Influence of valve size on the hemodynamic performance of a tissue-engineered valved conduit in pulmonary position.

INTRODUCTION

Tissue Engineering (TE) uses resorbable polymers to promote cellular growth, transforming the implant into a living valve. This study characterizes the three-dimensional flow field around TE valved conduits of varying sizes using a pulse duplicator with tomo-PIV imaging.

METHODS

Three Xeltis Pulmonary Valve (XPV) conduits (16, 18, and 20 mm) were tested under pulmonary conditions at a cardiac output of 5 L/min. Flow velocities, trans-valvular pressure gradients (), effective orifice areas , mean and turbulent kinetic energies ( and ), and viscous shear stresses were measured proximal and distal to the valves.

RESULTS

Peak bulk velocity was 0.5, 0.4, and 0.3 m/s, with local peak velocities reaching 2.3, 1.9, and 1.4 m/s upstream and 3.6, 3.1, and 2.5 m/s in the jet downstream of XPV16, XPV18, and XPV20, respectively. Respective were 1.02, 1.25, and 1.57 cm. The flow field proximal to the valve conduits did not show any significant perturbations and was one order of magnitude lower than . As the flow passed the valve, increased by 152%, 175%, and 218% for XPV16, XPV18, and XPV20, respectively, while increased by 62%, 138%, and 161%. The respective probability of encountering elevated shear stresses (>10Pa) was 6%, 2%, and less than 1%.

DISCUSSION

This work provides the first experimental assessment of the XPV valve, along with an exploration of how valve size affects its hemodynamic performance. Results confirm that for a given hemodynamic condition, larger valves exhibit better performance showing lower flow velocities, , kinetic energies, and stresses, along with higher .