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Bioengineering
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The Next Generation of Prosthetic Heart Valves
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The Next Generation of Prosthetic Heart Valves

A special issue of Bioengineering (ISSN 2306-5354).

Deadline for manuscript submissions: closed (10 November 2020) | Viewed by 15012

Special Issue Editor

Assoc. Prof. Dr. Hadi Mohammadi

E-Mail Website
Guest Editor
Heart Valve Performance Laboratory, School of Mechanical Engineering, Faculty of Medicine, University of British Columbia, Okanagan, Kelowna, BC, Canada
Interests: prosthetic heart valves; theory of elasticity; nonlinear solid mechanics; multiscale modeling; cardiovascular engineering and technology; atherosclerosis; articular cartilage mechanobiology and osteoarthritis; cellular and molecular biomechanics; mechanical vibrations on human performance

Special Issue Information

Dear Colleagues,

There are nearly 350,000 valve replacement procedures annually worldwide. The age range of the majority of patients with aortic valve pathology in need of replacement is between 60 and 80. Among the two main aortic valve diseases, replacement for aortic insufficiency is performed much less frequently for aortic stenosis of ~15% than for aortic stenosis of ~85%. Mitral regurgitation is one of the most common forms of heart valve disorders and occurs when blood leaks back into the left atrium from the left ventricle during heart contraction. This is a result of an apposition failure between the valve leaflets from a functional or congenital cause. Patients with a perceived risk from the procedure, usually due to age or additional issues, need a non-invasive procedure option to replace their incompetent heart valve. That is where development into catheter-based valve implantation is vital.

Mechanical heart valves are used to replace diseased human heart valves in approximately 50% of cases. Bioprosthetic heart valves are used in the other 45% of cases. Pulmonary autograft valves and human cryopreserved homograft valves represent the remainder of implanted valves. Autografts and homografts exhibit excellent durability after implantation but are not readily available for all patients.

Catheter-based, also known as transcatheter or percutaneous, heart valves have already had successful implantation into the aortic and pulmonary valve position and are commercially available. It is the success of these valves that has led to a new focus into the development of the mitral valve position. To date, there are no commercially available percutaneous mitral valve options, only designs in the clinical and research stages. There is a huge unmet need in percutaneous mitral valve design, as it is only at the infant stages of development.

This Special Issue will discuss all the concerns that are important to be taken into consideration for the design and development of the next generation of heart valve prostheses.

Assoc. Prof. Dr. Hadi Mohammadi
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Bioengineering is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Published Papers (4 papers)

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Research

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16 pages, 4135 KiB  
Article
Possible Early Generation of Physiological Helical Flow Could Benefit the Triflo Trileaflet Heart Valve Prosthesis Compared to Bileaflet Valves
by Ch. Bruecker and Qianhui Li
Bioengineering 2020, 7(4), 158; https://0-doi-org.brum.beds.ac.uk/10.3390/bioengineering7040158 - 08 Dec 2020
Cited by 6 | Viewed by 4053
Abstract
Background—Physiological helical flow in the ascending aorta has been well documented in the last two decades, accompanied by discussions on possible physiological benefits of such axial swirl. Recent 4D-MRI studies on healthy volunteers have found indications of early generation of helical flow, early [...] Read more.
Background—Physiological helical flow in the ascending aorta has been well documented in the last two decades, accompanied by discussions on possible physiological benefits of such axial swirl. Recent 4D-MRI studies on healthy volunteers have found indications of early generation of helical flow, early in the systole and close to the valve plane. Objectives—Firstly, the aim of the study is to investigate the hypothesis of premature swirl existence in the ventricular outflow tract leading to helical flow in the valve plane, and second to investigate the possible impact of two different mechanical valve designs on the preservation of this early helical flow and its subsequent hemodynamic consequences. Methods—We use a pulse duplicator with an aortic arch and High-Speed Particle Image Velocimetry to document the flow evolution in the systolic cycle. The pulse-duplicator is modified with a swirl-generating insert to generate early helical flow in the valve plane. Special focus is paid to the interaction of such helical flow with different designs of mechanical prosthetic heart valves, comparing a classical bileaflet mechanical heart valve, the St. Jude Medical Regent valve (SJM Regent BMHV), with the Triflo trileaflet mechanical heart valve T2B version (Triflo TMHV). Results—When the swirl-generator is inserted, a vortex is generated in the core flow, demonstrating early helical flow in the valve plane, similar to the observations reported in the recent 4D-MRI study taken for comparison. For the Triflo trileaflet valve, the early helical flow is not obstructed in the central orifice, similar as in the case of the natural valve. Conservation of angular momentum leads to radial expansion of the core flow and flattening of the axial flow profile downstream in the arch. Furthermore, the early helical flow helps to overcome separation at the outer and inner curvature. In contrast, the two parallel leaflets for the bileaflet valve impose a flow straightener effect, annihilating the angular momentum, which has a negative impact on kinetic energy of the flow. Conclusion—The results imply better hemodynamics for the Triflo trileaflet valve based on hydrodynamic arguments under the discussed hypothesis. In addition, it makes the Triflo valve a better candidate for valve replacements in patients with a pathological generation of nonaxial velocity in the ventricle outflow tract. Full article
(This article belongs to the Special Issue The Next Generation of Prosthetic Heart Valves)
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10 pages, 3718 KiB  
Communication
Bioengineering Case Study to Evaluate Complications of Adverse Anatomy of Aortic Root in Transcatheter Aortic Valve Replacement: Combining Biomechanical Modelling with CT Imaging
by Cristiano Spadaccio, Laura Mazzocchi, Irina Timofeva, Laurent Macron, Carlo Nicola De Cecco, Simone Morganti, Ferdinando Auricchio and Francesco Nappi
Bioengineering 2020, 7(4), 121; https://0-doi-org.brum.beds.ac.uk/10.3390/bioengineering7040121 - 01 Oct 2020
Cited by 8 | Viewed by 3612
Abstract
Gated computed tomography (CT) might not adequately predict occurrence of post-implantation transcatheter aortic valve replacement (TAVR) complications in hostile aortic root as it would require a more complex integration of morphological, functional and hemodynamical parameters. We used a computational framework based on finite [...] Read more.
Gated computed tomography (CT) might not adequately predict occurrence of post-implantation transcatheter aortic valve replacement (TAVR) complications in hostile aortic root as it would require a more complex integration of morphological, functional and hemodynamical parameters. We used a computational framework based on finite element analysis (FEA) to simulate patient-specific implantation. Application of biomechanical modelling using FEA to gated-CT was able to demonstrate the relation of the device with voluminous calcification, its consequent misalignment and a significant stent deformation. Use of FEA and other advanced computed predictive modelling techniques as an adjunct to CT scan could improve our understanding of TAVR, potentially predict complications and fate of the devices after implantation and inform patient-specific treatment. Full article
(This article belongs to the Special Issue The Next Generation of Prosthetic Heart Valves)
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15 pages, 3768 KiB  
Article
Hemodynamic Performance of Dysfunctional Prosthetic Heart Valve with the Concomitant Presence of Subaortic Stenosis: In Silico Study
by Othman Smadi, Anas Abdelkarim, Samer Awad and Thakir D. Almomani
Bioengineering 2020, 7(3), 90; https://0-doi-org.brum.beds.ac.uk/10.3390/bioengineering7030090 - 07 Aug 2020
Cited by 4 | Viewed by 3508
Abstract
The prosthetic heart valve is vulnerable to dysfunction after surgery, thus a frequent assessment is required. Doppler electrocardiography and its quantitative parameters are commonly used to assess the performance of the prosthetic heart valves and provide detailed information on the interaction between the [...] Read more.
The prosthetic heart valve is vulnerable to dysfunction after surgery, thus a frequent assessment is required. Doppler electrocardiography and its quantitative parameters are commonly used to assess the performance of the prosthetic heart valves and provide detailed information on the interaction between the heart chambers and related prosthetic valves, allowing early detection of complications. However, in the case of the presence of subaortic stenosis, the accuracy of Doppler has not been fully investigated in previous studies and guidelines. Therefore, it is important to evaluate the accuracy of the parameters in such cases to get early detection, and a proper treatment plan for the patient, at the right time. In the current study, a CFD simulation was performed for the blood flow through a Bileaflet Mechanical Heart Valve (BMHV) with concomitant obstruction in the Left Ventricle Outflow Tract (LVOT). The current study explores the impact of the presence of the subaortic on flow patterns. It also investigates the accuracy of (BMHV) evaluation using Doppler parameters, as proposed in the American Society of Echocardiography (ASE) guidelines. Full article
(This article belongs to the Special Issue The Next Generation of Prosthetic Heart Valves)
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Review

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18 pages, 2646 KiB  
Review
In Situ “Humanization” of Porcine Bioprostheses: Demonstration of Tendon Bioprostheses Conversion into Human ACL and Possible Implications for Heart Valve Bioprostheses
by Uri Galili and Kevin R. Stone
Bioengineering 2021, 8(1), 10; https://0-doi-org.brum.beds.ac.uk/10.3390/bioengineering8010010 - 12 Jan 2021
Cited by 5 | Viewed by 2867
Abstract
This review describes the first studies on successful conversion of porcine soft-tissue bioprostheses into viable permanently functional tissue in humans. This process includes gradual degradation of the porcine tissue, with concomitant neo-vascularization and reconstruction of the implanted bioprosthesis with human cells and extracellular [...] Read more.
This review describes the first studies on successful conversion of porcine soft-tissue bioprostheses into viable permanently functional tissue in humans. This process includes gradual degradation of the porcine tissue, with concomitant neo-vascularization and reconstruction of the implanted bioprosthesis with human cells and extracellular matrix. Such a reconstruction process is referred to in this review as “humanization”. Humanization was achieved with porcine bone-patellar-tendon-bone (BTB), replacing torn anterior-cruciate-ligament (ACL) in patients. In addition to its possible use in orthopedic surgery, it is suggested that this humanization method should be studied as a possible mechanism for converting implanted porcine bioprosthetic heart-valves (BHV) into viable tissue valves in young patients. Presently, these patients are only implanted with mechanical heart-valves, which require constant anticoagulation therapy. The processing of porcine bioprostheses, which enables humanization, includes elimination of α-gal epitopes and partial (incomplete) crosslinking with glutaraldehyde. Studies on implantation of porcine BTB bioprostheses indicated that enzymatic elimination of α-gal epitopes prevents subsequent accelerated destruction of implanted tissues by the natural anti-Gal antibody, whereas the partial crosslinking by glutaraldehyde molecules results in their function as “speed bumps” that slow the infiltration of macrophages. Anti-non gal antibodies produced against porcine antigens in implanted bioprostheses recruit macrophages, which infiltrate at a pace that enables slow degradation of the porcine tissue, neo-vascularization, and infiltration of fibroblasts. These fibroblasts align with the porcine collagen-fibers scaffold, secrete their collagen-fibers and other extracellular-matrix (ECM) components, and gradually replace porcine tissues degraded by macrophages with autologous functional viable tissue. Porcine BTB implanted in patients completes humanization into autologous ACL within ~2 years. The similarities in cells and ECM comprising heart-valves and tendons, raises the possibility that porcine BHV undergoing a similar processing, may also undergo humanization, resulting in formation of an autologous, viable, permanently functional, non-calcifying heart-valves. Full article
(This article belongs to the Special Issue The Next Generation of Prosthetic Heart Valves)
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