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Prosthetic heart valve design

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https://www.readbyqxmd.com/read/28722138/a-red-blood-cell-model-to-estimate-the-hemolysis-fingerprint-of-cardiovascular-devices
#1
Riccardo Toninato, Giuseppe Fadda, Francesca Maria Susin
One of the most relevant and open issues within cardiovascular prosthetic hemodynamic performance is a realistic quantification of the damage sustained by red blood cells (RBCs). Specifically, the optimal design of bileaflet mechanical heart valves (BMHVs) requires both low shear stresses along the leaflets and short particle resident times. This study approaches RBC damage estimation by developing a numerical model of RBCs and computing the damage sustained by a set of passive RBCs immersed within in vitro flows...
July 19, 2017: Artificial Organs
https://www.readbyqxmd.com/read/28644382/metal-ion-loaded-nanofibre-matrices-for-calcification-inhibition-in-polyurethane-implants
#2
Charanpreet Singh, Xungai Wang
Pathologic calcification leads to structural deterioration of implant materials via stiffening, stress cracking, and other structural disintegration mechanisms, and the effect can be critical for implants intended for long-term or permanent implantation. This study demonstrates the potential of using specific metal ions (MI)s for inhibiting pathological calcification in polyurethane (PU) implants. The hypothesis of using MIs as anti-calcification agents was based on the natural calcium-antagonist role of Mg(2+) ions in human body, and the anti-calcification effect of Fe(3+) ions in bio-prosthetic heart valves has previously been confirmed...
June 23, 2017: Journal of Functional Biomaterials
https://www.readbyqxmd.com/read/28631145/biaxial-mechanical-properties-of-bovine-jugular-venous-valve-leaflet-tissues
#3
Hsiao-Ying Shadow Huang, Jiaqi Lu
Venous valve incompetence has been implicated in diseases ranging from chronic venous insufficiency (CVI) to intracranial venous hypertension. However, while the mechanical properties of venous valve leaflet tissues are central to CVI biomechanics and mechanobiology, neither stress-strain curves nor tangent moduli have been reported. Here, equibiaxial tensile mechanical tests were conducted to assess the tangent modulus, strength and anisotropy of venous valve leaflet tissues from bovine jugular veins. Valvular tissues were stretched to 60% strain in both the circumferential and radial directions, and leaflet tissue stress-strain curves were generated for proximal and distal valves (i...
June 19, 2017: Biomechanics and Modeling in Mechanobiology
https://www.readbyqxmd.com/read/28544834/in-vitro-pulsatile-flow-measurement-in-prosthetic-heart-valves-an-inter-laboratory-comparison
#4
Stephen M Retta, Jeff Kepner, Salvador Marquez, Bruce A Herman, Mark C S Shu, Laurence W Grossman
BACKGROUND AND AIM OF STUDY: One of the first steps in qualifying a new prosthetic valve for eventual clinical use is preclinical flow performance testing in vitro. Such testing is typically performed in an in-vitro test system that simulates the pumping mechanics of the left ventricle of the heart, generally referred to as a pulse duplicator or duplicator. Historically, test results in these systems have varied from duplicator to duplicator. This collaborative effort between heart valve manufacturers and the Food and Drug Administration (FDA) was designed to evaluate the variability of the pulse duplicator test technology for pulsatile flow performance measurement in an interlaboratory round robin...
January 2017: Journal of Heart Valve Disease
https://www.readbyqxmd.com/read/28510720/effects-of-a-3d-segmental-prosthetic-system-for-tricuspid-valve-annulus-remodelling-on-the-right-coronary-artery-a-human-cadaveric-coronary-angiography-study
#5
Mohsen Riki-Marishani, Arash Gholoobi, Ghasem Sazegar, Mathias H Aazami, Aria Hedjazi, Maryam Sajjadian, Mahmoud Ebrahimi, Ahmad Aghaii-Zade Torabi
OBJECTIVES: A prosthetic system to repair secondary tricuspid valve regurgitation was developed. The conceptual engineering of the current device is based on 3D segmental remodelling of the tricuspid valve annulus in lieu of reductive annuloplasty. This study was designed to investigate the operational safety of the current prosthetic system with regard to the anatomical integrity of the right coronary artery (RCA) in fresh cadaveric human hearts. METHODS: During the study period, from January to April 2016, the current prosthetic system was implanted on the tricuspid valve annulus in fresh cadaveric human hearts that met the study's inclusion criteria...
May 16, 2017: Interactive Cardiovascular and Thoracic Surgery
https://www.readbyqxmd.com/read/28430305/turbulence-measurements-in-an-axial-rotary-blood-pump-with-laser-doppler-velocimetry
#6
Chan Y Schüle, Klaus Affeld, Max Kossatz, Christian O Paschereit, Ulrich Kertzscher
BACKGROUND: The implantation of rotary blood pumps as ventricular assist devices (VADs) has become a viable therapy for quite a number of patients with end-stage heart failure. However, these rotary blood pumps cause adverse events that are related to blood trauma. It is currently believed that turbulence in the pump flow plays a significant role. But turbulence has not been measured to date because there is no optical access to the flow space in rotary blood pumps because of their opaque casings...
April 18, 2017: International Journal of Artificial Organs
https://www.readbyqxmd.com/read/28228313/significant-intra-valvular-pressure-loss-across-epic-supra-and-perimount-magna-supra-annular-designed-aortic-bioprostheses-in-patients-with-normal-aortic-size
#7
Jagdish C Mohan, Vishwas Mohan, Madhu Shukla, Arvind Sethi
Doppler-derived trans-prosthetic gradients are higher and the estimated effective valve area is smaller than the catheter-derived and directly measured hemodynamic values, mostly due to pressure recovery phenomenon. Pressure recovery to a varying extent is common to all prosthetic heart valves including bioprostheses. Pressure recovery-related differences are usually small except in patients with bileaflet metallic prosthesis, wherein high-pressure local jets across central orifice have been documented since long back and also in patients with narrow aortic root...
January 2017: Indian Heart Journal
https://www.readbyqxmd.com/read/28040318/transcatheter-mitral-valve-replacement-for-patients-with-symptomatic%C3%A2-mitral%C3%A2-regurgitation-a-global-feasibility-trial
#8
David W M Muller, Robert Saeid Farivar, Paul Jansz, Richard Bae, Darren Walters, Andrew Clarke, Paul A Grayburn, Robert C Stoler, Gry Dahle, Kjell A Rein, Marty Shaw, Gregory M Scalia, Mayra Guerrero, Paul Pearson, Samir Kapadia, Marc Gillinov, Augusto Pichard, Paul Corso, Jeffrey Popma, Michael Chuang, Philipp Blanke, Jonathon Leipsic, Paul Sorajja
BACKGROUND: Symptomatic mitral regurgitation (MR) is associated with high morbidity and mortality that can be ameliorated by surgical valve repair or replacement. Despite this, many patients with MR do not undergo surgery. Transcatheter mitral valve replacement (TMVR) may be an option for selected patients with severe MR. OBJECTIVES: This study aimed to examine the effectiveness and safety of TMVR in a cohort of patients with native valve MR who were at high risk for cardiac surgery...
January 31, 2017: Journal of the American College of Cardiology
https://www.readbyqxmd.com/read/27915018/design-and-surface-immobilization-of-short-anti-biofilm-peptides
#9
Biswajit Mishra, Tamara Lushnikova, Radha M Golla, Xiuqing Wang, Guangshun Wang
Short antimicrobial peptides are essential to keep us healthy and their lasting potency can inspire the design of new types of antibiotics. This study reports the design of a family of eight-residue tryptophan-rich peptides (TetraF2W) obtained by converting the four phenylalanines in temporin-SHf to tryptophans. The temporin-SHf template was identified from the antimicrobial peptide database (http://aps.unmc.edu/AP). Remarkably, the double arginine variant (TetraF2W-RR) was more effective in killing methicillin-resistant Staphylococcus aureus (MRSA) USA300, but less cytotoxic to human skin HaCat and kidney HEK293 cells, than the lysine-containing dibasic combinations (KR, RK and KK)...
February 2017: Acta Biomaterialia
https://www.readbyqxmd.com/read/27873180/pledget-armed-sutures-affect-the-haemodynamic-performance-of-biologic-aortic-valve-substitutes-a-preliminary-experimental-and-computational-study
#10
Claudio Capelli, Chiara Corsini, Dario Biscarini, Francesco Ruffini, Francesco Migliavacca, Alfred Kocher, Guenther Laufer, Andrew M Taylor, Silvia Schievano, Martin Andreas, Gaetano Burriesci, Claus Rath
Surgical aortic valve replacement is the most common procedure of choice for the treatment of severe aortic stenosis. Bioprosthetic valves are traditionally sewed-in the aortic root by means of pledget-armed sutures during open-heart surgery. Recently, novel bioprostheses which include a stent-based anchoring system have been introduced to allow rapid implantation, therefore reducing the duration and invasiveness of the intervention. Different effects on the hemodynamics were clinically reported associated with the two technologies...
March 2017: Cardiovascular Engineering and Technology
https://www.readbyqxmd.com/read/27873034/on-the-mechanics-of-transcatheter-aortic-valve-replacement
#11
Lakshmi P Dasi, Hoda Hatoum, Arash Kheradvar, Ramin Zareian, S Hamed Alavi, Wei Sun, Caitlin Martin, Thuy Pham, Qian Wang, Prem A Midha, Vrishank Raghav, Ajit P Yoganathan
Transcatheter aortic valves (TAVs) represent the latest advances in prosthetic heart valve technology. TAVs are truly transformational as they bring the benefit of heart valve replacement to patients that would otherwise not be operated on. Nevertheless, like any new device technology, the high expectations are dampened with growing concerns arising from frequent complications that develop in patients, indicating that the technology is far from being mature. Some of the most common complications that plague current TAV devices include malpositioning, crimp-induced leaflet damage, paravalvular leak, thrombosis, conduction abnormalities and prosthesis-patient mismatch...
February 2017: Annals of Biomedical Engineering
https://www.readbyqxmd.com/read/27307007/effect-of-arched-leaflets-and-stent-profile-on-the-hemodynamics-of-tri-leaflet-flexible-polymeric-heart-valves
#12
Atieh Yousefi, David L Bark, Lakshmi P Dasi
Polymeric heart valves (PHV) can be engineered to serve as alternatives for existing prosthetic valves due to higher durability and hemodynamics similar to bioprosthetic valves. The purpose of this study is to evaluate the effect of geometry on PHVs coaptation and hemodynamic performance. The two geometric factors considered are stent profile and leaflet arch length, which were varied across six valve configurations. Three models were created with height to diameter ratio of 0.6, 0.7, and 0.88. The other three models were designed by altering arch height to stent diameter ratio, to be 0, 0...
February 2017: Annals of Biomedical Engineering
https://www.readbyqxmd.com/read/27140294/in-vitro-2d-piv-measurements-and-related-aperture-areas-of-tricuspid-bioprosthetic-mitral-valves-at-the-beginning-of-diastole
#13
Ovandir Bazan, Jayme Pinto Ortiz, Newton Kiyoshi Fukumasu, Antonio Luiz Pacifico, Jurandir Itizo Yanagihara
PURPOSE: Besides ventricular parameters, the design and angular orientation of a prosthetic heart valve induce a specific flow field. The aim of this study was to know the inflow characteristics of a left ventricular model (LVM), investigating the behavior of tricuspid bioprosthetic mitral valves in terms of velocity profiles and related valve aperture areas at the beginning of diastole, under different conditions. METHODS: 3 heart rates (HRs) were established in the LVM and each mitral bioprosthesis (27 and 31 mm diameter) was installed in 2 orientations, rotated by 180° ...
July 4, 2016: International Journal of Artificial Organs
https://www.readbyqxmd.com/read/27026750/contemporary-outcomes-after-surgical-aortic-valve-replacement-with-bioprostheses-and-allografts-a-systematic-review-and-meta-analysis
#14
REVIEW
Simone A Huygens, Mostafa M Mokhles, Milad Hanif, Jos A Bekkers, Ad J J C Bogers, Maureen P M H Rutten-van Mölken, Johanna J M Takkenberg
Many observational studies have reported outcomes after surgical aortic valve replacement (AVR), but there are no recent systematic reviews and meta-analyses including all available bioprostheses and allografts. The objective of this study is to provide a comprehensive and up-to-date overview of the outcomes after AVR with bioprostheses and allografts reported in the last 15 years. We conducted a systematic literature review (PROSPERO register: CRD42015017041) of studies published between 2000-15. Inclusion criteria were observational studies or randomized controlled trials reporting on outcomes of AVR with bioprostheses (stented or stentless) or allografts, with or without coronary artery bypass grafting (CABG) or valve repair procedure, with study population size n ≥ 30 and mean follow-up length ≥5 years...
October 2016: European Journal of Cardio-thoracic Surgery
https://www.readbyqxmd.com/read/26919564/reynolds-shear-stress-for-textile-prosthetic-heart-valves-in-relation-to-fabric-design
#15
David L Bark, Atieh Yousefi, Marcio Forleo, Antoine Vaesken, Frederic Heim, Lakshmi P Dasi
The most widely implanted prosthetic heart valves are either mechanical or bioprosthetic. While the former suffers from thrombotic risks, the latter suffers from a lack of durability. Textile valves, alternatively, can be designed with durability and to exhibit hemodynamics similar to the native valve, lowering the risk for thrombosis. Deviations from native valve hemodynamics can result in an increased Reynolds Shear Stress (RSS), which has the potential to instigate hemolysis or shear-induced thrombosis. This study is aimed at characterizing flow in multiple textile valve designs with an aim of developing a low profile valve...
July 2016: Journal of the Mechanical Behavior of Biomedical Materials
https://www.readbyqxmd.com/read/26915473/vortex-ring-behavior-provides-the-epigenetic-blueprint-for-the-human-heart
#16
Per M Arvidsson, Sándor J Kovács, Johannes Töger, Rasmus Borgquist, Einar Heiberg, Marcus Carlsson, Håkan Arheden
The laws of fluid dynamics govern vortex ring formation and precede cardiac development by billions of years, suggesting that diastolic vortex ring formation is instrumental in defining the shape of the heart. Using novel and validated magnetic resonance imaging measurements, we show that the healthy left ventricle moves in tandem with the expanding vortex ring, indicating that cardiac form and function is epigenetically optimized to accommodate vortex ring formation for volume pumping. Healthy hearts demonstrate a strong coupling between vortex and cardiac volumes (R(2) = 0...
February 26, 2016: Scientific Reports
https://www.readbyqxmd.com/read/26786673/effect-of-heart-rate-on-the-hemodynamics-of-bileaflet-mechanical-heart-valves-prostheses-st-jude-medical-in-the-aortic-position-and-in-the-opening-phase-a-computational-study
#17
Mehdi Jahandardoost, Guy Fradet, Hadi Mohammadi
To date, to the best of the authors' knowledge, in almost all of the studies performed around the hemodynamics of bileaflet mechanical heart valves, a heart rate of 70-72 beats/min has been considered. In fact, the heart rate of ~72 beats/min does not represent the entire normal physiological conditions under which the aortic or prosthetic valves function. The heart rates of 120 or 50 beats/min may lead to hemodynamic complications, such as plaque formation and/or thromboembolism in patients. In this study, the hemodynamic performance of the bileaflet mechanical heart valves in a wide range of normal and physiological heart rates, that is, 60-150 beats/min, was studied in the opening phase...
March 2016: Proceedings of the Institution of Mechanical Engineers. Part H, Journal of Engineering in Medicine
https://www.readbyqxmd.com/read/26781657/management-of-coronary-artery-disease-and-conduction-abnormalities-in-transcatheter-aortic-valve-implantation
#18
Anna Kostopoulou, Panagiotis Karyofillis, Efthimios Livanis, George Karavolias, George Theodorakis, John Paraskevaides, Vassilis Voudris
Transcatheter aortic valve replacement (TAVR) is an expanding, catheter-based technology that allows the implantation of a prosthetic valve without requiring open heart surgery for the treatment of severe aortic stenosis (AS). The frequency of coronary artery disease (CAD) in patients (pts) with severe AS undergoing surgical treatment ranges from 30 to 50 %. This tends to be higher in pts undergoing TAVR with a prevalence of 49-76 % and is more prevalent with older age and the fact that TAVR is commonly performed in high-risk groups with more advanced cardiovascular disease...
February 2016: Current Treatment Options in Cardiovascular Medicine
https://www.readbyqxmd.com/read/26737004/3d-velocity-field-characterization-of-prosthetic-heart-valve-with-two-different-valve-testers-by-means-of-stereo-piv
#19
COMPARATIVE STUDY
Giuseppe D'Avenio, Mauro Grigioni, Carla Daniele, Umberto Morbiducci, Kathrin Hamilton
BACKGROUND: Prosthetic heart valves can be associated to mechanical loading of blood, potentially linked to complications (hemolysis and thrombogenicity) which can be clinically relevant. In order to test such devices in pulsatile mode, pulse duplicators (PDs) have been designed and built according to different concepts. This study was carried out to compare anemometric measurements made on the same prosthetic device, with two widely used PDs. METHODS: The valve (a 27-mm bileaflet valve) was mounted in the aortic section of the PD...
2015: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/26736254/effect-of-valsalva-in-the-pulmonary-prosthetic-conduit-valve-on-hemodynamic-function-in-a-mock-circulatory-system
#20
Yusuke Tsuboko, Yasuyuki Shiraishi, Akihiro Yamada, Tomoyuki Yambe, Satoshi Matsuo, Yoshikatsu Saiki, Masaaki Yamagishi
Pulmonary conduit valves are used as one of the surgical treatment methods of congenital heart diseases. We have been designing a sophisticated pulmonary conduit valve for the right ventricular outflow tract reconstruction in pediatric patients. In this study, two types of polyester grafts with or without bulging structures for the conduit valves were used and evaluated from the hemodynamic point of view focusing on the application of these conduit valves in the grown-up congenital heart failure patients. We examined valvular function in the originally developed pulmonary mock circulatory system, which consisted of a pneumatic driven right ventricular model, a pulmonary valve chamber, and an elastic pulmonary compliance model with peripheral vascular resistance units...
2015: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
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