Artificial Aortic Valve Research Articles

QUALITY OF LIFE OF PATIENTS TREATED BY VALVE-SPARING AORTIC ROOT REPLACEMENT

The aim. To determine the effectiveness of David valve-preserving operation in comparison with Bentall operation based on the analysis of patients' quality of life after operations. Materials and methods. The study included 107 patients who underwent planned and urgent surgical treatment at the Heart Institute of the Ministry of Health of Ukraine from 2015 to 2023. The patients were divided into two groups depending on the type of surgical intervention: group A consisted of 53 patients (49,11±1,54 years; 47 (88,68%) males), who underwent the David procedure (valve-sparing replacement of aortic root and ascending aorta), group B – 55 patients (52,36±1,56 years; 53 (96,36%) males), who underwent Bentall surgery (replacement of the valve, root and ascending part of the aorta). The quality of life was assessed before the operation for each group, and in the long-term period after operation. The quality of life of the patients of both groups was compared. It was assessed using the Medical Outcomes Study Short Form 36 (MOS SF-36) questionnaire. Results. The obtained data indicated that the average preoperative values of quality of life indicators of patients of both groups with different types of aneurysm correction were significantly different from ideal health. The performed operations significantly improved the assessment of the quality of life. When comparing the quality of life in the remote period of the patients of both groups, the indicators were significantly better in group A. We noticed that the patients of group A had a significantly better psycho-social component, which probably influenced the assessment of other scales. Group A patients had statistically better all indicators of quality of life after surgery comparing with group B patients. Group B patients complained about the sound of the artificial aortic valve prosthesis, sometimes the occurrence of minor nosebleeds and the need for frequent visits of the doctor to monitor blood "thinning" indicators. Conclusions. The obtained results indicate a positive change in the quality of life in patients of both groups. When David operation is performed for aortic root and ascending aortic aneurysms, the quality of life is significantly better than in patients after Bentall operation. We recommend performing David operations at the highly specialized cardiac centers.

Vision–language foundation model for echocardiogram interpretation

The development of robust artificial intelligence models for echocardiography has been limited by the availability of annotated clinical data. Here, to address this challenge and improve the performance of cardiac imaging models, we developed EchoCLIP, a vision–language foundation model for echocardiography, that learns the relationship between cardiac ultrasound images and the interpretations of expert cardiologists across a wide range of patients and indications for imaging. After training on 1,032,975 cardiac ultrasound videos and corresponding expert text, EchoCLIP performs well on a diverse range of benchmarks for cardiac image interpretation, despite not having been explicitly trained for individual interpretation tasks. EchoCLIP can assess cardiac function (mean absolute error of 7.1% when predicting left ventricular ejection fraction in an external validation dataset) and identify implanted intracardiac devices (area under the curve (AUC) of 0.84, 0.92 and 0.97 for pacemakers, percutaneous mitral valve repair and artificial aortic valves, respectively). We also developed a long-context variant (EchoCLIP-R) using a custom tokenizer based on common echocardiography concepts. EchoCLIP-R accurately identified unique patients across multiple videos (AUC of 0.86), identified clinical transitions such as heart transplants (AUC of 0.79) and cardiac surgery (AUC 0.77) and enabled robust image-to-text search (mean cross-modal retrieval rank in the top 1% of candidate text reports). These capabilities represent a substantial step toward understanding and applying foundation models in cardiovascular imaging for preliminary interpretation of echocardiographic findings.

Branching externalized guidewire to facilitate retrograde endograft deployment in the hybrid aortic repair with aortic valve replacement

BackgroundThe hybrid aortic repair consisting of root replacement and endovascular arch repair is an optimal alternative for patients unfit for circulatory arrest. However, an artificial aortic valve prosthesis might impede the endovascular procedure. This study aims to present our experience with the branching retrograde externalized guidewire (BREG) technique in such situations, and discuss its utility and efficiency. MethodsFrom January 2015 to June 2021, a total of 112 patients underwent aortic root/valve replacement combined with aortic arch repair. Among them, the BREG technique was adopted on 24 patients, and the traditional frozen elephant trunk (FET) technique was used for 88 patients. The indication of the BREG was as follows: high-risk patients not suitable for traditional open surgery; meanwhile, the aortic disease required extended repair, and the aortic valve needed to be replaced concomitantly. The data of the 2 groups were compared. ResultsThe cardiopulmonary bypass time (213.5 ± 73.6 min vs. 246.5 ± 46.2 min, P = 0.046) and cross-clamped time (109.0 ± 27.6 min vs. 139.0 ± 24.6 min, P < 0.001) were significantly shorter in the BREG group than that in the FET group. Less operative red blood cell consumption was achieved in the BREG group (6.6 ± 5.7 vs. 9.4 ± 8.0 U, P = 0.046). The 30-day mortality was similar between the 2 groups (8.3% BREG vs. 9.1% FET, P > 0.999). ConclusionThe BREG technique facilitated the advancement of endovascular stent graft, avoided impeding the aortic valve prosthesis in hybrid aortic surgery with aortic valve replacement, and may benefit high-risk patients.

Multiscale model for blood flow after a bileaflet artificial aortic valve implantation

Cardiovascular diseases are the leading cause of mortality in the world, mainly due to atherosclerosis and its consequences. The article presents the numerical model of the blood flow through artificial aortic valve. The overset mesh approach was applied to simulate the valve leaflets motion and to realize the moving mesh, in the aortic arch and the main branches of cardiovascular system. To capture the cardiac system’s response and the effect of vessel compliance on the outlet pressure, the lumped parameter model has been also included within the solution procedure. Three different turbulence modeling approaches were used and compared — the laminar, k-ϵ and k-ω model. The simulation results were also compared with the model excluding the moving valve geometry and the importance of the lumped parameter model for the outlet boundary condition was analyzed. Proposed numerical model and protocol was found as suitable for performing the virtual operations on the real patient vasculature geometry. The time-efficient turbulence model and overall solving procedure allows to support the clinicians in making decisions about the patient treatment and to predict the results of the future surgery.

3D printing and medicine

In modern conditions, the possibilities of using 3D printing in medicine are expanding, and it occupies about 11% of the global additive manufacturing market. At the Kirov Military Medical Academy and the ERA Military Innovation Technopolis, 3D printing is used for training, preoperative planning, the creation of splints, the manufacture of non-invasive functional products, and the creation of COVID-19 prevention aids.&#x0D; In order to determine the prospects for development, foreign experience in the use of 3D printing in medicine has been studied over the past 5 years.&#x0D; It is established that a register of clinical data on 3D printing is being created for training, 3D models are being printed to simulate tissue resistance during surgery. With the help of preoperative planning, Siamese twins are separated, doctors are trained in surgical operations on 3D models of elastic resin feet, cardiological models are used to predict the risk of complications during transcatheter implantation of an artificial aortic valve, as well as rehearsals of operations with congenital heart anomalies. Individual implants are manufactured for the lumbar and cervical spine, replacement of the damaged area of the chest and rib, finger phalanges, hip and knee replacements. As auxiliary products, individual surgical instruments for operations with low trauma, orthopedic insoles, elastic stents for the urethra and mesh stents of the trachea are created. New materials made of polyamide (PA11), polyesteresterketone, titanium alloys, absorbable polymer and biocompatible resin are offered for 3D printing. There are new 3D printing software and updates of existing ones. Personalized braces and aligners are printed in dentistry. With the help of 3D printing, individual multi-layered polytablets, smart tablets that release medicinal substances on command from a smartphone, childrens chewing tablets are created. For research purposes, the following devices have been printed: simulating cardiac tissue with sensors to track the effects of drugs and toxins; predicting the individual response of the biopsy tumor material to treatment; diagnosing some infectious diseases using a smartphone and a silicon microfluidic chip.&#x0D; The use of 3D printing in medicine individualizes and improves the quality of medical care.

Fluid–Structure Interaction methods for the progressive anatomical and artificial aortic valve stenosis

Cardiovascular system diseases, as aortic valve stenosis, are the main cause of mortality and morbidity among patients. There is still a room for enhancement of the diagnostic and therapeutic procedures, which will lead to improvement of the treatment. One of the remedies are the computer tools to support the medical diagnoses and prostheses design. The development of a procedure for modeling the aortic valves: anatomical tricuspid valve and artificial bileaflet valve, still is a very challenging task. In presented work, the application of the novel, advanced moving mesh model, that consists of the coupling of the dynamic mesh smoothing and the overset mesh technique, to speed up the computation and improve the convergence and stability was shown. The real 2D and 3D vasculature and valve geometries were created based on the echocardiography images available in literature. The calculations of anatomical and artificial valve models were performed for the various severity of the atherosclerosis — not previously published for the bileaflet mechanical valve. The impact of calcification process onto natural and artificial aortic valves was assessed and compared.

Infective endocarditis of an artificial aortic valve and native mitral valve after transcatheter aortic valve implantation

Infective endocarditis of an artificial aortic valve and native mitral valve after transcatheter aortic valve implantation

The usefulness of cardiac computed tomography in the diagnosis of perivalvular complications in patients with prosthetic valve endocarditis

Abstract Background and purpose of the study Echocardiography remains the gold standard for the diagnosis of prosthetic valve endocarditis (PVE). But in around 15% of cases, its results can be false negative due to the acoustic shadow of artificial valves. The aim of the study was compare cardiac computed tomography (CT) with other imaging modalities in the diagnosis of perivalvular complications in patients with PVE. Material and methods The study included 35 consecutive patients with PVE. Thirty of them had an artificial aortic valve (17- mechanical valve, 13-biological valve), 7-mechanical mitral valve, and one patient was after biological pulmonary valve implantation. Three patients were after aortic and mitral valve replacement. Each patient underwent transthoracic (TTE) and transesophageal (TEE) echocardiography. ECG-gated CT examinations were performed with a dual source CT system. All patients were qualified for surgical treatment. The assessment included the presence of vegetation, perivalvular abscess/pseudoaneurysm, inflammatory infiltration and prosthesis dehiscence. Results Intraoperative assessment revealed the presence of vegetations in 16 patients. The sensitivity of echocardiography (TTE+TEE) and CT examinations was 100% and 93% respectively. Twenty one abscesses/pseudoaneurysms were found intraoperatively. The sensitivity of echocardiography and CT examinations was 76% and 85%, respectively. The analysis of total TTE, TEE and CT findings showed that supplementing echocardiography with CT had increased the sensitivity of the method for detecting abscess/pseudoaneurysms to 95%. In a patient in whom no abscesse was found, inflammatory infiltration was diagnosed in echocardiography. Inflammatory infiltration was diagnosed intraoperatively in 13 patients. The sensitivity of echocardiography and CT was 69% in both examinations. The sensitivity of the combination TTE + TEE + CT was 92%. Perivalvular leakage was found intraoperatively in 17 patients. The sensitivity of echocardiography and CT for the diagnosis of this complication was 100% and 87%, respectively. Conclusions CT is better than echocardiography in diagnosing abscesses/pseudoaneurysms and has the same sensitivity in detecting inflammatory infiltration. Adding CT to echocardiography improves the sensitivity of these complications detection. CT is not superior to echocardiography in the diagnosis of vegetations and perivalvular leakage, but it can be a useful tool when echocardiography findings are inconclusive. Funding Acknowledgement Type of funding source: None

Low Immunogenicity Pericardia from Gene Knockout Pigs as Biological Valve Materials

The immunogenicity of heterogeneous pericardium is a major factor causing the failure of commercial biological valves. Both decellularization and glutaraldehyde crosslinking can reduce the immunogenicity of pericardium, but it is difficult to completely remove it. Getting gene knockout pigs is considered a highly efficient method to obtain low-immunogenic biological tissues, including the pericardium. Our results showed that repeated cycles of decellularization could obviously reduce the residual DNA in tissues for pigs without gene knockout, but at the same time they could also break down the components of pericardia, resulting in a decline in mechanical properties. We compared the mechanical and biological properties of the glutaraldehyde crosslinked pericardia of GGTA1 knockout pig, GGTA1/CMAH knockout pig, GGTA1/β4GalNT2 knockout pig and wild type (WT) pig. The mechanical properties of the pericardia of GGTA1 knockout pig and GGTA1/CMAH knockout pig were similar to those of control pig (WT), and the experimental results of subdermal implantation in rats showed significantly reduced immune rejection and calcification. Pulsatile flow and fatigue in vitro tests showed that the fabricated artificial aortic valve met the hydrodynamic requirements after 2×10^8 accelerated fatigue cycles. Gene knockout pigs have great potential in the application of artificial biological valve products.

Externalized transapical guidewire technique after artificial aortic valve replacement during complete endovascular aortic arch repair.

An externalized transapical guidewire (ETAG) technique has been used for safe delivery of high-profile devices through a tortuous aorta to zone 0, which is currently precluded after mechanical artificial aortic valve replacement (AVR). The aim of the study was to report one center’s experience (based on 3 cases) of a unique modification to the ETAG technique used for the first time during total endovascular aortic arch repair after AVR.This report contains technical notes regarding a new method of steering the guidewire from the apex inside the artificial aortic valve during total endovascular aortic arch repair after AVR and the details crucial in preparation for this mini-invasive procedure.As a conclusion, the ETAG technique could be performed after mechanical AVR with active positioning of the guidewire carried out under the control of transesophageal echocardiography.

Uspešan tretman zahtevnog slučaja infektivnog endokarditisa

Introduction/aim: We are presenting the case of a patient suffering from fibrous cardiac skeleton damage caused by advanced infective endocarditis after aortic valve replacement surgery, whose cardiac surgery treatment proved to be successful. Case report: A redo procedure was performed through a median sternotomy using cardiopulmonary bypass. Artificial aortic and native mitral valves were excised and all infected tissue removed. Reconstruction of the fibrotic cardiac skeleton was done using two autologous pericardial patches according to Tyrone-David. Both mechanical valves were implanted. Conclusion: Successful treatment of one of the most difficult conditions in cardiac surgery can be achieved in our country.

Finite Element Analysis of a Novel Aortic Valve Stent.

Worldwide, one of the leading causes of death for patients with cardiovascular disease is aortic valve failure or insufficiency as a result of calcification and cardiovascular disease. The surgical treatment consists of repair or total replacement of the aortic valve. Artificial aortic valve implantation via a percutaneous or endovascular procedure is the minimally invasive alternative to open chest surgery, and the only option for high-risk or older patients. Due to the complex anatomical location between the left ventricle and the aorta, there are still engineering design optimization challenges which influence the long-term durability of the valve. In this study we developed a computer model and performed a numerical analysis of an original self-expanding stent for transcatheter aortic valve in order to optimize its design and materials. The study demonstrates the current valve design could be a good alternative to the existing commercially available valve devices.

A Proof of Concept Study of Using Machine-Learning in Artificial Aortic Valve Design: From Leaflet Design to Stress Analysis.

Artificial heart valves, used to replace diseased human heart valves, are life-saving medical devices. Currently, at the device development stage, new artificial valves are primarily assessed through time-consuming and expensive benchtop tests or animal implantation studies. Computational stress analysis using the finite element (FE) method presents an attractive alternative to physical testing. However, FE computational analysis requires a complex process of numeric modeling and simulation, as well as in-depth engineering expertise. In this proof of concept study, our objective was to develop machine learning (ML) techniques that can estimate the stress and deformation of a transcatheter aortic valve (TAV) from a given set of TAV leaflet design parameters. Two deep neural networks were developed and compared: the autoencoder-based ML-models and the direct ML-models. The ML-models were evaluated through Monte Carlo cross validation. From the results, both proposed deep neural networks could accurately estimate the deformed geometry of the TAV leaflets and the associated stress distributions within a second, with the direct ML-models (ML-model-d) having slightly larger errors. In conclusion, although this is a proof-of-concept study, the proposed ML approaches have demonstrated great potential to serve as a fast and reliable tool for future TAV design.

Autonomous piloting in a beating heart

Medical Robotics Catheter navigation in minimally invasive procedures is challenging. Fagogenis et al. trained a robotic catheter to identify blood, heart tissue, and an artificial aortic valve using a combination of visual and force data, an approach called haptic vision. They then programmed wall-following algorithms that directed the robot through a beating pig heart in vivo. The robot autonomously moved along the ventricular wall, to and around the valve, and to specific paravalvular leak sites, with a performance comparable to that of handheld catheter navigation and joystick control of the robot. Sci. Robot. 4 , eaaw1977 (2019).

FEA of displacements and stresses of aortic heart valve leaflets during the opening phase

Purpose: Modelling of biomechanical behaviour of heart valve materials aids improvement of biofunctional feature. The aim of the work was assessment of influence of material thickness of leaflets of artificial aortic valve on displacements and stresses during opening phase using finite element analysis (FEA). Design/methodology/approach: The model of aortic valve was developed on the basis of average anatomical valve shapes and dimensions. Nonlinear dynamic large displacements analysis with assumption of isotropic linear elastic material behaviour was used in simulation (Solidworks). The modulus of elasticity of 5.0 MPa was assumed and Poisson ratio set to 0.45. The rigidly supported leaflets was loaded by pressure increasing in the range 0-55 mmHg in time 0.1 s. Leaflets with material thickness 0.13 and 0.15 and 0.17 mm were analysed. The thickness was simulated with shell finite elements. Findings: The highest stresses were observed in the areas of fixation of the leaflets near the scaffold and were lower than dangerous value of fatigue of polyurethanes. Increasing the thickness of valve leaflet material in the range of 40 micrometres resulted in reduction of the valve outlet by almost 10 percent. Research limitations/implications: The FEA was limited to the isotropic linear-elastic behaviour of the material albeit can be used to assess leaflet deformation during dynamic load. Practical implications: Leaflets design may be start from efficient FEA which helps estimation of material impact on stress and fold formation which can affect local blood flow. Originality/value: Aortic heart valve leaflet material can be initially tested in dynamic conditions during opening phase with using FEA.

Leaflet Kinematics of Mechanical and Bioprosthetic Aortic Valve Prostheses.

The hemodynamic performance of artificial aortic valves (AVs) and the probability for structural valve deterioration can be linked to the valve kinematics. Comparability among different studies is limited because of variations in the experimental setups and physiologic boundary conditions. This study presents results of kinematic measurements of bioprosthetic and mechanical AVs that were tested in an identical experimental setting such that they can be directly compared with each other. The kinematics of AVs is typically presented in the form of the geometric orifice area and its temporal evolution. These parameters cannot capture asynchronous leaflet motion and out-of-plane leaflet velocity. In this work, each leaflet was tracked individually for a more detailed understanding of the leaflet kinematics, asynchronous leaflet motion, and leaflet tip velocities. A bioprosthetic valve, Edwards INTUITY (EINT), and two mechanical valves, Medtronic ADVANTAGE (MADV) and a Lapeyre-Triflo FURTIVA (TFUR), were tested in a compliant model of the aortic root in a physiologic flow loop. TFUR and MADV opened alike with maximum leaflet tip velocities of 0.77 and 0.66 m/s, respectively. The opening of EINT showed significantly higher local in-plane leaflet velocities of more than 2 m/s. EINT and TFUR exhibited similar early and slow closure. MADV closed significantly later with increased velocity. TFUR had a median maximum leaflet tip velocity of 0.39 m/s during valve closure and that of MADV was 0.83 m/s, whereas EINT exhibited a median maximum local in-plane leaflet velocity of 0.37 m/s. EINT experienced leaflet fluttering during systole with a flapping frequency of 36 Hz.

3D/2D Registration with superabundant vessel reconstruction for cardiac resynchronization therapy.

A key component of image guided interventions is the registration of preoperative and intraoperative images. Classical registration approaches rely on cross-modality information; however, in modalities such as MRI and X-ray there may not be sufficient cross-modality information. This paper proposes a fundamentally different registration approach which uses adjacent anatomical structures with superabundant vessel reconstruction and dynamic outlier rejection. In the targeted clinical scenario of cardiac resynchronization therapy (CRT) delivery, preoperative, non contrast-enhanced, MRI is registered to intraoperative, contrasted X-ray fluoroscopy. The adjacent anatomical structures are the left ventricle (LV) from MRI and the coronary veins reconstructed from two contrast-enhanced X-ray images. The novel concept of superabundant vessel reconstruction is introduced to bypass the standard reconstruction problem of establishing one-to-one correspondences. Furthermore, a new dynamic outlier rejection method is proposed, to enable globally optimal point set registration. The proposed approach has been qualitatively and quantitatively evaluated on phantom, clinical CT angiography with ground truth and clinical CRT data. A novel evaluation method is proposed for clinical CRT data based on previously implanted artificial aortic and mitral valves. The registration accuracy in 3D was 2.94 mm for the aortic and 3.86 mm for the mitral valve. The results are below the required accuracy identified by clinical partners to be the half-segment size (16.35 mm) of a standard American Heart Association (AHA) 16 segment model of the LV.

Recurrent myocardial infarction due to coronary artery embolisms in a patient with an artificial aortic valve

Recurrent myocardial infarction due to coronary artery embolisms in a patient with an artificial aortic valve

A rare case of obstruction of the artificial aortic valve with pannus formation

A rare case of obstruction of the artificial aortic valve with pannus formation

The Development of a New Physiological Flow Chamber for the Investigation of Artificial Aortic Valves

Objectives: An optimized fluid dynamic profile of artificial heart valves is crucial to result in excellent hemodynamic valve behavior. Therefore, the testing of prostheses under physiological conditions is mandatory to improve the flow characteristics of artificial heart valves. However, due to the very specific contraction of the left ventricle and the complex physical behavior of the aorta with its anatomic special conditions, the development of a realistic flow channel remains challenging.