An official website of the United States government
Age-related changes in hemodynamics and leaflet mechanics progressively reduce tissue flexibility and lead to structural valve degeneration (SVD) in bioprosthetic transcatheter aortic valve replacement (TAVR) devices. A novel pulmonary visceral pleura (PVP) tissue, which exhibits a substantially higher elastin-to-collagen ratio than bovine or porcine pericardium used in current commercial valves, has shown strong potential for improving resilience, biocompatibility, and long-term performance in next-generation TAVR designs. In this study, the dynamic behavior of a prototype PVP bioprosthetic valve was evaluated in vitro using a benchtop pulsatile flow loop that integrates optical and acoustic imaging modalities. Physiological aortic flow conditions were reproduced by a programmable pulsatile pump, and simultaneous measurements of pressure and flow were obtained using pressure transducers and flow instrumentation. High-speed optical imaging was used to quantify leaflet kinematics, while B-mode ultrasound, Doppler, and Particle Image Velocimetry (PIV) provided complementary characterization of leaflet motion and near-valvular flow. A comparative assessment was performed against a stented valve with stiff silicone leaflets to evaluate hemodynamic differences associated with the PVP material. Analysis of the valve opening area, timing, and corresponding flow waveform demonstrated that the PVP valve achieved a substantially larger effective orifice area, lower peak jet velocity and turbulence, and lower pressure gradient than the silicone leaflet control. The combined use of ultrasound imaging and optical PIV enabled versatile noninvasive characterization of these hemodynamic features, which establishes a robust experimental framework for evaluating emerging bioprosthetic valve materials and provides essential data to support future fluid–structure interaction simulations and the continued optimization of next generation TAVR designs.
more »
« less
ParaValve: An open source framework for parametric design and fluid–structure interaction simulation of bioprosthetic heart valves in patient-specific aortic geometries
Heart valve disease (HVD), a significant cardiovascular complication, is one of the leading global causes of morbidity and mortality. Treatment for HVD often involves medical devices such as bioprosthetic valves. However, the design and optimization of these devices require a thorough understanding of their biomechanical and hemodynamic interactions with patient-specific anatomical structures. Parametric procedural geometry has become a powerful tool in enhancing the efficiency and accuracy of design optimization for such devices, allowing researchers to systematically explore a wide range of possible configurations. In this work, we present a robust framework for parametric and procedural modeling of stented bioprosthetic heart valves and patient-specific aortic geometries. The framework employs non-uniform rational B-splines (NURBS)-based geometric parameterization, enabling precise control over key anatomical and design variables. By enabling a modular and expandable workflow, the framework supports iterative optimization of valve designs to achieve improved hemodynamic performance and durability. We demonstrate its applicability through simulations on bioprosthetic aortic valves, highlighting the impact of geometric parameters on valve function and their potential for personalized device design. By coupling parametric geometry with computational tools, this framework offers researchers and engineers a streamlined pathway toward innovative and patient-specific cardiovascular solutions.
more »
« less
- PAR ID:
- 10635752
- Publisher / Repository:
- Elsevier
- Date Published:
- Journal Name:
- Computer Aided Geometric Design
- Volume:
- 120
- ISSN:
- 0167-8396
- Page Range / eLocation ID:
- 102455
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
ABSTRACT Heart disease remains a major cause of morbidity and mortality in the United States, accounting for roughly 20% of all deaths. Minimally invasive procedures have been used to treat cardiovascular diseases; however, the heart's anatomical complexity and dynamics require proper hands‐on training on patient‐specific presurgical models to reduce procedural errors. Existing dynamic heart models often rely on animal cardiac tissues to support pumping mechanics, introducing ethical and policy concerns. Fully synthetic heart models offer an alternative by using actuation devices to reproduce cardiac circulation and contraction, yet accurately replicating the full dynamics of the heart remains challenging. This research presents a 3D‐printed dynamic heart model representing left‐side anatomy (atrium, ventricle, and mitral valve) to support minimally invasive procedures. Soft material 3D‐printing is employed to replicate key anatomical features. Sutures anchor the ventricle to the mitral valve, replicating chordae tendineae‐like structures, adding physiological realism and structural complexity. McKibben actuators are embedded within the myocardial walls, mimicking ventricular contraction and realistic mitral valve motion. Customized flexible pressure sensors are designed and incorporated to monitor pressure changes inside the model. These novel features enable the model to function as a platform for hemodynamic studies and simulation of edge‐to‐edge repair to mitigate atrioventricular valve regurgitation.more » « less
-
Left ventricular assist devices (LVADs) have been used for end-stage heart failure patients as a therapeutic option. The aortic valve plays a critical role in heart failure and its treatment with a LVAD. The cardiovascular-LVAD model is often used to investigate the physiological demands required by patients and predict the hemodynamic of the native heart supported with a LVAD. As it is a “ bridge-to-recovery ” treatment, it is important to maintain appropriate and active dynamics of the aortic valve and the cardiac output of the native heart, which requires that the LVAD pump be adjusted so that a proper balance between the blood contributed through the aortic valve and the pump is maintained. In this paper, we investigate how the pump power of the LVAD pump can affect the dynamic behaviors of the aortic valve for different levels of activity and different severities of heart failure. Our objective is to identify a critical value of the pump power (i.e., breakpoint ) to ensure that the LVAD pump does not take over the pumping function in the cardiovascular-pump system and share the ejected blood with the left ventricle to help the heart to recover. In addition, the hemodynamic often involves variability due to patients’ heterogeneity and the stochastic nature of the cardiovascular system. The variability poses significant challenges to understanding dynamic behaviors of the aortic valve and cardiac output. A generalized polynomial chaos (gPC) expansion is used in this work to develop a stochastic cardiovascular-pump model for efficient uncertainty propagation, from which it is possible to rapidly calculate the variance in the aortic valve opening duration and the cardiac output in the presence of variability. The simulation results show that the gPC-based cardiovascular-pump model is a reliable platform that can provide useful information to understand the effect of the LVAD pump on the hemodynamic of the heart.more » « less
-
Mechanical or biological aortic valves are incorporated in physical cardiac simulators for surgical training, educational purposes, and device testing. They suffer from limitations including either a lack of anatomical and biomechanical accuracy or a short lifespan, hence limiting the authentic hands-on learning experience. Medical schools utilize hearts from human cadavers for teaching and research, but these formaldehyde-fixed aortic valves contort and stiffen relative to native valves. Here, we compare a panel of different chemical treatment methods on explanted porcine aortic valves and evaluate the microscopic and macroscopic features of each treatment with a primary focus on mechanical function. A surfactant-based decellularization method after formaldehyde fixation is shown to have mechanical properties close to those of the native aortic valve. Valves treated in this method were integrated into a custom-built left heart cardiac simulator to test their hemodynamic performance. This decellularization, post-fixation technique produced aortic valves which have ultimate stress and elastic modulus in the range of the native leaflets. Decellularization of fixed valves reduced the valvular regurgitation by 60% compared to formaldehyde-fixed valves. This fixation method has implications for scenarios where the dynamic function of preserved valves is required, such as in surgical trainers or device test rigs.more » « less
-
Given the complexity of human left heart anatomy and valvular structures, the fluid–structure interaction (FSI) simulation of native and prosthetic valves poses a significant challenge for numerical methods. In this review, recent numerical advancements for both fluid and structural solvers for heart valves in patient-specific left hearts are systematically considered, emphasizing the numerical treatments of blood flow and valve surfaces, which are the most critical aspects for accurate simulations. Numerical methods for hemodynamics are considered under both the continuum and discrete (particle) approaches. The numerical treatments for the structural dynamics of aortic/mitral valves and FSI coupling methods between the solid Ωs and fluid domain Ωf are also reviewed. Future work toward more advanced patient-specific simulations is also discussed, including the fusion of high-fidelity simulation within vivo measurements and physics-based digital twining based on data analytics and machine learning techniques.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript
- Journal Article:
- https://doi.org/10.1016/j.cagd.2025.102455
