Design principles and performance of bioresorbable polymeric coronary scaffolds

Oberhauser, James P.; Hossainy, Syed; Rapoza, Richard

doi:10.4244/eijv5ifa3

Cited by 153 publications

(109 citation statements)

References 30 publications

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“…Detailed characteristics of BVS implanted in this study have been previously described [18][19][20]. Briefly, the scaffold is made of a polymer backbone of poly-L-lactide (PLLA) covered with a thin layer of a 1:1 mixture of poly-D,L-lactide polymer (PDLLA).…”

Section: Methodsmentioning

confidence: 99%

Bioresorbable everolimus-eluting vascular scaffold in patients with ST-segment elevation myocardial infarction: Optical coherence tomography evaluation and clinical outcomes

et al. 2015

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Section: Methodsmentioning

confidence: 99%

Bioresorbable everolimus-eluting vascular scaffold in patients with ST-segment elevation myocardial infarction: Optical coherence tomography evaluation and clinical outcomes

et al. 2015

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“…The processes for production and implantation for both stents and scaffolds appear superficially similar: tube formation, lasercutting of the strut lattice, crimping, and deployment (8). However, the strain fields and their effect on material structure and properties are dramatically different.…”

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confidence: 99%

“…Further, they present a lifelong risk of late stent thrombosis (3-6). A new technology is poised to displace metal stents: bioresorbable vascular scaffolds (BVS), which have been deemed the "fourth revolution" in percutaneous coronary intervention (7,8).The goal of tissue scaffolds is to restore the healthy state of the tissue, rather than merely ameliorating the diseased state (9-11). Poly(L-lactide) (PLLA) was selected as the material for BVS because its semicrystalline structure gives it adequate radial strength [>300 mm Hg (12)], and it degrades into products that are metabolized by the human body (13-16).…”

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confidence: 99%

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

Ailianou

Ramachandran

Kossuth³

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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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. structural transformation | ductility | poly (L-lactide) | coronary heart disease | microdiffraction C ardiovascular disease (CVD) claims over 15 million lives per year-more lives than communicable, maternal, neonatal, and nutritional disorders combined and more than twice the number of deaths due to all cancers (1). Coronary heart disease (CHD), the narrowing of coronary arteries due to the deposition of plaque, accounts for nearly 50% of all CVD deaths (1). To restore blood flow, most patients receive minimally invasive balloon angioplasty followed by stent implantation (1 million in 2008 in the United States) (2). Stents are metal mesh tubes that are delivered to the target lesion while they are crimped onto a balloon. Once they are positioned at the lesion, inflation of the balloon compresses the plaque against the vessel wall and deploys the stent to provide support at the enlarged diameter after the balloon is deflated and withdrawn. Metal stents are permanent, and their stiffness prohibits vasomotion and dilation (3, 4). Further, they present a lifelong risk of late stent thrombosis (3-6). A new technology is poised to displace metal stents: bioresorbable vascular scaffolds (BVS), which have been deemed the "fourth revolution" in percutaneous coronary intervention (7,8).The goal of tissue scaffolds is to restore the healthy state of the tissue, rather than merely ameliorating the diseased state (9-11). Poly(L-lactide) (PLLA) was selected as the material for BVS because its semicrystalline structure gives it adequate radial strength [>300 mm Hg (12)], and it degrades into products that are metabolized by the human body (13-16). Clinically, bioresorption of PLLA vascular sca...

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“…First, this novel technology provides transient vessel support with drug delivery capability without the long-term limitations of metallic stents, such as permanent vessel caging, that may lead to late acquired malapposition, thus potentially reducing the rate of late adverse events. Second, once the absorption process is complete, BRS allow the recovery of a normal vascular function, with physiological vasomotion and a theoretical increase of the vessel area (late lumen enlargement) (1). Moreover, BRS implantation allows surgical anastomosis in the treated coronary segment, whereas traditional metallic stents preclude it (2).…”

Section: Introductionmentioning

confidence: 99%

Methods to assess bioresorbable vascular scaffold devices behaviour after implantation

et al. 2017

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Bioresorbable vascular scaffolds (BRS) represent a novel approach for coronary revascularization offering several advantages as compared to current generation DES, potentially reducing rate of late adverse events and avoiding permanent vessel caging. Nevertheless, safety concerns have been raised for an increased risk of scaffold thrombosis (ScT) in both early and late phases, probably related to a suboptimal scaffold implantation. In this context, the use of different imaging methodologies has been strongly suggested in order to guarantee an optimal implantation. We herein analyze the different imaging methodologies available to assess BRS after implantation and at follow-up. J Thorac Dis 2017;9(Suppl 9):S959-S968 jtd.amegroups.com for BRS implantation in order to confirm optimal scaffold expansion, to exclude edge dissections, struts malapposition or underexpansion. Furthermore, imaging technique may evaluate at follow-up scaffold reabsorption and vessel changes over time. Keywords: Scaffold; intravascular ultrasound (IVUS); echogenicity; virtual histology-IVUS (VH-IVUS); optical coherence tomography (OCT); multislice coronary tomography (MSCT)SubmittedWe herein analyze the different imaging methodologies available to assess BRS after implantation and at follow-up. Quantitative coronary angiography (QCA)Coronary angiography is the most important method for assessing BRS implantation. As well as for conventional stent, at least two different projections with at least 30° difference for the right coronary artery and 3 different projections with at least 30° difference for the left coronary artery must be acquired before and after BRS implantation. The treated segment and the 5 mm proximal and distal to scaffold edges should be analyzed. As the bioresorbable devices are radiolucent, the QCA analysis may be performed visualizing the metallic markers of the scaffold.The following parameters can be measured. Acute recoilIt is defined as the difference between the mean diameter of the BRS delivery balloon (or, in case of post-dilatation, mean diameter of post-dilatation balloon) at the highest pressure and the mean lumen diameter (MLD) of the stented segment after balloon deflation. It can be expressed as absolute or relative value. The acute recoil is an important parameter in relation to the success of a PCI in acute and long-time period, as it has a direct impact on minimum stent area (MSA). A MSA less than 5.0 mm 2 is associated with high probability of in-stent restenosis (6).T h e a c u t e r e c o i l o f A b s o r b B V S 1 . 1 ( A b b o t t Laboratories, Abbott park, Illinois, USA) in the Absorb Cohort B trials and DESolve Nx BRS (Elixir Medical, Sunnyvale, California, USA) were 6.7%±6.4% and 6.4%±4.6%, respectively (7,8). These values are not dissimilar to those of metallic stent, showed in a Japanese study of 154 lesions comparing the biolimus eluting stent (Nobori stent, Terumo, Tokyo, Japan), cobalt chromium everolimus eluting stent (Xience V stent, Abbott Vascular, Santa Clara, CA, USA) and pl...

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Design principles and performance of bioresorbable polymeric coronary scaffolds

Abstract: Limited clinical data speak to the potential of bioresorbable scaffolds as a new therapy, and future studies will prove critical to inspiring a fourth revolution in PCI.

Cited by 153 publications

References 30 publications

Bioresorbable everolimus-eluting vascular scaffold in patients with ST-segment elevation myocardial infarction: Optical coherence tomography evaluation and clinical outcomes

Bioresorbable everolimus-eluting vascular scaffold in patients with ST-segment elevation myocardial infarction: Optical coherence tomography evaluation and clinical outcomes

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

Methods to assess bioresorbable vascular scaffold devices behaviour after implantation

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