scholarly journals Numerical Investigation of the Effects of Prosthetic Aortic Valve Design on Aortic Hemodynamic Characteristics

2020 ◽  
Vol 10 (4) ◽  
pp. 1396
Author(s):  
Guang-Yu Zhu ◽  
Hai Huang ◽  
Ya-Li Su ◽  
Joon-Hock Yeo ◽  
Xiao-Qin Shen ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Computational Models ◽  
Single Point ◽  
Superior Performance ◽  
Patient Specific ◽  
Valve Design ◽  
Prosthetic Aortic Valve ◽  
Hemodynamic Characteristics ◽  
Aortic Hemodynamic

The superior performance of single-point attached commissures (SPAC) molded valve design has been validated by several numerical, in vitro and in vivo animal studies. However, the impacts of the SPAC molded valve design on aortic hemodynamic environments are yet to be investigated. In this study, multiscale computational models were prepared by virtually implanting prosthetic aortic valves with SPAC tubular, SPAC molded and conventional designs into a patient-specific aorta, respectively. The impacts of the valve designs on efferent flow distribution, flow pattern and hemodynamic characteristics in the aorta were numerically investigated. The results showed that despite the overall flow phenomena being similar, the SPAC tubular valve exhibited a suboptimal performance in terms of higher spatially averaged wall shear stress (SAWSS) in ascending aorta (AAo), higher helix grade, stronger secondary flow mean secondary velocity in descending aorta, as well as more complex vortex distribution. The results from the current study extend the understanding of hemodynamic impacts of the valve designs, which would further benefit the optimization of the prosthetic aortic valve.

scholarly journals Patient-Specific Aortic Phantom With Tunable Compliance

2019 ◽  
Vol 2 (4) ◽  
Author(s):  
Antonio Gallarello ◽  
Andrea Palombi ◽  
Giacomo Annio ◽  
Shervanthi Homer-Vanniasinkam ◽  
Elena De Momi ◽  
...  
Keyword(s):  
Aortic Arch ◽  
Computational Models ◽  
Three Dimensional ◽  
Complex Interventions ◽  
Patient Specific ◽  
Arch Model ◽  
Magnetic Resonance Imaging Mri ◽  
Variable Wall ◽  
Silicone Model

Abstract Validation of computational models using in vitro phantoms is a nontrivial task, especially in the replication of the mechanical properties of the vessel walls, which varies with age and pathophysiological state. In this paper, we present a novel aortic phantom reconstructed from patient-specific data with variable wall compliance that can be tuned without recreating the phantom. The three-dimensional (3D) geometry of an aortic arch was retrieved from a computed tomography angiography scan. A rubber-like silicone phantom was manufactured and connected to a compliance chamber in order to tune its compliance. A lumped resistance was also coupled with the system. The compliance of the aortic arch model was validated using the Young's modulus and characterized further with respect to clinically relevant indicators. The silicone model demonstrates that compliance can be finely tuned with this system under pulsatile flow conditions. The phantom replicated values of compliance in the physiological range. Both, the pressure curves and the asymmetrical behavior of the expansion, are in agreement with the literature. This novel design approach allows obtaining for the first time a phantom with tunable compliance. Vascular phantoms designed and developed with the methodology proposed in this paper have high potential to be used in diverse conditions. Applications include training of physicians, pre-operative trials for complex interventions, testing of medical devices for cardiovascular diseases (CVDs), and comparative Magnetic-resonance-imaging (MRI)-based computational studies.

scholarly journals Sinus Hemodynamics in Representative Stenotic Native Bicuspid and Tricuspid Aortic Valves: An In-Vitro Study

Fluids ◽  
2018 ◽  
Vol 3 (3) ◽  
pp. 56 ◽  
Author(s):  
Hoda Hatoum ◽  
Lakshmi Prasad Dasi
Keyword(s):  
Aortic Valve ◽  
In Vitro Study ◽  
Patient Specific ◽  
Shear Stresses ◽  
Flow Shear ◽  
Aortic Sinus ◽  
Image Velocimetry ◽  
3D Printed ◽  
Sinus Flow

(1) The study’s objective is to assess sinus hemodynamics differences between stenotic native bicuspid aortic valve (BAV) and native tricuspid aortic valve (TrAV) sinuses in order to assess sinus flow shear and vorticity dynamics in these common pathological states of the aortic valve. (2) Representative patient-specific aortic roots with BAV and TrAV were selected, segmented, and 3D printed. The flow dynamics within the sinus were assessed in-vitro using particle image velocimetry in a left heart simulator at physiological pressure and flow conditions. Hemodynamic data calculations, vortex tracking, shear stress probability density functions and sinus washout calculations based on Lagrangian particle tracking were performed. (3) (a) At peak systole, velocity and vorticity in BAV reach 0.67 ± 0.02 m/s and 374 ± 5 s−1 versus 0.49 ± 0.03 m/s and 293 ± 3 s−1 in TrAV; (b) Aortic sinus vortex is slower to form but conserved in BAV sinus; (c) BAV shear stresses exceed those of TrAV (1.05 Pa versus 0.8 Pa); (d) Complete TrAV washout was achieved after 1.5 cycles while it was not for BAV. 4) In conclusion, sinus hemodynamics dependence on the different native aortic valve types and sinus morphologies was clearly highlighted in this study.

A Simulator for the In Vitro Study of the Dynamics of the Aortic Valve: Design and Test

2009 ◽  
Author(s):  
Riccardo Vismara ◽  
Dario Comparolo ◽  
Andrea Mangini ◽  
Carlo Antona ◽  
Gianfranco B. Fiore
Keyword(s):  
Animal Models ◽  
Aortic Valve ◽  
Heart Valves ◽  
In Vitro Study ◽  
Vitro Study ◽  
Valve Design ◽  
Experimental Conditions ◽  
Insight Into ◽  
Physiological Complexity

The in vitro approach to the study of the hemodynamics of heart valves allows easier-to-control and well repeatable experimental conditions, if compared with studies on animal models. A deep, detailed insight into specific issues is possible, despite the unavoidable simplification of the physiological complexity.

Successful cure of daptomycin-non-susceptible, vancomycin-intermediate Staphylococcus aureus prosthetic aortic valve endocarditis directed by synergistic in vitro time-kill study

2019 ◽  
Vol 51 (4) ◽  
pp. 287-292 ◽  
Author(s):  
Zarchi E. Sumon ◽  
Charles S. Berenson ◽  
John A. Sellick ◽  
Zackery P. Bulman ◽  
Brian T. Tsuji ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Aortic Valve ◽  
Prosthetic Aortic Valve ◽  
Time Kill

In Vitro Forward Flow Performance of the EDWARDS INTUITY Elite Rapid Deployment Aortic Valve Replacement in Patient-Specific Anatomy

2019 ◽  
Vol 3 (sup1) ◽  
pp. 63-63 ◽  
Author(s):  
Vahid Sadri ◽  
Immanuel David Madukauwa-David ◽  
Charles Bloodworth ◽  
Prem A. Midha ◽  
Vrishank Raghav ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Aortic Valve Replacement ◽  
Valve Replacement ◽  
Patient Specific ◽  
Forward Flow ◽  
Rapid Deployment

scholarly journals Hemodynamic characterization of Aortic Valve Bypass Surgery (AVBS) using patient-specific computational models based on MRA and PCMR

2012 ◽  
Vol 14 (S1) ◽  
Author(s):  
Adrian Lam ◽  
Stephanie Clement-Guinaudeau ◽  
Muralidhar Padala ◽  
Vinod Thourani ◽  
John N Oshinski
Keyword(s):  
Aortic Valve ◽  
Computational Models ◽  
Bypass Surgery ◽  
Patient Specific ◽  
Aortic Valve Bypass

scholarly journals In Silico Modelling of Aortic Valve Implants – Predicting In Vitro Performance using Finite Element Analysis

2021 ◽  
Author(s):  
Robert Whiting ◽  
Elizabeth Sander ◽  
Claire Conway ◽  
Ted J Vaughan
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Aortic Valve ◽  
In Silico ◽  
Dynamic Parameters ◽  
Valve Design ◽  
Element Analysis ◽  
Orifice Area ◽  
In Silico Modelling

The competing structural and hemodynamic considerations in valve design generally require a large amount of in vitro hydrodynamic and durability testing during development, often resulting in inefficient “trial-and-error” prototyping. While in silico modelling through Finite Element Analysis (FEA) has been widely used to inform valve design by optimizing structural performance, few studies have exploited the potential insight FEA could provide into critical hemodynamic performance characteristics of the valve. The objective of this study is to demonstrate the potential of FEA to predict the hydrodynamic performance of aortic valve implants obtained during development through in vitro testing. Several variations of surgical tri-leaflet aortic valves were de-signed and manufactured using a synthetic polymer and hydrodynamic testing carried out using a pulsatile flow rig according to ISO 5840, with bulk hydro-dynamic parameters measured. In silico models were developed in tandem and suitable surrogate measures were investigated as predictors of the hydro-dynamic parameters. Through regression analysis, the in silico parameters of leaflet coaptation area, geometric orifice area and opening pressure were found to be suitable indicators of experimental in vitro hydrodynamic param-eters: regurgitant fraction, effective orifice area and transvalvular pressure drop performance, respectively.

scholarly journals Design of an In Vitro Mock Circulatory Loop to Reproduce Patient-Specific Vascular Conditions: Toward Precision Medicine

2019 ◽  
Vol 2 (4) ◽  
Author(s):  
Gaia Franzetti ◽  
Vanessa Díaz-Zuccarini ◽  
Stavroula Balabani
Keyword(s):  
Computational Models ◽  
Pulse Frequency ◽  
Patient Specific ◽  
Cardiovascular Research ◽  
Inlet Flow Rate ◽  
Physical Testing ◽  
Experimental Approaches ◽  
Computer Controlled ◽  
Overall Reliability

Abstract Patient-specific hemodynamic studies have attracted considerable attention in recent years due to their potential to improve diagnosis and optimize clinical treatment of cardiovascular diseases. Personalized computational models have been extensively investigated as a tool to improve clinical outcomes and are often validated against in vitro experimental data. Replicating patient-specific conditions in vitro is thus becoming increasingly important in cardiovascular research; experimental platforms can not only allow validation of in silico approaches but can also enable physical testing of various intervention scenarios and medical devices. Current experimental approaches suffer from shortcomings regarding personalization and biomimicry. To address some of these limitations, we have designed and developed a novel in vitro platform for the study of complex patient-specific vascular pathologies. This is achieved by using novel tunable three-element Windkessel vasculature simulators and a computer controlled pulsatile pump, coupled with mathematical models and computer routines to calibrate the parameters according to the available clinical datasets. In particular, the vessel inlet flow rate waveform and the afterload resistances and compliances are tuned in order to obtain target systolic and diastolic pressures, and cardiac output (CO) distribution. Pulse frequency (40–70 bpm), CO (2–5 l/min), resistance (0.03–10.6 mmHg s/ml), and compliance (0.07–1 ml/mmHg) values have been tested and the overall reliability of the platform components as well as its computer routines to reproduce controlled physiological conditions demonstrated.

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