Search Results (24)

Background: Plaque protrusion after stent implantation is frequently observed in acute coronary syndrome (ACS) patients, yet studies on its long-term progression and clinical significance are limited. Methods: Seventy-eight ACS patients underwent optical coherence tomography (OCT)-guided PCI and follow-up OCT at 1 year. A total of 101 protruding lesions were classified into atherogenic neointima (AN) and non-AN groups based on OCT findings. Qualitative and quantitative assessments of protruding plaque, including irregularity and plaque intensity, were conducted. Results: AN developed in 17% of irregular protrusion (IP) lesions, whereas no smooth protrusion progressed to AN. Lesions in the AN group showed greater increases in protruding plaque volume (2.80 ± 0.46 mm² vs. 0.67 ± 0.16 mm², p < 0.001) and diameter stenosis (16.5% vs. 10.1%, p = 0.02). Follow-up LDL levels were higher in the AN group compared with the non-AN group (76.9 vs. 61.2 mg/dL, p = 0.02), despite similar baseline levels. Conclusions: Low-intensity IP after stent implantation in ACS patients carries a high risk of progression to AN, particularly under poor LDL control. Aggressive lipid-lowering therapy may mitigate this risk. Full article

Magnesium-based coronary stents have gained significant interest due to their excellent biocompatibility, biodegradability, and mechanical properties. However, a key limitation of magnesium in biomedical applications is its low corrosion resistance, which compromises its structural integrity and mechanical strength over time. Polymeric coatings can overcome this challenge, enhancing magnesium-based implants’ corrosion resistance and overall performance. This study applied a polylactic acid (PLA) nanofiber coating to WE43 magnesium (Mg) stents via electrospinning to reduce their corrosion rate. Both uncoated and coated stents underwent in vitro immersion tests in Hank’s solution for 1, 3, 7, and 14 days. The effectiveness of the PLA coating was evaluated through morphological analysis, chemical composition assessment, corrosion behavior (weight change), magnesium ion release, and in vitro biocompatibility. The corrosion observed in the uncoated WE43 stents indicates that protective coatings are necessary to regulate degradation rates over extended implantation periods. The results demonstrated that coated stents exhibited improved performance, maintaining the integrity of the PLA coating for up to 14 days. The coated stents demonstrated reduced surface damage and lower weight loss resulting from lower magnesium release. In our study, the coated stents demonstrated a reduced corrosion rate (0.216 ± 0.013 mm/year) compared with the uncoated stents (0.312 ± 0.010 mm/year), both after 14 days. Additionally, in vitro biocompatibility results confirmed the non-toxic nature of PLA-coated stents, which enhances cellular proliferation and contributes to a more favorable environment for vascular healing. These findings suggest that PLA coatings can effectively prolong the functional durability of WE43 Mg stents, offering a promising solution for enhancing the performance of biodegradable stents in cardiovascular applications. Full article

A 75-year-old man, with a history of descending thoracic aortic rupture and dissection treated with aortic stenting at 73 years old, was admitted for rehabilitation following recurrent cerebral ischemic attacks. Upon admission, blood tests revealed elevated inflammatory markers, including a C-reactive protein (CRP) level of 10.75 mg/dL and a D-dimer level of 4.2 µg/mL, alongside microcytic anemia. Despite thorough evaluations using computed tomography (CT) and ultrasound, the origin of these abnormalities remained unidentified. Two months later, MRI using diffusion-weighted whole-body imaging with background body signal suppression (DWIBS) revealed hyperintensities in the thoracic aorta. He remained asymptomatic and progressed well during rehabilitation, prompting continued observation. However, three months after admission, he developed hemoptysis. Contrast-enhanced CT showed pneumonia, as well as enhanced lesions in the aortic wall, confirming aortic inflammation. Due to concerns about aortic stent ulceration, an emergency stent graft insertion extending to the superior mesenteric artery was performed. He recovered uneventfully and was discharged. DWIBS is an MRI-based tool that avoids exposure to radiation or contrast agents and is cost-effective. MRI using DWIBS demonstrated high signal accumulations in the aortic wall, indicative of inflammation. These findings suggest that DWIBS holds significant potential as a powerful imaging tool for detecting and assessing inflammation, particularly in the aorta. Full article

Coated metallic stents are the next generation of metallic stents with improved surface properties. To evaluate the degradation behavior of stents in vitro, different in vitro degradation models can be applied: (i) static immersion test: degradation under static fluid condition, (ii) fluid dynamic test: degradation under flowing fluid, and (iii) electrochemical corrosion test: degradation under the influence of electric potential. During these experimental procedures, stents interact with the simulated blood plasma, and degradation products are formed in the form of depositions on the stent surface, likewise in vivo experiments. These deposited crystals act as a hindrance to the application of important characterization techniques (e.g., mass loss measurement for the calculation of corrosion rate and examining the adhesion of the coating to metallic stents after fluid dynamic exposure). Therefore, to better characterize the coatings, the removal of these depositions is significant. In this work, we investigate the influence of in vitro test conditions in fluid dynamic biostability tests on the biostability of titanium oxynitride (TiO_XN_Y) coated stainless steel stents by adapting various fluid dynamic experimental parameters. The experimental conditions are based on modification in the components of fluid dynamic setup (e.g., tubings), simulated body fluid (SBF), with and without Ca⁺⁺ and Mg⁺⁺ ions, and the cleaning procedure (use of water, acetone, and isopropanol). Four different experiments were conducted under various experimental parameter sets. SEM and EDX measurements were used for the identification of degradation products after each experiment. This study highlights the importance of optimized experimental conditions showing negligible depositions when utilizing Puriflex tubing or a comparable artificial vessel, SBF devoid of Ca⁺⁺ and Mg⁺⁺ ions, and performing sample cleaning with distilled water in an ultrasonic bath. The presented conditions were optimized for titanium oxynitride coated samples. A similar approach could be applied to other samples with or without some small variation. Full article

Background/Objectives: Epidemiological studies indicate a potential correlation between the consumption of polyphenols and a reduced risk of developing cardiovascular disorders. The present study investigates the potential of a red wine polyphenol oral extract, Provinols™, to reduce neointimal hyperplasia following angioplasty in a hypercholesterolemic rabbit model. Methods: New Zealand white rabbits were fed 1% cholesterol-enriched chow for a period of eight weeks prior to the induction of iliac balloon injury and subsequent stent placement. Following the implantation of the stent, Provinols™ (20 mg/kg/day) or an identical placebo was administered orally for a period of four weeks in a randomized manner. Twenty-eight days following the stenting procedure, the arteries were harvested after euthanasia and subjected to histology assignment analysis. Results: The administration of Provinols™ did not result in a statistically significant change in either blood pressure or plasma cholesterol levels. However, Provinols™ treatment led to a notable reduction in the growth of the intima within the stented area, as well as a reduction in the thickness and surface area of the intima. It is of note that treatment with Provinols™ was associated with a reduction in the accumulation of fat within the arteries and a diminished inflammatory response to injury. Conclusions: The findings demonstrate that oral administration of Provinols™ has the potential to reduce in-stent neointimal growth and lipid deposition, likely due to its anti-inflammatory properties in iliac arteries from hypercholesterolemic rabbits. Additionally, these findings provide an evidence-based rationale for the potential therapeutic benefits of plant-derived polyphenols in the prevention of restenosis associated with stent placement. Full article

Mg metal vascular stents not only have good mechanical support properties but also can be entirely absorbed by the human body as a trace element beneficial to the human body, but because Mg metal is quickly dissolved and absorbed in the human body, magnesium metal alone cannot be ideally used as a vascular stent. Since the dense oxide Zn film formed by Zn contact with oxygen in the air has good anti-corrosion performance, the Zn nanolayer film deposited on the Mg matrix vascular scaffold by magnetron sputtering can effectively inhibit the rapid dissolution of Mg metal. However, there are few studies on the molecular dynamic structural defects of Mg-matrix Zn atomic magnetron sputtering, and the atomic level simulation of Mg-matrix Zn thin-film depositions can comprehensively understand the atomic level structural defects in the deposition process of Zn thin films from a theoretical perspective to further guide experimental research. Based on this, this research first studied and analyzed the atomic layer structure defects, surface morphology, surface roughness, atomic density of different deposited layers, radial distribution function, and residual stress of the thin-film deposition layer of 1500 deposited Zn atoms at the initial deposition stage, during and after deposition under Mg-matrix thermal layer 500K and a deposited velocity 5 Å/ps by molecular dynamics. At the same time, the effects of temperature and deposited velocity of the Mg-matrix thermal layer on the surface morphology, roughness, and biaxial stress of the deposited films were studied. Full article

This article reviews the research and development focus of metallic glasses in the field of biomedical applications. Metallic glasses exhibit a short-range ordered and long-range disordered glassy structure at the microscopic level, devoid of structural defects such as dislocations and grain boundaries. Therefore, they possess advantages such as high strength, toughness, and corrosion resistance, combining characteristics of both metals and glasses. This novel alloy system has found applications in the field of biomedical materials due to its excellent comprehensive performance. This review discusses the applications of Ti-based bulk metallic glasses in load-bearing implants such as bone plates and screws for long-term implantation. On the other hand, Mg-based metallic glasses, owing to their degradability, are primarily used in degradable bone nails, plates, and vascular stents. However, metallic glasses as biomaterials still face certain challenges. The Young’s modulus value of Ti-based metallic glasses is higher than that of human bones, leading to stress-shielding effects. Meanwhile, Mg-based metallic glasses degrade too quickly, resulting in the premature loss of mechanical properties and the formation of numerous bubbles, which hinder tissue healing. To address these issues, we propose the following development directions: (1) Introducing porous structures into titanium-based metallic glasses is an important research direction for reducing Young’s modulus; (2) To enhance the bioactivity of implant material surfaces, the surface modification of titanium-based metallic glasses is essential. (3) Developing antibacterial coatings and incorporating antibacterial metal elements into the alloys is essential to maintain the long-term effective antibacterial properties of metallic biomaterials. (4) Corrosion resistance must be further improved through the preparation of composite materials, while ensuring biocompatibility and safety, to achieve controllable degradation rates and degradation modes. Full article

Introduction: The application of double-J ureteral stents in urology is widespread, but their use is often accompanied by complications and bothersome symptoms, affecting patients’ quality of life (QoL). While various medications have been tested for alleviating the symptoms associated with double-J stents, consensus on their effectiveness remains elusive. This study aims to investigate the effectiveness of tamsulosin, solifenacin, mirabegron, desloratadine, and combination therapy using a Romanian-adapted version of the Ureteral Stent Symptom Questionnaire (USSQ). Materials and Methods: A prospective, observational, randomised trial was conducted at the Urology and Renal Transplant Clinic of Dr. “C.I. Parhon” Clinical Hospital in Iasi between 1 January 2022 and 1 August 2023. Three hundred twenty seven patients who underwent their first double-J stent insertion were evaluated with the Romanian-adapted USSQ at baseline and 30 days post-insertion. Patients were randomly divided into six groups based on the prescribed medications: control, tamsulosin, mirabegron, solifenacin, desloratadine, and combination therapy. Results: The data suggest a significant reduction in symptoms in patients who received medication compared with the control group. Furthermore, the combined medication of solifenacin 10 mg and tamsulosin 0.4 mg was particularly effective in reducing pain with statistical significance compared to the control group (p = 0.001). The highest mean scores for urinary symptom severity were observed in the control group (12.37 ± 6.82), and the lowest was in the mirabegron group (9.94 ± 5.82). The individuals who received a daily dose of 50 mg of mirabegron saw the most notable influence on their job. Conclusions: While no single medication emerged as a “miracle drug” for managing symptoms related to double-J stent insertion, the combination therapy of solifenacin and tamsulosin is the most promising option for improving symptoms related to double-J stent insertion and QoL. Additional extensive research is required to validate these initial results. Full article

The human body comprises various tubular structures that have essential functions in different bodily systems. These structures are responsible for transporting food, liquids, waste, and other substances throughout the body. However, factors such as inflammation, tumors, stones, infections, or the accumulation of substances can lead to the narrowing or blockage of these tubular structures, which can impair the normal function of the corresponding organs or tissues. To address luminal obstructions, stenting is a commonly used treatment. However, to minimize complications associated with the long-term implantation of permanent stents, there is an increasing demand for biodegradable stents (BDS). Magnesium (Mg) metal is an exceptional choice for creating BDS due to its degradability, good mechanical properties, and biocompatibility. Currently, the Magmaris^® coronary stents and UNITY-B^TM biliary stent have obtained Conformité Européene (CE) certification. Moreover, there are several other types of stents undergoing research and development as well as clinical trials. In this review, we discuss the required degradation cycle and the specific properties (anti-inflammatory effect, antibacterial effect, etc.) of BDS in different lumen areas based on the biocompatibility and degradability of currently available magnesium-based scaffolds. We also offer potential insights into the future development of BDS. Full article

(1) Background: The diagnostic accuracy of coronary computed tomography angiography (CCTA) for coronary artery disease (CAD) has greatly improved so CCTA represents a transition in the care of patients suffering from CAD. Magnesium-based bioresorbable stents (Mg-BRS) secure acute percutaneous coronary intervention (PCI) results without leaving, in the long term, a metallic caging effect. The purpose of this real-world study was to assess clinical and CCTA medium- and long-term follow-up of all our patients with implanted Mg-BRS. (2) Methods: The patency of 52 Mg-BRS implanted in 44 patients with de novo lesions (24 of which had acute coronary syndrome (ACS)) was evaluated by CCTA and compared to quantitative coronary angiography (QCA) post-implantation. (3) Results: ten events including four deaths occurred during a median follow-up of 48 months. CCTA was interpretable and in-stent measurements were successful at follow-up without being hindered by the stent strut’s “blooming effect”. Minimal in-stent diameters on CCTA were found to be 1.03 ± 0.60 mm smaller than the expected diameter after post-dilation on implantation (p < 0.05), a difference not found in comparing CCTA and QCA. (4) Conclusions: CCTA follow-up of implanted Mg-BRS is fully interpretable and we confirm the long-term Mg-BRS safety profile. Full article

Drug eluting magnesium (Mg) bioresorbable scaffolds represent a novel paradigm in percutaneous coronary intervention because Mg-based alloys are biocompatible, have adequate mechanical properties and can be resorbed without adverse events. Importantly, Mg is fundamental in many biological processes, mitigates the inflammatory response and is beneficial for the endothelium. Sirolimus is widely used as an antiproliferative agent in drug eluting stents to inhibit the proliferation of smooth muscle cells, thus reducing the occurrence of stent restenosis. Little is known about the potential interplay between sirolimus and Mg in cultured human coronary artery endothelial cells (hCAEC). Therefore, the cells were treated with sirolimus in the presence of different concentrations of extracellular Mg. Cell viability, migration, barrier function, adhesivity and nitric oxide synthesis were assessed. Sirolimus impairs the viability of subconfluent, but not of confluent cells independently from the concentration of Mg in the culture medium. In confluent cells, sirolimus inhibits migration, while it cooperates with Mg in exerting an anti-inflammatory action that might have a role in preventing restenosis and thrombosis. Full article

Due to the spontaneous degradability, excellent biocompatibility, favorable bone−inducibility, and antimicrobial properties, Mg−based alloys acting as miniature intravascular stents and bone−fixation materials have shown great development−potential. Regrettably, the uneven degradation model and excessive dissolution rate restricted their clinical application. In this study, the latest research on five methods (high−purity or amorphous, micro−alloying, heat−treatment, plastic−deformation, and surface modification) in medical Mg alloy degradation behaviors was reviewed. The corrosion mechanisms of Mg alloys under different processes were summarized. In addition, the effects of microstructure characteristics and film−layer features on corrosion resistance were systematically discussed. Ultimately, existing problems and future development directions of medical Mg−based alloys were reviewed. Full article

Magnesium alloys have attracted considerable interest as prospective biodegradable materials in cardiovascular stents because of their metal mechanical properties and biocompatibility. However, fast degradation and slow endothelialization results in the premature disintegration of mechanical integrity and the restenosis of implanted Mg-based stents, which is the primary hurdle limiting their predicted clinical applicability. The development of bioinspired strategies is a burgeoning area in cardiovascular stents’ fields of research. Inspired by the unique features of lotus leaves, pitcher plants, healthy endothelial cells (ECs), marine mussels, and extracellular matrix, various bioinspired strategies have been developed to build innovative artificial materials with tremendous promise for medicinal applications. This perspective focuses on bioinspired strategies to provide innovative ideas for reducing corrosion resistance and accelerating endothelialization. The bioinspired strategies are envisaged to serve as a significant reference for future research on Mg-based medical devices. Full article

Functional Arg-Gly-Asp (RGD) tripeptide has a tremendous potential in clinical applications to accelerate the endothelialization of Magnesium (Mg) alloy vascular stent surface. The interaction mechanism of RGD on different surfaces of Mg and Mg alloy is important for promoting the development of Mg alloy vascular stent, yet still unclear. In the present work, first-principles calculation within density functional theory (DFT) was performed to investigate the interaction mechanism. The electron redistribution, effect of alloying elements and changes in the density of states of the adsorption systems were studied. The results revealed that RGD interacted with different surfaces of Mg (0001), Mg(11$\overline{2}$0) and Mg(10$\overline{1}$1) through ligand covalent bond; the pronounced localization of electrons of Mg(11$\overline{2}$0) and Mg(10$\overline{1}$1) surfaces promoted the adsorption of RGD tripeptide compared with that on the Mg(0001) surface; Zn/Y/Nd alloying elements improved the adsorption of RGD. Calculated results could provide insight for the interaction mechanism of biomolecule on the Mg and Mg-based alloy surfaces, and point out some directions for the future experimental efforts. Full article

Magnesium (Mg) alloys have received increasing interest in the past two decades as biomaterials due to their excellent biological compatibility. However, the corrosion resistance of Mg alloys is relativity low which limits their usage in degradable implant applications, and controlling the corrosion resistance is the key to solving this problem. This review discusses the relative corrosion mechanisms, including pitting, filiform, high temperature, stress corrosion, etc., of Mg alloys. Various approaches like purification (Fe, Ni, Cu, etc.), micro-alloying (adding Zn, Mn, Ca, RE elements, and so on), grain refinement (severe plastic deformation, SPD, etc.), and surface modifications (various coating methods) to control corrosion and biological performance are summarized. Moreover, the in vivo implantations of Mg alloy vascular stents and the issues that have emerged based on the reports in recent years are introduced. It is recommended that corrosion mechanisms should be further investigated as there is no method that can remove all the impurities and a new purification approach needs to be developed. The concentration of micro-alloy elements should be carefully controlled to avoid superfluous compounds. Developing new continuous SPD methods to achieve fine-grained Mg alloys with a large size scale is necessary. The development of a multifunctional coating could also be considered in controlling the Mg degradation rate. Moreover, the research trends and challenges in the future of Mg biomaterials are proposed. Full article