In Vitro Hemodynamic Assessment of a Novel Pulmonary Visceral Pleura (PVP) Transcatheter Aortic Valve Replacement Prototype Based on Optical and Acoustic Measurements

Structural valve degradation remains a key limitation of bioprosthetic transcatheter aortic valve replacement (TAVR) devices, whose bovine or porcine pericardium leaflets are prone to calcification and long-term failure. Pulmonary visceral pleura (PVP), a thin, elastin-rich tissue, has emerged as a promising alternative leaflet material. This study presents an in vitro hemodynamic evaluation of a prototype PVP valve under physiologically representative pulsatile flow in a custom benchtop flow loop. A multimodal framework combined four techniques: high-speed imaging with U-Net deep learning segmentation of the geometric orifice area, quantitative Doppler velocity extraction developed on a Verasonics research ultrasound platform, double-pulse particle image velocimetry (PIV) of the downstream flow field, and transvalvular pressure measurement. The PVP valve was compared with a stiff silicone valve representing a stenotic reference condition. At 75 bpm and 5 L/min, the PVP valve reached a peak geometric orifice area of 2.91 cm2, a mean pressure gradient of 4.3 mmHg, and a peak jet velocity of 2.46 m/s, meeting the ASE velocity and gradient criteria for normal prosthetic valve function. The silicone valve opened to 1.1 cm2 with a gradient of 36.9 mmHg, consistent with moderate-to-severe stenosis. The framework provides a basis for characterizing new bioprosthetic valve materials and benchmark data for fluid–structure interaction modeling.