Influence of the Bulging Sinus Size of the Eptfe Valve Conduit on the Flow and Opening Area of the Valve Conduit

Abstract

There is no optimal substitute for right ventricular outflow tract (RVOT) reconstruction in congenital heart defects yet. Good clinical records seem to show expanded polytetrafluoroethylene (ePTFE) valve conduits may be a good choice for treating this defect. Bulging sinus of the ePTFE valve seem to have favorable effect on hemodynamic performance, however, fluid mechanical research proving this effect has been limited. This research aims to study the effect of the bulging sinus itself and size of the ePTFE valve on a flow phenomenon inside the conduit.

Several valve conduit models with different bulging sinus sizes were used. Considering bulging sinus size proportion similar to natural Aorta being “normal”, straight model, reduced 50% model, normal model and enlarged 150% model were prepared. Effect of the bulging sinus size on a flow field inside the valve conduit was analyzed using Dynamic PIV system running at 1900 frames/s and valve opening areas were directly recorded using high speed digital camera running at 300 frames/s.

Comparison of flow field results between a straight model and normal model showed that the valve with normal model had strong vortex close to the leaflet location and resulted in wider valve opening area compared to a straight model.

Flow field of valve conduits with normal and enlarged 150% model generated strong vortex immediately behind the leaflet edge. Valve opened and closed early with normal and enlarged 150% model compared to reduced 50% model. Direct observation of the opening area of the valve showed that wider opening area was observed with normal and enlarged 150% model.

Valve with normal and enlarged 150 strong vortex close to the leaflet location and resulted in wider valve opening area. Relative location of vortex seems to play important roll on valve open and close mechanism.