Laser Doppler anemometry measurements of steady flow through two bi-leaflet prosthetic heart valves

Introduction

In vitro hydrodynamic characterization of prosthetic heart valvesprovides important information regarding their operation, especially if performedby noninvasive techniques of anemometry. Once velocity profiles for each valve areprovided, it is possible to compare them in terms of hydrodynamic performance. Inthis first experimental study using laser doppler anemometry with mechanicalvalves, the simulations were performed at a steady flow workbench.

Objective

To compare unidimensional velocity profiles at the central plane of twobi-leaflet aortic prosthesis from St. Jude (AGN 21 - 751 and 21 AJ - 501 models)exposed to a steady flow regime, on four distinct sections, three downstream andone upstream.

Methods

To provide similar conditions for the flow through each prosthesis by a steadyflow workbench (water, flow rate of 17L/min. ) and, for the same sections andsweeps, to obtain the velocity profiles of each heart valve by unidimensionalmeasurements.

Results

It was found that higher velocities correspond to the prosthesis with smallerinner diameter and instabilities of flow are larger as the section of interest iscloser to the valve. Regions of recirculation, stagnation of flow, low pressure,and flow peak velocities were also found.

Conclusions

Considering the hydrodynamic aspect and for every section measured, it could beconcluded that the prosthesis model AGN 21 - 751 (RegentTM) is superior to the 21AJ - 501 model (Master Series). Based on the results, future studies can choose tofocus on specific regions of the these valves.