Biomechanical Engineering Analysis of Pulmonary Valve Leaflet Hemodynamics and Kinematics in the Ross Procedure
Yuanjia Zhu, Robert J. Wilkerson, Pearly K. Pandya, Danielle M. Mullis, Catherine Wu, Sarah Madira, Mateo Marin-Cuartas, Matthew Park, Annabel Imbrie-Moore, *Y. Joseph Woo
Cardiothoracic Surgery, Stanford University, Stanford, California, United States
The Ross procedure using the inclusion technique with anti-commissural plication (ACP) is associated with excellent valve hemodynamics and favorable leaflet kinematics. The objective was to evaluate individual pulmonary cusp’s biomechanics and fluttering by including coronary flow in the Ross procedure using an ex vivo 3D-printed heart simulator.
Ten porcine and five human pulmonary autografts were harvested from hearts obtained from a meat abattoir and heart transplant recipients and donors. Five of the porcine autografts served as controls without reinforcement. The other five porcine autografts and human autografts were prepared using the inclusion technique both with and without ACP. All samples included coronary flows. Hemodynamic, echocardiography, and high-speed videography data were collected using the ex vivo heart simulator (Fig.1). Leaflet motion of each cusp was tracked throughout a cardiac cycle and was further analyzed for velocity, relative force, flutter frequency, and flutter amplitude comparison.
Porcine autograft regurgitation was significantly lower after using the inclusion technique with (5.9±3.8%, p=.006) and without ACP (6.2±4.5%, p=.009) compared to controls (17.5±5.9%, Fig.2). ACP compared to non-ACP in porcine and human pulmonary autografts was associated with lower leaflet rapid opening mean velocity in the right (p=.001, p=.02) and left coronary cusps (p=.004, p=.003), but not in the non-coronary cusp (p=.18, p=.66). Compared to controls, the non-ACP porcine autografts were associated with higher leaflet rapid opening mean velocity and relative rapid opening force of the right (p=.05) and left coronary cusps (p=.05). Relative rapid opening force was also higher in the non-coronary cusp in the non-ACP autografts compared to controls (p=.04). There was no significant difference in the rapid opening mean velocity in the non-coronary cusp between the controls and the non-ACP autografts (p=.29). The leaflet rapid closing mean velocities and relative rapid closing forces were similar in all porcine and human autografts (Fig.3). Porcine non-ACP autografts were associated with significantly higher leaflet flutter frequency in the right (p=.05) and left coronary cusp (p=.04), but not the non-coronary cusp (p=.17) compared to controls. The human autografts showed similar leaflet flutter frequency in the right (p=.16) and left coronary cusp (p=.35), but the non-coronary cusp flutter frequency was significantly higher without ACP compared to with ACP (p=.02, Fig.4).
In conclusion, the Ross procedure using the inclusion technique with ACP is associated with excellent hemodynamics and more favorable leaflet biomechanics in the right and left coronary cusps compared to autografts prepared without ACP. These results may translate to improved long-term durability of the pulmonary autografts.
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