 67.7%, respectively; hazard ratio: 0.94; 95% CI: 0.86 to 1.04; p = 0.22). The rates of the individual components of the composite endpoints were comparable in both groups. The incidence of definite/probable stent thrombosis over 10 years was low and comparable in both groups (1.6% vs. 1.9%; hazard ratio: 0.85; 95% CI: 0.46 to 1.54; p = 0.58). ConclusionsAt 10 years, there were no measurable differences in outcomes between patients treated with polymer-free versus durable polymer DES. The incidence of stent thrombosis was low and comparable in both groups. High overall adverse clinical event rates were observed during extended follow-up. (Test Efficacy of Sirolimus- and Probucol-Eluting Versus Zotarolimus-Eluting Stents [ISAR-TEST-5]; NCT00598533)

Photofunctionalized and Drug-Loaded TiO2 Nanotubes with Improved Vascular Biocompatibility as a Potential Material for Polymer-Free Drug-Eluting Stents.

Implantation of a drug-eluting stent is the most common treatment method for patients with cardiovascular atherosclerosis. However, this treatment may delay re-endothelialization, and the drug polymer-coated stent may induce thrombosis months after a stent implantation. The development of polymer-free drug-eluting stents is a promising approach to overcome these shortcomings. Titanium dioxide nanotubes (TiO2-NTs) are excellent drug carriers and have been considered as a potential material for polymer-free drug-eluting stents. However, TiO2-NTs reportedly induce severe blood clotting, which is a significant shortcoming for use as a stent. Vascular stents must be compatible with blood and must have antibacterial, anti-inflammatory, and selective inhibitory activities in the abnormal hyperplasia of smooth muscle cells, instead of delaying the re-endothelialization of endothelial cells. To meet these requirements, we presented a composite material that featured ultraviolet (UV) irradiation of TiO2-NTs-containing silver nanoparticles (AgNPs). The AgNPs were loaded in the lumen of TiO2-NTs as a representative compound to suppress the inflammatory response and hyperplasia. UV irradiation was performed as a novel method to improve the anticoagulant ability of the AgNP-loaded TiO2-NTs. The chemical state and biocompatibility of the UV-TiO2-NTs@AgNPs were evaluated. UV irradiation strongly improved the anticoagulant ability of the TiO2-NTs and moderated the release of Ag+ from AgNPs, which selectively suppressed the inflammatory response and hyperplasia. Furthermore, the UV-TiO2-NTs@AgNPs-2 displayed enhanced biocompatibility evidenced by the inhibition of platelet adhesion, bactericidal activity, selective suppression of the smooth muscle cell proliferation, and inhibition of the adhesion of macrophages. The collective findings indicate the potential of the photofunctionalized TiO2-NTs loaded with AgNPs as a material for polymer-free drug-eluting stents.

The Cre8 amphilimus-eluting stent for the treatment of coronary artery disease: safety and efficacy profile

ABSTRACT Introduction: Polymer-free drug-eluting stents are designed with stent surface modifications and drug-matrix formulations in order to release antiproliferative agents without the need of a polymer coating. Polymer-free technologies have the potential to overcome complications due to polymer persistence over time, such as local inflammatory reactions, delayed arterial healing, neoatherosclerosis, and subsequent ischemic adverse events. Areas covered: The Cre8 polymer-free amphilimus-eluting stent received CE mark in 2011 and was conceived with the aim of addressing the safety and efficacy limitations of early generation drug-eluting stents based on permanent polymer coatings. Besides the absence of polymer, the main features of the Cre8 stent include the abluminal reservoirs, the passive carbon film coating, and the antiproliferative agent formulation based on sirolimus mixed with free-fatty acid chain – namely amphilimus. This review will focus on the Cre8 development, technical characteristics, preclinical evidence, clinical efficacy and safety, and future perspectives. Expert opinion: The Cre8 stent has shown favorable angiographic and clinical outcomes at short and medium-term follow-up. This technology might provide a benefit in patients with diabetes. Further randomized evidence is required to provide an adequate clinical evaluation of this promising technology in patients with and without diabetes.

Potential and Capabilities of Porous Silicon as a Material for Intravascular Drug-Eluting Stents: Brief Summary

In search for a drug-containing material when creating polymer-free drug-eluting stents, an analysis of the available literature is carried out. It is shown that one of the promising materials for this purpose is mesoporous silicon (the cross-sectional pore diameter is 2–50 nm), which has high biocompatibility and biodegradability. The main requirements for the porous silicon coating as a drug carrier of metal intravascular stents are formulated. The results of experimental studies are presented, including those performed by the authors, showing the possibility of continuous silicon coating application up to 0.6 μm thick on the stents by magnetron sputtering or plasma-immersion ion implantation and deposition (PIII@D). These methods provide high coating adhesion to the stent material and allow coating both on the external and internal stent surfaces.

Polymer-Free vs. Polymer-Coated Drug-Eluting Stents for the Treatment of Coronary Artery Disease: A Meta-Analysis of 16 Randomized Trials

BackgroundPolymer-coating represents one of components of drug-eluting stents (DES) to have experienced a more intensive technological evolution. Polymer-free DES (PF-DES) have offered promising angiographic results, with earlier complete re-endothelization, potentially reducing the thrombotic risk and offering the option of a shorter antiplatelet therapy. However, contrasting prognostic data have been reported so far with PF-DES. Therefore, the aim of the present study was to perform a comprehensive updated meta-analysis of randomized trials (RCT) comparing the impact of PF-DES vs polymer- coated DES (PC-DES) on clinical outcome. MethodsLiterature and main scientific session abstracts were searched for RCTs comparing PF-DES vs PC-DES for the treatment of CAD. The primary efficacy endpoint was mortality, secondary endpoints were cardiovascular death, myocardial infarction, target lesion revascularization (TLR) and stent thrombosis. ResultsWe included 16 randomized clinical trials, with a total of 15,689 patients, including 50.6% randomized to PF-DES. At a median follow-up of 24 months, PF-DES were associated to a significant reduction in mortality as compared to PC-DES (0.82 [0.68, 0.99], p = .03, I2 = 0%; phet = 0.93). However, no significant benefit was observed in terms of cardiovascular death or major ischemic endpoints (respectively CV death: OR [95% CI] = 0.92 [0.71, 1.18] p = .50, I2 = 0.50; phet = 0.84; MI: OR [95% CI] = 1.08 [0.90, 1.29], p = .42; I2 = 0%, phet = 0.98; TLR: OR [95% CI] = 1.02 [0.78, 1.32], p = .91; I2 = 0.63 phet = 0.0003; ST: OR [95% CI] = 0.98 [0.87, 1.10], p = .72; I2 = 0% phet = 0.64). By meta-regression analysis, the mortality benefits of PF-DES were not conditioned by the rate of diabetes mellitus or acute coronary syndromes. ConclusionsBased on the current meta-analysis, PF-DES are associated to a significant reduction in mortality as compared to PC-DES, but not in the occurrence of major ischemic events. Future larger studies are certainly needed to further investigate and confirm our findings, especially in particular subsets of patients, such as those with high bleeding risk or acute myocardial infarction.

P3386Angioscopic comparison between polymer-free biolimus A9-coated stent and durable polymer drug-eluting stent 10 months after the implantation

Abstract Background Polymer-free biolimus A9-coated stent (DCS) has currently emerged as expected better arterial healing compared to durable polymer drug-eluting stent (DP-DES). However, superiority of DCS on arterial healing over DP-DES has not been well elucidated using intracoronary images. Methods This study examined 288 stents in 224 patients with de novo coronary artery lesions. We angioscopically compared 55 DCS from 35 patients with 233 DP-DES from 189 patients 10±2 months after the implantation. We assessed thrombus adhesion, which is a marker of incomplete re-endothelialization. Dominant neointimal coverage (NIC) grade, heterogeneity of NIC and maximum yellow color of plaque underneath the stent were also evaluated. Neointimal coverage was graded as follows: grade 0, stent struts exposed; grade 1, struts bulged into the lumen, although covered; grade 2, struts embedded by the neointima, but translucent; grade 3, struts fully embedded and invisible. NIC was judged as heterogeneous when differences in the NIC grade became apparent. Yellow plaque was graded as follows: grade 0, white; grade 1, light yellow; grade 2, yellow; grade 3, intensive yellow. Results Thrombus adhesion was similar between DCS and DP-DES (29% versus 23%, P=0.32). Dominant NIC was greater in DCS than in BP-DES (P&lt;0.001), while NIC was more heterogeneous in DCS than in BP-DES (P=0.001, Figure). Maximum yellow color of stented segment was similar between DCS and DP-DES (P=0.09). Conclusion DCS provided similar thrombus adhesion to DP-DES, which suggested similar re-endothelialization 10 months after implantation. However, DCS showed thick and heterogeneous NIC compared to DP-DES. The specific feature of polymer-free and Biolimus A9 would cause the difference, and further investigation is necessary to evaluate the longer-term safety and efficacy. Acknowledgement/Funding None

Thromboresistance and functional healing in the COBRA PzF stent versus competitor DES: implications for dual antiplatelet therapy.

The aim of this study was to investigate the COBRA PzF stent (C-PzF) with respect to thrombogenicity and healing versus conventional drug-eluting stents (DES) in dedicated preclinical models to evaluate their suitability for short-term dual antiplatelet therapy (DAPT). To examine acute thrombogenicity, the C-PzF durable polymer drug-eluting stent (DP-DES), and a bioabsorable polymer DES (BP-DES) were compared in a porcine arteriovenous shunt model and in a rabbit model to evaluate endothelial coverage at 14 days. Barrier function at 28 days in the rabbit was assessed in the former stents as well as in a polymer-free DES (PF-BES). The number of clots by scanning electron microscopy (SEM) was significantly less in the C-PzF and DP-EES versus the BP-EES. Endothelial coverage at 14 days was significantly greater in the C-PzF versus the DP-EES and BP-EES by CD31/PECAM-1 positive area in confocal microscopy (CM) (24.7% vs 11.9% vs 3.7%, respectively) and SEM (99.0% vs 29.6% vs 17.7%, respectively). Barrier protein expression by CM for p120/vascular-endothelial cadherin complex was significantly greater in the C-PzF versus the DP-EES, BP-EES, and PF-BES (82.6% vs 12.8% vs 14.4% vs 18.1%, respectively). The percentage of Evan's Blue positive area was least in the C-PzF versus all groups (22.0% vs 70.7% vs 66.4% vs 55.2%, respectively). The C-PzF demonstrated a unique combination of thrombogenicity and healing advantages compared to contemporary DES and may be uniquely suitable for very short-term DAPT.

Resultado del tratamiento percutáneo de la reestenosis de stents farmacoactivos: ¿depende de si el stent tenía o no recubrimiento polimérico?

Introduction and objectivesOutcomes of patients undergoing percutaneous intervention for drug-eluting stent (DES) restenosis are poorer than those in patients with bare-metal stent restenosis. It is unknown if this is related to the presence of polymer coating. We sought to compare outcomes after interventions for in-stent restenosis (ISR) of polymer-free DES vs durable polymer DES. MethodsPatients enrolled in the ISAR-TEST 5 randomized trial who underwent repeat percutaneous intervention for ISR during follow-up were included. Angiographic outcomes at 6 to 8 months and clinical outcomes at 2 years were analyzed and compared between 2 groups according to whether the restenosed stent was a polymer-free or a durable polymer DES. Multivariate analysis was used to adjust for differences between groups. ResultsA total of 326 patients with ISR were included: 220 with ISR in polymer-free DES and 106 with ISR in durable polymer DES. Angiographic follow-up was available for 83.4% of patients. No difference was observed in recurrent binary restenosis between the 2 groups (31.7% vs 27.0%; P=.38; Padjusted=.29). At 2 years, the composite of death, myocardial infarction, or repeat target lesion revascularization were similar between the 2 groups (35.7% vs 34.0%; HR=1.04, 95%CI, 0.70-1.55; P=.83; Padjusted=.79). The rate of repeat target lesion revascularization was also similar in the 2 groups (29.8% vs 31.5%; HR=0.91, 95%CI, 0.60-1.39; P=.68; Padjusted=.62). ConclusionsIn patients undergoing reintervention for DES-ISR, we found no evidence of differences in outcomes according to whether the restenosed stent was a polymer-free or durable polymer DES.

Rationale and design of the Onyx ONE global randomized trial: A randomized controlled trial of high-bleeding risk patients after stent placement with 1 month of dual antiplatelet therapy

Background and RationalePolymer-free drug-eluting stent (DES) implantation in combination with 1-month dual antiplatelet therapy (DAPT) has shown superior safety and efficacy outcomes compared with bare-metal stents among patients with high-bleeding risk (HBR) treated with 1-month DAPT. The safety and efficacy of the newer-generation durable-polymer DES Resolute Onyx compared with polymer-free DES among HBR patients treated with 1-month DAPT is unknown. Trial DesignThe Onyx ONE global randomized trial is an international, prospective, randomized, blinded, controlled study enrolling HBR patients undergoing percutaneous coronary intervention. The trial will randomize up to 2,000 patients in a 1:1 fashion to receive either the durable-polymer Resolute Onyx DES or the polymer-free Biosensors BioFreedom DES. After index procedure, patients in both arms will be treated with 1 month of DAPT (aspirin and oral P2Y12 inhibitor), followed by single antiplatelet therapy thereafter. The primary end point is the composite end point of cardiac death, myocardial infarction, or stent thrombosis at 1-year follow-up. The powered secondary end point is target lesion failure (defined as the composite of cardiac death, target vessel myocardial infarction, or clinically driven target lesion revascularization) at 1 year. Patient follow-up is planned for 1, 2, and 6 months and 1 and 2 years after the procedure. ConclusionsThe Onyx ONE global randomized trial is the first study to directly compare the safety and efficacy of a durable polymer DES (Resolute Onyx) with a polymer-free DES (BioFreedom) in HBR patients treated with 1 month of DAPT.

Safety and Efficacy of Polymer-Free Drug-Eluting Stents.

Background Polymer-free drug-eluting stents are based on different technologies for drug binding and release without the use of polymer coatings. It is unknown whether different polymer-free drug-eluting stents are comparable in terms of safety and efficacy profiles. Methods and Results Polymer-free BioFreedom biolimus-eluting stents (BES) and polymer-free Cre8 amphilimus-eluting stents (AES) were investigated in 2 recent multicenter registries including 2320 all-comer patients undergoing percutaneous coronary interventions at 22 Italian centers. Using propensity score matching, safety and efficacy outcomes were compared among 1280 patients (640 matched pairs) treated with BioFreedom BES or Cre8 AES. The primary end point was target lesion failure-a composite of cardiac death, target vessel myocardial infarction, and target lesion revascularization (TLR). At 1 year, target lesion failure occurred in 4.0% of BES and 4.2% of AES-treated patients (hazard ratio [HR] 0.98, 95% CI, 0.57-1.70). Risks of cardiac death (2.0% versus 2.1%; HR, 1.03; 95% CI, 0.47-2.26), target vessel myocardial infarction (0.8% versus 0.3%; HR, 1.89; 95% CI, 0.50-6.80), TLR (1.5% versus 2.2%; HR, 0.74; 95% CI, 0.34-1.62), and definite/probable stent thrombosis (0.9% versus 0.8%; HR, 1.17; 95% CI, 0.36-3.81) were comparable in patients treated with BioFreedom BES and Cre8 AES. A differential treatment effect by diabetes mellitus status was observed, indicating a benefit of AES in patients with diabetes mellitus ( P interaction=0.003). Conclusions The present study shows that BioFreedom BES and Cre8 AES have favorable and comparable safety and efficacy profiles in all-comer patients undergoing percutaneous coronary intervention. Further evaluation in large-scale, randomized trials are necessary to confirm our findings.