Clinical utility of platinum chromium bare-metal stents in coronary heart disease

Standardized Bench Test Evaluation of Biomechanical Characteristics of Stents Used in Right Ventricular Outflow Tract Revalvulation

PURPOSE

Pre-stenting of the right ventricular outflow tract (RVOT) is commonly performed before percutaneous pulmonary valve implantation (PPVI), to relieve obstruction, prevent valved stent fractures, and provide a landing zone. This study aimed to evaluate the biomechanical characteristics of the stents currently used to perform pre-stenting of the RVOT.

METHODS

We assessed five commercially available stents: Cheatham-Platinum Stent ("CP Stent"), AndraStent XL, AndraStent XXL, Optimus XL, and Optimus XXL. Following stent deployment at nominal pressure, radial and longitudinal elastic recoils and radial resistance were measured. The bending stiffness of the stents crimped onto the balloons was also evaluated.

RESULTS

Three samples were tested for each stent. Our study showed no significant difference between the stent platforms in terms of radial elastic recoil, which was relatively low (< 10%). The longitudinal elastic recoil was also low for all the devices (< 5%). Significant differences were observed in radial resistance (P < 0.001). CP Stent and AndraStent XL exhibited the highest radial resistances. The bending stiffnesses of the stents crimped on their balloons were significantly different (P < 0.00001). Optimus XL and XXL were more flexible than the other stents.

CONCLUSION

This study highlights the significant differences between the stents currently used in RVOT pre-stenting. Stents with good radial resistance are preferred, especially for calcified vessels, and flexibility is crucial for tortuous vessels. We proposed an algorithm for selecting the most suitable stent according to the need for radial force and flexibility, which will help inform clinicians considering RVOT revalvulation.

Investigation of optical and biocompatible properties of polyethylene glycol-aspirin loaded commercial pure titanium for cardiovascular device applications

This research investigates the optical and biocompatible properties of alkali-treated cpTi immersed in aspirin and different molecular weights of polyethylene (PEG). Instrumental characterizations were performed using scanning electron microscopy (SEM), Raman spectroscopy, and ultraviolet–visible spectroscopy. Additionally, drug release, antithrombotic, and cell adhesion studies were conducted in in-vitro conditions. The SEM micrographs showed that heat treatment of NaOH modified cpTi substrates increased the average surface pore size by 217%. Raman spectra’s active modes confirmed the presence of titanate groups which intensified the semiconductive nature of alkali-treated cpTi substrates. Further, the semiconductive nature was confirmed through the shift of the energy bandgap from 2.69 to 2.9 eV. The continuous redshift of the absorbance edge with an increase in the molecular weight of PEG indicates improved optical property. Following the Rigter–Peppas dynamic model, the drug release kinetics showed a non-Fickian dispersion (n < 1) and super case II transport (n = 2.21) for PEG-coated cpTi substrates. The alkali-treated cpTi-aspirin-PEG surface exhibits suitable antithrombotic property and interstitial cell adhesion with PEG coating. The modified surface on cpTi demonstrated a promising technique to improve the optical, antithrombotic, and biocompatibility performances, which are the prime requirement for the blood-interacted cardiovascular devices such as stents.

The Early Outcomes of BeGraft Peripheral Plus in Branched Endovascular Repair of Thoracoabdominal Aneurysms

OBJECTIVE

No bridging stent-graft (BSG) has been specifically designed for branched endovascular aortic repair (BEVAR) and therefore different "off-label" stent-grafts have been used. Recently, a third generation of balloon-expandable stent-graft has become available. Here we evaluate the outcomes of the BeGraft Peripheral Plus (B+) used as a BSG for internal/externalor inner branches during BEVAR.

MATERIALS AND METHODS

Consecutive patients undergoing BEVAR using B+ as a BSG since its release in 2017 were included into the study. The primary endpoints were technical success and target vessel patency during follow-up. Secondary endpoints included the need for adjunct extension and relining of the BSG, branch instability rate, including occlusion, reinterventions for restonosis, kink, fracture, or endoleak (types 1 and 3).

RESULTS

A total of 163 visceral branches in 46 patients were included with a median follow-up 15 months (4-36 months). Primary technical success was achieved in all visceral branches (69 inner branches and 94 internal/external branches) with the exception of 1 BSG that required serial dilatation until full expansion was achieved with overall branch patency was 98% at 2 years. An additional stent-graft was necessary in 35 branches (21%) following deployment of a B+ BSG to cover a longer bridging distance and optimize the distal and proximal sealing. Relining of B+ BSG was not routinely carried out during the index procedure and a self-expanding uncovered nitinol stent was necessary in only 3% of branches to smooth the distal transition zone between the BSG and target vessel. There were 4 events (2.4%) of branch related instability, including 2 occlusions and 2 late reinterventions for a partial in-stent-graft thrombosis.

CONCLUSION

Our study findings show satisfactory early outcomes of B+ as a BSG in BEVAR with low occlusion and reintervention rates. Extensions of BSG might be required to achieve adequate seal in the target vessels but routine relining BSG in branches was not required.

A Review of the Ultrathin Orsiro Biodegradable Polymer Drug-eluting Stent in the Treatment of Coronary Artery Disease

Drug-eluting stents (DES) have revolutionised the treatment of coronary artery disease (CAD) in patients undergoing percutaneous coronary intervention. In recent years, there has been a focus on a new generation of DES, such as biodegradable polymer DES (BP-DES). This novel stent platform was developed with the hope of eliminating the risk of very late stent thrombosis associated with the current gold-standard durable polymer DES (DP-DES). Ultrathin Orsiro BP-DES (Biotronik, Bülach, Switzerland) are based on a cobalt-chromium stent platform that is coated with a bioresorbable polymer coating containing sirolimus. These devices have one of the thinnest struts available in the current market and have the theoretical benefit of reducing a chronic inflammatory response in the vessel wall. In 2019, the United States Food and Drug Administration (FDA) approved the use of Orsiro BP-DES in patients with CAD based on promising results in recent landmark trials, such as BIOFLOW V and BIOSTEMI. The aim of the present review article was to discuss the history of stent technology and the continued opportunities for improvements, focusing on the potential benefits of Orsiro BP-DES.

Image quality and radiation dose of ECG-triggered High-Pitch Dual-Source cardiac computed tomography angiography in children for the evaluation of central vascular stents

Assess image quality and radiation dose of ECG-triggered High-Pitch Dual-Source CTA for the evaluation central vascular stents in children. We included all children ≤ 21 years old with one or more central vascular stents and available prospective ECG-triggered High-Pitch Dual-Source CTA performed at our institution between January 2015 and August 2017. Demographic and scanner information was retrieved. Two board-certified pediatric radiologists blinded to the clinical data, independently reviewed and scored each case using a four-point quality score. Scores 1, 2 and 3 were considered of diagnostic image quality. Inter-observer agreement and non-parametric test were used. 18 patients (10 girls, 8 boys) with a mean age of 9.47 ± 7.38 years (mean ± SD) met inclusion criteria. Thirty-two central vascular stents were evaluated. Mean quality score was 2.07 ± 0.94 with 12.5% (4/32) of the cases classified as unevaluable. Interobserver agreement was excellent (k = 0.86). There is no significant difference between quality score and stent location (p = 0.07). There is a significant difference with stent material as all non-diagnostic scores were only seen in covered stents made of platinum-iridium (p < 0.001). There was no association between image quality and age, height, weight, BSA, heart rate, radiation dose or stent lumen size (p > 0.05). ECG-triggered high-pitch spiral DS-CTA offers appropriate image quality for assessment of central vascular stents in children.

Analysis of 12 Months Clinical Outcomes Associated with Implantation of Ultrathin (60 μm) Bare Metal Stent in an Unselected Real-world Population with Coronary Artery Disease

INTRODUCTION

In the era of drug-eluting stents, Bare Metal Stent (BMS) has worked its way up to be recognized in several indications. Moreover, literature suggests that strut thickness has been directly related to the restenosis rate.

AIM

We intended to evaluate the clinical performance of the ultrathin (60 μm) Flexinnium stent (Sahajanand Medical Technologies Pvt. Ltd. Surat, India) for treatment of a wide range of patients with coronary artery disease in routine clinical practice.

MATERIALS AND METHODS

This was an observational, non-randomized, retrospective, single-arm study carried out in real-world patients at three clinical centres of India. A total of 419 consecutive patients' data was collected for the study, who underwent treatment for coronary lesions by implantation of Flexinnium stent, between April 2013 and December 2014. The primary endpoint of the study was Major Adverse Cardiac Events (MACE), a conglomerate of cardiac death, Myocardial Infarction (MI) (Q-wave and non-Q-wave), Target Lesion Revascularization (TLR) and Target Vessel Revascularization (TVR). Any incidence of Stent Thrombosis (ST) was also observed as safety endpoint. These endpoints were observed during in-hospital stay, at 30 days, six months and at 12 months follow up. All data were analysed using the Statistical Package for Social Sciences (SPSS; Chicago, IL, USA) program, version 15.

RESULTS

A total of 491 lesions were treated in 419 patients having mean age of 54.1 years. A total of 525 Flexinnium stents were implanted. There were 243 (58.0%) patients with hypertension. At 12 months the total incidences of MACE were 14 (3.5%). These included 9 (2.3%) cardiac deaths, 1 (0.3%) MI, 3 (0.8%) TLRs and 1 (0.3%) TVR. There was one incidence of definite ST at 12 months follow up.

CONCLUSION

Our results demonstrate that the Flexinnium stent is associated with a low 12 months incidence of MACE in a wide range of real-world population. Long-term follow up would further confirm its clinical performance profile.

Revolution of Drug-Eluting Coronary Stents: An Analysis of Market Leaders

Percutaneous coronary intervention with drug-eluting stents (DES) is a well-established and widely-accepted treatment approach in patients with coronary artery disease. Although the underlying principle of DES remains constant for different stents available on the market, certain factors may offer variations with respect to deliverability (ease of placement), efficacy (preventing restenosis), and safety (thrombosis rates). These factors may include the type of drug (sirolimus, everolimus, biolimus, zotarolimus, novolimus, paclitaxel, docetaxel), type of stent platforms (stainless steel, platinum, cobalt-chromium, cobalt-nickel, platinum-chromium), type of polymers (permanent, biodegradable, polymer-free), thickness of stent struts (thick, thin, ultra-thin), type of coating (abluminal, conformal), and type of stent design (open-cell, closed-cell, combination of open-closed cell). In this context, we present a review on characteristic features of several of the most widely used coronary stents worldwide. Furthermore, the advancements of completely biodegradable stents are discussed. In addition, the future directions for the development of creating an ideal or perfect DES are debated.

Tubular organ epithelialisation

Hollow, tubular organs including oesophagus, trachea, stomach, intestine, bladder and urethra may require repair or replacement due to disease. Current treatment is considered an unmet clinical need, and tissue engineering strategies aim to overcome these by fabricating synthetic constructs as tissue replacements. Smart, functionalised synthetic materials can act as a scaffold base of an organ and multiple cell types, including stem cells can be used to repopulate these scaffolds to replace or repair the damaged or diseased organs. Epithelial cells have not yet completely shown to have efficacious cell-scaffold interactions or good functionality in artificial organs, thus limiting the success of tissue-engineered grafts. Epithelial cells play an essential part of respective organs to maintain their function. Without successful epithelialisation, hollow organs are liable to stenosis, collapse, extensive fibrosis and infection that limit patency. It is clear that the source of cells and physicochemical properties of scaffolds determine the successful epithelialisation. This article presents a review of tissue engineering studies on oesophagus, trachea, stomach, small intestine, bladder and urethral constructs conducted to actualise epithelialised grafts.