Bioresorbable Scaffold Research Articles

Clinical outcomes with biodegradable versus durable polymer drug-eluting stents in patients with ST-elevation myocardial infarction

BackgroundCoronary drug-eluting stents (DES) built with either durable (DP) or biodegradable (BP) polymeric coatings have been largely tested and are extensively available for routine use. However, their comparative performance remains an open question, particularly in more complex subsets of patients. AimsWe evaluated the outcomes of patients with ST-elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (pPCI) using DP-DES versus BP-DES in a large multicenter real-world registry. MethodsThe population comprised patients with STEMI treated with pPCI within 12 h of symptoms onset. Those treated with more than one DES who received different polymer types were excluded. The final cohort for analysis was selected after propensity score matching (PSM), computed to generate similar groups of DP DES versus BP DES. Primary endpoint was the incidence of major adverse cardiac events (MACE), defined as the composite of total death, myocardial infarction and target lesion revascularization at 2 years. ResultsFrom January 2017 to April 2022, a total of 1527 STEMI patients underwent pPCI with a single DES type (587 DP-DES; 940 BP-DES). After PSM, 836 patients (418 patients in the DP-DES and 418 patients in the BP-DES groups), comprised the final study population. Both study groups had a similar baseline profile. Patients treated with BP-DES group had similar rates of MACE (15.3 % vs. 19.4 %, HR 0.69, 95 % CI 0.50–0.94, p = 0.022). Rates of target lesion revascularization was lower in BP DES group (0.7 % vs. 3.8 %, HR 0.17, 95 % CI 0.05–0.51, p = 0.006). ConclusionIn a cohort of STEMI patients submitted to pPCI, BP and DP DES had similar rates of the primary outcome. Patients treated with BP DES, however, had a decreased incidence of TLR at after 2-year follow-up.

P2Y12 Inhibitor Monotherapy vs Dual Antiplatelet Therapy After Deployment of a Drug-Eluting Stent

P2Y12 inhibitor monotherapy after dual antiplatelet therapy (DAPT; a P2Y12 inhibitor plus aspirin) for a brief duration has recently emerged as an attractive alternative for patients undergoing percutaneous coronary intervention (PCI) with a drug-eluting stent. To investigate whether P2Y12 inhibitor monotherapy after 3 months of DAPT was noninferior to 12 months of DAPT following PCI with a drug-eluting stent. The Short-Term Dual Antiplatelet Therapy After Deployment of Bioabsorbable Polymer Everolimus-Eluting Stent (SHARE) open-label, noninferiority randomized clinical trial was conducted from December 15, 2017, through December 14, 2020. Final 1-year clinical follow-up was completed in January 2022. This study was a multicenter trial that was conducted at 20 hospitals in South Korea. Patients who underwent successful PCI with bioabsorbable polymer everolimus-eluting stents were enrolled. Patients were randomly assigned to receive P2Y12 inhibitor monotherapy after 3 months of DAPT (n = 694) or 12 months of DAPT (n = 693). The primary outcome was a net adverse clinical event, a composite of major bleeding (based on Bleeding Academic Research Consortium type 3 or type 5 bleeding) and major adverse cardiac and cerebrovascular events (cardiac death, myocardial infarction, stent thrombosis, stroke, or ischemia-driven target lesion revascularization) between 3 and 12 months after the index PCI. The major secondary outcomes were major adverse cardiac and cerebrovascular events and major bleeding. The noninferiority margin was 3.0%. Of the total 1452 eligible patients, 65 patients were excluded before the 3-month follow-up, and 1387 patients (mean [SD] age, 63.0 [10.7] years; 1055 men [76.1%]) were assigned to P2Y12 inhibitor monotherapy (n = 694) or DAPT (n = 693). Between 3 and 12 months of follow-up, the primary outcome (using Kaplan-Meier estimates) occurred in 9 patients (1.7%) in the P2Y12 inhibitor monotherapy group and in 16 patients (2.6%) in the DAPT group (absolute difference, -0.93 [1-sided 95% CI, -2.64 to 0.77] percentage points; P < .001 for noninferiority). For the major secondary outcomes (using Kaplan-Meier estimates), major adverse cardiac and cerebrovascular events occurred in 8 patients (1.5%) in the P2Y12 inhibitor monotherapy group and in 12 patients (2.0%) in the DAPT group (absolute difference, -0.49 [95% CI, -2.07 to 1.09] percentage points; P = .54). Major bleeding occurred in 1 patient (0.2%) in the P2Y12 inhibitor monotherapy group and in 5 patients (0.8%) in the DAPT group (absolute difference, -0.60 [95% CI, -1.33 to 0.12] percentage points; P = .10). In patients with coronary artery disease undergoing PCI with the latest generation of drug-eluting stents, P2Y12 inhibitor monotherapy after 3-month DAPT was not inferior to 12-month DAPT for net adverse clinical events. Considering the study population and lower-than-expected event rates, further research is required in other populations. ClinicalTrials.gov Identifier: NCT03447379.

Research on theoretical and experimental investigations of burr formation mechanism in micro-milling process of medical ploy-l-lactide

Medical grade poly-l-lactide (PLLA) has been widely applied for medical devices and consumables, e.g. biodegradable cardiovascular stents and surgical thread, due to its excellent biocompatibility. High-speed micro-milling technology shows great potential in high-precision and high-quality manufacturing of material PLLA, while it usually produces problems such as material burrs and defects. There is few research and analysis on the material removal mechanism and theory in the micro-milling process of polymers, and thus this paper aims to investigate the burr formation mechanism and processing quality in micro-milling process of medical PLLA. Firstly, a novel thermal-mechanical coupled theoretical model was proposed by considering the minimum cutting thickness and cutting-edge radius size effects, which can reveal the plastic flow law during micro-milling process of polymer material. This model was used to calculate the burr width at up and down milling sides of cutting area. Then material characterization and micro-milling experiments on two types of PLLA with different molecular weights were carried out to validate the established theoretical model, and further the micro-milling parameters were optimized to achieve the control of material burr formation and growth. As a result, a cardiovascular stent was fabricated by micro-milling with the optimized parameters (spindle speed of 25,000 rpm, feed rate of 100 mm/min and axial depth of cut of 5 μm), and the stents obtained significantly high surface quality. These results suggest that the proposed theoretical model has great advantages in the high-quality micro-milling of medical material PLLA. This work provides a potential stent manufacture technique in the development and clinical application of bioresorbable polymeric stents.

Anti-fibrotic and anti-stricture effects of biodegradable biliary stents braided with dexamethasone-impregnated sheath/core structured monofilaments

Endoscopic biliary stent insertion has been widely used for the treatment of benign biliary stricture (BBS). Thus, the development of stent materials in the perspectives of structure, mechanical properties, and biocompatibility has been also studied. However, conventional metal and plastic stents have several disadvantages, such as repeated procedures to remove or exchange them, dislodgment, restenosis, biocompatibility, and poor mechanical properties. Sustainable effectiveness, attenuation and prevention of fibrosis, and biocompatibility are key factors for the clinical application of stents to BBS treatment. In addition, loading drugs could show synergistic effects with stents’ own performance. We developed a dexamethasone-eluting biodegradable stent (DBS) consisting of a sheath/core structure with outstanding mechanical properties and sustained release of dexamethasone, which maintained its functions in a BBS duct over 12 weeks in a swine model. The insertion of our DBS not only expanded BBS areas but also healed secondary ulcers as a result of the attenuation of fibrosis. After 16 weeks from the insertion, BBS areas were totally improved, and the DBS was degraded and thoroughly disappeared without re-intervention for stent removal. Our DBS would be an effective clinical tool for non-vascular diseases. Statement of significanceThis study describes the insertion of a drug-eluting biodegradable stent (DBS) into the bile duct. The sheath/core structure of DBS confers substantial durability and a sustained drug release profile. Drug released from the DBS exhibited anti-fibrotic effects without inflammatory responses in both in vitro and in vivo experiments. The DBS maintained its function over 12 weeks after insertion into the common bile duct, expanding benign biliary stricture (BBS) and reducing inflammation to heal secondary ulcers in a swine BBS model. After 16 weeks from the DBS insertion, the DBS thoroughly disappeared without re-intervention for stent removal, resulting in totally improved BBS areas. Our findings not only spotlight the understanding of the sheath/core structure of the biodegradable stent, but also pave the way for the further application for non-vascular diseases.

Weekly journal scan: do biodegradable polymer stents provide a durable benefit in patients with ST-segment elevation myocardial infarction?

Weekly journal scan: do biodegradable polymer stents provide a durable benefit in patients with ST-segment elevation myocardial infarction?

Surface Modification of Zn-Cu Alloy with Heparin Nanoparticles for Urinary Implant Applications.

In this work, an investigation on the Zn-Cu alloy coated with heparin was conducted in order to explore the potentiality of its application as a feasible alternative for biodegradable implants, with the specific goal of addressing the issue of encrustation in the urinary system. The stability of the nanoparticles were characterized by dynamic light scattering. Typical surface characterization such as X-ray photoelectron spectroscopy, scanning electron microscopy, and atomic force microscopy were used to demonstrate a successful immobilization of the NPs. The in vitro corrosion behavior was studied by potentiodynamic polarization and immersion tests in artificial urine (AU) at 37 °C. The 8 weeks in vivo degradation, encrustation resistance, hemocompatibility, and histocompatibility were investigated by means of implantation into the bladders of rats. Both in vitro and in vivo degradation tests exhibited a higher degradation rate for Zn-Cu and NPs groups when compared to pure Zn. Histological evaluations and hemocompatibility revealed that there was no tissue damage or pathological alterations caused by the degradation process. Furthermore, antiencrustation performance and urinalysis results confirmed that the modified alloy demonstrated significant encrustation inhibitory properties and bactericidal activity compared to the pure Zn control. Our findings highlight the potential of this modified alloy as an antiencrustation biodegradable ureteral stent.

Strengthen oriented poly (L-lactic acid) monofilaments via mechanical training

Polymer materials have found extensive applications in the clinical and medical domains due to their exceptional biocompatibility and biodegradability. Compared to metallic counterparts, polymers, particularly Poly (L-lactic acid) (PLLA), are more suitable for fabricating biodegradable stents. As a viscoelastic material, PLLA monofilaments exhibit a creep phenomenon under sustained tensile stress. This study explores the use of creep to enhance the mechanical attributes of PLLA monofilaments. By subjecting the highly oriented monofilaments to controlled, constant force stretching, we achieved notable improvements in their mechanical characteristics. The results, as confirmed by tensile testing and dynamic mechanical analysis, revealed a remarkable 67 % increase in total elongation and over a 20 % rise in storage modulus post-mechanical training. Further microscopic analyses, including Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM), revealed enhanced spacing and cavity formation. These mechanical advancements are attributed to the unraveling and a more orderly arrangement of molecular chains in the amorphous regions. This investigation offers a promising approach for augmenting the mechanical properties of PLLA monofilaments, potentially benefiting their application in biomedical engineering.

Structural design optimization through finite element analysis of additive manufactured bioresorbable polymeric stents

Coronary stents help to treat coronary artery disease. Polymeric-based stents are considered the next generation of these medical devices since the materials are more compatible with human cells. Developing a polymeric bioresorbable stent with a different and optimized design can improve the mechanical performance of polymeric additively manufactured coronary stents. In this study, two different polymers were processed by additive manufacturing, and their mechanical properties were analyzed: poly(lactic acid) (PLA) and poly(ε-caprolactone) (PCL). Five different designs (A, B, C, D, and E) were then conceptualized with three different thicknesses. Finite element analysis (FEA) of a stent implantation process, using the mechanical properties of the additively manufactured materials, was used to evaluate the influence of the design, after the stent expansion, on the radial recoil ratio (RRR) and foreshortening. The in-silico results demonstrated that reducing strut thickness originates more plastic deformation, which reduces the RRR and increases the absolute value of foreshortening. PLA-based stents presented less RRR but, simultaneously, more risk of fracture. In the case of PCL-based devices, only designs A, B, and C presented acceptable recoil ratios. Design A is the chosen design as it reduces the RRR for lower thicknesses without risk of fracture during the stent deployment.

Pedicled pericardial patch in tracheal reconstruction in children – Novel technique to provide vascularized tissue for salvaging difficult airways

BackgroundManagement of large central airway defects are often complex. Children who present with these defects have multiple co-morbidities or have had previous surgeries. Surgical options include various tissue cover for these defects without longer term benefits. Vascularized autologous pericardial patch offers a better solution to these defects by providing vascularity and potential for remodelling in future. Methods41 children (M:F of 24:17) were operated for large trachea-bronchial defects between January 2015 and August 2022. The median age of was 12 months with median weight of 8.9 kg (IQR 3.3 kg–17.7 kg) Causes leading to the central tracheal defect include failed repair of previous trachea-oesophageal fistula (TOF) (n = 21) and acquired fistula due to button battery injury (n = 11). Surgical repair consisted of autologous pedicled pericardial patch repair for the airway defect under cardiopulmonary bypass. ResultsThere were two operative deaths related to extensive sepsis and necrosis of reconstructed trachea. Four children had further reoperation with additional patch. Bronchoscopy was used as surveillance in all these children, with use of airway stents (biodegradable stent) in 9 children. The median ventilation time was 8 days, with tracheostomy being needed in 5 for long term support. ConclusionsAutologous pericardial patch is a versatile technique and can be used to salvage large tracheal defects when other method have failed or not feasible. Tracheomalacia at the site of repair could be managed with biodegradable stents. Vascularity and ciliary function of the patch still needs to be evaluated.

Plasma electrolytic oxidation of AZ31 magnesium stents for degradation rate control

Cardiovascular disease caused by the accumulation of atheroma plaques in the coronary arteries and the subsequent decrease in the blood flow through the affected vessel, known as atherosclerosis, is responsible for a high percentage of deaths worldwide. Angioplasty is practiced to treat atherosclerosis which involves inserting a stent inside the occluded vessel to expand it and restore normal blood flow. In this work, temporary biodegradable stents made of AZ31 magnesium alloy have been fabricated using photo-chemical etching. The stents were coated via plasma electrolytic oxidation (PEO) technique. The radial strength of the stents was evaluated by cyclic compression, and the corrosion protection provided by the PEO coatings was studied by electrochemical and in vitro corrosion tests respectively. The stents showed an optimal maximum radial force of 0.147 N/mm and revealed elastic recuperation lower than 7 % of the total deformation after expansion. The applied PEO coating helped to control the corrosion of the magnesium alloy, delaying its initiation and, once it has started, decreased the degradation rate compared with the bare AZ31 samples. Thus, the stents treated with the PEO coatings developed in this research present promising results for their use as temporary medical devices used in angioplasty.

Optimal lesion preparation before implantation of a Magmaris bioresorbable scaffold in patients with coronary artery stenosis: Rationale, design and methodology of the OPTIMIS study

IntroductionPercutaneous coronary intervention with implantation of a bioresorbable scaffold (BRS) provide the vessel support for a limited period allowing the vessel to restore normal vasomotion after degradation of the BRS, opposed to treatment with drug-eluting stents where the metal persist in the vessel wall. Late lumen loss and reduction in lumen area after implantation have been reported. The purpose of this study was to investigate whether intense pre-dilatation before BRS implantation resulted in less reduction of minimal lumen area at 6- and 12-month follow-up after implantation of a Magmaris BRS (MgBRS). Coronary imaging with optical coherence tomography (OCT) and intravascular ultrasound (IVUS) was assessed to track changes in lumen and vessel dimensions. MethodsThe prospective Optimal lesion PreparaTion before Implantation of the Magmaris bioresorbable scaffold In patients with coronary artery Stenosis (OPTIMIS) study randomly assigned eighty-two patients with chronic coronary syndrome to two pre-dilatation treatment strategies. Patients were randomized in a 1:1 ratio to pre-dilatation with either a non-compliant scoring balloon or a standard non-compliant balloon prior to implantation of a MgBRS. The treated segment was evaluated with OCT and IVUS at baseline, after 6 and 12 months to assess changes in lumen and vessel dimensions. The hypothesis was that more intense pre-dilatation with a non-compliant scoring balloon before MgBRS implantation can reduce the risk of late lumen reduction compared to standard pre-dilatation. The power calculation used expected MLA after 6 months (6.22 mm2 for the scoring balloon and 5.01 mm2 for the standard non-compliant balloon), power of 80 %, significance level of 0.05 and expected drop-out rate of 15 %, requiring 82 patients to be enrolled. ResultsEighty-two patients were included in the study. Enrollment was from December 2020 to September 2023. ConclusionThe hypothesis was that more intense pre-dilatation with a non-compliant scoring balloon before MgBRS implantation can reduce the risk of late lumen reduction compared to standard pre-dilatation.

Size effects and the deformation behaviour of a dilute Mg-Zn-Ca alloy subjected to cyclic four-point bending

In biodegradable stents made from dilute Mg-Zn-Ca alloys a small number of grains constitute the thickness of a sample limiting the mechanical constrain typically seen in polycrystalline alloys. At the same time such stents are exposed to complex loading conditions, which could potentially lead to premature failure particularly in the presence of limited slip mode activation. In order to improve our understanding of the prevailing micromechanics for such conditions hot-rolled, thin strip samples were produced with thickness to grain size ratios (t/D) of 100 and 17. Samples were extracted from such thin strips and subjected to interrupted cyclic four-point bending in order to study the in-grain misorientation axis (IGMA) evolution of selected grains during cyclic loading using quasi-in-situ electron back-scattered diffraction (EBSD). Grains were selected at the tensile and compressive faces of samples, and in the vicinity of the neutral band. Analysis of the evolution of IGMA and misorientation profiles during the bending showed that extension twinning was the dominant deformation mode in the compressive region for both t/D ratios. In addition, non-basal <a>-type slip systems were active as a result of work hardening. In the tensile region, the activity of <a>-type non-basal slip systems was observed for the t/D of 100, but basal/double basal slip was the dominant deformation mode for the t/D of 17. No signs of failure were observed for the sample with a t/D of 17 at the tensile region, implying that these basal slip modes can accommodate deformation largely without the assistance of other deformation modes. The neutral band evolution was mapped using grain orientation spread (GOS) analysis. In contrast to the continuum mechanics solution, a neutral band was observed instead of an axis. The position of the neutral band was dependant on the local orientation organization of the grains and the extent of work-hardening.

Prostatic stents: a narrative review of current evidence.

Benign prostatic hyperplasia (BPH) is a common chronic urologic condition affecting approximately 50% of men above the age of 60. As per European Association of Urology Guidelines, BPH can be treated according to a stepwise approach starting from a conservative management, a pharmacologic approach, and finally surgery. Both medical and surgical therapies have side effects, impacting on ejaculation and sexual function and patients with multiple comorbidities might not be considered surgically suitable candidates. Prostatic stents offer a minimally invasive procedures in an out-patient setting, possibly under local anaesthesia. Utilized since the 1980s, the past stents encompassed permanent (epithelializing) or temporary (non-epithelializing) devices, like the Uro-Lume (American Medical Systems, Minnetonka, MN, USA) and the Memokath, or Memotherm (Engineers & Doctors A/S, Denmark), and the biodegradable stents made of self-reinforced poly-L-lactide or braided poly lactic-co-glycolic acid. Previous stents however showed a quite high rate of complications among which pain, incontinence, infections, stent migration or blockage, and incomplete degradation that might lead to premature removal of stent. The stents currently available on the market instead are the temporary device Allium Triangular Prostatic Urethral Stent (Allium Urological Solutions, Caesarea, Israel) and the temporary stent SPANNER (AbbeyMoor Medical, Inc., Parkers Prairie, MN, USA), which might be used in case of bladder outflow obstruction, post-operatively, or for acute urinary retention. Studies showed encouraging results, in terms of effectiveness and safety improving patients' quality of life and International Prostate Symptom Score, but longer-term studies are needed to identify the most suitable patients who might benefit from their use. Newer stents and nitinol devices are currently investigated, and we are waiting for the results of the ongoing clinical trials.

An integrated mechanical degradation model to explore the mechanical response of a bioresorbable polymeric scaffold

Simulation of bioresorbable medical devices is hindered by the limitations of current material models. Useful simulations require that both the short- and long-term response must be considered; existing models are not physically-based and provide limited insight to guide performance improvements. This study presents an integrated degradation framework which couples a physically-based degradation model, which predicts changes in both crystallinity (Xc) and molecular weight (Mn), with the results of a micromechanical model, which predicts the effective properties of the semicrystalline polymer. This degradation framework is used to simulate the deployment of a bioresorbable PLLA (Poly (L-lactide) stent into a mock vessel and the subsequent mechanical response during degradation under different diffusion boundary conditions representing neointimal growth. A workflow is established in a commercial finite element code that couples both the immediate and long-term responses. Clinically relevant lumen loss is reported and used to compare different responses and the effect of neo-intimal tissue regrowth post-implantation on degradation and on the mechanical response is assessed. In addition, the effects of possible changes in Xc, which could occur during processing and stent deployment, are explored.

Aneurysm healing following treatment with biodegradable embolization materials: assessment in a rat sidewall aneurysm model

BackgroundBiodegradable materials that dissolve after aneurysm healing are promising techniques in the field of neurointerventional surgery. We investigated the effects of various bioabsorable materials in combination with degradable magnesium alloy...

Effect of trimethylene carbonate segments on the structure and properties of poly(L‐lactide‐glycolide‐trimethylene carbonate) terpolymers for biodegradable vascular stents

AbstractThe total biodegradable vascular stent made of poly(L‐lactide‐glycolide‐trimethylene carbonate) terpolymers with excellent performances has the potential to be used in a new generation of medical implant devices. In this work, the properties and structure of terpolymers were investigated, which were found to be controlled by the composition of the copolymer chain. The amorphous trimethylene carbonate segments not only disturbed the sequence regularity of the L‐lactide segment, but also reduced the crystallization ability of the material. Furthermore, it is the flexible segments in the terpolymer chains that improve the plastic flow capacity, increase the flexibility of chains as well as reduce the apparent activation energy of thermal degradation of materials. Such a chain structured terpolymer exhibited good extrudability and buildability in 3D printing and formed a vascular stent with a cohesion entanglement characteristic microstructure during the process. The crush resistance with radially applied load and crush resistance with parallel plates of stent were 2561.4 mm Hg and 0.24 N/mm, respectively.

Design of novel poly(L-lactide)-based shape memory multiblock copolymers for biodegradable esophageal stent application

Esophageal cancer is a globally prevalent malignancy known for its extremely aggressive nature and high fatality rates. However, the conventional stents used in its treatment pose limitations including rigidity, non-degradability, and a lack of anti-inflammatory action. Shape memory multiblock copolymer stents (SMBS) have attracted considerable attention because of their distinctive characteristics. Nonetheless, achieving a variety of key functionalities, such as biocompatibility, biodegradability, thermoresponsiveness (body temperature, 37 °C), water responsiveness (biofluid), flexibility, and robustness, in a simple polymer system for practical applications still presents a significant problem. Herein, a versatile SMBS that is capable of delivering all the aforementioned key functionalities is proposed. This SMBS can efficiently be prepared via a rapid two-step strategy, leveraging the shape memory effect (SME) of a poly(L-lactide) (PLA)-based physical crosslinking network programmed into specific shapes. The proposed stent design incorporates bio-based PLA with flexible and hydrophilic polyethylene glycol (PEG), resulting in PEG-PLA multiblock copolymers with tunable transition temperatures (31.90–54.60 °C), effectively covering the body temperature (37 °C). Additionally, PEG-PLA exhibited a wide range of water uptake ratio of 41 % to 328 % and satisfactory elongation at break (142.8 % to 1920.6 %), and desired pH-dependent and simulated gastrointestinal biodegradability. Specifically, PEG4000PLA1500 displayed excellent body temperature-triggered (with a recovery rate of 99.5 %) and water-triggered dual SME, which allowed it to potentially be fabricated into on-demand synchronous shape memory and drug-release functional SMBS for esophageal stenosis therapy. The results of this study indicate that the proposed SMBS holds substantial potential for biomedical applications.

A phenomenological model of pulsatile blood pressure-affected degradation of polylactic acid (PLA) vascular stent.

The stent implantation may alter the post-operative patient's blood pressure, and bioresorbable vascular stents (BVS) as a candidate to treat vascular diseases, its degradation is affected by mechanical stress, thus, the altered pressure representing varying stress level will result in different degradation behaviors of the BVS. This paper first proposed a novel stress-regulated PLA degradation model that included swelling factor, and then the degradation evolutions of a PLA BVS within 180days under normal and high blood pressures were simulated by finite element method, and more four degradation indexes were defined to study the effects of the two blood pressures on the degradation of the PLA BVS. The results showed that the high pressure weakly accelerated the degradation of the PLA BVS with respect to the normal pressure by examining the four indexes, e.g., the residual stent volume decreased to 0.72 and 0.69, respectively for the normal and high pressures at day 180. The current finding provided a theoretical understanding of the PLA BVS degradation, and hinted that the PLA BVS may not need to be elaborately selected in clinical practices for treating hypertensive patients.

A Versatile Passivated Protein‐Adsorption Platform for Rapid Healing of Vascular Stents by Modulating the Microenvironment

AbstractBiodegradable stents have paved the way to treat coronary artery disease. However, rapid reendothelialization is required to solve the problems of mismatched degradation rates, localized inflammation, and insufficient biocompatibility. Herein, a novel passivated protein‐adsorption coating is synthesized by coordination chelation, oxidation, cross‐linking, polymerization, and deposition of dopamine, (‐)‐epigallocatechin gallate (EGCG), and copper ions (Cu2+) using two‐electron oxidation. This coating exhibits hierarchical functionality, that is, at the macroscale, its superhydrophilicity conveys antifouling ability; whereas at the microscale, the active groups (quinone‐, amino‐, hydroxyphenyl groups and aromatic ring) facilitate protein adsorption. Antifouling ability prevents acute thrombosis and inflammation and maintains initial microenvironment stability post‐implantation. The active groups facilitate gradual endothelial cells (ECs) adhesion. Meanwhile, the decomposition of nitric oxide (NO) donors to release NO is catalyzed by Cu2+, and EGCG alleviates or prevents oxidative stress damage, inflammatory responses, thrombosis formation, and excessive smooth muscle cells proliferation in the stent microenvironment. This provides favorable conditions for the rapid and healthy growth of ECs. This study proposes a novel strategy for rapid neointima formation comprising healthy ECs on the surfaces of biodegradable stents by depositing a passivated protein‐adsorption coating (polydopamine/EGCG/Cu), opening new possibilities for the efficient treatment of coronary artery disease.

Safety and efficacy of everolimus-eluting bioresorbable vascular scaffold for cardiac allograft vasculopathy (CART).

Cardiac allograft vasculopathy (CAV) is still the main drawback of heart transplantation (HTx) and percutaneous coronary intervention (PCI) is a palliative measure because of the high incidence of failure. This study aimed to investigate the safety and efficacy of bioresorbable scaffolds (BRSs) as potential novel therapeutic tool for the treatment of coronary stenoses in CAV. This is a multicenter, single-arm, prospective, open-label study (CART, NCT02377648), that included patients affected by advanced CAV treated with PCI and second-generation ABSORB BRS (Abbott Vascular). The primary endpoint was the incidence of 12-month angiographic in-segment scaffold restenosis (ISSR). Secondary endpoints were the incidence of major adverse cardiac events (MACEs) at 12- and 36-month follow-up and the incidence of ISSR at 36months. A paired intracoronary imaging analysis at baseline and follow-up was also performed. Between 2015 and 2017 35 HTx patients were enrolled and treated for 44 coronary lesions with 51 BRSs. The primary endpoint occurred in 13.5% of the lesions (5/37), with a cumulative ISSR rate up to 3years of 16.2% (6/37). Angiographic lumen loss was 0.40 ± 0.62mm at 12months and 0.53 ± 0.57mm at 36months. Overall survival rate was 91.4% and 74.3%, and MACEs incidence 14.2% and 31.4% at 12 and 36months, respectively. At the paired intracoronary imaging analysis, a significant increase of the vessel external elastic membrane area in the treated segment and some progression of CAV proximally to the BRS were detected. BRS-based PCI for the treatment of CAV is feasible and safe, with an ISSR incidence similar to what reported in retrospective studies with drug-eluting stents.