Time-dependent analysis of leaflets in mechanical aortic bileaflet heart valves in closing phase using the finite strip method

Mohammadi, H ; Sharif University of Technology | 2006

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  1. Type of Document: Article
  2. DOI: 10.1016/j.medengphy.2005.03.013
  3. Publisher: 2006
  4. Abstract:
  5. Background and aims of the study: Mechanical heart valves (MHV) are widely used to replace dysfunctional and failed heart valves. The bileaflet MHV design is very popular due to its superior hemodynamics. Since their introduction in 1977, the hemodynamics of bileaflet prostheses has been extensively studied. In this study the dynamic behaviour during the closing phase of a bileaflet MHV under normal physiological conditions has been investigated. Methods: Fluid analysis is based on the control volume with moving boundaries in the vicinity of the occluder. Unsteady continuity equation, unsteady momentum equation on the control volume and unsteady Bernoulli's equation have been used to calculate velocity of blood flow and force on the occluder tip. To solve the governing equations for the calculation of pressure and the related force, the finite strips method has been implemented. Only 32 strips are sufficient to calculate the force due to pressure on the leaflets. The equations of motion have been solved using the Runge-Kutta method in the fourth order. Results: The maximum velocity of the leakage flow in the closing phase falls within the range of 3.5-4.4 m/s. The maximum velocity of the occluder tip is in the range of 2.4-3.2 m/s. The backflow also exhibits oscillation similar to that of the occluder with net backflow rate in the range of 9.7-12.3 ml/beat. The impact force between occluder and its housing is in the range of 80-140 N and impact occurs during 33.1-41.0 ms and the leaflets are completely settled at 108-115 ms in the closing phase. Conclusion: The finite strip method was implemented to study the closing phase of a bileaflet MHV. Results are consistent with the previous experimental data. This method is of general applicability to study dynamic behaviour of MHVs. © 2005 IPEM. Published by Elsevier Ltd. All rights reserved
  6. Keywords:
  7. Blood ; Hemodynamics ; Oscillations ; Physiology ; Runge Kutta methods ; Unsteady flow ; Aortic pressure ; Back flow ; Closing phase ; Finite strip method ; Impact force ; Mechanical heart valve ; Ventricular pressure ; Heart valve prostheses ; Blood flow ; Finite element analysis ; Heart valve ; Mathematical analysis ; Priority journal ; Saint Jude heart valve prosthesis ; Aorta ; Blood Flow Velocity ; Blood Pressure ; Computer Simulation ; Equipment Failure Analysis ; Heart Valve Prosthesis ; Heart Ventricles ; Humans ; Models, Cardiovascular ; Time Factors
  8. Source: Medical Engineering and Physics ; Volume 28, Issue 2 , 2006 , Pages 122-133 ; 13504533 (ISSN)
  9. URL: https://www.sciencedirect.com/science/article/abs/pii/S1350453305000792