Multiplicity of morphologies in poly (l-lactide) bioresorbable vascular scaffolds

Poly(l-lactide) (PLLA) is the structural material of the first clinically approved bioresorbable vascular scaffold (BVS), a promising alternative to permanent metal stents for treatment of coronary heart disease. BVSs are transient implants that support the occluded artery for 6 mo and are completely resorbed in 2 y. Clinical trials of BVSs report restoration of arterial vasomotion and elimination of serious complications such as late stent thrombosis. It is remarkable that a scaffold made from PLLA, known as a brittle polymer, does not fracture when crimped onto a balloon catheter or during deployment in the artery. We used X-ray microdiffraction to discover how PLLA acquired ductile character and found that the crimping process creates localized regions of extreme anisotropy; PLLA chains in the scaffold change orientation from the hoop direction to the radial direction on micrometer-scale distances. This multiplicity of morphologies in the crimped scaffold works in tandem to enable a low-stress response during deployment, which avoids fracture of the PLLA hoops and leaves them with the strength needed to support the artery. Thus, the transformations of the semicrystalline PLLA microstructure during crimping explain the unexpected strength and ductility of the current BVS and point the way to thinner resorbable scaffolds in the future.

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Crimping-induced structural gradients explain the lasting strength of poly l-lactide bioresorbable vascular scaffolds during hydrolysis

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1807347115 ◽

2018 ◽

Vol 115 (41) ◽

pp. 10239-10244 ◽

Cited By ~ 2

Author(s):

Karthik Ramachandran ◽

Tiziana Di Luccio ◽

Artemis Ailianou ◽

Mary Beth Kossuth ◽

James P. Oberhauser ◽

...

Keyword(s):

Molecular Weight ◽

Heart Disease ◽

Morphological Changes ◽

Metal Stents ◽

Radial Load ◽

Late Stent Thrombosis ◽

X Ray ◽

Radial Strength ◽

Vascular Scaffolds ◽

Bioresorbable Vascular Scaffolds

Biodegradable polymers open the way to treatment of heart disease using transient implants (bioresorbable vascular scaffolds, BVSs) that overcome the most serious complication associated with permanent metal stents—late stent thrombosis. Here, we address the long-standing paradox that the clinically approved BVS maintains its radial strength even after 9 mo of hydrolysis, which induces a ∼40% decrease in the poly l-lactide molecular weight (Mn). X-ray microdiffraction evidence of nonuniform hydrolysis in the scaffold reveals that regions subjected to tensile stress during crimping develop a microstructure that provides strength and resists hydrolysis. These beneficial morphological changes occur where they are needed most—where stress is localized when a radial load is placed on the scaffold. We hypothesize that the observed decrease in Mn reflects the majority of the material, which is undeformed during crimping. Thus, the global measures of degradation may be decoupled from the localized, degradation-resistant regions that confer the ability to support the artery for the first several months after implantation.

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Pre-Emptive OCT-Guided Angioplasty of Vulnerable Intermediate Coronary Lesions: Results from the Prematurely Halted PECTUS-Trial

Journal of Interventional Cardiology ◽

10.1155/2020/8821525 ◽

2020 ◽

Vol 2020 ◽

pp. 1-8

Author(s):

Jan-Quinten Mol ◽

Michiel J. Bom ◽

Peter Damman ◽

Paul Knaapen ◽

Niels van Royen

Keyword(s):

Composite Endpoint ◽

Coronary Intervention ◽

Future Research ◽

Fractional Flow ◽

Bioresorbable Vascular Scaffold ◽

Flow Reserve ◽

Vulnerable Plaques ◽

Vascular Scaffolds ◽

Bioresorbable Vascular Scaffolds ◽

Absorb Bvs

Objectives. To assess the safety and efficacy of pre-emptive treatment of optical coherence tomography- (OCT-) derived vulnerable, non-flow-limiting, non-culprit lesions in patients with myocardial infarction (MI). Background. Intracoronary imaging with OCT can aid in the decision to treat non-flow-limiting lesions by identifying vulnerable plaques. Pre-emptive treatment of these lesions might improve patient outcome by “sealing” these plaques. Bioresorbable vascular scaffolds (BVS) have theoretical benefit for this treatment because they dissolve completely over time. Methods. In patients presenting with MI, non-culprit lesions with a fractional flow reserve ≥0.8 were imaged with OCT. Vulnerable plaques were randomised to either percutaneous coronary intervention (PCI) with bioresorbable vascular scaffold (BVS) placement or optimal medicinal therapy (OMT). The primary outcome was a composite of all-cause mortality, non-fatal MI, and unplanned revascularisation at 1-year follow-up. Results. The trial was stopped prematurely after retraction from the market of the Absorb BVS. At that time, a total of 34 patients were randomised. At two years, the composite endpoint occurred 3 times (18.8%) in the BVS group and 1 time (6.3%) in the OMT group. Apart from one elective PCI for stable angina in the OMT group, no target lesions in any group were revascularised. Conclusions. Pre-emptive stenting of vulnerable plaques had no evident benefit compared to conservative treatment. However, due to the low number of included patients, no definite conclusions could be drawn. Identifying and potentially treating vulnerable plaques remains an important target for future research. This trial is registered under https://www.trialregister.nl/trial/NL4177 on 08-12-2015.

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Clinical and angiographic outcome of a single center, real world population treated with a dedicated technique of implantation for bioresorbable vascular scaffolds. The FAtebenefratelli Bioresorbable Vascular Scaffold (FABS) registry

Journal of Interventional Cardiology ◽

10.1111/joic.12415 ◽

2017 ◽

Vol 30 (5) ◽

pp. 427-432 ◽

Cited By ~ 4

Author(s):

Bernardo Cortese ◽

Gaetano di Palma ◽

Enrico Cerrato ◽

Roberto A. Latini ◽

Mostafa Elwany ◽

...

Keyword(s):

Real World ◽

World Population ◽

Single Center ◽

Bioresorbable Vascular Scaffold ◽

Vascular Scaffold ◽

Vascular Scaffolds ◽

Bioresorbable Vascular Scaffolds

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Vollständig resorbierbare Stents – eine neue Ära in der Behandlung der koronaren Herzkrankheit?

Praxis ◽

10.1024/1661-8157/a002584 ◽

2017 ◽

Vol 106 (2) ◽

pp. 85-89

Author(s):

Zaid Sabti ◽

Raban Jeger

Keyword(s):

Bare Metal Stents ◽

Drug Eluting Stents ◽

Metal Stents ◽

Bare Metal ◽

Vascular Scaffolds ◽

Drug Eluting ◽

Bioresorbable Vascular Scaffolds

Zusammenfassung. Die perkutane Ballonangioplastie revolutionierte die Behandlung der koronaren Herzkrankheit. Der Einsatz von Gefässstützen (Stents) setzte diese Revolution fort. Nach den reinen Metallstents (Bare metal stents, BMS) und den Medikamenten-beschichteten Stents (drug-eluting stents, DES) folgen nun bioresorbierbare Stents (bioresorbable vascular scaffolds, BVS). Im Gegensatz zu den ersten zwei Stent-Generationen werden die BVS nach einer bestimmten Zeit vollständig abgebaut und versprechen eine Antwort für bisher ungelöste Probleme von BMS und DES.

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How to Select the Most Appropriate Patient and Lesion to be Treated with a Coronary Bioresorbable Vascular Scaffold

Interventional Cardiology Review ◽

10.15420/icr.2013.8.2.90 ◽

2013 ◽

Vol 8 (2) ◽

pp. 90

Author(s):

Charis Costopoulos ◽

Azeem Latib ◽

Antonio Colombo ◽

◽

...

Keyword(s):

Percutaneous Treatment ◽

Bioresorbable Vascular Scaffold ◽

Diffuse Disease ◽

Novel Treatment ◽

Vascular Scaffold ◽

Vascular Scaffolds ◽

Bioresorbable Vascular Scaffolds ◽

Artery Disease ◽

Novel Devices ◽

Complex Lesions

Bioresorbable vascular scaffolds (BVS) are an exciting novel treatment for coronary artery disease (CAD) as their eventual resorption renders the artery free from a permanent metallic cage. Clinical trials regarding these novel devices have demonstrated promising results, although their use in this context has largely been restricted to simple lesions. More recently, BVS use has expanded to patients with more complex lesions including those with long diffuse disease, and results from several registries are awaited with regard to their efficacy in ‘real-world’ patients. Although any patient who requires percutaneous treatment for CAD could benefit from BVS implantation, there are certain cohorts of patients and lesions in whom BVS could be of particular benefit. In this review, we attempt to identify which patient and lesion cohort is most suitable for treatment with these novel devices.

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When to Use Bioresorbable Vascular Scaffolds

US Cardiology Review ◽

10.15420/usc.2017:3:2 ◽

2017 ◽

Vol 11 (1) ◽

pp. 25 ◽

Cited By ~ 1

Author(s):

Xiaoyu Yang ◽

Mohamed Ahmed ◽

Donald E Cutlip ◽

◽

...

Keyword(s):

Bare Metal Stents ◽

Percutaneous Treatment ◽

The United States ◽

Lessons Learned ◽

High Rate ◽

Drug Eluting Stent ◽

Metal Stents ◽

Scaffold Thrombosis ◽

Vascular Scaffolds ◽

Bioresorbable Vascular Scaffolds

The development of the drug eluting stent (DES) was an important milestone in percutaneous treatment of coronary artery disease. The DES overcomes vessel recoil and restenosis to decrease the high rate of target lesion revascularization associated with balloon angioplasty and bare metal stents. Despite these benefits, the DES has an ongoing risk of stent-related complications because of permanent implantation of a foreign body and restriction of vascular vasomotion. Bioresorbable vascular scaffolds (BVS) are designed to provide mechanical support and drug delivery similar to the DES, followed by complete resorption over several years. Recent trials have demonstrated clinical non-inferiority of the BVS compared with contemporary DES, although certain clinical outcomes are concerning, particularly with regard to higher rates of scaffold thrombosis. The theoretical long-term benefits are promising, but remain unproven. Early adoption of this new technology in the United States should apply the lessons learned regarding rigorous strategies to decrease adverse events, including careful patient and lesion selection and meticulous implantation techniques.

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