Poster U2 - In-Silico Modeling of Fluid Dynamics in a Designed Stenotic Aortic Valve: Assessing Functionality Under Physiological Conditions

Introduction: Computational modeling is a powerful tool in cardiovascular research that helps improve our understanding of the field. In-silico models allow us to investigate the dynamics of the cardiovascular system without the constraints and ethical concerns of physical approaches. These models are especially useful in analyzing the behavior of the heart valves, which are critical for the proper functioning of the cardiac cycle. This study aims to advance the availability of these models by designing and evaluating an anatomically accurate stenotic aortic valve and testing its flow functionality using a computational fluid dynamics (CFD) in-silico model with COMSOL. Valvular stenosis, a common cardiac condition, significantly contributes to cardiovascular morbidity and mortality, presenting a critical area for research to advance the understanding of stenotic valve dynamics. By combining an anatomically faithful design with COMSOL modeling, this study provides an approach to a more accurate understanding of valve performance under stenotic conditions and their impact on the cardiac cycle without the limitations of living systems methods. Furthermore, this type of modeling can offer a new platform for testing the efficacy and safety of medical devices that address valve deficiencies or deformities. These devices play a crucial role in treating patients with these issues and their rigorous testing is crucial for regulatory approval and for increasing patient outcomes. In essence, this approach offers a methodology to better understand stenotic valve dynamics, and a new way to optimize medical devices tailored towards treating valve deformities and deficiencies.

Materials and

Methods: We first designed the stenotic aortic valve in SolidWorks. The valve consisted of two one-inch inner diameter cylinders on either side of a nodular compartment containing three distinct semi-lunar leaflets. We chose this type of design to accurately model the anatomical structure of a stenotic aortic valve in the heart, see Figure 1. We then exported the designed aortic valve into COMSOL. Using CFD in-silico modeling, we assessed the functional aspects of the valve to simulate its performance under physiological conditions, mimicking those of a stenotic valve in the heart, and observed how the fluid traveled through our designed valve. This type of analysis was chosen to observe the fluid-structure interactions and assess if it functions like a natural stenotic aortic valve.

Results, Conclusions, and Discussions: To test the functionality of our designed stenotic valve, we simulated flow conditions typical of the aortic valve in the heart, setting a 1 m/s inlet initial condition and simulating water as the fluid. We then analyzed the velocity at a point close to the center of the valve. Results showed an increase in velocity at the valves, which peaked at 5.2 m/s and gradually decreased as it exited the valve to a range of 1.7 - 3.2 m/s, see Figures 2-5. The data obtained highlights the velocity profile in the valve when subjected to fully developed flow and in the open position. The in-silico model results indicate the designed stenotic aortic valve exhibits similar behaviors to a stenotic aortic valve in the heart. The model shows high ejection of fluid from the valve at 5.2 m/s, indicating severe stenosis of the valve. The model also exhibits the gradual decrease in velocity and smooth flow suggesting the valve has effective operational dynamics to prevent backflow and can maintain fluid circulation. Moving forward, the next phase of our study involves using 3D printing methods to construct a physical model of the valve and then implementing it into a mock circulation loop (MCL) for further analysis. This type of modeling could be applied to diverse valve conditions to understand their effects on cardiovascular functioning, providing insights into potential treatment strategies and assisting in testing devices that correct valve issues. This study utilized COMSOL for conducting in-silico testing of a designed stenotic aortic valve. Our findings indicate that the tested valve functions similarly to a stenotic aortic valve in the heart by exhibiting high ejection velocity. Future work for this research involves creating a physical model of the valve using 3D printing and integrating it into an MCL. These methods will enable researchers to design and print valves of any kind, providing new insights into how valve deficiencies or deformities impact the cardiac cycle without the constraints of traditional research methods. Furthermore, this type of modeling can offer a unique approach to optimizing treatment devices.

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