Clinical Outcomes of Polytetrafluoroethylene-Covered Stents for Coronary Artery Perforation in Elderly Patients Undergoing Percutaneous Coronary Interventions

Electrospun bioresorbable polymer membranes for coronary artery stents

Percutaneous coronary intervention, a common treatment for atherosclerotic coronary artery lesions, occasionally results in perforations associated with increased mortality rates. Stents coated with a bioresorbable polymer membrane may offer an effective solution for sealing coronary artery perforations. Additionally, such coatings could be effective in mitigating neointimal hyperplasia within the vascular lumen and correcting symptomatic aneurysms. This study examines polymer membranes fabricated by electrospinning of polycaprolactone, polydioxanone, polylactide-co-caprolactone, and polylactide-co-glycolide. In uniaxial tensile tests, all the materials appear to surpass theoretically derived elongation thresholds necessary for stent deployment, albeit polydioxanone membranes are found to disintegrate during the experimental balloon expansion. As revealed by in vitro hemocompatibility testing, polylactide-co-caprolactone membranes exhibit higher thrombogenicity compared to other evaluated polymers, while polylactide-co-glycolide samples fail within the first day post-implantation into the abdominal aorta in rats. The PCL membrane exhibited significant water leakage in the permeability test. Comprehensive evaluation of mechanical testing, bio- and hemocompatibility, as well as biodegradation dynamics shows the advantage of membranes based on and the mixture of polylactide-co-caprolactone and polydioxanone over other polymer groups. These findings lay a foundational framework for conducting preclinical studies on stent configurations in large laboratory animals, emphasizing that further investigations under conditions closely mimicking clinical use are imperative for making definitive conclusions.

Applying Principles of Regenerative Medicine to Vascular Stent Development

Stents are a widely-used device to treat a variety of cardiovascular diseases. The purpose of this review is to explore the application of regenerative medicine principles into current and future stent designs. This review will cover regeneration-relevant approaches emerging in the current research landscape of stent technology. Regenerative stent technologies include surface engineering of stents with cell secretomes, cell-capture coatings, mimics of endothelial products, surface topography, endothelial growth factors or cell-adhesive peptides, as well as design of bioresorable materials for temporary stent support. These technologies are comparatively analyzed in terms of their regenerative effects, therapeutic effects and challenges faced; their benefits and risks are weighed up for suggestions about future stent developments. This review highlights two unique regenerative features of stent technologies: selective regeneration, which is to selectively grow endothelial cells on a stent but inhibit the proliferation and migration of smooth muscle cells, and stent-assisted regeneration of ischemic tissue injury.

Efficacy and Biosafety of a New Bioresorbable Vascular Scaffold Covered with Biodegradable Film in Rabbits: An In Vivo Study

BACKGROUND

We developed a new fully bioresorbable vascular scaffold covered with biodegradable poly-L-lactic acid film (Firesorb-C) for coronary artery perforation. Our vitro tests have demonstrated that Firesorb-C was technically feasible but its biosafety and efficacy warranted further validation in vivo.

OBJECTIVE

The aim of this study was to evaluate the biosafety and efficacy of Firesorb-C in rabbits.

METHODS

Firesorb-C was deployed at the zone from the abdominal aorta to the right iliac artery in five rabbits. Angiography was conducted for evaluation of the immediate efficacy and 6-month biosafety and biodegradability of the Firesorb-C. Meanwhile, optical coherence tomography (OCT), histological light microscopy (HLM) and scan electron microscopy (SEM) were performed to evaluate the biosafety.

RESULTS

All Firesorb-C applications were successfully implanted without procedure-related complications. In all treated rabbits, angiography showed that the Firesorb-C had completely sealed the opening of the left iliac artery without blood flow in its branches but with full patency of the right iliac artery immediately post-procedurally, while the covered membrane of Firesorb-C had been degraded and blood flow was restored in the left iliac artery and its branches at 6 months. OCT also found that the occluded left iliac artery had been reopened and the stented segment was almost fully endothelialized without in-stent restenosis at 6 months, meanwhile HLM and SEM confirmed comparable results.

CONCLUSIONS

Firesorb-C is associated with excellent efficacy, biosafety and biodegradability in rabbits. It shows promise as a replacement for conventional covered stents for treatment of coronary artery perforation or for use in other clinical situations.

Very long-term outcome of coronary covered stents: a report from the SCAAR registry

AIMS

Covered stents are mostly used for coronary perforations with a high risk of early adverse events; however, their long-term outcome is unknown. The aim of this study was to elucidate the short- and long-term outcome of patients treated with covered stents compared to all other stented patients.

METHODS AND RESULTS

The Swedish national registries from 2005-2017 disclosed 265 patients who had received 366 covered stents. Their outcomes were compared to all other stented patients (197,948) who had received 320,784 stents. Compared to regular stents, covered stents showed significant differences (p<0.001) in the short and long term in relation to in-stent restenosis (ISR), target lesion revascularisation (TLR), re-infarction (MI), re-PCI and mortality, the rates of which were all higher. The higher mortality was concentrated within the first month, as a landmark analysis at that time point, adjusted for age and procedural indication, demonstrated no future difference in mortality (HR 1.02 [0.78-1.33], p=0.877). Stent thrombosis (ST) within one year was reported to be higher in covered stents than in other stents. However, no ST was reported in equine pericardial covered stents.

CONCLUSIONS

This observational study including the entire Swedish population shows that patients receiving covered stents have a significantly higher risk of all adverse events. Reassuringly, in the long term, mortality appears to be similar to that in other stented patients.