The ABSORB bioresorbable vascular scaffold: A novel, fully resorbable drug-eluting stent: Current concepts and overview of clinical evidence

Polysaccharide-Based Membrane Biocompatibility Study of Anacardium occidentale L. and Polyvinyl Alcohol after Subcutaneous Implant in Rats

Polymeric membranes are a viable and sustainable option for the biotechnology industry from an economic and environmental point of view. In this study, we evaluated tissue response and tolerance to the implantation of a polymeric membrane prepared with cashew gum polysaccharide (CGP) associated with polyvinyl alcohol (PVA). The objective was to characterize the biocompatibility of the CGP/PVA membrane in vivo. Following the evaluation criteria of the ISO 10993-6 standard, we demonstrated that the CGP/PVA membrane showed moderate tissue reaction, with a non-irritating ISO pattern, a thinner fibrous capsule, and a smaller amount of collagen compared to the positive control group. At 30 and 60 days, the membrane presented a similar amount of mast cells to that observed in the negative control group. The data demonstrate that the CGP/PVA membrane presents biocompatibility in accordance with the ISO 10993-6 standard.

Cardiovascular Stents: A Review of Past, Current, and Emerging Devices

One of the leading causes of morbidity and mortality worldwide is coronary artery disease, a condition characterized by the narrowing of the artery due to plaque deposits. The standard of care for treating this disease is the introduction of a stent at the lesion site. This life-saving tubular device ensures vessel support, keeping the blood-flow path open so that the cardiac muscle receives its vital nutrients and oxygen supply. Several generations of stents have been iteratively developed towards improving patient outcomes and diminishing adverse side effects following the implanting procedure. Moving from bare-metal stents to drug-eluting stents, and recently reaching bioresorbable stents, this research field is under continuous development. To keep up with how stent technology has advanced in the past few decades, this paper reviews the evolution of these devices, focusing on how they can be further optimized towards creating an ideal vascular scaffold.

Innovative interventional catheterization techniques for congenital heart disease

Since 1929, when the first cardiac catheterization was safely performed in a human by Dr. Werner Forssmann (on himself), there has been a rapid progression of cardiac catheterization techniques and technologies. Today, these advances allow us to treat a wide variety of patients with congenital heart disease using minimally invasive techniques; from fetus to infants to adults, and from simple to complex congenital cardiac lesions. In this article, we will explore some of the exciting advances in cardiac catheterization for the treatment of congenital heart disease, including transcatheter valve implantation, hybrid procedures, biodegradable technologies, and magnetic resonance imaging (MRI)-guided catheterization. Additionally, we will discuss innovations in imaging in the catheterization laboratory, including 3D rotational angiography (3DRA), fusion imaging, and 3D printing, which help to make innovative interventional approaches possible.

Optical Coherence Tomography and Stent Boost Imaging Guided Bioresorbable Vascular Scaffold Overlapping for Coronary Chronic Total Occlusion Lesion

We report herein the optical coherence tomography (OCT) and stent boost imaging guided bioresorbable vascular scaffold (BVS) implantation for right coronary artery (RCA) chronic total occlusion (CTO) lesion. The gold standard for evaluating BVS expansion after percutaneous coronary intervention is OCT. However, stent boost imaging is a new technique that improves fluoroscopy-based assessments of stent overlapping, and the present case shows clinical usefulness of OCT and stent boost imaging guided 'overlapping' BVS implantation via antegrade approach for a typical RCA CTO lesion.

Mechanical behavior of polymer-based vs. metallic-based bioresorbable stents

Bioresorbable scaffolds (BRS) were developed to overcome the drawbacks of current metallic drug-eluting stents (DES), such as late in-stent restenosis and caging of the vessel permanently. The concept of the BRS is to provide transient support to the vessel during healing before being degraded and resorbed by the body, freeing the vessel and restoring vasomotion. The mechanical properties of the BRS are influenced by the choice of the material and processing methods. Due to insufficient radial strength of the bioresorbable material, BRS often required large strut profile as compared to conventional metallic DES. Having thick struts will in turn affect the deliverability of the device and may cause flow disturbance, thereby increasing the incidence of acute thrombotic events. Currently, the bioresorbable poly-l-lactic acid (PLLA) polymer and magnesium (Mg) alloys are being investigated as materials in BRS technologies. The bioresorption process, mechanical properties, in vitro observations and clinical outcomes of PLLA-based and Mg-based BRS will be examined in this review.

Neointimal Healing Evaluated by Optical Coherence Tomography after Drug-Eluting Absorbable Metal Scaffold Implantation in de novo Native Coronary Lesions: Rationale and Design of the Magmaris-OCT Study

Objectives: We sought to explore neointimal healing assessed by optical coherence tomography (OCT) following implantation of the Magmaris sirolimus-eluting absorbable metal scaffold. Methods: The Magmaris-OCT is a prospective, multicenter, single-arm observational clinical study, intended to enrol 60 consecutive patients with up to 2 de novo native coronary lesions, each located in different major epicardial vessels, with a reference vessel diameter of 2.5-3.5 mm, and a maximum lesion length of 20 mm. Patients will undergo Magmaris scaffold implantation in the target lesion, according to the standard practice. Clinical follow-up will take place at 30 days, and at 3, 6, 9, and 12 months. For invasive-imaging follow-up, patients will be classified into 3 groups: cohort A will be scheduled for follow-up at 3 months, cohort B at 6 months, and cohort C at 12 months. Invasive imaging will include quantitative coronary angiography, OCT evaluation, and coronary flow reserve measurement. The primary end point will be the percentage of uncovered scaffold struts assessed by OCT at the prespecified follow-up. Conclusions: This study will provide insight into the short- and mid-term healing properties following Magmaris scaffold implantation, with special emphasis on the neointimal coverage of scaffold struts.

Bioresorbable Polymers and Stent Devices

OPINION STATEMENT

Percutaneous coronary interventions will never become obsolete, as evolution is inherent to interventional cardiology. Current drug-eluting platforms have appreciably improved their safety and efficacy profiles in different clinical settings compared to first-generation devices such that it is difficult to consider other alternatives. However, there is definite biological plausibility to consider devices with bioabsorbable polymers and/or scaffolds. It is also an undeniable fact that many patients, based on variety of belief systems, would prefer not to have a permanently implanted device. BP DES with or without bioresorbable scaffolds offer advantages over durable polymer DES in restoring normal coronary physiology and vascular adaptive responses, resulting in late lumen gain and plaque regression. They will likely allow flexibility in treating complex CAD. However, so far, we have been able to prove non-inferiority in a selected population of patients without long-term data. Is "as good as" good enough? Are we ready to reach for the BRS or a BP DES in our catheterization laboratory based on preclinical and mechanistic data (endothelialization, OCT imaging, vasomotion) with limited human experience? I am not. While I will maximize my efforts to recruit patients in related randomized controlled trials, the technology is not ready for prime time. Randomized controlled trials are needed to determine whether any or all of these devices improve long-term outcome compared to best in class DP DES. Most definitive evidence is likely about a decade away. Until then, we can learn to be disciplined implanters not only in selecting the appropriate patient but also in perfecting implantation techniques.

Patient profile and periprocedural outcomes of bioresorbable vascular scaffold implantation in comparison with drug-eluting and bare-metal stent implantation. Experience from ORPKI Polish National Registry 2014-2015

INTRODUCTION

There are limited data on the comparison of bioresorbable vascular scaffold (BVS) and drug-eluting stent (DES)/bare-metal stent (BMS) implantation in an unselected population of patients with coronary artery disease.

AIM

To compare the periprocedural outcomes and patient profile of BVS and DES/BMS implantation in an all-comer population from the ORPKI Polish National Registry.

MATERIAL AND METHODS

A total of 141,324 consecutive patients from 151 invasive cardiology centers in Poland were included in this prospective registry between January 2014 and June 2015. Periprocedural data on patients with at least one BVS (Absorb, Abbott Vascular, Santa Clara, CA, USA), DES or BMS (all available types) implantation in de novo lesions during index percutaneous coronary intervention for stable angina (SA) or acute coronary syndrome were collected.

RESULTS

Bioresorbable vascular scaffold was the most often used in patients with SA, in single-vessel disease and in younger male patients. Bioresorbable vascular scaffold implantation was significantly more often associated with periprocedural administration of ticagrelor/prasugrel (6.8% vs. 3.6%; p = 0.001) and use of intravascular ultrasound and optical coherence tomography in comparison with the DES/BMS group (2.8% vs. 0.6% and 1.8% vs. 0.1%, respectively; p = 0.001 for both). The incidence of periprocedural death was significantly lower in the BVS group than the DES/BMS group (0.04% vs. 0.32%; p = 0.02), but this difference was no longer significant after adjustment for covariates. On the other hand, coronary artery perforation occurred significantly more often during BVS delivery (0.31% vs. 0.12%; p = 0.01), and BVS implantation was identified as an independent predictor of coronary artery perforation in multivariate logistic regression analysis (OR = 6.728, 95% CI: 2.394-18.906; p = 0.001).

CONCLUSIONS

Patients treated with BVS implantation presented an acceptable safety and efficacy profile in comparison with the DES/BMS group. However, lower risk patients were the most frequent candidates for BVS implantation.

The pathology of the foreign body reaction against biomaterials

The healing process after implantation of biomaterials involves the interaction of many contributing factors. Besides their in vivo functionality, biomaterials also require characteristics that allow their integration into the designated tissue without eliciting an overshooting foreign body reaction (FBR). The targeted design of biomaterials with these features, thus, needs understanding of the molecular mechanisms of the FBR. Much effort has been put into research on the interaction of engineered materials and the host tissue. This elucidated many aspects of the five FBR phases, that is protein adsorption, acute inflammation, chronic inflammation, foreign body giant cell formation, and fibrous capsule formation. However, in practice, it is still difficult to predict the response against a newly designed biomaterial purely based on the knowledge of its physical-chemical surface features. This insufficient knowledge leads to a high number of factors potentially influencing the FBR, which have to be analyzed in complex animal experiments including appropriate data-based sample sizes. This review is focused on the current knowledge on the general mechanisms of the FBR against biomaterials and the influence of biomaterial surface topography and chemical and physical features on the quality and quantity of the reaction. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 927-940, 2017.

A review of bioresorbable scaffolds: hype or hope?

In the field of percutaneous coronary intervention, the evolution of coronary metal stents has been well established for the past three decades, but research on bioresorbable scaffolds has only gained momentum in the recent past. Although second-generation drug-eluting metal stents are the gold standard for the treatment of obstructive coronary artery disease, a few drawbacks exist. The development of bioresorbable scaffolds is an attempt to overcome the limitations of metal stents. This review highlights the rationale for the bioresorbable scaffold, its properties and potential applications. It also focuses on the current evidence and concerns regarding the application of the bioresorbable scaffold in day-to-day practice.

Bioresorbable vascular scaffold thrombosis in a consecutive cohort of 550 patients

OBJECTIVE

To determine the rate of bioresorbable vascular scaffold (BVS) thrombosis in a large, real-world population.

BACKGROUND

There is some concern about device thrombosis after percutaneous coronary intervention (PCI) using BVS. No data have been published for PCI using both BVS and metal stents.

METHODS

A cohort of 550 consecutive patients who underwent PCI for stable chest pain or acute coronary syndromes with implantation of at least one BVS (Absorb, Abbott Vascular) was systematically followed up by telephone interview and review of medical charts. Data on device thrombosis were retrospectively analyzed in relationship to clinical and angiographic characteristics.

RESULTS

Follow-up was achieved in 533 patients (97%, median follow-up 233 days). A total of 964 BVS were implanted in 645 vessels. In addition, 234 metal stents were implanted in 149 patients, including "hybrid intervention" with the combined use of BVS and stents in the same artery in 122 patients. Documented were 15 definite, 1 probable, and 8 possible cases of device thrombosis (rate of definite/probable device thrombosis: 3.0%). Of these, 6 definite and 6 possible thromboses could be unambiguously attributed to BVS (1.1%), whereas a total of 11 definite, 1 probable, and 8 possible thromboses were potentially attributable to BVS (2.3%). Definite device thrombosis occurred in 7/122 patients with "hybrid intervention" (5.7%).

CONCLUSIONS

In a large real-world cohort treated with BVS, the rate of scaffold thrombosis was higher than published for randomized trials. A high rate of thrombosis was observed after combined implantation of BVS and stents within one vessel. © 2016 Wiley Periodicals, Inc.

Bioresorbable vascular scaffolds for the treatment of coronary artery disease: what have we learned from randomized-controlled clinical trials?

Although current everolimus-eluting coronary stents have shown improved event-free survival within the first year following implantation compared with bare-metal stents or earlier generation drug-eluting stents, they remain associated with an ongoing risk for adverse outcomes (thrombosis, myocardial infarction, and restenosis) beyond 1 year at rates similar to those observed following bare-metal stent deployment. This ongoing very late hazard has been attributed to the permanent presence of the metal frame and/or polymer in these stents. The Absorb everolimus-eluting bioresorbable vascular scaffold (Absorb BVS) has been developed to provide mechanical support and drug-delivery functions similar to metallic drug-eluting stents, followed by complete resorption with recovery of more normal vascular structure and function, thus avoiding the limitations associated with permanent metallic endovascular prostheses. Absorb BVS has shown safety and efficacy in the dedicated clinical trial development program of Abbott Vascular and in an array of investigator-sponsored studies involving a broad spectrum of clinical (patient) as well as coronary anatomic complexity. Longer-term evidence, largely limited to single-arm studies, appears to reflect durable safety and efficacy and suggests Absorb BVS to be an attractive therapeutic option. Interim evidence from a series of randomized-clinical trials (RCTs) comparing Absorb BVS with the Xience cobalt-chromium metallic everolimus-eluting stent has shown noninferiority of Absorb BVS with respect to target lesion failure (composite occurrence of cardiac death, target vessel-related myocardial infarction, and ischemia-driven target lesion revascularization) beyond the first year, with no statistically significant differences in other safety/efficacy measures. However, concerns do exist in terms of increased rates of scaffold thrombosis, the risk for which may be mitigated by improved patient and lesion selection, procedural technique, and device iteration. We provide an overview of the evolution of percutaneous coronary intervention, in-vivo characterization of Absorb BVS resorption, and a summary with a critical evaluation of available evidence from RCTs, pooled analyses, and meta-analyses of RCTs for the safety and efficacy of Absorb BVS obtained primarily following the treatment of noncomplex coronary lesions in patients with stable ischemic heart disease and/or stabilized acute coronary syndromes.