Safety and efficacy of everolimus-eluting bioresorbable vascular scaffolds versus durable polymer everolimus-eluting metallic stents assessed at 1-year follow-up: A systematic review and meta-analysis of studies

Nanotechnology in development of next generation of stent and related medical devices: Current and future aspects

Coronary stents have saved millions of lives in the last three decades by treating atherosclerosis especially, by preventing plaque protrusion and subsequent aneurysms. They attenuate the vascular SMC proliferation and promote reconstruction of the endothelial bed to ensure superior revascularization. With the evolution of modern stent types, nanotechnology has become an integral part of stent technology. Nanocoating and nanosurface fabrication on metallic and polymeric stents have improved their drug loading capacity as well as other mechanical, physico-chemical, and biological properties. Nanofeatures can mimic the natural nanofeatures of vascular tissue and control drug-delivery. This review will highlight the role of nanotechnology in addressing the challenges of coronary stents and the recent advancements in the field of related medical devices. Different generations of stents carrying nanoparticle-based formulations like liposomes, lipid-polymer hybrid NPs, polymeric micelles, and dendrimers are discussed highlighting their roles in local drug delivery and anti-restenotic properties. Drug nanoparticles like Paclitaxel embedded in metal stents are discussed as a feature of first-generation drug-eluting stents. Customized precision stents ensure safe delivery of nanoparticle-mediated genes or concerted transfer of gene, drug, and/or bioactive molecules like antibodies, gene mimics via nanofabricated stents. Nanotechnology can aid such therapies for drug delivery successfully due to its easy scale-up possibilities. However, limitations of this technology such as their potential cytotoxic effects associated with nanoparticle delivery that can trigger hypersensitivity reactions have also been discussed in this review. This article is categorized under: Implantable Materials and Surgical Technologies > Nanotechnology in Tissue Repair and Replacement Therapeutic Approaches and Drug Discovery > Nanomedicine for Cardiovascular Disease Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Stent Thrombosis After Percutaneous Coronary Intervention: From Bare-Metal to the Last Generation of Drug-Eluting Stents

Since their introduction in clinical practice in 1986, different types of coronary stents have been developed and become available for the treatment of coronary artery disease. Stent thrombosis (ST) is an uncommon but harmful complication after percutaneous coronary implantation, with a high occurrence of acute myocardial infarction and risk of mortality. Among several procedural and clinical predictors, the type of coronary stent is a strong determinant of ST. This article reviews the available evidence on the most used coronary stent types in the modern era and the related risk of ST.

Stent Thrombosis After Percutaneous Coronary Intervention: From Bare-Metal to the Last Generation of Drug-Eluting Stents

Since their introduction in clinical practice in 1986, different types of coronary stents have been developed and become available for the treatment of coronary artery disease. Stent thrombosis (ST) is an uncommon but harmful complication after percutaneous coronary implantation, with a high occurrence of acute myocardial infarction and risk of mortality. Among several procedural and clinical predictors, the type of coronary stent is a strong determinant of ST. This article reviews the available evidence on the most used coronary stent types in the modern era and the related risk of ST.

Major coronary evaginations following implantation of bioresorbable vascular scaffolds - Clinical and OCT characteristics

BACKGROUND

Coronary evaginations can occur after implantation of bioresorbable vascular scaffolds (BRS) and may be associated with scaffold thrombosis. Aim of this study was to clarify the clinical manifestation, extent and time course of coronary artery remodeling in vessel segments that develop angiographically detectable evaginations following BRS implantation through optical coherence tomography (OCT) analysis.

METHODS

In 8 patients, 10 BRS (Absorb, Abbott Vascular, Santa Clara, CA, USA) which displayed coronary evaginations in clinically driven late invasive coronary angiograms were identified and findings were compared to 10 BRS in 8 patients without coronary evaginations. Vessel and device geometry was analyzed in serial OCT cross-sections at a spacing of 200 μm. Measured BRS dimensions were normalized to the reference vessel size at implantation.

RESULTS

In OCT, major evaginations on average affected 24 ± 19% of the scaffold length. Scaffolds with major evaginations had a significantly larger lumen area than scaffolds without evaginations (mean normalized lumen area 1.19 ± 0.58 vs. 0.77 ± 0.38; p < 0.001), and also displayed a significantly larger scaffold area (mean normalized scaffold area: 1.36 ± 0.6 vs. 1.13 ± 0.43; p < 0.001), and scaffold diameter (mean normalized scaffold diameter: 1.17 ± 0.33 vs.1.04 ± 0.19; p < 0.001). Lumen area (r = 0.47; p < 0.001), scaffold area (r = 0.52; p < 0.001), and scaffold diameter (r = 0.74; p < 0.001) in the evagination group were positively correlated to the time since scaffold implantation.

CONCLUSION

Coronary evaginations following BRS implantation are associated with an increased scaffold area, indicating that the scaffold follows the outward remodeling of the artery. The process affects the entire scaffold length and seems to be continuously progressing following implantation.

Hemodynamic analysis of a novel bioresorbable scaffold in porcine coronary artery model

BACKGROUND

The shear stress distribution assessment can provide useful insights for the hemodynamic performance of the implanted stent/scaffold. Our aim was to investigate the effect of a novel bioresorbable scaffold, Mirage on local hemodynamics in animal models.

METHOD

The main epicardial coronary arteries of 7 healthy mini-pigs were implanted with 11 Mirage Microfiber sirolimus-eluting Bioresorbable Scaffolds (MMSES). Optical coherence tomography (OCT) was performed post scaffold implantation and the obtained images were fused with angiographic data to reconstruct the coronary artery anatomy. Blood flow simulation was performed and Endothelial Shear Stress(ESS) distribution was estimated for each of the 11 scaffolds. ESS data were extracted in each circumferential 5-degree subunit of each cross-section in the scaffolded segment. The generalized linear mixed-effect analysis was implemented for the comparison of ESS in two scaffold groups; 150-µm strut thickness MMSES and 125-µm strut thickness MMSES.

RESULTS

ESS was significantly higher in MMSES (150 µm) [0.85(0.49-1.40) Pa], compared to MMSES (125 µm) [0.68(0.35-1.18) Pa]. Both MMSES (150 µm) and MMSES (125 µm) revealed low recirculation zone percentages per luminal surface area [3.17% ± 1.97% in MMSES (150 µm), 2.71% ± 1.32% in MMSES (125 µm)].

CONCLUSION

Thinner strut Mirage scaffolds induced lower shear stress due to the small size vessels treated as compared to the thick strut version of the Mirage which was implanted in relatively bigger size vessels. Vessel size should be taken into account in planning BRS implantation. Small vessels may not get benefit from BRS implantation even with a streamlined strut profile. This pilot study warrants comparative assessment with commercially available bioresorbable scaffolds.

Consensus Document ANMCO/ANCE/ARCA/GICR-IACPR/GISE/SICOA: Long-term Antiplatelet Therapy in Patients with Coronary Artery Disease

Dual antiplatelet therapy (DAPT) with aspirin and a P2Y12 receptor inhibitor is the cornerstone of pharmacologic management of patients with acute coronary syndrome (ACS) and/or those receiving coronary stents. Long-term (>1 year) DAPT may further reduce the risk of stent thrombosis after a percutaneous coronary intervention (PCI) and may decrease the occurrence of non-stent-related ischaemic events in patients with ACS. Nevertheless, compared with aspirin alone, extended use of aspirin plus a P2Y12 receptor inhibitor may increase the risk of bleeding events that have been strongly linked to adverse outcomes including recurrent ischaemia, repeat hospitalisation and death. In the past years, multiple randomised trials have been published comparing the duration of DAPT after PCI and in ACS patients, investigating either a shorter or prolonged DAPT regimen. Although the current European Society of Cardiology guidelines provide a backup to individualised treatment, it appears to be difficult to identify the ideal patient profile which could safely reduce or prolong the DAPT duration in daily clinical practice. The aim of this consensus document is to review contemporary literature on optimal DAPT duration, and to guide clinicians in tailoring antiplatelet strategies in patients undergoing PCI or presenting with ACS.

[Stent thrombosis: what's up in 2017?]

Stent thrombosis (ST) is still a dreadful and threatening complication of percutaneous coronary intervention (PCI) with a high risk of morbi-mortality. Nevertheless, it becomes exceptional (0.6% at 1 year and 0.15%/year later) thanks to improvement of stents and use of new P2Y12 inhibitors. Endo-coronary imaging and especially Optical Coherence Tomography (OCT) change radically its understanding with revealing quiet systematic morphologic endoluminal abnormalities (97% of the cases). OCT becomes an essential tool in practice (ESC recommendation class IIa) and allows a therapeutic strategy optimization. Its prevention is based on mechanical causes correction and a personalized adaptation of anti-platelet treatment.

Bioresorbable Vascular Scaffolds - Are We Facing a Time of Crisis or One of Breakthrough?

Current 2nd-generation drug-eluting stents (DES) have dramatically improved clinical outcomes after percutaneous coronary intervention for coronary artery disease. However, DES implantation has major long-term limitations related to the permanent presence of foreign material in the coronary artery. Bioresorbable vascular scaffolds (BVS) were designed to overcome this limitation of permanent metal-based DES. However, because of immature manufacturing technology, BVS have several drawbacks, such as the thicker strut, poor deliverability, poor radio-opacity, poor radial strength, and cumbersome procedure to meet the principle of PSP (Preparation, Sizing, and Post-dilatation). Initial studies indicated that BVS outcomes were non-inferior to those of current DES and recent follow-up data of trials have revealed an additional critical drawback, higher rate of scaffold thrombosis, on the top of the existing limitations of BVS. Thus attention must be paid to the appropriate BVS-specific implantation protocols (i.e., PSP), as well as adequate intensity and duration of dual antiplatelet therapy. In any case, current BVS need further technical evolution to replace current metallic DES in routine clinical use.

Management of ischemic coronary disease in patients receiving chemotherapy: an uncharted clinical challenge

Acute coronary syndrome (ACS) coinciding with active malignancy presents a unique clinical challenge given intersecting pathophysiology and treatment-related effects. There is little established clinical guidance on management strategies, rendering most treatment approaches anecdotal. We present a case highlighting the complexity of managing a patient being treated for malignancy who concurrently suffers from ACS. We then review the literature on co-management of ACS and malignancy, including reports of specific cancer therapies associated with ACS, unique features of clinical presentation and optimal use of dual antiplatelet therapy to minimize risks of bleeding and thrombosis. We also describe gaps in current literature, challenges in systematically studying the clinical intersection of these disease processes and propose alternative methodologies for further research.

Coronary Aneurysm Formation After Bioresorbable Vascular Scaffold Implantation Resulting in Acute Myocardial Infarction

BACKGROUND Development of a true coronary aneurysm after percutaneous coronary intervention is a rare event, and a coronary aneurysm resulting in acute myocardial infarction is even rarer. Coronary aneurysm formation after bioresorbable vascular scaffold (BVS) implantation, eventually leading to thrombosis, embolization, and myocardial infarction, has never been reported before in the literature. CASE REPORT A 62-year-old man received an elective BVS for a proximal left anterior descending lesion. Two months later, he suffered from a non-ST-segment myocardial infarction. Coronary angiography showed a non-significant distal stent edge restenosis over the left anterior descending artery and a small aneurysm after the first diagonal branch. A XIENCE Xpedition stent was used to cover both lesions and final angiography showed shrinkage of the aneurysm and resolution of the restenosis. CONCLUSIONS Since a consensus or an established treatment guideline for treating coronary aneurysms is currently lacking, each case should be treated with caution and should be guided by the accompanying circumstances presented during the procedure. Although size, rapidity of growth, and the presence of high-risk features are the main determinants of whether to treat the lesion, the inherent risk of restenosis or reocclusion after use of drug-eluting stents and the coronary intervention procedure itself should also be taken into consideration. However, one must not take lightly a small coronary aneurysm when discovered, as the abnormal fluid dynamics inside may result in thrombus formation and embolization. The fundamental technical aspects of stent deployment, such as avoiding overstretching during lesion preparation, use of balloons shorter than the implanted device, and normal-to-normal or healthy "landing zone" of the device, should be followed.

The Absorb bioresorbable vascular scaffold for the treatment of coronary artery disease

INTRODUCTION

Every decade the field of interventional cardiology is revolutionized by new technology. The fully bioresorbable everolimus-eluting scaffold (ABSORB BVS) technology would preserve the benefits of metallic stents by sealing balloon-induced dissections, avoiding elastic recoil and vessel occlusion. The polymeric scaffold would be resorbed to restore the natural integrity of the vessel, superseding the consequence of the permanent presence of a foreign body in the coronary artery.

AREAS COVERED

This technology evaluation focuses on the clinical evidence for the use of bioresorbable everolimus-eluting scaffold for the treatment of coronary artery disease.

EXPERT OPINION

The current generation of the bioresorbable scaffold has structural and mechanical limitations that might preclude the widespread use in clinical practice. The strut thickness (150 µm) limits deliverability and creates laminar flow disruptions that might be the nidus of an increased rate of scaffold thrombosis. In the next generation of bioresorbable scaffolds, the resorption process should be faster and in particular, strut thickness must be reduced. This will probably represent a significant step forward in an attempt to increase the efficacy and safety profile of the device and achieve a similar performance with the current generation drug-eluting stent even in complex scenarios.