Search Results (28)

Since the 1960s, efforts have been made to develop new technologies to eliminate the risk of thrombosis in medical devices that come into contact with blood. Preventing thrombosis resulting from the contact of a medical device, such as an implant, with blood is a challenge due to the high mortality rate of patients and the high cost of medical care. To this end, various types of biomaterials coated with polymer-drug layers are being designed to reduce their thrombogenicity and improve their hemocompatibility. This review presents the latest developments in the use of polymer-drug systems to produce anti-thrombogenic surfaces in medical devices in contact with blood, such as stents, catheters, blood pumps, heart valves, artificial lungs, blood vessels, blood oxygenators, and various types of tubing (such as for hemodialysis) as well as microfluidic devices. This paper presents research directions and potential clinical applications, emphasizing the importance of continued progress and innovation in the field. Full article

Heart failure is a cardiovascular condition, leading to fatigue, breathlessness, and fluid retention. It affects around 56 million people globally and is a leading cause of hospitalization and mortality. Its prevalence is rising due to aging populations and lifestyle factors. Managing heart failure demands a multidisciplinary approach, encompassing medications, lifestyle modifications, and often medical devices or surgeries. The treatment burden is substantial, impacting patients’ daily lives and straining healthcare systems. Improving early detection, novel therapies, and patient education are crucial for alleviating the burden and enhancing the quality of life. There are notable advancements in the field of heart failure treatment and prevention. We will discuss significant pharmacological and device advances related to heart failure, including angiotensin receptor–neprilysin inhibitor, sodium–glucose co-transporter inhibition, glucagon-like peptide-1 agonist, cardiac resynchronization therapy, cardiac contractility modulation, mechanical circulatory support devices, and transcatheter valve interventions. We will also review novel therapies on the horizon, emerging technologies like CRISPR-based treatments for genetic anomalies, and the involvement of artificial intelligence in heart failure detection and management. Full article

The inherent disadvantages of traditional non-flexible aerogels, such as high fragility and moisture sensitivity, severely restrict their applications. To address these issues and make the aerogels efficient, especially for advanced medical applications, different techniques have been used to incorporate flexibility in aerogel materials. In recent years, a great boom in flexible aerogels has been observed, which has enabled them to be used in high-tech biomedical applications. The current study comprises a comprehensive review of the preparation techniques of pure polymeric-based hybrid and single-component aerogels and their use in biomedical applications. The biomedical applications of these hybrid aerogels will also be reviewed and discussed, where the flexible polymeric components in the aerogels provide the main contribution. The combination of highly controlled porosity, large internal surfaces, flexibility, and the ability to conform into 3D interconnected structures support versatile properties, which are required for numerous potential medical applications such as tissue engineering; drug delivery reservoir systems; biomedical implants like heart stents, pacemakers, and artificial heart valves; disease diagnosis; and the development of antibacterial materials. The present review also explores the different mechanical, chemical, and physical properties in numerical values, which are most wanted for the fabrication of different materials used in the biomedical fields. Full article

Mitral valve regurgitation (MR) is a multifaceted valvular heart disease. Echocardiography plays a central role in etiology assessment, severity quantification, treatment candidacy, outcome evaluation, and patient follow-up. In this review, we describe the comprehensive echocardiographic assessment of MR, including transthoracic (TTE) and transesophageal (TEE) approaches, 2D and 3D modalities, strain imaging, stress echocardiography, and artificial intelligence (AI) applications. Transcatheter edge-to-edge mitral valve repair (TEER) has been established as a key therapy for patients with severe, symptomatic MR and high surgical risk. TEER is performed under TEE guidance. We outline a practical overview of echocardiographic guidance on TEER. Full article

Although regenerative medicine necessitates advanced three-dimensional (3D) scaffolds for organ and tissue applications, creating intricate structures across scales, from nano- to meso-like biological tissues, remains a challenge. Electrospinning of nanofibers offers promise due to its capacity to craft not only the dimensions and surfaces of individual fibers but also intricate attributes, such as anisotropy and porosity, across various materials. In this study, we used a 3D printer to design a mold with polylactic acid for gel modeling. This gel template, which was mounted on a metal wire, facilitated microfiber electrospinning. After spinning, these structures were treated with EDTA to remove the template and were then cleansed and dried, resulting in 3D microfibrous (3DMF) structures, with average fiber diameters of approximately 1 µm on the outer and inner surfaces. Notably, these structures matched their intended design dimensions without distortion or shrinkage, demonstrating the adaptability of this method for various template sizes. The cylindrical structures showed high elasticity and stretchability with an elastic modulus of 6.23 MPa. Furthermore, our method successfully mimicked complex biological tissue structures, such as the inner architecture of the voice box and the hollow partitioned structure of the heart’s tricuspid valve. Achieving specific intricate shapes required multiple spinning sessions and subsequent assemblies. In essence, our approach holds potential for crafting artificial organs and forming the foundational materials for cell culture scaffolds, addressing the challenges of crafting intricate multiscale structures. Full article

The electrocardiogram (ECG), considered by some diagnosticians of cardiovascular diseases to be a slightly anachronistic tool, has acquired a completely new face and importance thanks to its three modern features: the digital form of recording, its very frequent use, and the possibility of processing thousands of records by artificial intelligence (AI). In this review of the literature on this subject from the first 3 months of 2023, the use of many types of software for extracting new information from the ECG is described. These include, among others, natural language processing, backpropagation neural network and convolutional neural network. AI tools of this type allow physicians to achieve high accuracy not only in ECG-based predictions of the patient’s age or sex but also of the abnormal structure of heart valves, abnormal electrical activity of the atria, distorted immune response after transplantation, good response to resynchronization therapy and an increased risk of sudden cardiac death. The attractiveness of the presented results lies in the simplicity of the examination by the staff, relatively low costs and even the possibility of performing the examination remotely. The twelve studies presented here are just a fraction of the novelties that the current year will bring. Full article

Severe tricuspid valve (TV) regurgitation (TR) has been associated with adverse long-term outcomes in several natural history studies, but isolated TV surgery presents high mortality and morbidity rates. Transcatheter tricuspid valve interventions (TTVI) therefore represent a promising field and may currently be considered in patients with severe secondary TR that have a prohibitive surgical risk. Tricuspid transcatheter edge-to-edge repair (T-TEER) represents one of the most frequently used TTVI options. Accurate imaging of the tricuspid valve (TV) apparatus is crucial for T-TEER preprocedural planning, in order to select the right candidates, and is also fundamental for intraprocedural guidance and post-procedural follow-up. Although transesophageal echocardiography represents the main imaging modality, we describe the utility and additional value of other imaging modalities such as cardiac CT and MRI, intracardiac echocardiography, fluoroscopy, and fusion imaging to assist T-TEER. Developments in the field of 3D printing, computational models, and artificial intelligence hold great promise in improving the assessment and management of patients with valvular heart disease. Full article

The development of a novel artificial heart valve with outstanding durability and safety has remained a challenge since the first mechanical heart valve entered the market 65 years ago. Recent progress in high-molecular compounds opened new horizons in overcoming major drawbacks of mechanical and tissue heart valves (dysfunction and failure, tissue degradation, calcification, high immunogenic potential, and high risk of thrombosis), providing new insights into the development of an ideal artificial heart valve. Polymeric heart valves can best mimic the tissue-level mechanical behavior of the native valves. This review summarizes the evolution of polymeric heart valves and the state-of-the-art approaches to their development, fabrication, and manufacturing. The review discusses the biocompatibility and durability testing of previously investigated polymeric materials and presents the most recent developments, including the first human clinical trials of LifePolymer. New promising functional polymers, nanocomposite biomaterials, and valve designs are discussed in terms of their potential application in the development of an ideal polymeric heart valve. The superiority and inferiority of nanocomposite and hybrid materials to non-modified polymers are reported. The review proposes several concepts potentially suitable to address the above-mentioned challenges arising in the R&D of polymeric heart valves from the properties, structure, and surface of polymeric materials. Additive manufacturing, nanotechnology, anisotropy control, machine learning, and advanced modeling tools have given the green light to set new directions for polymeric heart valves. Full article

(1) Background: Artificial Intelligence (AI) is a modern tool with numerous applications in the medical field. The case series reported here aimed to investigate the diagnostic performance of the fetal intelligent navigation echocardiography (FINE) method applied for the first time in the prenatal identification of atrioventricular septal defects (AVSD). This congenital heart disease (CHD) is associated with extracardiac anomalies and chromosomal abnormalities. Therefore, an early diagnosis is essential to advise parents and make adequate treatment decisions. (2) Methods: Four fetuses diagnosed with AVSD via two-dimensional (2D) ultrasound examination in the second trimester were enrolled. In all cases, the parents chose to terminate the pregnancy. Since the diagnosis of AVSD with 2D ultrasound may be missed, one or more four-dimensional (4D) spatiotemporal image correlation (STIC) volume datasets were obtained from a four-chamber view. The manual navigation enabled by the software is time-consuming and highly operator-dependent. (3) Results: FINE was applied to these volumes and nine standard fetal echocardiographic views were generated and optimized automatically, using the assistance of the virtual intelligent sonographer (VIS). Here, 100% of the four-chamber views, and after the VISA System application the five-chamber views, of the diagnostic plane showed the atrioventricular septal defect and a common AV valve. The autopsies of the fetuses confirmed the ultrasound results. (4) Conclusions: By applying intelligent navigation technology to the STIC volume datasets, 100% of the AVSD diagnoses were detected. Full article

Polylactic acid (PLA) is one of the market’s most commonly used biodegradable polymers, with diverse applications in additive manufacturing, specifically fused deposition modeling (FDM) 3D printing. The use of PLA in complex and sophisticated FDM applications is continually growing. However, the increased range of applications requires a better understanding of the material properties of this polymer. For example, recent studies have shown that PLA has the potential to be used in artificial heart valves. Still, the durability and longevity of this material in such a harsh environment are unknown, as heart valve failures have been attributed to salification. Additionally, there is a gap in the field for in situ material characterization of PLA surfaces during stiffening. The present study aims to benchmark different dynamic atomic force microscopy (AFM) techniques available to study the salification phenomenon of PLA at micro-scales using different PLA thin films with various salt concentrations (i.e., 10%, 15%, and 20% of sodium chloride (NaCl)). The measurements are conducted by tapping mode AFM, bimodal AFM, the force spectroscopy technique, and energy quantity analysis. These measurements showed a stiffening phenomenon occurring as the salt solution is increased, but the change was not equally sensitive to material property differences. Tapping mode AFM provided accurate topographical information, while the associated phase images were not considered reliable. On the other hand, bimodal AFM was shown to be capable of providing the topographical information and material compositional mapping through the higher eigenmode’s phase channel. The dissipated power energy quantities indicated that how the polymers become less dissipative as salt concentration increases can be measured. Lastly, it was shown that force spectroscopy is the most sensitive technique in detecting the differences in properties. The comparison of these techniques can provide a helpful guideline for studying the material properties of PLA polymers at micro- and nano-scales that can prove beneficial in various fields. Full article

Background and Objectives: Developing a prosthetic heart valve that combines the advantageous hemodynamic properties of its biological counterpart with the longevity of mechanical prostheses has been a major challenge for heart valve development. Anatomically inspired artificial polymeric heart valves have the potential to combine these beneficial properties, and innovations in 3D printing have given us the opportunity to rapidly test silicone prototypes of new designs to further the understanding of biophysical properties of artificial heart valves. TRISKELION is a promising prototype that we have developed, tested, and further improved in our institution. Materials and Methods: STL files of our prototypes were designed with FreeCad 0.19.2 and 3D printed with an Agilista 3200W (Keyence, Osaka, Japan) using silicones of Shore hardness 35 or 65. Depending on the valve type, the support structures were printed in AR-M2 plastics. The prototypes were then tested using a hemodynamic pulse duplicator (HKP 2.0) simulating an aortic valve cycle at 70 bpm with 70 mL stroke volume (cardiac output 4.9 L/min). Valve opening cycles were visualized with a high-speed camera (Phantom Miro C320). The resulting values led to further improvements of the prototype (TRISKELION) and were compared to a standard bioprosthesis (Edwards Perimount 23 mm) and a mechanical valve (Bileaflet valve, St. Jude Medical). Results: We improved the silicone prototype with currently used biological and mechanical valves measured in our setup as benchmarks. The regurgitation fractions were 22.26% ± 4.34% (TRISKELION) compared to 8.55% ± 0.22% (biological) and 13.23% ± 0.79% (mechanical). The mean systolic pressure gradient was 9.93 ± 3.22 mmHg (TRISKELION), 8.18 ± 0.65 mmHg (biological), and 10.15 ± 0.16 mmHg (mechanical). The cardiac output per minute was at 3.80 ± 0.21 L/min (TRISKELION), 4.46 ± 0.01 L/min (biological), and 4.21 ± 0.05 L/min (mechanical). Conclusions: The development of a heart valve with a central structure proves to be a promising concept. It offers another principle to address the problem of longevity in currently used heart valves. Using 3D printing to develop new prototypes provides a fast, effective, and accurate way to deepen understanding of its physical properties and requirements. This opens the door for translating and combining results into modern prototypes using highly biocompatible polymers, internal structures, and advanced valve layouts. Full article

The deformation behavior of an artificial heart valve was analyzed using the explicit dynamic finite element method. Time variations of the left ventricle and the aortic pressure were considered as the mechanical boundary conditions in order to reproduce the opening and closing movements of the valve under the full cardiac cycle. The valve was assumed to be made from a medical polymer and hence, a hyperelastic Mooney–Rivlin model was assigned as the material model. A simple formula of the damage mechanics was also introduced into the theoretical material model to express the hysteresis response under the unloading state. Effects of the hysteresis on the valve deformation were characterized by the delay of response and the enlargement of displacement. Most importantly, the elastic vibration observed in the pure elastic response under the full close state was dramatically reduced by the conversion of a part of elastic energy to the dissipated energy due to hysteresis. Full article

Background: Detailed surgical techniques for treating canine mitral regurgitation have not been previously reported. Method: This case series included six consecutive client-owned dogs with mitral regurgitation. All dogs underwent a combined protocol, including the modified loop technique and De Vega annuloplasty (MODEL surgery), in 2021. Artificial loops covering 80% of the length of the strut chordae tendineae were used for chordal replacement. Mitral annuloplasty was subjectively performed, targeting the circumference of the septal leaflet. Results: The breeds were Chihuahua-mixed breed, Spitz, Pomeranian, Cavalier King Charles Spaniel, and Chihuahua, with average ages and weights of 11.4 ± 2.3 years and 5.49 ± 2.98 kg, respectively. The aortic cross-clamp, pumping, and surgery times were 64.0 ± 7.5 min, 168.5 ± 39.1 min, and 321.0 ± 53.1 min, respectively. After MODEL surgery, left atrial-to-aortic ratios significantly decreased from 2.20 ± 0.18 to 1.26 ± 0.22 (p < 0.01), and left ventricular end-diastolic internal diameter normalized to body weight significantly decreased from 2.03 ± 0.26 to 1.48 ± 0.20 (p < 0.01). In all cases, the clinical signs disappeared or improved significantly. Conclusions: MODEL surgery increased mitral valve coaptation, normalized heart sizes, and significantly improved clinical signs in dogs with mitral regurgitation. Full article

Background and aims: Auscultation is a cheap and fundamental technique for detecting cardiovascular disease effectively. Doctors’ abilities in auscultation are varied. Sometimes, there may be cases of misdiagnosis, even when auscultation is performed by an experienced doctor. Hence, it is necessary to propose accurate computational tools to assist auscultation, especially in developing countries. Artificial intelligence technology can be an efficient diagnostic tool for detecting cardiovascular disease. This work proposed an automatic multiple classification method for cardiovascular disease detection by heart sound signals. Methods and results: In this work, a 1D heart sound signal is translated into its corresponding 3D spectrogram using continuous wavelet transform (CWT). In total, six classes of heart sound data are used in this experiment. We combine an open database (including five classes of heart sound data: aortic stenosis, mitral regurgitation, mitral stenosis, mitral valve prolapse and normal) with one class (pulmonary hypertension) of heart sound data collected by ourselves to perform the experiment. To make the method robust in a noisy environment, the background deformation technique is used before training. Then, 10 transfer learning networks (GoogleNet, SqueezeNet, DarkNet19, MobileNetv2, Inception-ResNetv2, DenseNet201, Inceptionv3, ResNet101, NasNet-Large, and Xception) are used for comparison. Furthermore, other models (LSTM and CNN) are also compared with our proposed algorithm. The experimental results show that four transfer learning networks (ResNet101, DenseNet201, DarkNet19 and GoogleNet) outperformed their peer models with an accuracy of 0.98 to detect the multiple heart diseases. The performances have been validated both in the original heart sound and the augmented heart sound using 10-fold cross validation. The results of these 10 folds are reported in this research. Conclusions: Our method obtained high classification accuracy even under a noisy background, which suggests that the proposed classification method could be used in auxiliary diagnosis for cardiovascular diseases. Full article

Hemocompatibility of biomaterials in contact with the blood of patients is a prerequisite for the short- and long-term applications of medical devices such as cardiovascular stents, artificial heart valves, ventricular assist devices, catheters, blood linings and extracorporeal devices such as artificial kidneys (hemodialysis), extracorporeal membrane oxygenation (ECMO) and cardiopulmonary bypass. Although lower blood compatibility of materials and devices can be handled with systemic anticoagulation, its side effects, such as an increased bleeding risk, make materials that have a better hemocompatibility highly desirable, particularly in long-term applications. This review provides a short overview on the basic mechanisms of blood coagulation including plasmatic coagulation and blood platelets, as well as the activation of the complement system. Furthermore, a survey on concepts for tailoring the blood response of biomaterials to improve the hemocompatibility of medical devices is given which covers different approaches that either inhibit interaction of material surfaces with blood components completely or control the response of the coagulation system, blood platelets and leukocytes. Full article