Prospective multi-center registry to evaluate efficacy and safety of the newly developed diamond-like carbon-coated cobalt-chromium coronary stent system

Development of Antimicrobial Surfaces Using Diamond-like Carbon or Diamond-like Carbon-Based Coatings

The medical device market is a high-growth sector expected to sustain an annual growth rate of over 5%, even in developed countries. Daily, numerous patients have medical devices implanted or inserted within their bodies. While medical devices have significantly improved patient outcomes, as foreign objects, their wider use can lead to an increase in device-related infections, thereby imposing a burden on healthcare systems. Multiple materials with significant societal impact have evolved over time: the 19th century was the age of iron, the 20th century was dominated by silicon, and the 21st century is often referred to as the era of carbon. In particular, the development of nanocarbon materials and their potential applications in medicine are being explored, although the scope of these applications remains limited. Technological innovations in carbon materials are remarkable, and their application in medicine is expected to advance greatly. For example, diamond-like carbon (DLC) has garnered considerable attention for the development of antimicrobial surfaces. Both DLC itself and its derivatives have been reported to exhibit anti-microbial properties. This review discusses the current state of DLC-based antimicrobial surface development.

Clinical features, future cardiac events, and prognostic factors following percutaneous coronary intervention in young female patients

BACKGROUND

The proportion of young females among the patients who undergo percutaneous coronary intervention (PCI) is relatively small, and information on their clinical characteristics is limited. This study investigated the clinical characteristics and prognostic factors for future cardiac events in young females who underwent PCI.

METHODS

This multicenter observational study included 187 consecutive female patients aged < 60 years who underwent PCI in seven hospitals. The primary composite endpoint was the incidence of cardiac death, nonfatal myocardial infarction, and target vessel revascularization.

RESULTS

The mean patient age was 52.1 ± 6.1 years and 89 (47.6%) had diabetes, and renal dysfunction (an estimated glomerular filtration rate < 60 mL/min/1.73 m2) was observed in 38 (20.3%). During a median follow-up of 3.3 years, the primary endpoint occurred in 28 patients. The Cox proportional hazards models showed that renal dysfunction was an independent predictor for the primary endpoint (hazard ratio 3.04, 95% confidence interval 1.25-7.40, p = 0.01), as well as multivessel disease (hazard ratio 2.79, 95% confidence interval 1.12-6.93, p = 0.03). Patients with renal dysfunction had a significantly higher risk for the primary endpoint than those without renal dysfunction.

CONCLUSIONS

Renal dysfunction was strongly associated with future cardiac events in young females who underwent PCI.

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.

Diamond-like Carbon Coatings in the Biomedical Field: Properties, Applications and Future Development

Repairment and replacement of organs and tissues are part of the history of struggle against human diseases, in addition to the research and development (R&D) of drugs. Acquisition and processing of specific substances and physiological signals are very important to understand the effects of pathology and treatment. These depend on the available biomedical materials. The family of diamond-like carbon coatings (DLCs) has been extensively applied in many industrial fields. DLCs have also been demonstrated to be biocompatible, both in vivo and in vitro. In many cases, the performance of biomedical devices can be effectively enhanced by coating them with DLCs, such as vascular stents, prosthetic heart valves and surgical instruments. However, the feasibility of the application of DLC in biomedicine remains under discussion. This review introduces the current state of research and application of DLCs in biomedical devices, their potential application in biosensors and urgent problems to be solved. It will be useful to build a bridge between DLC R&D workers and biomedical workers in order to develop high-performance DLC films/coatings, promote their practical use and develop their potential applications in the biomedical field.

Surface engineering at the nanoscale: A way forward to improve coronary stent efficacy

Coronary in-stent restenosis and late stent thrombosis are the two major inadequacies of vascular stents that limit its long-term efficacy. Although restenosis has been successfully inhibited through the use of the current clinical drug-eluting stent which releases antiproliferative drugs, problems of late-stent thrombosis remain a concern due to polymer hypersensitivity and delayed re-endothelialization. Thus, the field of coronary stenting demands devices having enhanced compatibility and effectiveness to endothelial cells. Nanotechnology allows for efficient modulation of surface roughness, chemistry, feature size, and drug/biologics loading, to attain the desired biological response. Hence, surface topographical modification at the nanoscale is a plausible strategy to improve stent performance by utilizing novel design schemes that incorporate nanofeatures via the use of nanostructures, particles, or fibers, with or without the use of drugs/biologics. The main intent of this review is to deliberate on the impact of nanotechnology approaches for stent design and development and the recent advancements in this field on vascular stent performance.

Carbon-Coated Stent and the Role of the Kallikrein-Kinin System in Peripheral Angioplasty

OBJECTIVE

The purpose of this study was to investigate the clinical evolution of patients treated with carbon-coated stent, as well as its patency and the inflammatory response triggered by this process through the quantification of serum elements of the kallikrein-kinin system (KKS).

METHODS

This was a single-center prospective study with 27 patients with peripheral artery disease (PAD) who required percutaneous transluminal angioplasty and stenting of the iliacofemoropopliteal segment using carbon-coated stent grafts (carbostents). The blood concentrations of the total and kininogen fractions were evaluated using immunoenzymatic methods. Plasma kallikrein levels were assessed by the colorimetric method and tissue kallikrein levels were evaluated by the spectrophotometric method. The activity of kininase II was measured by -fluorometric analysis.

RESULTS

Of the 27 patients who completed the 6 months of the study (11 iliac territory, 16 femoropopliteal territory), only one experienced restenosis (3.7%) (femoropopliteal segment) and no patient had occlusion (96.3% of patency). In 1 year, four patients were lost to follow-up and all 23 patients evaluated maintained stent patency, except for the patient who had restenosis throughout the first 6 months. We report complete (100%) member salvage in 12 months of follow-up. The activity levels of high- and low-molecular-weight kininogens decreased significantly over time (before vs. 24 h, p < 0.01; before vs. 6 months, p < 0.001, and before vs. 24 h, p < 0.01; before vs. 6 months, p < 0.001; 24 h vs. 6 months, p < 0.001, respectively). Patients also had significantly lower levels of plasma and tissue kallikrein (before vs. 24 h, p < 0.001; before vs. 6 months, p < 0.001, and before vs. 24 h, p < 0.01; before vs. 6 months, p < 0.05, respectively). There was a significant increase in the enzymatic activity of kininase II at 24 h and after 6 months compared to the pre-treatment control (p < 0.001).

CONCLUSION

Our early experience shows that the use of carbon-coated stents in PAD appears to be safe, with low rates of early restenosis (3.7% in the first 6 months and 5% in the 12 months of follow-up). We concluded that KKS was involved in the inflammatory response caused by the placement of carbon-coated stents.

Reappraisal of Percutaneous Transluminal Laser Angioplasty

Background and aims

We devised a technique to treat peripheral arterial disease (PAD) with laser, i.e. percutaneous transluminal laser angioplasty (PTLA). Considerable good results were obtained with PTLA, but it is apparently considered obsolete as a technique to treat occlusive arterial disease of peripheral arteries, perhaps because of the development and improvement of stents and the ease of their use compared to the somewhat intricate technique required for PTLA. Although the author admits the usefulness of stents, they are foreign to a human body. PTLA does not use a foreign body and contributes to the regeneration of the body's own artery.The aim of this article is to elucidate the beneficial effects of laser procedures in the treatment of PAD and to show the resulting good long-term patency, and to propose PTLA as an option to treat PAD.Some basic experiments and their results useful for PTLA will be introduced.

Materials and Methods

Ninety cases with occlusive peripheral arterial diseases were treated with PTLA during the period of March 1985 to March 1991.Our method of PTLA consists of occlusion of the proximal artery by a dilated balloon of a percutaneously introduced balloon catheter, and flushing with normal saline during irradiation by Nd:YAG laser.We used a ceramic tip attached to a laser catheter most of the time and a bare laser fiber under angioscopy or a bare laser fiber itself to treat smaller arteries in the legs.

Results

The initial success rate was 90%.The patency rates of PAD at 6 years are 91.4% (iliac artery) and 85.8% (femoropopliteal artery), and the patency rate of leg artery lesions is 100% at 5 years.Some clinical cases with long-term patency (6 and 30 years) will be introduced.Some fundamental experiments useful to the application of laser to atheroma or thrombi will be introduced.

Conclusions

PTLA could be a useful option to treat occlusive PAD, because it can produce longterm patency of natural arteries, provided a proper lesion was selected.

Diamond thin films: giving biomedical applications a new shine

Progress made in the last two decades in chemical vapour deposition technology has enabled the production of inexpensive, high-quality coatings made from diamond to become a scientific and commercial reality. Two properties of diamond make it a highly desirable candidate material for biomedical applications: first, it is bioinert, meaning that there is minimal immune response when diamond is implanted into the body, and second, its electrical conductivity can be altered in a controlled manner, from insulating to near-metallic. In vitro, diamond can be used as a substrate upon which a range of biological cells can be cultured. In vivo, diamond thin films have been proposed as coatings for implants and prostheses. Here, we review a large body of data regarding the use of diamond substrates for in vitro cell culture. We also detail more recent work exploring diamond-coated implants with the main targets being bone and neural tissue. We conclude that diamond emerges as one of the major new biomaterials of the twenty-first century that could shape the way medical treatment will be performed, especially when invasive procedures are required.