Neoatherosclerosis 5 Years After Bioresorbable Vascular Scaffold Implantation

Coronary bioresorbable metallic stents: Advancements and future perspectives

Percutaneous coronary intervention is a critical treatment for coronary artery disease, particularly myocardial infarction, and is highly recommended in clinical guidelines. Traditional metallic stents, although initially effective, remain permanently in the artery and can lead to complications such as in-stent restenosis, late thrombosis, and chronic inflammation. Given the temporary need for stenting and the potential for late complications, bioresorbable stents have emerged as a promising alternative. However, bioresorbable polymeric stents have encountered significant clinical challenges due to their low mechanical strength and ductility, which increase the risks of thrombosis and local inflammation. Consequently, bioresorbable metals are being considered as a superior option for coronary stents. This review examines the progress of bioresorbable metallic stents from both preclinical and clinical perspectives, aiming to provide a theoretical foundation for future research. Iron, zinc, and magnesium are the primary materials used for these stents. Zinc-based bioresorbable stents have shown promise in preclinical studies due to their biocompatibility and vascular protective properties, although human clinical studies are still limited. Magnesium-based stents have demonstrated positive clinical outcomes, being fully absorbed within 12 months and showing low rates of late lumen loss and target lesion failure at 6- and 12-months post-implantation. Initial trials of iron-based stents have indicated favorable mid-term safety and efficacy, with complete absorption by the body within three years and consistent luminal expansion beyond six months post-implantation. Despite these advancements, further trials are needed for comprehensive validation. In conclusion, while current materials do not fully meet the ideal requirements, ongoing research should focus on developing bioresorbable stents with enhanced performance characteristics to better meet clinical needs.

Innovations in Intracoronary Imaging: Present Clinical Practices and Future Outlooks

Engaging intracoronary imaging (IC) techniques such as intravascular ultrasound or optical coherence tomography enables the precise description of vessel architecture. These imaging modalities have well-established roles in providing guidance and optimizing percutaneous coronary intervention (PCI) outcomes. Furthermore, IC is increasingly recognized for its diagnostic capabilities, as it has the unique capacity to reveal vessel wall characteristics that may not be apparent through angiography alone. This manuscript thoroughly reviews the contemporary landscape of IC in clinical practice. Focused on current methodologies, the review explores the utility and advancements in IC techniques. Emphasizing their role in clarifying coronary pathophysiology, guiding PCI, and optimizing patient outcomes, the manuscript critically evaluates the strengths and limitations of each modality. Additionally, the integration of IC into routine clinical workflows and its impact on decision-making processes are discussed. By synthesizing the latest evidence, this review provides valuable insights for clinicians, researchers, and healthcare professionals involved in the dynamic field of interventional cardiology.

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

BACKGROUND

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.

OBJECTIVE

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.

METHODS

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 36 months. A paired intracoronary imaging analysis at baseline and follow-up was also performed.

RESULTS

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 3 years of 16.2% (6/37). Angiographic lumen loss was 0.40 ± 0.62 mm at 12 months and 0.53 ± 0.57 mm at 36 months. Overall survival rate was 91.4% and 74.3%, and MACEs incidence 14.2% and 31.4% at 12 and 36 months, 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.

CONCLUSIONS

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.

Microfluidic-based cardiovascular systems for advanced study of atherosclerosis

Atherosclerosis (AS) is a significant global health concern due to its high morbidity and mortality rates. Extensive efforts have been made to replicate the cardiovascular system and explore the pathogenesis, diagnosis, and treatment of AS. Microfluidics has emerged as a valuable technology for modeling the cardiovascular system and studying AS. Here a brief review of the advances of microfluidic-based cardiovascular systems for AS research is presented. The critical pathogenetic mechanisms of AS investigated by microfluidic-based cardiovascular systems are categorized and reviewed, with a detailed summary of accurate diagnostic methods for detecting biomarkers using microfluidics represented. Furthermore, the review covers the evaluation and screening of AS drugs assisted by microfluidic systems, along with the fabrication of novel drug delivery carriers. Finally, the challenges and future prospects for advancing microfluidic-based cardiovascular systems in AS research are discussed and proposed, particularly regarding new opportunities in multi-disciplinary fundamental research and therapeutic applications for a broader range of disease treatments.

Histopathological findings of late-phase restenosis after directional coronary atherectomy with drug-coated balloon angioplasty: a case report

Background

Drug-coated balloon angioplasty after directional coronary atherectomy (DCA) allows for a stentless strategy providing good short-term outcomes; however, late-phase restenosis and its mechanism remain unclear. Moreover, histopathological evaluation for late-phase restenosis post-drug-coated balloon angioplasty after DCA has never been reported.

Case summary

We report the first case of late-phase restenosis post-drug-coated balloon angioplasty after DCA, wherein tissue analysis using intravascular coronary imaging and histopathology suggested neovascularization in newly developed neointimal proliferation. A 52-year-old man with a history of dyslipidaemia presented with exertional angina pectoris. He underwent percutaneous coronary intervention (PCI) with drug-coated balloon angioplasty after DCA for the proximal left anterior descending artery. Although coronary angiography after nine months revealed no restenosis, he experienced recurrent chest discomfort after 25 months. Coronary angiography confirmed late-phase restenosis, and intravascular ultrasound showed progressively developed neointima above the underlying residual plaque. Optical coherence tomography suggested developing neovascularization within the neointima. Stentless PCI with drug-coated balloon angioplasty after DCA was re-performed, and collected restenotic sample. The histopathological evaluation confirmed less-cellular neointimal proliferation with rich neovascularization and concomitant diffuse vascular endothelial growth factor (VEGF) expression.

Discussion

Late-phase restenosis post-drug-coated balloon angioplasty after DCA comprised less-cellular neointima, suggesting inhibition of cell proliferation by drug-coated balloon efficacy. However, diffuse VEGF expression and concomitant rich neovascularization with haemorrhage and inflammation might indicate neointimal proliferation. Further large-scale investigations of the restenotic mechanism should be performed to avoid long-term target vascular failure after drug-coated balloon angioplasty post-DCA.

Evolution of drug-eluting coronary stents: a back-and-forth journey from the bench-to-bedside

Coronary stents have revolutionized the treatment of coronary artery disease. Compared with balloon angioplasty, bare-metal stents effectively prevented abrupt vessel closure but were limited by in-stent restenosis due to smooth muscle cell proliferation and neointimal hyperplasia. The first-generation drug-eluting stent (DES), with its antiproliferative drug coating, offered substantial advantages over bare-metal stents as it mitigated the risk of in-stent restenosis. Nonetheless, they had several design limitations that increased the risk of late stent thrombosis. Significant advances in stent design, including thinner struts, enhanced polymers' formulation, and more potent antiproliferative agents, have led to the introduction of new-generation DES with a superior safety profile. Cardiologists have over 20 different DES types to choose from, each with its unique features and characteristics. This review highlights the evolution of stent design and summarizes the clinical data on the different stent types. We conclude by discussing the clinical implications of stent design in high-risk subsets of patients.

Curcumin attenuates inflammation of Macrophage-derived foam cells treated with Poly-L-lactic acid degradation via PPARγ signaling pathway

Poly-L-lactic acid (PLLA) is considered to be a promising candidate material for biodegradable vascular scaffolds (BVS) in percutaneous coronary intervention (PCI). But, PLLA-BVS also faces the challenge of thrombosis (ST) and in-stent restenosis (ISR) caused by in-stent neo-atherosclerosis (ISNA) associated with inflammatory reactions in macrophage-derived foam cells. Our previous studies have confirmed that curcumin alleviates PLLA-induced injury and inflammation in vascular endothelial cells, but it remains unclear whether curcumin can alleviate the effect of inflammatory reactions in macrophage-derived foam cells while treated with degraded product of PLLA. In this study, PLLA-BVS was implanted in the porcine coronary artery to examine increased macrophages and inflammatory cytokines such as NF-κb and TNF-α by histology and immunohistochemistry. In vitro, macrophage-derived foam cells were induced by Ox-LDL and observed by Oil Red Staining. Foam cells were treated with pre-degraded PLLA powder, curcumin and PPARγ inhibitor GW9662, and the expression of IL-6, IL-10, TNF-α, NF-κb, PLA2 and PPARγ were investigated by ELISA or RT-qPCR. This study demonstrated that the macrophages and inflammatory factors increased after PLLA-BVS implantation in vivo, and foam cells derived from macrophages promoted inflammation by products of PLLA degradation in vitro. This present study was found that the inflammation of foam cells at the microenvironment of PLLA degraded products were significantly increased, and curcumin can attenuate the inflammation caused by the PLLA degradation via PPARγ signal pathway. In addition, curcumin should be further studied experimentally in vivo experiments on animal models as a potential therapeutic to reduce ISNA of PLLA-BVS. Graphical abstract.

Structure attention co-training neural network for neovascularization segmentation in intravascular optical coherence tomography

PURPOSE

To development and validate a Neovascularization (NV) segmentation model in intravascular optical coherence tomography (IVOCT) through deep learning methods.

METHODS AND MATERIALS

A total of 1950 2D slices of 70 IVOCT pullbacks were used in our study. We randomly selected 1273 2D slices from 44 patients as the training set, 379 2D slices from 11 patients as the validation set, and 298 2D slices from the last 15 patients as the testing set. Automatic NV segmentation is quite challenging, as it must address issues of speckle noise, shadow artifacts, high distribution variation, etc. To meet these challenges, a new deep learning-based segmentation method is developed based on a co-training architecture with an integrated structural attention mechanism. Co-training is developed to exploit the features of three consecutive slices. The structural attention mechanism comprises spatial and channel attention modules and is integrated into the co-training architecture at each up-sampling step. A cascaded fixed network is further incorporated to achieve segmentation at the image level in a coarse-to-fine manner.

RESULTS

Extensive experiments were performed involving a comparison with several state-of-the-art deep learning-based segmentation methods. Moreover, the consistency of the results with those of manual segmentation was also investigated. Our proposed NV automatic segmentation method achieved the highest correlation with the manual delineation by interventional cardiologists (the Pearson correlation coefficient is 0.825).

CONCLUSION

In this work, we proposed a co-training architecture with an integrated structural attention mechanism to segment NV in IVOCT images. The good agreement between our segmentation results and manual segmentation indicates that the proposed method has great potential for application in the clinical investigation of NV-related plaque diagnosis and treatment. This article is protected by copyright. All rights reserved.

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.

Serial Baseline, 12-, 24-, and 60-Month Optical Coherence Tomography Evaluation of ST Segment Elevation Myocardial Infarction Patients Treated with Absorb Bioresorbable Vascular Scaffold

Data on long-term neointimal healing and neoatherosclerosis progression after primary percutaneous coronary intervention (PCI) with implantation of everolimus-eluting bioresorbable vascular scaffold (BVS) (ABSORB BVS 1.0, Abbott Vascular) are limited. The mechanisms underlying very late scaffold failure remain to be further elucidated. This study sought to assess healing pattern and presence of neoatherosclerosis. This was a single-center, prospective, longitudinal study with serial optical coherence tomography (OCT) assessment at baseline, 12, 24 and 60 months after PCI performed in 12 patients presenting with ST-segment elevation myocardial infarction (STEMI). The median follow-up was 59 months. The diameter stenosis increased from 7.11 ± 4.99% at 1-year to 21.00 ± 11.31% at 5 years, (p = 0.03), whereas minimum lumen diameter remained stable throughout the follow-up period, as assessed by angiography. Minimum and mean lumen area declined over the 5-year follow-up by 1.00 ± 1.57 mm2 and 1.75 ± 0.87 mm2, respectively; a significant decrease in minimum and mean lumen area in the first two years, was followed by stable luminal dimensions between 2 and 5 years of follow-up. The lumen eccentricity (0.85 ± 0.03) and asymmetry (0.43 ± 0.10) indexes showed no change over 60-month follow-up. The incidence of atherosclerosis was high both in the in-scaffold (IS) and out-scaffold (OS) regions consisting of calcifications (IS = 100%, OS = 92%, p = 0.99), macrophages (IS = 92% and OS = 67%, p = 0.31), neovascularization (IS = 75%, OS = 50%, p = 0.40). In conclusion, serial OCT imaging up to 5 years after implantation of BVS in STEMI indicated complete scaffold resorption, stable lumen area following period of neointima growth in the first two years after PCI and high incidence of neoatherosclerosis.

Development of a polycaprolactone/poly(p-dioxanone) bioresorbable stent with mechanically self-reinforced structure for congenital heart disease treatment

Recent progress in bioresorbable stents (BRSs) has provided a promising alternative for treating coronary artery disease. However, there is still lack of BRSs with satisfied compression and degradation performance for pediatric patients with congenital heart disease, leading to suboptimal therapy effects. Here, we developed a mechanically self-reinforced composite bioresorbable stent (cBRS) for congenital heart disease application. The cBRS consisted of poly(p-dioxanone) monofilaments and polycaprolactone/poly(p-dioxanone) core-shell composite yarns. Interlacing points in cBRS structure were partially bonded, offering the cBRS with significantly higher compression force compared to typical braids and remained good compliance. The suitable degradation profile of the cBRS can possibly preserve vascular remodeling and healing process. In addition, the controllable structural organization provides a method to customize the performance of the cBRS by altering the proportion of different components in the braids. The in vivo results suggested the cBRS supported the vessel wall similar to that of metallic stent. In both abdominal aorta and iliac artery of porcine, cBRS was entirely endothelialized within 1 month and maintained target vessels with good patency in the 12-month follow-up. The in vivo degradation profile of the cBRS is consistent with static degradation results in vitro. It is also demonstrated that there is minimal impact of pulsatile pressure of blood flow and variation of radial force on the degradation rate of the cBRS. Moreover, the lumen of cBRS implanted vessels were enlarged after 6 months, and significantly larger than the vessels implanted with metallic stent in 12 months.

Five-year angiographic, OCT and clinical outcomes of a randomized comparison of everolimus and biolimus-eluting coronary stents with everolimus-eluting bioresorbable vascular scaffolds

Aims

To compare 5‐year angiographic, optical coherence tomography (OCT), and clinical outcomes between patients treated with bioresorbable vascular scaffolds (BVS) and drug‐eluting stents (DES).

Methods

The EverBio‐2 trial (Comparison of Everolimus‐ and Biolimus‐Eluting Coronary Stents with Everolimus‐Eluting Bioresorbable Vascular Scaffold) was a single‐center, assessor‐blinded, randomized controlled trial in which 240 patients were randomly allocated (1:1:1) to BVS, everolimus‐eluting (EES) or biolimus‐eluting (BES) DES. Clinical follow‐up was scheduled up to 5 years. All patients, alive and who did not have repeat revascularization of the target lesion during follow‐up were asked to return for angiographic follow‐up at 5 years.

Results

Five‐year angiographic follow‐up was completed in 122 patients (51%) and OCT analysis was performed in 86 (36%) patients. In‐stent late lumen loss was similar in both groups with 0.50 ± 0.38 mm in BVS versus 0.58 ± 0.36 mm in EES/BES, p = 0.20. Clinical follow‐up was complete in 232 patients (97%) at 5 years. The rate of the device‐oriented endpoint was 22% in the BVS and 18% in the EES/BES group (p = 0.49). The patient‐oriented composite endpoint occurred in 40% of BVS‐ and 43% of EES/BES‐treated patients (p = 0.72) at 5 years. No acute coronary syndrome due to stent thrombosis was detected after 2 years. Complete BVS strut resorption was observed at 5 years in the OCT subgroup.

Conclusion

Five‐year clinical outcomes were similar between BVS and DES patients as well as angiographic outcomes in a selected subgroup. However, a definitive conclusion cannot be drawn because the EverBio‐2 trial was not powered for clinical and angiographic endpoints at 5 years of follow‐up.

First-in-Man trial of a drug-free bioresorbable stent designed to minimize the duration of coronary artery scaffolding

For the last two decades, various degradable stents have been proposed to treat coronary artery diseases and replace metallic stents to avoid residual foreign material after healing. To date, the right balance between suitable scaffolding and loss of radial strength soon after endothelium restoration is still an unmet need. The present article reports on the First-in-Man trial of a drug-free bioresorbable stent based on a lactic acid stereocopolymer composed of 98% l-lactyl units selected to release stress shielding earlier than in the case of homopoly(l-lactic acid). Thirty patients with single de novo coronary lesions were included in the trial. The fate of scaffolds was monitored by clinical and imaging follow-ups to assess rate of adverse events, acute recoil, late luminal loss, and late lumen recovery. There was no death, no myocardial infarction, and no stent thrombosis observed over the 36 months trial. Dismantling occurred about 3 months after implantation. Bioresorption was almost completed at 2 years. The late lumen loss observed at the end of the first year was partly compensated one year later by enlarging remodeling. At one year, a neointimal hyperplasia slightly greater than for drug-eluting metallic and bioresorbable stents was shown using optical coherence tomography. The excess of hyperplasia was discussed relative to struts thickness, absence of anti-proliferative drug, and release of degradation by-products.

Restenosis of a drug eluting stent on the previous bioresorbable vascular scaffold successfully treated with a drug-coated balloon: A case report

BACKGROUND

The in-stent restenosis (ISR) rates are reportedly inconsistent despite the increased use of second-generation drug eluting stent (DES). Although bioresorbable vascular scaffold (BVS) have substantial advantages with respect to vascular restoration, the rate of scaffold thrombosis is higher with BVS than with DES. Optimal treatment strategies have not been established for DES-ISR to date.

CASE SUMMARY

We report on a case of a 60-year-old man patient with acute coronary syndrome. He had a history of ST-segment elevation myocardial infarction associated with very late scaffold thrombosis and treated with a DES. Coronary angiography revealed significant stenosis, suggesting DES-ISR on the previous BVS. Optical coherence tomography (OCT) identified a plaque rupture and a disrupted scaffold strut in the neointimal proliferation of DES. To treat the DES-ISR on the previous BVS, we opted for a drug-coated balloon (DCB) after a balloon angioplasty using a semi-compliant and non-compliant balloon. The patient did not experience adverse cardiovascular events on using a DCB following the use of intensive dual antiplatelet therapy and statin for 24 mo.

CONCLUSION

This case highlights the importance of OCT as an imaging modality for characterizing the mechanism of target lesion failure. The use of a DCB following the administration of optimal pharmacologic therapy may be an optimal strategy for the treatment and prevention of recurrent BVS thrombosis and DES-ISR.

Final report of the 5-year clinical outcomes of the XINSORB bioresorbable sirolimus-eluting scaffold in the treatment of single de novo coronary lesions in a first-in-human study

Background

We aimed to report the 5-year outcomes of XINSORB bioresorbable sirolimus-eluting scaffolds in the treatment of single de novo coronary lesions in a first-in-human (FIM) study. This is the final report of the long-term clinical outcomes of the study. Recent studies have shown that bioresorbable scaffolds (BRSs) increase the risks of late target lesion failure (TLF) and thrombosis.

Methods

In this prospective, single-arm study, eligible patients with single de novo coronary lesions were enrolled and treated with XINSORB scaffolds. The scaffolds measured 3.0 mm in diameter and 12, 15, and 18 mm in length. The clinical endpoints included TLF [cardiac death, target vessel-related myocardial infarction (TV-MI), or ischaemia-driven target lesion revascularization (ID-TLR)], its components, major adverse cardiac events (MACE), and scaffold thrombosis.

Results

From September 2013 to January 2014, 30 patients were enrolled and treated with XINSORB scaffolds. The procedure had a 100% success rate. None of the patients died during the 5 years of follow-up. The primary endpoint of TLF occurred in 4 patients (13.3%). Six patients were recanalized by intervention, including 4 by ID-TLR. The rate of MACE was 16.7% (5/30). One very late case of scaffold thrombosis was recorded, which led to TV-MI. No more cases of thrombosis were recorded beyond 2 years of follow-up. The rates of clinical endpoints remained steady with no changes after 3 years of follow-up.

Conclusions

Considering that this FIM study was launched at an early stage of the BRS era and without optimal implantation techniques, the clinical outcomes of TLF during the 5-year follow-up were acceptable. The rate of thrombosis was relatively low.

Peri-strut low intensity areas and in-scaffold neointima growth after bioresorbable scaffold implantation in STEMI. A serial optical coherence tomography study

BACKGROUND

Peri-strut low intensity areas (PLIA) visualized by optical coherence tomography (OCT) have been related to neointimal proliferation and increased incidence of target lesion revascularization in stable coronary artery disease. The aim of this study was to determine the association between PLIA by OCT and the long-term vascular healing response after bioresorbable scaffold (BRS) implantation in the setting of ST-segment elevation myocardial infarction (STEMI).

METHODS

This is a single-centre, longitudinal, cohort study with a serial: baseline, 1, 2 and 5 years OCT evaluation of neointimal response (lumen area and neoatherosclerosis) after percutaneous coronary intervention (PCI) with BRS Absorb™ 1.0 implantation in patients presenting with STEMI. PLIA was analyzed in every cross section and scored: 0-no PLIA; 1-PLIA < 1 quadrant; 2-PLIA ≥ 1 and <2 quadrants; 3-PLIA ≥ 2 and <3 quadrants; 4-PLIA in ≥3 quadrants.

RESULTS

Of the 23 patients implanted BRS, 18 completed 2-year follow-up, whereas complete OCT data up to 5 years were available in 12 patients. Presence of PLIA was identified in 100% patients at 1 and 2 years, whereas at 5 years neither PLIA nor scaffold struts were visualized by OCT. Neoatherosclerosis was identified in 73,68% patients after 1 year and in all patients at 2 and 5 years. The mean PLIA score > 1 at 2 years was associated with greater percentage of minimum lumen area decrease after 2 years from index procedure.

CONCLUSIONS

The extent of PLIA by OCT at 2 years after primary PCI with BRS was associated with lumen area decrease. Neoatherosclerosis formation was detected in all patients at 2 and 5 years. PLIA assessment could serve as an additive means to predict neointimal healing pattern after next generation BRS implantation.

Time-Varying Outcomes With the Absorb Bioresorbable Vascular Scaffold During 5-Year Follow-up: A Systematic Meta-analysis and Individual Patient Data Pooled Study

Importance

Bioresorbable scaffolds were designed to provide clinical benefits after their complete bioresorption. Prior studies demonstrated early risks with the Absorb polymeric bioresorbable vascular scaffold (BVS). Whether this risk profile changes over time during the course of its bioresorption is unknown.

Objective

To examine outcomes of the first-generation BVS before and after 3 years, the point of its complete bioresorption in animals.

Data Sources

We searched MEDLINE and the Cochrane database, conference proceedings, and public websites for relevant studies.

Study Selection

Eligible studies were randomized clinical trials of BVS vs metallic drug-eluting stents in patients with coronary artery disease with at least 5-year follow-up. Four trials of BVS vs everolimus-eluting stents (EES) with 3384 patients met criteria.

Data Extraction and Synthesis

Individual patient data from the 4 trials were pooled, and summary-level meta-analysis was performed.

Main Outcomes and Measures

The major effectiveness and safety measures were target lesion failure (TLF; cardiac death, target vessel-related myocardial infarction, or ischemia-driven target lesion revascularization) and device thrombosis. Outcomes were examined through 5-year follow-up and between 0 to 3 and 3 to 5 years.

Results

Mean age for the 3384 patients was 62.8 years; 2452 patients were men (72.5%), and diabetes was present in 1020 patients (30.2%). Through 5-year follow-up, treatment with BVS compared with EES was associated with higher rates of TLF (14.9% vs 11.6%; HR, 1.26; 95% CI, 1.03-1.54; P = .03) and device thrombosis (2.5% vs 0.8%; HR, 2.87; 95% CI, 1.46-5.65; P = .002). Target lesion failure occurred in 11.6% of BVS-treated patients vs 7.9% of EES-treated patients between 0 to 3 years (HR, 1.42; 95% CI, 1.12-1.80), and 4.3% of BVS-treated patients vs 4.5% of EES-treated patients between 3 to 5 years (HR, 0.92; 95% CI, 0.64-1.31) (P for interaction = .046). Device thrombosis occurred in 2.4% of BVS-treated patients vs 0.6% of EES-treated patients between 0 to 3 years (HR, 3.86; 95% CI, 1.75-8.50) and 0.1% of BVS-treated patients vs 0.3% of EES-treated patients between 3 to 5 years (HR, 0.44; 95% CI, 0.07-2.70) (P for interaction = .03). These results were consistent by spline analysis and after multiple imputation and multivariable analysis.

Conclusions and Relevance

The period of excess risk for the first-generation Absorb BVS ends at 3 years. These data provide mechanistic insights into the timing of adverse events after BVS and identify the hurdles to be overcome for bioresorbable technology to be accepted as a valid alternative for patients with coronary artery disease.

Trial Registration

ClinicalTrials.gov identifiers: NCT01751906, NCT01844284, NCT01923740, and NCT01425281.

Bioresorbable vascular scaffolds versus everolimus-eluting metallic stents in patients with ST-segment elevation myocardial infarction: 5-year results of the BVS-EXAMINATION study

AIMS

The aim of this study was to compare five-year clinical outcomes between an everolimus-eluting bioresorbable scaffold (BRS) and an everolimus-eluting metallic stent (EES) in STEMI patients.

METHODS AND RESULTS

This observational and retrospective study included 235 consecutive STEMI patients treated with BRS, compared with 235 STEMI patients treated with EES from the EXAMINATION trial, by applying propensity score matching. The primary endpoint was a device-oriented endpoint (DOCE), including cardiac death, target vessel myocardial infarction and target lesion revascularisation at five-year follow-up. Device thrombosis, according to the ARC criteria, was also evaluated. Optical coherence tomography (OCT) analysis was also performed at five years in event-free BRS patients. The cumulative incidence of five-year DOCE was higher in the BRS group as compared to the EES group (13.2% vs 7.6%, HR 1.87, 95% CI: 0.94-3.44, p=0.071), mainly driven by a higher rate of TLR (7.6% vs 1.7%, HR 1.15, 95% CI: 0.44-2.30, p=0.004). The five-year definite BRS thrombosis rate was also higher as compared to EES (4.2% vs 1.2%, HR 3.49, 95% CI: 0.95-12.82, p=0.054). OCT analysis showed a high incidence of neoatherosclerosis in the BRS group.

CONCLUSIONS

The five-year event risk was higher with BRS versus EES in STEMI. This suggests that the probability of obtaining favourable results at very long-term follow-up is low. Whether better results will be obtained with new-generation BVS remains to be determined.

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.

Neoatherosclerosis - Long-Term Assessment of Bioresorbable Vascular Scaffold

Although metallic stents improved the safety and efficacy of percutaneous coronary intervention (PCI), even the latest generation of drug-eluting stents (DES) is still limited by several factors. The limitations of DES are mainly related to the permanent metallic caging in vessel, chronic inflammatory response to the polymer and adverse effects of antiproliferative drug on endothelial tissue, leading to impaired physiological vasomotor response and late stent-related adverse events such as stent thrombosis and neoatherosclerosis. Bioresorbable vascular scaffold (Absorb BVS; Abbott Vascular) was designed to overcome these drawbacks of DES by disappearing from the vessel wall. Absorb BVS, however, was withdrawn from the world market because of increased incidence of scaffold thrombosis compared with DES. Importantly, only very limited long-term post-BVS implantation data are available, especially with regard to neoatherosclerosis, which can lead to very late adverse events even after resorption of the scaffold. Therefore, the goal of this review was to highlight the mid to long term clinical outcomes published to date, and to describe the features of the intimal healing process and neoatherosclerosis in the 5 years following Absorb BVS implantation, mainly based on our previous study. This may provide important information on the pathophysiology of the scaffolded vessel for clinicians, and promote identification of future bioresorbable materials for PCI that will minimize the stimulus for neoatherosclerosis.

In vivo and in vitro evaluation of a biodegradable magnesium vascular stent designed by shape optimization strategy

The performance of biodegradable magnesium alloy stents (BMgS) requires special attention to non-uniform residual stress distribution and stress concentration, which can accelerate localized degradation after implantation. We now report on a novel concept in stent shape optimization using a finite element method (FEM) toolkit. A Mg-Nd-Zn-Zr alloy with uniform degradation behavior served as the basis of our BMgS. Comprehensive in vitro evaluations drove stent optimization, based on observed crimping and balloon inflation performance, measurement of radial strength, and stress condition validation via microarea-XRD. Moreover, a Rapamycin-eluting polymer coating was sprayed on the prototypical BMgS to improve the corrosion resistance and release anti-hyperplasia drugs. In vivo evaluation of the optimized coated BMgS was conducted in the iliac artery of New Zealand white rabbit with quantitative coronary angiography (QCA), optical coherence tomography (OCT) and micro-CT observation at 1, 3, 5-month follow-ups. Neither thrombus or early restenosis was observed, and the coated BMgS supported the vessel effectively prior to degradation and allowed for arterial healing thereafter. The proposed shape optimization framework based on FEM provides an novel concept in stent design and in-depth understanding of how deformation history affects the biomechanical performance of BMgS. Computational analysis tools can indeed promote the development of biodegradable magnesium stents.

Clinical Outcomes Before and After Complete Everolimus-Eluting Bioresorbable Scaffold Resorption: Five-Year Follow-Up From the ABSORB III Trial

BACKGROUND

The Absorb everolimus-eluting bioresorbable vascular scaffold (BVS) provides early drug delivery and mechanical support similar to those of metallic drug-eluting stents, followed by complete resorption in ≈3 years with recovery of vascular structure and function. The ABSORB III trial demonstrated noninferior rates of target lesion failure (cardiac death, target vessel myocardial infarction, or ischemia-driven target lesion revascularization) at 1 year with BVS compared with cobalt chromium everolimus-eluting stents. Between 1 and 3 years and cumulative to 3 years, adverse event rates (particularly target vessel myocardial infarction and scaffold thrombosis) were increased after BVS. We sought to assess clinical outcomes after BVS through 5 years, including beyond the 3-year time point of complete scaffold resorption.

METHODS

Clinical outcomes from ABSORB III were analyzed by randomized device (intention to treat) cumulative to 5 years and between 3 and 5 years.

RESULTS

Rates of target lesion failure, target vessel myocardial infarction, and scaffold thrombosis were increased through the 5-year follow-up with BVS compared with everolimus-eluting stents. However, between 3 and 5 years, reductions in the relative hazards of the BVS compared with everolimus-eluting stents were observed, particularly for target lesion failure (hazard ratio, 0.83 [95% CI, 0.55-1.24] versus 1.35 [95% CI, 1.02-1.78]; P^int=0.052) and scaffold thrombosis (hazard ratio, 0.26 [95% CI, 0.02-2.87] versus 3.23 [95% CI, 1.25-8.30]; P^int=0.056) compared with the 0- to 3-year time period.

CONCLUSIONS

In the ABSORB III trial, cumulative 5-year adverse event rates were increased after BVS compared with everolimus-eluting stents. However, the period of excess risk for BVS ended at 3 years, coincident with complete scaffold resorption.

CLINICAL TRIAL REGISTRATION

URL: https://clinicaltrials.gov. Unique identifier: NCT01751906.

Major trials in coronary intervention from 2018

PURPOSE OF REVIEW

This article will review the major clinical trials related to coronary intervention that were released in 2018. Areas of interest include lesion assessment, novel stent design, acute coronary syndromes (ACSs), and major breakthroughs in chronic total occlusion interventions.

RECENT FINDINGS

The benefit of intracoronary imaging and hemodynamic assessment was demonstrated by multiple studies, which found improved procedural and clinical outcomes in patients who underwent advanced assessment of intracoronary lesions. The optimal use of drug-coated balloons in coronary disease still remains unclear with conflicting data regarding the benefit of DCB over everolimus-eluting stents for the treatment of in-stent restenosis. Trials in bioresorbable scaffolds also saw a high level of interest after the ABSORB IV trial showed promising results with changes in implantation technique. Multiple studies evaluated complete revascularization versus infarct-related only revascularization in patients with ACS; however, data was conflicting in regard to what is the best strategy. Lastly, the EUROCTO study was released in 2018 and was the first trial to show symptomatic benefit of revascularization of chronic total occlusions.

SUMMARY

The ESC/EACTS guidelines on complete versus partial revascularization, treatment of in-stent restenosis, and revascularization during cardiogenic shock were updated to reflect data obtained from trials released in 2018.

Editor-in-Chief's Top Picks From 2018

Each week, I record audio summaries for every article in JACC, as well as an issue summary. Although this process is quite time-consuming, I have become familiar with every paper that we publish. Thus, I have personally selected the top 100 papers (both Original Investigations and Review Articles) from 15 distinct specialties each year. In addition to my personal choices, I have included papers that have been the most accessed or downloaded on our websites, as well as those selected by the JACC Editorial Board members. In order to present the full breadth of this important research in a consumable fashion, we will present these abstracts in this issue of JACC. The highlights comprise the following sections: Basic & Translational Research, Cardiac Failure, Cardiomyopathies/Myocardial & Pericardial Diseases, Cardio-oncology, Congenital Heart Disease, Coronary Disease & Interventions, CVD Prevention & Health Promotion, CV Medicine & Society, Hypertension, Imaging, Metabolic & Lipid Disorders, Rhythm Disorders, Valvular Heart Disease, and Vascular Medicine (1-100).

Understanding the Impact of Stent and Scaffold Material and Strut Design on Coronary Artery Thrombosis from the Basic and Clinical Points of View

The technology of percutaneous coronary intervention (PCI) is constantly being refined in order to overcome the shortcomings of present day technologies. Even though current generation metallic drug-eluting stents (DES) perform very well in the short-term, concerns still exist about their long-term efficacy. Late clinical complications including late stent thrombosis (ST), restenosis, and neoatherosclerosis still exist and many of these events may be attributed to either the metallic platform and/or the drug and polymer left behind in the arterial wall. To overcome this limitation, the concept of totally bioresorbable vascular scaffolds (BRS) was invented with the idea that by eliminating long-term exposure of the vessel wall to the metal backbone, drug, and polymer, late outcomes would improve. The Absorb-bioabsorbable vascular scaffold (Absorb-BVS) represented the most advanced attempt to make such a device, with thicker struts, greater vessel surface area coverage and less radial force versus contemporary DES. Unfortunately, almost one year after its initial approval by the U.S. Food and Drug Administration, this scaffold was withdrawn from the market due to declining devise utilization driven by the concerns about scaffold thrombosis (ScT) seen in both early and late time points. Additionally, the specific causes of ScT have not yet been fully elucidated. In this review, we discuss the platform, vascular response, and clinical data of past and current metallic coronary stents with the Absorb-BVS and newer generation BRS, concentrating on their material/design and the mechanisms of thrombotic complications from the pre-clinical, pathologic, and clinical viewpoints.