Nobori Stent Shows Less Vascular Inflammation and Early Recovery of Endothelial Function Compared With Cypher Stent

Long-Term Clinical Outcomes of Biodegradable- Versus Durable-Polymer-Coated Everolimus-Eluting Stents in Real-World Post-Marketing Study

BACKGROUND

Long-term clinical data on biodegradable-polymer (BP) drug-eluting stents (DES) are limited. The objective of this study was to assess the long-term safety and efficacy of the BP-DES SYNERGY compared to XIENCE V, a durable-polymer (DP)-DES.

METHODS

We compared patients treated with BP-DES or DP-DES at our center from 2008 to 2020. The primary outcome was major adverse cardiac events (MACE), defined as the composite of all-cause death, Q-wave myocardial infarction (MI), and target vessel revascularization (TVR). Secondary endpoints were all-cause death, Q-wave MI, target lesion revascularization (TLR), and stent thrombosis (ST).

RESULTS

A total of 4255 patients underwent propensity-score matching, and 380 patients from each cohort were matched. There was no significant difference between BP-DES and DP-DES concerning MACE (5-year estimates: 21.6% vs. 26.6%, log-rank p = 0.259). Furthermore, there was no difference in the TLR rate (5-year estimates: 7.3% vs. 8.6%, log-rank p = 0.781). All-cause death (5-year estimates: 13.6% vs. 12.9%, log-rank p = 0.72) and Q-wave MI (5-year estimates: 0.53% vs. 1.7%, log-rank p = 0.427) were also comparable between the two groups. Of note, the rate of very late ST was very low and similar between the groups (5-year estimates: 0.26% vs. 0.64%, log-rank p = 0.698).

CONCLUSION

BP-DES and DP-DES demonstrate similar safety and efficacy at 5-year follow-up. Both can be used for the effective treatment of coronary artery disease.

Efficacy and Safety of Sirolimus-Eluting Stent With Biodegradable Polymer Ultimaster™ in Unselected Korean Population: A Multicenter, Prospective, Observational Study From Korean Multicenter Ultimaster Registry

BACKGROUND AND OBJECTIVES

Ultimaster™, a third-generation sirolimus-eluting stent using biodegradable polymer, has been introduced to overcome long term adverse vascular events, such as restenosis or stent thrombosis. In the present study, we aimed to evaluate the 12-month clinical outcomes of Ultimaster™ stents in Korean patients with coronary artery disease.

METHODS

This study is a multicenter, prospective, observational registry across 12 hospitals. To reflect real-world clinical evidence, non-selective subtypes of patients and lesions were included in this study. The study end point was target lesion failure (TLF) (the composite of cardiac death, target vessel myocardial infarction [MI], and target lesion revascularization [TLR]) at 12-month clinical follow up.

RESULTS

A total of 576 patients were enrolled between November 2016 and May 2021. Most of the patients were male (76.5%), with a mean age of 66.0±11.2 years. Among the included patients, 40.1% had diabetes mellitus (DM) and 67.9% had acute coronary syndrome (ACS). At 12 months, the incidence of TLF was 4.1%. The incidence of cardiac death was 1.5%, MI was 1.0%, TLR was 2.7%, and stent thrombosis was 0.6%. In subgroup analysis based on the presence of ACS, DM, hypertension, dyslipidemia, or bifurcation, there were no major differences in the incidence of the primary endpoint.

CONCLUSIONS

The present registry shows that Ultimaster™ stent is safe and effective for routine real-world clinical practice in non-selective Korean patients, having a low rate of adverse events at least up to 12 months.

Coronary bioresorbable stents: Non-invasive quantitative evaluation of intra- and juxta-stent plaque composition-A computed tomography longitudinal study

PURPOSE

Coronary bioresorbable stents (BRS) do not produce blooming artifacts on computed tomography (CT), in contrast to metallic stents, as they are made of a bioresorbable polymer and are radiolucent. They allow to evaluate the coronary plaque beneath. The low-attenuation plaque (LAP) suggests plaque vulnerability and is CT assessable. The aim of our study was to show the possibility of a non-invasive CT evaluation of the volume and the LAP composition of the intra- and juxta-stent plaque.

METHODOLOGY

In our prospective longitudinal study, we recruited 27 consecutive patients (35 BRS stents total; mean age 60 +/- 9 years) with bioresorbable stents for a 256-slice ECG-synchronized CT evaluation at 1- and 12-months post stent implantation. Total plaque volume (mm3), absolute and relative (%) LAP volume per block in the pre- intra- and post-stent zones were analyzed; comparison 1- and 12-months post-implantation of BRS. Changes in the previously mentioned variables were assessed by the mixed effects models with and without spline, which also accounted for the correlation between repeated measurements.

RESULTS

Our block or spline model analysis has shown no significant difference in plaque or absolute LAP volumes in pre- intra- and post-stent zones between 1 and 12 months. Interestingly, % LAP volume increases near-significantly in the distal block of the intrastent at 12-mo follow-up (from 23.38 ± 1.80% to 26.90 ± 2.22% (increase of 15%), p = 0.052).

CONCLUSION

Our study demonstrates the feasibility of the repeated non-invasive quantitative analysis of the intrastent coronary plaque and of the in-stent lumen by CT scan.

Everolimus-Eluting Biodegradable Abluminal Coating Stent versus Durable Conformal Coating Stent: Termination of the Inflammatory Response Associated with Neointimal Healing in a Porcine Coronary Model

Objectives

We evaluated the effect of the different carrier systems on early vascular response through histological analysis and scanning electron microscopy using a porcine model.

Background

Although Synergy™ and Promus PREMIER™ share an identical stent material and drug elution (everolimus), they use different drug carrier systems: biodegradable abluminal coating polymer or durable conformal coating polymer, respectively. However, data regarding the impact of the different coating systems on vessel healing are currently limited.

Methods

Twelve Synergy™ and Promus PREMIER™ were implanted in 12 swine. Histopathological analysis of the stented segments was performed on the 2^nd and 14^th days after implantation. Morphometric analysis of the inflammation and intimal fibrin content was also performed.

Results

On the 2^nd day, neointimal thickness, percentage of neointimal area, and inflammatory and intimal fibrin content scores were not significantly different between the two groups. On the 14^th day, the inflammatory and intimal fibrin content scores were significantly lower in Synergy™ versus those observed in Promus PREMIER™. In Synergy™, smooth muscle cells were found and the neointimal layers were smooth. In contrast, inflammatory cells were observed surrounding the struts of Promus PREMIER™.

Conclusions

These results demonstrate that termination of reactive inflammation is accelerated after abluminal coating stent versus implantation of conformal coating stent.

Effects of Catheterization on Artery Function and Health: When Should Patients Start Exercising Following Their Coronary Intervention?

Coronary artery disease (CAD) is a leading cause of death worldwide, and percutaneous transluminal coronary angiography (PTCA) and/or percutaneous coronary intervention (PCI; angioplasty) are commonly used to diagnose and/or treat the obstructed coronaries. Exercise-based rehabilitation is recommended for all CAD patients; however, most guidelines do not specify when exercise training should commence following PTCA and/or PCI. Catheterization can result in arterial dysfunction and acute injury, and given the fact that exercise, particularly at higher intensities, is associated with elevated inflammatory and oxidative stress, endothelial dysfunction and a pro-thrombotic milieu, performing exercise post-PTCA/PCI may transiently elevate the risk of cardiac events. This review aims to summarize extant literature relating to the impacts of coronary interventions on arterial function, including the time-course of recovery and the potential deleterious and/or beneficial impacts of acute versus long-term exercise. The current literature suggests that arterial dysfunction induced by catheterization recovers 4-12 weeks following catheterization. This review proposes that a period of relative arterial vulnerability may exist and exercise during this period may contribute to elevated event susceptibility. We therefore suggest that CAD patients start an exercise training programme between 2 and 4 weeks post-PCI, recognizing that the literature suggest there is a 'grey area' for functional recovery between 2 and 12 weeks post-catheterization. The timing of exercise onset should take into consideration the individual characteristics of patients (age, severity of disease, comorbidities) and the intensity, frequency and duration of the exercise prescription.

Cardiovascular therapies utilizing targeted delivery of nanomedicines and aptamers

Cardiovascular ailments are the foremost trigger of death in the world today, including myocardial infarction and ischemic heart diseases. To date, extraordinary measures have been prescribed, from the perspectives of both conventional medical therapies and surgeries, to enforce cardiac cell regeneration post cardiac traumas, albeit with limited long-term success. The prospects of successful heart transplants are also grim, considering exorbitant costs and unavailability of suitable donors in most cases. From the perspective of cardiac revascularization, use of nanoparticles and nanoparticle mediated targeted drug delivery have garnered substantial attention, attributing to both active and passive heart targeting, with enhanced target specificity and sensitivity. This review focuses on this aspect, while outlining the progress in targeted delivery of nanomedicines in the prognosis and subsequent therapy of cardiovascular disorders, and recapitulating the benefits and intrinsic challenges associated with the incorporation of nanoparticles. This article categorically provides an overview of nanoparticle-mediated targeted delivery systems and their implications in handling cardiovascular diseases, including their intrinsic benefits and encountered procedural trials and challenges. Additionally, the solicitations of aptamers in targeted drug delivery with identical objectives, are presented. This includes a detailed appraisal on various aptamer-navigated nanoparticle targeted delivery platforms in the diagnosis and treatment of cardiovascular maladies. Despite a few impending challenges, subject to additional investigations, both nanoparticles as well as aptamers show a high degree of promise, and pose as the next generation of drug delivery vehicles, in targeted cardiovascular therapy.

A comparison of the main outcomes from BP-BES and DP-DES at five years of follow-up: A systematic review and meta-analysis

Biodegradable polymer biolimus-eluting stents (BP-BES) are third-generation drug-eluting stents (DES) composed of biodegradable polymers that may improve prognosis after percutaneous coronary intervention (PCI). After five years of follow-up, BP-BES showed conflicting results compared to durable polymer drug-eluting stents (DP-DES). We performed a meta-analysis of the outcomes of studies on BP-BES and DP-DES after percutaneous coronary intervention (PCI) at five years of follow-up. Eligible studies were retrieved from PubMed, Embase and the Cochrane Library and reported the results of all-cause mortality, myocardial infarction (MI), target lesion revascularization (TLR), target vessel revascularization (TVR) and stent thrombosis (ST) at five years of follow-up. Five studies of a total of 4687 patients were included in the meta-analysis. At five years of follow-up, BP-BES was associated with lower rates of major adverse cardiac events (MACE) (OR = 0.83, 95%CI = [0.71, 0.97]), TLR (OR = 0.77, 95%CI = [0.62, 0.96]) and ST (OR = 0.60, 95%CI = [0.43 to 0.84]), whereas no significant differences in mortality, MI, or TVR rates were detected. Our results demonstrated that at five years of follow-up, BP-BES can significantly reduce the risk of MACE, TLR and ST, which indicate that safety and efficacy were increased after PCI.

In vitro and in vivo degradation of microfiber bioresorbable coronary scaffold

The degradation of Mirage Bioresorbable Microfiber Scaffold was evaluated in vitro and in vivo. The degradation in polymer molecular weight (MW), strut morphology, and integrity was accessed using gel permeation chromatography (GPC), X‐ray micro‐computed tomography (micro‐CT) evaluation. To simulate the physiological degradation in vitro, scaffolds were deployed in silicone mock vessels connected to a peristaltic pumping system, which pumps 37°C phosphate‐buffered saline (PBS, pH 7.4) at a constant rate. At various time points (30D, 60D, 90D, 180D, 270D, and 360D), the MW of microfibers decreased to 57.3, 49.8, 36.9, 13.9, 6.4, and 5.1% against the baseline. The in vivo degradation study was performed by implanting scaffolds in internal thoracic arteries (ITAs) of mini‐swine. At the scheduled sacrifice time points (30D, 90D, 180D, 270D, 360D, and 540D), the implanted ITAs were excised for GPC analysis; the MW of the implanted scaffolds dropped to 58.5, 34.7, 24.8, 16.1, 12.9, and 7.1, respectively. Mass loss of scaffolds reached 72.4% at 540D of implantation. Two stages of hydrolysis were observed in in vitro and in vivo degradation kinetics, and the statistical analysis suggested a positive correlation between in vivo and in vitro degradation. After 6 months of incubation in animals, significant strut degradation was seen in the micro‐CT evaluation in all sections as strut fragments and separations. The micro‐CT results further confirmed that every sample at 720D had X‐ray transmission similar to surrounding tissue, thereby indicating full degradation within 2 years. © 2017 The Authors. Journal of Biomedical Materials Research Part B: Applied Biomaterials published by Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1842–1850, 2018.

Safety and Efficacy of New Biodegradable Polymer-based Sirolimus-Eluting Stents in a Preclinical Model

INTRODUCTION AND OBJECTIVES

New drug-eluting stents (DES) designed to overcome the limitations of existing devices should initially be tested in preclinical studies. Our objective was to analyze the safety and efficacy of new biodegradable polymer-based DES compared with bare-metal stents (BMS) and commercially available DES in a model of normal porcine coronary arteries.

METHODS

We randomly implanted 101 stents (BMS and biodegradable polymer-based sirolimus-eluting stents: 3 test stent iterations [BD1, BD2, and BD3], Orsiro, Biomime and Biomatrix) in the coronary arteries of 34 domestic pigs. Angiographic and histomorphometric studies were conducted 1 month (n = 83) and 3 months (n = 18) later.

RESULTS

The stents were implanted at a stent/artery ratio of 1.31 ± 0.21, with no significant differences between groups. At 1 month, the new test stents (BD1, BD2 and BD3) showed less late loss and angiographic restenosis, as well as lower histologic restenosis and neointimal area (P < .0005), than the BMS. There were no differences in endothelialization, vascular injury, or inflammation between the new test stents and BMS, although the new stents showed higher fibrin deposition (P = .0006). At 3 months, all these differences disappeared, except for a lower neointimal area with the new BD1 stent (P = .027). No differences at any time point were observed between the new test stents and commercially available controls.

CONCLUSIONS

In this preclinical model, the new biodegradable polymer-based DES studied showed less restenosis than BMS and no significant differences in safety or efficacy vs commercially available DES.

Early endothelialization associated with a biolimus A9 bioresorbable polymer stent in a porcine coronary model

Although Nobori^®, with a bioresorbable polymer and biolimus A9 abluminal coating, has unique characteristics, few data exist regarding endothelialization early after implantation. Fifteen Nobori^® and 14 control bare-metal stents (S-stent™) were implanted in 12 pigs. Histopathology of stented segments, inflammation, and intimal fibrin content was evaluated on the 2nd and 14th day after implantation. On the 2nd day, endothelial cells were morphologically and immunohistologically confirmed on the surface of both stents, although some inflammatory cells might be involved. Stent surface endothelialization evaluated with a scanning electron microscope showed partial cellular coverage in both stents. On the 14th day, neointimal thickness and percentage of the neointimal area were significantly lower in Nobori^® than in S-stent™ (51.4 ± 4.5 vs. 76.4 ± 23.6 µm, p < 0.05 and 10.8 ± 2.6 vs. 14.1 ± 4.2%, p < 0.01). No significant differences were found in these parameters on the 2nd day (17.3 ± 14.9 vs. 26.7 ± 13.6 µm and 3.7 ± 3.0 vs. 6.7 ± 3.7%), in inflammatory and intimal fibrin content scores. These results demonstrate that endothelialization could occur early after Nobori^® implantation with similar inflammatory reaction to bare-metal stents, probably contributing to low frequency of in-stent thrombosis and restenosis.

Effect of biodegradable polymer drug-eluting stents versus biocompatible polymer everolimus-eluting stents: a meta-analysis

OBJECTIVE

Biocompatible polymer everolimus-eluting stents (EES) are associated with risk of stent thrombosis (ST); biodegradable polymer drug-eluting stents (BP-DES) were designed to reduce these risks. However, the long-term benefits are not completely clear.

METHOD

We undertook a meta-analysis of randomized studies identified in systematic searches of MEDLINE, EMBASE, and the Cochrane Database. Primary outcome was the risk of ST.

RESULTS

Twelve studies (11,692 patients) were included. Overall, compared with EES, BP-DES were associated with a broadly equivalent risk of definite and probable ST (OR, 0.91; 95% CI, 0.55 to 1.50; P = 0.71; I²= 0.0%), early ST (OR, 2.25; 95% CI, 0.78 to 6.47; P = 0.13; I²= 0.0%), late ST (OR, 3.57; 95% CI, 0.42 to 30.58; P = 0.25; I²= 0.0%) and very late ST (OR, 0.50; 95% CI, 0.05 to 5.52; P = 0.57). Meanwhile, there was no significant difference in all-cause mortality (OR, 1.07; 95% CI, 0.86 to 1.32; P = 0.54; I²= 0.0%), myocardial infarction (OR, 1.07; 95% CI, 0.88 to 1.30; P = 0.47; I²= 0.0%), target vessel revascularization (OR, 1.02; 95% CI, 0.86 to 1.21; P = 0.80; I²= 12.0%), and major adverse cardiac events (OR, 1.04; 95% CI, 0.93 to 1.16; P = 0.53; I²= 0.0%). Furthermore, angiographic data showed that in-stent and in-segment late luminal loss were similar between the two groups.

CONCLUSIONS

Compared with biocompatible polymer EES, biodegradable polymer stents appear to have equivalent clinical benefits.

Nanomedicine in coronary artery disease

Nanomedicine is one of the most promising therapeutic modalities researchers are working on. It involves development of drugs and devices that work at the nanoscale (10-9m). Coronary artery disease (CAD) is responsible for more than a third of all deaths in age group >35 years. With such a huge burden of mortality, CAD is one of the diseases where nanomedicine is being employed for preventive and therapeutic interventions. Nanomedicine can effectively deliver focused drug payload at sites of local plaque formation. Non-invasive strategies include thwarting angiogenesis, intra-arterial thrombosis and local inflammation. Invasive strategies following percutaneous coronary intervention (PCI) include anti-restenosis and healing enhancement. However, before practical application becomes widespread, many challenges need to be dealt with. These include manufacturing at the nanoscale, direct nanomaterial cellular toxicity and visualization.

Histopathological background data of the systemic organs of CLAWN miniature swine with coronary artery stent implantation

The aim of this study was to identify potential changes that could occur during histological evaluations of CLAWN miniature swine, with potential consequences for subsequent experiments. The systemic organs from male and female CLAWN miniature swine (16.3–42.3 months old) that had been used in long-term studies of coronary stent implantation were examined histologically. Commonly observed histopathological findings were testicular/epididymal atrophy, cyst-like follicles in the ovaries, hemosiderin deposition in the spleen, lipofuscin deposition in the proximal tubular epithelia and presence of eosinophilic globules in the Bowman’s space and the lumen of the proximal tubules in the kidneys, and cellular infiltration in several organs, including the eyelids, respiratory organs, and digestive tract. However, none of these changes were serious enough to indicate a significant impact on research. In conclusion, this study identified CLAWN miniature swine as a suitable animal model for various experiments.

Fabrication and characterization of shape memory polymers based bioabsorbable biomedical drug eluting stent

Present investigation deals with, tacrolimus eluting, self-expandable, biodegradable stent fabricated by solvent casting method. The design was based on shape memory polymers, which possess the ability to memorize temporary shape that can substantially differ from their initial permanent shape. A set of biodegradable polymers blend was used such as poly-lactic acid (PLA) and poly-l-glycolic acid (PLGA) to study the shape memory effect of polymer. The prepared stent was assessed for various parameters like Scanning Electron Microscopy (SEM), In-vitro and Ex vivo expansion, Drug content, In-vitro drug release, Haemocompatibility, Differential Scanning Calorimetry (DSC), Fourier Transform Infrared spectroscopy (FTIR), and Textural Characterization.

Current State of Bioabsorbable Polymer-Coated Drug-Eluting Stents

Drug-eluting stents (DES) have been shown to significantly reduce clinical and angiographic restenosis compared to bare metal stents (BMS). The polymer coatings on DES elute antiproliferative drugs to inhibit intimal proliferation and prevent restenosis after stent implantation. Permanent polymers which do not degrade in vivo may increase the likelihood of stent-related delayed arterial healing or polymer hypersensitivity. In turn, these limitations may contribute to an increased risk of late clinical events. Intuitively, a polymer which degrades after completion of drug release, leaving an inert metal scaffold in place, may improve arterial healing by removing a chronic source of inflammation, neoatherosclerosis, and/or late thrombosis. In this way, a biodegradable polymer may reduce late ischemic events. Additionally, improved healing after stent implantation could reduce the requirement for long-term dual antiplatelet therapy and the associated risk of bleeding and cost. This review will focus on bioabsorbable polymer-coated DES currently being evaluated in clinical trials.

Beneficial Effects of a Novel Bioabsorbable Polymer Coating on Enhanced Coronary Vasoconstricting Responses After Drug-Eluting Stent Implantation in Pigs in Vivo

OBJECTIVES

The aim of this study was to examine which component of drug-eluting stents (DES) plays a major role in enhanced coronary vasoconstricting responses after DES implantation in pigs.

BACKGROUND

Recent studies have reported unremitting angina due to vasomotion abnormalities even after successful DES implantation. However, it remains to be elucidated which component of DES (metal stent, polymer coating, or antiproliferative drug) is responsible for DES-induced coronary hyperconstricting responses.

METHODS

We developed poly-dl-lactic acid and polycaprolactone (PDLLA-PCL) copolymer technology with higher biocompatibility that is resorbed within 3 months. Four types of coronary stents were made: 1) a stent with polylactic acid (PLA) polymer coating containing antiproliferative drug (P1+D+); 2) a stent with PLA polymer coating alone without any drug (P1+D-); 3) a stent with novel PDLLA-PCL polymer coating alone (P2+D-); and 4) a bare metal stent (P-D-). The 4 stents were randomly deployed in the left anterior descending and left circumflex coronary arteries in 12 pigs.

RESULTS

After 1 month, coronary vasoconstriction by intracoronary serotonin was enhanced at P1+D+ and P1+D- stent edges compared with P2+D- and P-D- stent edges and was prevented by a specific Rho-kinase (a central molecule of coronary spasm) inhibitor, hydroxyfasudil. Immunostainings showed that inflammatory changes and Rho-kinase activation were significantly enhanced at P1+D+ and P1+D- sites compared with P2+D- and P-D- sites. There were significant positive correlations between the extent of inflammation or Rho-kinase expression/activation and that of coronary vasoconstriction.

CONCLUSIONS

These results indicate the important roles of PLA polymer coating in DES-induced coronary vasoconstricting responses through inflammatory changes and Rho-kinase activation in pigs in vivo, which are ameliorated by PDLLA-PCL copolymers.

Characterization of platelet aggregation responses in microminipigs: Comparison with miniature pigs and the influence of dual antiplatelet administration of aspirin plus prasugrel

We aimed to characterize platelet aggregation responses and the impact of dual antiplatelet therapy in microminipigs. In this in vitro study, both adenosine-5'-diphosphate (ADP, 5-50μM) and collagen (2-20μg/ml) induced concentration-related platelet aggregation in the microminipigs; 20μM ADP and 5 and 12.5μg/ml collagen were selected for further ex vivo studies. Aspirin plus prasugrel were administered orally for 7days (n=4/each group). Ex vivo platelet aggregation was analyzed on Day 1 (1 and 4h after administration), Day 4 (4h), and Day 7 (4h) under three different prasugrel dosing regimens: LD0/MD1 (1mg/kg/day), LD0/MD3 (3mg/kg/day), and LD10/MD1 (10mg/kg loading dose and 1mg/kg/day maintenance dose). Aspirin (10mg/kg/day) was administered to all groups. In the presence of aspirin, prasugrel at 3 and 10mg/kg significantly inhibited ADP-induced platelet aggregation on Day 1. On Days 4 and 7, significant inhibition of platelet aggregation (IPA) was also observed in each group. With 5μg/ml collagen-induced platelet aggregation, all three groups showed significant IPA at 4h on Day 1 or later. In 12.5μg/ml collagen-induced platelet aggregation, all groups showed significant effects on Days 4 and 7; however, the 30%-35% IPA was considerably lower than that (50%-60%) found with 5μg/ml collagen. In Clawn miniature pigs, similar inhibitory patterns were observed for both ADP- and collagen-induced ex vivo platelet aggregation. In conclusion, these results indicated that microminipigs as well as miniature pigs may represent useful experimental animals for thrombosis research.

Stent Thrombosis with Biodegradable Polymer Drug-Eluting Stents versus Durable Polymer Sirolimus-Eluting Stents: An Update Meta-Analysis

Objective: Durable polymer sirolimus-eluting stents (DP-SES) are associated with a low risk of stent thrombosis; biodegradable polymer drug-eluting stents (BP-DES) were designed to reduce these risks. However, their benefits are still variable. Method: We undertook a meta-analysis of randomized trials identified by systematic searches of Medline, Embase, and the Cochrane Database. Results: Eleven studies (9,676 patients) with a mean follow-up of 22.6 months were included. Overall, compared with DP-SES, BP-DES significantly lowered the rate of definite or probable stent thrombosis (RR, 0.73; 95% CI, 0.55-0.97; p = 0.03; I2 = 0.0%) due to a decreased risk of very late stent thrombosis (RR, 0.26; 95% CI, 0.11-0.63; p = 0.00; I2 = 0.0%). However, BP-DES were associated with a comparable rate of early and late stent thrombosis. Meanwhile, BP-DES were associated with a broadly equivalent risk of target vessel revascularization (RR, 0.90; 95% CI, 0.78-1.03; p = 0.13; I2 = 0.0%), cardiac death (RR, 0.89; 95% CI, 0.72-1.09; p = 0.24; I2 = 0.0%), myocardial infarction (RR, 1.03; 95% CI, 0.84-1.26; p = 0.79; I2 = 0.0%), and major adverse cardiac events (MACE; RR, 0.91; 95% CI, 0.83-1.0; p = 0.08; I2 = 0.0%). Furthermore, angiographic data showed that in-stent and in-segment late luminal loss were similar between the two groups. Conclusions: Compared with DP-SES, BP-DES were associated with a lower rate of very late stent thrombosis and an equivalent risk of MACE. Larger randomized studies are needed to confirm this finding.

Reduced sirolimus systemic exposure and improved bioresorbable polymer properties: new allies for the treatment of patients with coronary artery disease

This prospective, first-in-man, open-label multicenter study sought to assess the pharmacokinetics of sirolimus after Ultimaster drug-eluting stent implantation (coated with sirolimus and bioabsorbable co-polymer) in patients with de novo coronary artery disease (the TCD-10023 PK study). The primary endpoint was sirolimus concentration in peripheral whole blood at 28 days after stent implantation. In addition, safety, tolerability, therapeutic outcome and vasomotor response after stent implantation were studied. Twenty patients were enrolled in the study. Blood samples for the measurements of sirolimus concentration were collected at eight time points during first 48 h, at 7 days and 28 days after stent implantation. Patients underwent 6-month angiographic and up to 12 months clinical follow-up. At 28 days, only two of 20 patients had sirolimus concentrations above lower limit of quantification (20.0 pg/mL). The highest sirolimus blood concentration was 105 pg/mL. The median maximum concentration was 36.8 pg/mL (range 22.9-41.5 pg/mL) for stent 3.0 × 15 mm and 87.2 pg/mL (range 60.0-105.0 pg/mL) for 3 × 28 mm stent. The median systemic exposure, as measured by the area under the time-concentration curve, was 8.3 ng h/mL (range 6.47-28.0 ng h/mL). At 6 months, endothelial function was well preserved, and up to 12 months, there were no signs of sirolimus toxicity nor any other safety concerns. Our results demonstrate that implantation of Ultimaster stent resulted in almost nondetectable sirolimus in blood after 28 days. These findings were translated into exceptional safety profile, without any sign of systemic toxicity.

Nobori biolimus-eluting stent vs. permanent polymer drug-eluting stents in patients undergoing percutaneous coronary intervention

BACKGROUND

Permanent polymer coatings on drug-eluting stents (DES) surface have been identified as triggers of adverse events following percutaneous coronary intervention (PCI). However, efficacy and safety data for the Nobori biolimus-eluting stent (BES), a biodegradable polymer DES, are limited, so the aim of this study was to evaluate clinical outcomes associated with the Nobori BES compared with permanent polymer DES in patients undergoing PCI.

METHODS AND RESULTS

Randomized trials comparing Nobori BES vs. other DES were included in the meta-analysis. The 12-month clinical endpoints were: target lesion revascularization (TLR), all-cause mortality, myocardial infarction (MI) and stent thrombosis (ST). Seven trials totaling 12,090 PCI patients met the inclusion criteria. Nobori BES vs. other DES had a comparable risk of TLR (odds ratio [OR] 0.94; 95% confidence interval [CI], 0.66-1.34; P=0.74), mortality (OR 1.00; 95% CI, 0.78-1.28; P=0.98), MI (OR 1.10; 95% CI, 0.87-1.40; P=0.42) and definite/probable ST (OR 1.01; 95% CI, 0.45-2.25; P=0.99). Despite Nobori BES showing similar clinical results to sirolimus-, everolimus- and zotarolimus-eluting stents, it was superior to paclitaxel-eluting stents in reducing the risk of TLR (OR 0.31; 95% CI, 0.10-0.90; P=0.03)CONCLUSIONS:Nobori BES use is associated with a similar safety and efficacy as permanent polymer DES at 1-year follow-up, albeit it is superior to paclitaxel-eluting stents in terms of TLR. Long-term follow-up data are needed in order to establish whether polymer degradation related to Nobori BES implantation improves clinical outcomes.

Long-term vascular responses to Resolute® and Xience V® polymer-based drug-eluting stents in a rabbit model of atherosclerosis

OBJECTIVES

To assess the late postinterventional response to iliac stenting in atheromatous rabbits using the Xience V everolimus-eluting stent (Xience V EES; Abbott Vascular) and the Resolute zotarolimus-eluting stent (Resolute ZES; Medtronic Vascular) with the MultiLink Vision bare metal stent (BMS; Abbott Vascular) as a reference.

BACKGROUND

Xience V EES and Resolute ZES were developed to overcome shortcomings of first-generation DES.

METHODS

Functional and microscopic changes were assessed by organ bath experiments and histopathologic examination. Gene expression was investigated using RT-PCR.

RESULTS

After 91 days, re-endothelialization was nearly complete (BMS: 93 ± 3%; Resolute ZES: 92 ± 2%; Xience V EES: 94 ± 3%; P = 0.10). Neointima thickness was similar in Resolute ZES (0.17 ± 0.08 mm) and BMS (0.17 ± 0.09 mm), and reduced in Xience V EES (0.03 ± 0.01 mm; P < 0.0001). Xience V EES had less peri-strut inflammation compared with BMS (P = 0.001) and Resolute ZES (P = 0.0001), while arterial segments distal to Xience V EES were more sensitive to acetylcholine than those distal to BMS and Resolute ZES (P = 0.02). Lectin-like oxidized receptor-1 was overexpressed in stented arteries (P < 0.001), whereas thrombomodulin was downregulated in Resolute ZES (P = 0.01) and BMS (P = 0.02) compared to unstented arteries of rabbits on regular chow. No significant changes were seen for vascular cell adhesion molecule-1, nitric oxide synthase 3, or endothelin-1.

CONCLUSIONS

At 3-month follow-up, nearly complete re-endothelialization was achieved for all stent groups. Xience V EES induced greater suppression of neointimal growth and peri-strut inflammation, higher vasorelaxation to acetylcholine, and expression of thrombomodulin at the level of unstented controls.

Preclinical study of a biodegradable polymer-based stent with abluminal sirolimus release

Background

Bioabsorbable polymer stents with drug elution only on the abluminal surface may be safer than durable polymer drug-eluting stents.

Objective

To report the experimental findings with the Inspiron^TM stent - a bioabsorbable polymer-coated stent with sirolimus release from the abluminal surface only, recently approved for clinical use.

Methods

45 stents were implanted in the coronary arteries of 15 pigs. On day 28 after implantation, angiographic, intracoronary ultrasonographic and histomorphological data were collected. Five groups were analyzed: Group I (nine bare-metal stents); Group II (nine coated with bioabsorbable polymer on the luminal and abluminal surfaces); Group III (eight stents coated with bioabsorbable polymer on the abluminal surface); Group IV (nine stents with bioabsorbable polymer and sirolimus on the luminal and abluminal surfaces); and Group V (ten stents with bioabsorbable polymer and sirolimus only on the abluminal surface).

Results

The following results were observed for Groups I, II, III, IV and V, respectively: percentage stenosis of 29 ± 20; 36 ± 14; 33 ± 19; 22 ± 13 and 26 ± 15 (p = 0.443); late lumen loss (in mm) of 1.02 ± 0.60; 1.24 ± 0.48; 1.11 ± 0.54; 0.72 ± 0.44 and 0.78 ± 0.39 (p = 0.253); neointimal area (in mm²) of 2.60 ± 1.99; 2.74 ± 1.51; 2.74 ± 1.30; 1.30 ± 1.14 and 0.97 ± 0.84 (p = 0.001; Groups IV and V versus Groups I, II and III); and percentage neointimal area of 35 ± 25; 38 ± 18; 39 ± 19; 19 ± 18 and 15 ± 12 (p = 0.001; Groups IV and V versus Groups I, II and III). Injury and inflammation scores were low and with no differences between the groups.

Conclusion

The Inspiron^TM stent proved to be safe and was able to significantly inhibit the neointimal hyperplasia observed on day 28 after implantation in porcine coronary arteries.

The Nobori biolimus-eluting stent: update of available evidence

Despite first-generation drug-eluting stents (DES) dramatically reduced the need for repeat revascularization in patients undergoing percutaneous coronary intervention, their use was associated with an increased risk of thrombotic events at long-term follow-up. The Nobori biolimus-eluting stent (BES) is a second-generation DES with a biodegradable poly-lactic acid polymer. During the last few years, several randomized trials have compared the Nobori BES with other DES, making this device the most investigated biodegradable DES. In this article, we reviewed current available data about Nobori BES from pharmacokinetic and observational studies to randomized clinical trials.

Biodegradable polymer DES versus durable polymer everolimus-eluting stents for patients undergoing PCI: a meta-analysis

BACKGROUND

Everolimus-eluting stents are associated with low risk of stent thrombosis and stent restenosis, and the new generation of stents with biodegradable polymer were designed to reduce that risk. However, the benefits have been variable.

METHODS AND RESULTS

Four RCTs with a total of 8282 patients were included. Overall, BP-DES was not inferior to EES with equivalent risk of TVR (relative risk [RR], 1.07; 95% confidence interval [CI], 0.91-1.27; P=0.414; I(2)=0.0%) and ARC definite and/or probable ST (RR, 1.06; 95% CI, 0.66-1.70; P=0.810; I(2)=4.8%). Furthermore, there was no difference in all-cause mortality (RR, 1.06; 95% CI, 0.84-1.33; P=0.651; I(2)=0.0%), myocardial infarction (RR, 1.12; 95% CI, 0.88-1.44; P=0.360; I(2)=0.0%), and MACE (RR, 1.00; 95% CI, 0.87-1.15; P=0.975; I(2)=0.0%) between the two groups.

CONCLUSIONS

The new generation of biodegradable polymer stents were not inferior to EES for equivalent risk of MACE and ST.

Efficacy and safety of biodegradable polymer biolimus-eluting stents versus durable polymer drug-eluting stents: a meta-analysis

Backgrounds

Drug-eluting stents (DES) with biodegradable polymers have been developed to address the risk of thrombosis associated with first-generation DES. We aimed to determine the efficacy and safety of biodegradable polymer biolimus-eluting stents (BES) versus durable polymer DES.

Methods

Systematic database searches of MEDLINE (1950 to June 2013), EMBASE (1966 to June 2013), the Cochrane Central Register of Controlled Trials (Issue 6 of 12, June 2013), and a review of related literature were conducted. All randomized controlled trials comparing biodegradable polymer BES versus durable polymer DES were included.

Results

Eight randomized controlled trials investigating 11,015 patients undergoing percutaneous coronary interventions were included in the meta-analysis. The risk of major adverse cardiac events did not differ significantly between the patients treated with the biodegradable polymer BES and the durable polymer DES (Relative risk [RR], 0.970; 95% CI, 0.848–1.111; p = 0.662). However, biodegradable polymer BES was associated with reduced risk of very late ST compared with the durable polymer DES, while the risk of early or late ST was similar (RR for early or late ST, 1.167; 95% CI 0.755–1.802; p = 0.487; RR 0.273; 95% CI 0.115–0.652; p = 0.003; p for interaction = 0.003).

Conclusions

In this meta-analysis of randomized controlled trials, treatments with biodegradable polymer BES did not significantly reduce the risk of major adverse cardiac events, but demonstrated a significantly lower risk of very late ST when compared to durable polymer DES. This conclusion requires confirmation by further studies with long-term follow-up.

PROSPERO register number

http://www.crd.york.ac.uk/PROSPERO/display_record.asp?ID=CRD42013004364#.UnM2lfmsj6J

Dexamethasone-eluting vascular stents

Percutaneous transluminal angioplasty (PTA) with stenting is widely used in the treatment of vascular disorders, but restenosis remains a significant problem. Drug-eluting stents (DES) have been developed as an attempt to reduce the intimal response leading to restenosis. Drugs used in DES include mainly immunosuppressive and anti-proliferative compounds. Glucocorticoids are also an interesting possibility for those purposes because they have anti-proliferative effects in vascular smooth muscle cells and down-regulate the production of cytokines and growth factors driving inflammation and fibrosis. In this MiniReview, feasibility and safety of drug-eluting metal and biodegradable vascular stents are discussed with special emphasis on dexamethasone-eluting stents.