Bioresorbable Vascular Scaffold Research Articles

The Absorb GT1 Bioresorbable Vascular Scaffold System - 5-Year Post-Market Surveillance Study in Japan.

The 1-year clinical outcomes of the Absorb GT1 Japan post-market surveillance (PMS) suggested that an appropriate intracoronary imaging-guided bioresorbable vascular scaffold (BVS) implantation technique may reduce the risk of target lesion failure (TLF) and scaffold thrombosis (ST) associated with the Absorb GT1 BVS. The long-term outcomes through 5 years are now available.Methods and Results: This study enrolled 135 consecutive patients (n=139 lesions) with ischemic heart disease in whom percutaneous coronary intervention (PCI) with the Absorb GT1 BVS was attempted. Adequate lesion preparation, imaging-guided appropriate sizing, and high-pressure post-dilatation using a non-compliant balloon were strongly encouraged. All patients had at least 1 Absorb GT1 successfully implanted at the index procedure. Intracoronary imaging was performed in all patients (optical coherence tomography: 127/139 [91.4%] lesions) and adherence to the implantation technique recommendations was excellent: predilatation, 100% (139/139) lesions; post-dilatation, 98.6% (137/139) lesions; mean (±SD) post-dilatation pressure, 18.8±3.5 atm. At 5 years, the follow-up rate was 87.4% (118/135). No definite/probable ST was reported through 5 years. The cumulative TLF rate was 5.1% (6/118), including 2 cardiac deaths, 1 target vessel-attributable myocardial infarction, and 3 ischemia-driven target lesion revascularizations. Appropriate intracoronary imaging-guided BVS implantation, including the proactive use of pre- and post-balloon dilatation during implantation may be beneficial, reducing the risk of TLF and ST through 5 years.

Drug-Eluting Balloon for Coronary In-Stent Restenosis: Could it be an Emerging Strategy?

Despite significant improvement in PCI, including drug-eluting stent (DES) applications, in-stent restenosis (ISR) remains a problem. ISR is challenging to manage. Repeat stenting with bare metal stent (BMS), repeat stenting with DES and bioresorbable vascular scaffolds is primarily used to prevent and treat ISR. Current European guidelines recommend DES or a drug-eluting balloon (DEB) to treat ISR with a Class I indication. However, its use in coronary artery interventions has not yet been approved in the United States. DEB allows the application of the antiproliferative drug to the ISR site without leaving an additional layer of stent strut. Studies show that DEB is superior to plain balloon alone and comparable to DES in ISR treatment. They are increasingly preferred due to their good therapeutic effect in preventing intimal proliferation and restenosis. This review aims to provide an overview on the feasibility of using DEB in ISR management based on current knowledge

Peripheral vascular bioresorbable scaffolds: Past, present, and future

As peripheral vascular disease affects more and more people in the world, interventional treatment of peripheral blood vessels evolves from percutaneous transluminal angioplasty to bioresorbable vascular scaffolds (BVS). At present, the materials of peripheral vascular bioresorbable scaffolds mainly include polymers and metal materials, and have achieved certain clinical application effects. Examples of these BVS are provided, and their advantages and defects are discussed. Poly-L-lactic acid is most commonly used in polymer BVS. There have been some polymer BVS entering clinical research for peripheral blood vessels since the 10 s, and have various outcomes. Metal materials for BVS mainly include magnesium alloy, iron alloy, and zinc alloy. The improved magnesium alloy BVS show excellent antiplatelet adhesion ability and can reduce the formation of acute stent thrombosis in clinical research. The iron alloy BVS and zinc alloy BVS also show excellent performance in animal experiments. The drug coating of BVS is expected to be improved. Finally, prospects of future development are highlighted. With the continuous improvement of manufacturing and drug-coating process, their therapeutic effect is expected to continue to improve.

Bioresorbable vascular scaffolds - a single center experience

Abstract Funding Acknowledgements None. Background/Introduction Bioresorbable vascular scaffolds (BVS) were considered promising alternatives to drug-eluting stents in percutaneous coronary interventions (PCI). They would restore the normal vasomotor tone and allow positive remodeling, reducing the trigger for inflammation and facilitating further interventions. Although randomized trials showed beneficial outcomes up to 1 year of follow-up, longer-term results have been disappointing, with increased rates of events, leading to its discontinuation. Purpose This study aims to evaluate our center’s 5-year follow-up of the BVS implantations, in terms of safety and efficacy. Methods Retrospective cohort of 46 patients submitted to PCI with a BVS was evaluated. The outcomes assessed were composite endpoint of death, myocardial infarction (MI), and revascularization (DMR), target vessel failure (TVF) and cardiovascular death, and each endpoint individually. Data analysis was done with SPSS software. Results The cohort was a total of 46 patients, with a mean age 69,5±1,5 years, and 23,9% women (n=11). The mean follow-up time was 5,6±0,2 years. BVS were implanted 74% (n=34) of the times in acute coronary syndromes, and 68% (n=31) were PCI on previous stent failure. Total of 24% (n=11) had an episode in the follow-up. Regarding each individual outcome, there was 9% (n=4) of MI, 0% (n=0) of cardiovascular deaths and 15,2% (n=7) of BVS re-stenosis requiring revascularization. Only 4% (n=2) of patients had complete BVS resorption on reassessment coronary angiography. Conclusions In the 5-year follow-up, there was a high rate of events, with 24% (n=11) of events, of which the most common was BVS re-stenosis, with 15,2% cases (n=7), and MI in 9% (n=4). Despite theoretical benefits with the resorption of BVS, it was only verified in 4% of the cases (n=2). According to the recent data, from the longer-term follow-up, BVS have been associated with a higher number of events, with the intended benefit not being verified.

3D-printed, citrate-based bioresorbable vascular scaffolds for coronary artery angioplasty

Fully bioresorbable vascular scaffolds (BVSs) aim to overcome the limitations of metallic drug-eluting stents (DESs). However, polymer-based BVSs, such as Abbott's Absorb, the only US FDA-approved BVS, have had limited use due to increased strut thickness (157 μm for Absorb), exacerbated tissue inflammation, and increased risk of major cardiac events leading to inferior clinical performance when compared to metallic DESs. Herein we report the development of a drug-eluting BVS (DE-BVS) through the innovative use of a photopolymerizable, citrate-based biomaterial and a high-precision additive manufacturing process. BVS with a clinically relevant strut thickness of 62 μm can be produced in a high-throughput manner, i.e. one BVS per minute, and controlled release of the anti-restenosis drug everolimus can be achieved by engineering the structure of polymer coatings to fabricate drug-eluting BVS. We achieved the successful deployment of BVSs and DE-BVSs in swine coronary arteries using a custom-built balloon catheter and BVS delivery system and confirmed BVS safety and efficacy regarding maintenance of vessel patency for 28 days, observing an inflammation profile for BVS and DE-BVS that was comparable to the commercial XIENCE™ DES (Abbott Vascular).

Solid-Phase Orientation (Die Drawing) of Polymer Tubes to Enhance Mechanical Properties of Bioresorbable Vascular Scaffolds

Die-drawing, also known as solid phase orientation, is a technique used to enhance the mechanical properties of polymers for non-medical applications [1]. Arterius has adapted and optimised this technology to manufacture state-of-the-art bioresorbable polymeric scaffolds (stents) based on polylactic acid (PLA) for vascular and non-vascular applications. The mechanical properties of the polymer are improved by orientating the polymer chains and introducing crystallinity to the polymer. As the PLA polymer is drawn over a mandrel and through a die, close to the glass transition temperature (Tg > 55 °C), the polymer chains align, gradually increasing orientation with the bi-axial draw, thus promoting significantly improved mechanical properties. In-house testing of the die-drawn tubing compared to the extruded tubing showed an increase in tensile modulus up to 79.7%, yield strength increases of up to 121.5%, ultimate tensile strength increases of up to 267.9% and elongation at break increase of up to 1,022.8%. The die-drawing process also introduces crystallinity into the PLLA tubing, initially the amorphous extruded tube has a crystallinity of around 1.3% which increased to around 40% crystallinity after the die-drawn process. Another attribute of the orientated polymer tubing is the radial strength it provides to the scaffold once it has been laser cut into an innovative closed-cell design, which is comparable to market-leading metallic stents.

Investigation of 3D Printed Bioresorbable Vascular Scaffold Crimping Behavior

AbstractThe rise in additive manufacturing (AM) offers myriad opportunities for 3D printed polymeric vascular scaffolds, such as customization and on‐the‐spot manufacturing, in vivo biodegradation, incorporation of drugs to prevent restenosis, and visibility under X‐ray. To maximize these benefits, informed scaffold design is critical. Polymeric bioresorbable vascular scaffolds (BVS) must undergo significant deformation prior to implantation in a diameter‐reduction process known as crimping that enables minimally invasive surgery. Understanding the behavior of vascular scaffolds in this step provides twofold benefits: first, it ensures the BVS is able to accommodate stresses occurring during this process to prevent failure, and further, it provides information on the radial strength of the BVS, a key metric to understanding its post‐implant performance in the artery. To capitalize on the fast manufacturing speed AM provides, a low time cost solution for understanding scaffold performance during this step is necessary. Through simulation of the BVS crimping process in ABAQUS using experimentally obtained bulk material properties, a qualitative analysis tool is developed that is capable of accurately comparing relative performance trends of varying BVS designs during crimping in a fraction of the time of experimental testing, thereby assisting in the integration of informed design into the additive manufacturing process.

Late acquired coronary aneurysm and restenosis after bioresorbable vascular scaffold implantation: a case report

Abstract Background Although the technology of bioresorbable vascular scaffold (BVS) aroused the peak of interest a few years ago and currently remains available only as part of experimental research, patients who have had BVS implanted should be still carefully monitored to detect possible long-term complications. Case summary We present the case of a 47-year-old man who had received BVS implantation for ST-segment elevation myocardial infarction. Six years later, computed tomography coronary angiography (CTCA) demonstrated in-segment restenosis in between two newly formed coronary aneurysms at the site of the implanted BVS. The patient received successful optical coherence tomography–guided percutaneous intervention with a new metallic drug-eluting stent implantation. Discussion Our case demonstrates that coronary aneurysms can be well characterized with CTCA and are often incidentally discovered as they cause no symptoms. The incidence of coronary aneurysm at the site of a previously implanted BVS is not defined, and little is known about the pathophysiology and evolution of these lesions. Therefore, the decision to proceed with conservative management or intervention must be tailored to the clinical conditions of the patient, the anatomy, the rapidity of growth, and the possible thrombotic burden.

10-Year optical coherence tomography follow-up of 'full-plastic jacket' with bioresorbable vascular scaffolds.

10-Year optical coherence tomography follow-up of 'full-plastic jacket' with bioresorbable vascular scaffolds.

Impact of intracoronary imaging-guided percutaneous coronary intervention on procedural outcomes among complex patient groups

Abstract Background Intracoronary imaging (ICI) has been previously shown to improve survival and clinical outcomes after percutaneous coronary intervention (PCI). However, whether this prognostic benefit is sustained across different indications/patient groups remains unclear. Methods All PCI procedures performed in England and Wales between 1st April 2014 and 31st March 2020 were retrospectively analysed. The association between ICI use and in-hospital MACCE (major adverse cardiovascular and cerebrovascular outcomes; composite of all-cause mortality, stroke and reinfarction) and mortality was examined using multivariable logistic regression analysis for each imaging-recommended indication (stent thrombosis (ST), in-stent restenosis, stent length>60mm, acute coronary syndrome (ACS) indications, chronic total occlusion, left main stem (LMS) intervention, renal failure and bioresorbable vascular scaffolds (BVS)). Results Of 555,398 PCI procedures, 10.8% (n=59,752) were performed under ICI guidance. ICI use doubled between 2014 (7.8%) and 2020 (17.5%). ICI use was highest for BVS (44.7%) and LMS PCI (41.2%) cases and lowest in ACS (9%). Overall, the odds ratios (OR) of in-hospital MACCE and mortality were only reduced with ICI-guided PCI in cases with an imaging-recommended indication (OR 0.75 95% confidence interval (CI) 0.69-0.81 and OR 0.69 95%CI 0.63-0.76, respectively). Only specific imaging-recommended indications were associated with reduced MACCE and mortality, including LMS PCI (OR 0.45 95%CI 0.39-0.52 and 0.41 95%CI 0.35-0.48, respectively), ACS (OR 0.76 95%CI 0.70-0.82 and 0.70 95%CI 0.63-0.77), stent length>60mm (OR 0.75 95%CI 0.59-0.94 and 0.72 95%CI 0.54-0.95). ST was only associated with lower mortality (OR: 0.69 95%CI 0.52-0.91) while renal failure was associated with reduced MACCE (OR 0.77 95%CI 0.60-0.99) but not mortality. (Figure 1) Conclusion The utilisation of ICI has more than doubled over a seven-year period at a national level but remains low, with less than 1-in-5 procedures performed under ICI guidance. In-hospital survival was better with ICI-guided than angiography-guided PCI, albeit only for specific indications.Figure 1

Bioresorbable Vascular Scaffolds: Should We use Them Again?

Context: An important development in the percutaneous management of coronary artery disease was the creation of the drug-eluting stent (DES). The DES reduces the high incidence of target lesion revascularization associated with balloon angioplasty and bare metal stents by overcoming vessel recoil and restenosis. Despite these advantages, DES carries a persistent risk of stent-related problems due to the permanent implantation of a foreign body and the limitation of arterial vasomotion. Similar to DES, bioresorbable vascular scaffolds (BRS) are intended to distribute drugs and offer mechanical support before completely degrading over the years. Evidence Acquisition: This study was a review article. The data were acquired from PubMed and Google Scholar. Medical Subject Headings (MeSH) terms were used when available, and only English articles were included in the review. Results: Recent studies have shown that the BRS is not inferior to modern DES clinically, although some clinical results are worrying, particularly the greater rates of scaffold thrombosis. Early studies showed that BRS was superior to DES; nevertheless, larger-scale applications and longer observations revealed serious problems with their use, such as reduced radial strength and a higher risk of thrombosis, which led to a higher rate of serious adverse cardiac events. Conclusions: The position of DES was not directly challenged by additional attention to procedural details and research on the second generation of BRS with innovative features. Bioresorbable vascular scaffolds still have an opportunity to demonstrate their supremacy in standout indicators.

TCT-440 Physiological Patterns of Coronary Artery Disease and Percutaneous Coronary Intervention With Bioresorbable Vascular Scaffolds

TCT-440 Physiological Patterns of Coronary Artery Disease and Percutaneous Coronary Intervention With Bioresorbable Vascular Scaffolds

Safety and efficacy of anovel 3D-printed bioresorbable sirolimus-eluting scaffold in aporcine model.

The effect of 3D-printed bioresorbable vascular scaffolds (BRS) in coronary heart disease has not been clarified. We aimed to compare the safety and efficacy of 3D-printed BRS with that of metallic sirolimus-eluting stents (SES). Thirty-two BRS and 32 SES were implanted into 64 porcine coronary arteries. Quantitative coronary angiography (QCA) and optical coherence tomography (OCT) were performed at 14, 28, 97, and 189 days post-implantation. Scanning electron microscopy (SEM) and histopathological analyses were performed at each assessment. All stents/scaffolds were successfully implanted. All animals survived for the duration of the study. QCA showed the two devices had asimilar stent/scaffold-to-artery ratio and acute percent recoil. OCT showed the lumen area (LA) and scaffold/stent area (SA) of the BRS were significantly smaller than those of the SES at 14 and 28 days post-implantation (14-day LA: BRS vs SES 4.52±0.41 mm2 vs 5.69±1.11 mm2; p=0.03; 14-day SA: BRS vs SES 4.99±0.45 mm2 vs 6.11±1.06 mm2; p=0.03; 28-day LA: BRS vs SES 2.93±1.03 mm2 vs 4.82±0.74 mm2; p=0.003; 28-day SA: BRS vs SES 3.86±0.98 mm2 vs 5.75±0.71 mm2; p=0.03). Both the LA and SA of the BRS increased over time and were similar to those of the SES at the 97-day and 189-day assessments. SEM and histomorphological analyses showed no significant between-group differences in endothelialisation at each assessment. The novel 3D-printed BRS showed safety and efficacy similar to that of SES in aporcine model. The BRS also showed along-term positive remodelling effect.

Highlighting Hemodynamic Risks for Bioresorbable Stents in Coronary Arteries

A three-dimensional, transient computational fluid dynamics analysis was conducted on an idealised geometry of a coronary artery fitted with representative geometries of an Absorb bioresorbable vascular scaffold (BVS) or a Xience drug-eluting stent (DES) in order to identify and compare areas of disturbed flow and potential risk sites. A non-Newtonian viscosity model was used with a transient velocity boundary condition programmed with user-defined functions. At-risk areas were quantified in terms of several parameters linked to restenosis: wall shear stress, time-averaged wall shear stress, oscillatory shear index, particle residence time, and shear rate. Results indicated that 71% of the BVS stented surface area had time-averaged wall shear stress values under 0.4 Pa compared to 45% of the DES area. Additionally, high particle residence times were present in 23% and 8% of the BVS and DES areas, respectively, with risk areas identified as being more prominent in close proximity to crowns and link struts. These results suggest an increased risk for thrombosis and neointimal hyperplasia for the BVS compared to the DES, which is in agreement with the outcomes of clinical trials. It is intended that the results of this study may be used as a pre-clinical tool to aid in the design of bioresorbable coronary stents.

Impact of post-implantation time on bioresorbable vascular scaffold outcomes for type C versus non-type C coronary lesions: A longer-term study

We have demonstrated that bioresorbable vascular scaffold (BVS) for ACC/AHA type C lesions was associated with higher risks of long-term target lesion revascularization (TLR) and target lesion failure (TLF). We determined the specific time after which higher risks of BVS for type C lesions are reduced in a longer-term follow-up. We analyzed data of 457 patients (59±12 years, 87% male) with 714 BVS implanted for 529 lesions and a median follow-up of 56.4 (48.6-62.6) months. Patients with BVS for at least one type C lesion (N=177) at index intervention and all non-type C lesions (N=280) were compared for TLF (cardiac death, target vessel myocardial infarction, TLR). We specified the interactions between the non-type C versus type C group and the event-free survival times dichotomized at 24, 30, 32, 33, 36, and 39 months respectively. The type C group had more multivessel disease (86% versus 65%, p<0.001), left anterior descending artery treated (68% versus 53%, p=0.002), intravascular imaging used (48% vs. 25%, p<0.001), and BVS (2.3±0.9 vs. 1.1±0.3, p<0.001) implanted with a longer total length (57±21 vs. 29±8mm, p<0.001). The TLR or TLF was higher (both log-rank p<0.05) in the type C than in the non-type C group. However, the risks of TLR (hazard ratio: 3.6, 95% CI=1.1-11.6) and TLF (hazard ratio: 3.8, 95% CI=1.2-12.1) for type C lesions only remained higher until 24 months post-BVS implantation. BVS provides a longer-term advantage, particularly for type C lesions with the majority requiring long stenting.

Long-term multimodality imaging follow-up of ST-segment elevation myocardial infarction patients treated with bioresorbable vascular scaffold: advantages and challenges.

Multislice computed tomography (MSCT) offers a non-invasive method of imaging bioresorbable scaffolds (BRS). To investigate the advantages and challenges using MSCT in the follow-up after BRS implantation. The BRS cohort consisting of 31 patients in the 'BRS in STEMI' trial was examined by multimodality imaging and followed long-term. Minimum lumen area (MLA) and average lumen area (ALA) were examined 12 and 36 months after BRS implantation with MSCT. Optical coherence tomography (OCT) at 12 months was used as a reference. Measured by MSCT, the mean MLA was 0.05 ± 1.32 mm² ( P = 0.85), but ALA was 1.32 (±2.59 mm², P = 0.015) greater than by OCT. ALA and MLA did not change significantly from 12 to 36 months. MSCT identified all cases of restenosis but missed one patient with massive malapposition. Our data support using MSCT in the follow-up after BRS implantation. Invasive investigation should still be considered for patients with unexplained symptoms.

Structural and temporal dynamics analysis on drug-eluting stents: History, research hotspots and emerging trends.

This review aims to explore the history, research hotspots, and emerging trends of drug-eluting stents(DES)in the last two decades from the perspective of structural and temporal dynamics. Publications on DES were retrieved from WoSCC. The bibliometric tools including CiteSpace and HistCite were used to identify the historical features, the evolution of active topics, and emerging trends on the DES field. In the last 20 years, the field of DES is still in the hot phase and there is a wide range of extensive scientific collaborations. In addition, active topics emerge in different periods, as evidenced by a total of 41 disciplines, 511 keywords, and 1377 papers with citation bursts. Keyword clustering anchored five emerging research subfields, namely #0 dual antiplatelet therapy, #3 drug-coated balloon, #4 bifurcation, 5# rotational atherectomy, and 6# quantitative flow ratio. The keyword alluvial map shows that the most persistent research concepts in this field are thrombosis, restenosis, etc., and the emerging keywords are paclitaxel eluting balloon, coated balloon, drug-eluting balloon, etc. There are 7 recent research subfields anchored by reference clustering, namely #2 dual antiplatelet therapy, #4 drug-coated balloon, #5 peripheral artery disease, #8 fractional flow reserve, #10 bioresorbable vascular scaffold, # 13 intravascular ultrasound, #14 biodegradable polymer. The findings based on the bibliometric studies provide the current status and trends in DES research and may help researchers to identify hot topics and explore new research directions in this field.

Impact of Selection Preference on Longer-Term Outcomes between Bioresorbable Vascular Scaffold versus Everolimus-Eluting Stent for True Lumen Tracking-Recanalized Chronic Total Occlusion.

Creation of sizable subintima during intervention for chronic total occlusions (CTO) could lead to the key selection preference of metallic stents rather than bioresorbable vascular scaffolds (BVS) and then possibly deviate the outcome comparisons in real-world studies. By including recanalized CTO with true lumen tracking, we tested if any selection preference remained and compared the outcomes between everolimus-eluting stent (EES) and BVS implantation.Among 211 consecutive CTO interventions with true lumen tracking from August 2014 to April 2018 when BVS was available, we compared the clinical and interventional features between 28 patients with BVS and 77 patients with EES implantation. With propensity score matching and a median follow-up of 50.5 (37.3-60.3) months, we further assessed 25 patients with BVS and 25 with EES for target vessel failure (TVF: cardiac death, target vessel myocardial infarction, and target lesion revascularization).Multivariate analyses showed that BVS was still favored in the presence of LAD CTO (odds ratio (OR) = 3.4, 95% confidence interval (CI) = 1.0-11.7) and an average scaffold/stent size ≥ 3 mm (OR = 10.5, 95% CI = 3.0-37.3). EES was preferred for lesions with a J-CTO score ≥ 3 (OR = 19.3, 95% CI = 3.4-110.8) and multivessel intervention necessary at index procedure (OR = 11.3, 95% CI = 1.9-67.3). With matched comparisons, the TVF-free survival of EES was better than that of BVS for CTO recanalization (P = 0.049 by log-rank test) at long-term follow-up.Even with true lumen tracking techniques, selection bias remained substantial when determining either device for CTO implantation. The matched comparison of outcomes suggested the unfavorable longer-term impacts of the first generation of BVS on CTO lesions.

Drug-Eluting, Balloon-Expandable, Bioresorbable Vascular Scaffolds Reduce Neointimal Thickness and Stenosis in an Animal Model of Percutaneous Peripheral Intervention

Drug-Eluting, Balloon-Expandable, Bioresorbable Vascular Scaffolds Reduce Neointimal Thickness and Stenosis in an Animal Model of Percutaneous Peripheral Intervention

Preclinical Evaluation of an Everolimus-Eluting Bioresorbable Vascular Scaffold Via a Long-Term Rabbit Iliac Artery Model.

Biodegradable poly (l-lactic acid) (PLLA), a bio safe polymer with a large elastic modulus, is widely used in biodegradable medical devices. However, because of its poor mechanical properties, a PLLA strut must be made twice as thick as a metal strut for adequate blood vessel support. Therefore, the mechanical properties of a drug-eluting metal-based stents (MBS) and a bioresorbable vascular scaffolds (BVS) were evaluated and their safety and efficacy were examined via a long-term rabbit iliac artery model. The surface morphologies of the MBSs and BVSs were investigated via optical and scanning electron microscopy. An everolimus-eluting (EE) BVS or an EE-MBS was implanted into rabbit iliac arteries at a 1.1:1 stent-to-artery ratio. Twelve months afterward, stented iliac arteries from each group were analyzed via X-ray angiography, optical coherence tomography (OCT), and histopathologic evaluation. Surface morphology analysis of the EE coating on the MBS confirmed that it was uniform and very thin (4.7μm). Comparison of the mechanical properties of the EE-MBS and EE-BVS showed that the latter outperformed the former in all aspects (radial force (2.75 vs. 0.162N/mm), foreshortening (0.24% vs. 1.9%), flexibility (0.52 vs. 0.19N), and recoil (3.2% vs. 6.3%). At all time points, the percent area restenosis was increased in the EE-BVS group compared to the EE-MBS group. The OCT and histopathological analyses indicate no significant changes in strut thickness. BVSs with thinner struts and shorter resorption times should be developed. A comparable long-term safety/efficacy evaluation after complete absorption of BVSs should be conducted.