Comparison of the hinge flow fields of two bileaflet mechanical heart valves under aortic and mitral conditions.
BACKGROUND
Animal and clinical studies have shown that bileaflet mechanical heart valve designs are plagued by thromboembolic complications, with higher rates in the mitral than in the aortic position. This study evaluated the hinge flow dynamic of the 23 mm St. Jude Medical (SJM) Regent and the 23 mm CarboMedics (CM) valves under aortic conditions and compared these results with previous findings under mitral conditions.


METHODS
Velocity and Reynolds shear stress fields were captured using two-component laser Doppler velocimetry.


RESULTS
Under aortic conditions, both the SJM and CM hinge flow fields exhibited a strong forward flow pattern during systole (maximum velocities of 2.31 and 1.75 m/s, respectively) and two main leakage jets during diastole (maximum velocities of 3.08 and 2.27 m/s, respectively).


CONCLUSIONS
Aortic and mitral flow patterns within the two hinges were similar, but with a more dynamic flow during the forward flow phase under aortic conditions. Velocity magnitudes and shear stresses measured under mitral conditions were generally higher than those obtained in the aortic position, which may explain the higher rates of thromboembolism in the mitral implants when compared with the aortic implants.
Simon
Hélène A
HA
School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0535, USA.
Leo
Hwa-Liang
HL
Carberry
Josie
J
Yoganathan
Ajit P
AP
D001011:Aorta; D001698:Biomedical Engineering; D001783:Blood Flow Velocity; D006354:Heart, Artificial; D006801:Humans; D008943:Mitral Valve; D008955:Models, Cardiovascular; D011474:Prosthesis Design; D011475:Prosthesis Failure; D011673:Pulsatile Flow; D013314:Stress, Mechanical; D013927:Thrombosis