Long-term outcomes following bioresorbable vascular scaffolds

INTRODUCTION

The higher scaffold thrombosis rates observed with the first-generation bioresorbable scaffolds (BRSs) compared to conventional drug-eluting stents were likely due in part to bioresorbable polymers having insufficient radial strength, necessitating larger strut profiles. Meta-analysis of the long-term outcomes from the first-generation Absorb bioresorbable vascular scaffold (BVS) showed that this period of excess risk ended at 3 years. Therefore, current attention has been focused on improving early outcomes by increasing the scaffold's tensile strength and reducing strut thickness.

AREAS COVERED

This review summaries the lessons learned from the first-generation BRS. It updates the long-term clinical outcomes of trials evaluating the ABSORB BVS and metallic alloy-based BRS. In addition, it reviews the next-generation BRSs manufactured in Asia.

EXPERT OPINION

Critical areas to improve the performance and safety of biodegradable scaffolds include further development in material science, surface modification, delivery systems, and long-term follow-up studies.

Negative findings but positive contributions in cardiovascular research

Researchers have always concluded that results that do not support the hypothesis as unimportant, unworthy, or simply not good enough for publication. However, negative findings are essential for the progress of science and its self-correcting nature. We also believe in the importance and indispensability of negative results. Therefore, in this review, we discussed the factors contributing to the publication bias of negative results and the problems to assess the factuality and validity of negative results. Moreover, we emphasized the importance of reporting negative results in cardiovascular research, including treatments, and suggest that the negative results could clarify previously controversial topics in the treatment of cardiovascular diseases and prompt the translation of research on precision cardiovascular disease prevention and treatment.

Three-year clinical outcomes of the novel sirolimus-eluting bioresorbable scaffold for the treatment of de novo coronary artery disease: A prospective patient-level pooled analysis of NeoVas trials

OBJECTIVES

We aimed to evaluate the long-term outcomes of the novel NeoVas sirolimus-eluting bioresorbable scaffold (BRS) for the treatment of de novo coronary artery disease.

BACKGROUND

The long-term safety and efficacy of the novel NeoVas BRS are still needed to be elucidated.

METHODS

A total of 1103 patients with de novo native coronary lesions for coronary stenting were enrolled. The primary endpoint of target lesion failure (TLF) was defined as a composite of cardiac death (CD), target vessel myocardial infarction (TV-MI), or ischemia-driven-target lesion revascularization (ID-TLR).

RESULTS

A three-year clinical follow-up period was available for 1,091 (98.9%) patients. The cumulative TLF rate was 7.2% with 0.8% for CD, 2.6% for TV-MI, and 5.1% for ID-TLR. Additionally, 128 (11.8%) patient-oriented composite endpoint and 11 definite/probable stent thromboses (1.0%) were recorded.

CONCLUSIONS

The extended outcomes of the NeoVas objective performance criterion trial demonstrated a promising 3-year efficacy and safety of the NeoVas BRS in low-risk patients with low complexity in terms of lesions and comorbidities.

Current status and outlook of biodegradable metals in neuroscience and their potential applications as cerebral vascular stent materials

Over the past two decades, biodegradable metals (BMs) have emerged as promising materials to fabricate temporary biomedical devices, with the purpose of avoiding potential side effects of permanent implants. In this review, we first surveyed the current status of BMs in neuroscience, and briefly summarized the representative stents for treating vascular stenosis. Then, inspired by the convincing clinical evidence on the in vivo safety of Mg alloys as cardiovascular stents, we analyzed the possibility of producing biodegradable cerebrovascular Mg alloy stents for treating ischemic stroke. For these novel applications, some key factors should also be considered in designing BM brain stents, including the anatomic features of the cerebral vasculature, hemodynamic influences, neuro-cytocompatibility and selection of alloying elements. This work may provide insights into the future design and fabrication of BM neurological devices, especially for brain stents.

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The current status of the application of biodegradable metals (BM) in neuroscience was presented.

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We analyzed the possibility of producing biodegradable cerebrovascular Mg alloy stents for ischemic stroke treatment.

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Key factors in designing BM brain stents were discussed.

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This work may provide insights into the future design and fabrication of BM neurological devices, especially for brain stents.

Two-stage degradation and novel functional endothelium characteristics of a 3-D printed bioresorbable scaffold

Bioresorbable scaffolds have emerged as a new generation of vascular implants for the treatment of atherosclerosis, and designed to provide a temporary scaffold that is subsequently absorbed by blood vessels over time. Presently, there is insufficient data on the biological and mechanical responses of blood vessels accompanied by bioresorbable scaffolds (BRS) degradation. Therefore, it is necessary to investigate the inflexion point of degradation, the response of blood vessels, and the pathophysiological process of vascular, as results of such studies will be of great value for the design of next generation of BRS. In this study, abdominal aortas of SD rats were received 3-D printed poly-l-actide vascular scaffolds (PLS) for various durations up to 12 months. The response of PLS implanted aorta went through two distinct processes: (1) the neointima with desirable barrier function was obtained in 1 month, accompanied with slow degradation, inflammation, and intimal hyperplasia; (2) significant degradation occurred from 6 months, accompanied with decreasing inflammation and intimal hyperplasia, while the extracellular matrix recovered to normal vessels which indicate the positive remodeling. These in vivo results indicate that 6 months is a key turning point. This “two-stage degradation and vascular characteristics” is proposed to elucidate the long-term effects of PLS on vascular repair and demonstrated the potential of PLS in promoting endothelium function and positive remodeling, which highlights the benefits of PLS and shed some light in the future researches, such as drug combination coatings design.

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Proposed two-stage degradation of a PLLA BRS to reveal distinct neointimal recovery and vascular responsive processes.

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Revealed novel benefits of BRS, including fine endothelium function, anti-thrombosis, and anti-inflammatory.

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Drug combination coatings should be designed concerning special degradation of BRS and the key turning point, 6 months.

Current perspectives on bioresorbable scaffolds in coronary intervention and other fields

Introduction: The first-generation bioresorbable scaffolds (BRSs) had a large strut profile to compensate for the insufficient radial strength of bioresorbable polymer materials, resulting in higher scaffold thrombosis rates than conventional drug-eluting stents. To improve the clinical safety and efficacy, the new generation BRSs have been improved by optimal structure design, post-processing of bioresorbable polymer materials, or altering bioresorbable metallic alloys.Areas covered: This review summarizes the lessons learned from the first-generation BRS, updates the clinical outcomes of trials evaluating ABSORB bioresorbable vascular scaffold at long-term and bioresorbable metallic alloy-based devices, and examines recent outcomes of BRS treated in STEMI patients. This review also provides an overview of the current clinical data of seven BRSs manufactured in Asia, and of the BRSs extended application in other clinical arenas.Expert opinion: Drawbacks of the first-generation BRSs need to be addressed by the next generation of these stents with novel materials and technologies. Clinical research, including randomized controlled trials, are required to further evaluate BRSs application in coronary artery disease. The encouraging results of BRSs innovation applied in the peripheral arteries and gastrointestinal tracts support other potential clinical applications of BRS technology.

Fully bioresorbable vascular scaffolds: lessons learned and future directions

Fully bioresorbable scaffolds (BRS) were designed to overcome the limitations of metallic drug-eluting stents, which permanently cage the vessel wall, thereby preventing normal coronary vasomotion, preclude bypass grafting and can provoke long-term foreign-body responses. Although multiple scaffolds have been or are in development, the Absorb Bioresorbable Vascular Scaffold (BVS; Abbott Vascular) was the first FDA-approved device and was widely expected to fulfil the dream of interventional cardiologists of a transient scaffold that would disappear 'when the job was done' and would not hamper further treatment options. Although early, small studies and even large, randomized trials showed beneficial outcomes up to 1 year of follow-up, longer-term results have been disappointing, with increased rates of device thrombosis and target-lesion revascularization. The Absorb BVS device was withdrawn from the market because of low demand. In this Review, we summarize the preclinical and clinical data available for BRS to understand how the vascular biological reactions to these devices differ from biological reactions to metallic drug-eluting stents and how these responses translate into clinical outcomes. We also discuss next-generation BRS and outline modifications that are needed to improve the long-term outcomes with these devices so that they eventually become a viable option for patients with symptomatic obstructive coronary artery disease.

Twelve-month angiographic and clinical outcomes of the XINSORB bioresorbable sirolimus-eluting scaffold and a metallic stent in patients with coronary artery disease

BACKGROUND

Recent studies showed bioresorbable scaffold (BRS) increased risks of late target lesion failure (TLF) and thrombosis. XINSORB scaffold is a poly-L-lactic acid based BRS.

METHODS

The study included randomization and registry parts. Eligible patients with one or two de novo lesions were randomly 1:1 assigned to XINSORB scaffold and sirolimus-eluting stent (SES) in randomization part. These patients were clinically and angiographically assessed. In registry part, patients were treated with XINSORB scaffold only and were clinically assessed. The primary endpoint was in-segment late luminal loss (LLL) at 12-month in randomization part. The secondary endpoint was 12-month TLF in all XINSORB-treated patients.

RESULTS

Total 395 and 798 patients were enrolled in randomization and registry part, respectively. Device success was 98.0% (1069/1091) in all XINSORB-treated and 100% (221/221) in SES-treated lesions. The primary endpoint of in-segment LLL at 12-month was 0.19 ± 0.32 mm in XINSORB and 0.31 ± 0.41 mm in SES (P = 0.003), which met the noninferior margin of 0.195 mm (95% CI: -0.20, -0.04, P ≪ 0.0001). No difference was found in TLF between two devices. In all XINSORB-treated patients, 12-month TLF was 0.8% (8/998), which also met the noninferior margin of 9.0% (95% CI: 0.3%, 1.4%, P ≪ 0.0001). Only one device thrombosis was recorded in all XINSORB-treated patients while none in SES.

CONCLUSIONS

In the multicenter clinical trial, XINSORB BRS was noninferior to sirolimus-eluting stent for the primary endpoint of in-segment LLL at 12-month in patients with simple and moderate complex de novo coronary lesions. TLF at 12-month was low and comparable.

One-year clinical outcomes and multislice computed tomography angiographic results following implantation of the NeoVas bioresorbable sirolimus-eluting scaffold in patients with single de novo coronary artery lesions

BACKGROUND

Tremendous efforts have been made to establish the concept of vascular restoration therapy with a fully bioresorbable scaffold for coronary artery disease. With an improved scaffold design and technologies, the novel NeoVas scaffold has shown promising clinical performance at 6 months follow-up.

OBJECTIVE

The aim of this study was to investigate the 1 year clinical outcomes and multislice computed tomography (MSCT) angiographic results after implantation of the NeoVas scaffold in patients with single de novo coronary artery lesions.

METHODS

The NeoVas first-in-man study was a prospective, two-center, single-arm study enrolling 31 patients who were eligible for the treatment. The composite endpoint of target lesion failure (TLF)-defined as cardiac death, target vessel myocardial infarction, and clinically indicated target lesion revascularization (TLR)-was assessed. Of the 31 patients scheduled for 1 year clinical follow-up, 29 patients received MSCT examinations.

RESULTS

At 1 year follow-up, there was only 1 (3.2%) TLF, attributed to 1 patient who suffered ischemia-driven TLR at 181 days postprocedure. No cardiac deaths or scaffold thrombosis were observed. MSCT analysis demonstrated excellent vessel patency, with a median in-scaffold lumen area of 10.6 mm² (interquartile range [IQR]: 8.2-11.7 mm² ) and a minimal lumen diameter of 2.7 mm (IQR: 2.4-3.0 mm).

CONCLUSIONS

This study demonstrated the safety and efficacy of the NeoVas scaffold for patients with single de novo coronary artery lesions at 1 year of follow-up. Noninvasive MSCT data confirmed vessel patency and the maintenance of vessel dimensions following implantation of the NeoVas bioresorbable sirolimus-eluting scaffold.

Bioresorbable Scaffolds in Coronary Intervention: Unmet Needs and Evolution

Bioresorbable scaffolds (BRS) represent a novel paradigm in the 40-year history of interventional cardiology. Restoration of cyclic pulsatility and physiologic vasomotion, adaptive vascular remodeling, plaque regression, and removal of the trigger for late adverse events are expected BRS benefits over current metallic drug-eluting stents. However, first-generation BRS devices have significant manufacturing limitations and rely on optimal implantation technique to avoid experiencing an excess of clinical events. There are currently at least 22 BRS devices in different stages of development, including many trials of device iterations with thinner (<150 µm) struts than first-generation BRS. This article reviews the outcomes of commercially available and potentially upcoming BRS, focusing on the most recent stages of clinical development and future directions for each scaffold type.