Bernoulli Verification

 

Background

In clinical routine the hydrodynamic performance of heart valve prostheses is determined with Echo-Doppler. Though the pressure gradient of the heart valve prostheses is calculated from the measured distal and proximal velocities with the simplified Bernoulli equation ∆P=C(vd˛-vp˛), whereas the coefficient C is equal to 4. With the Bernoulli verification test the coefficient 4 is verified for the tested heart valve prosthesis. That means the prosthesis dependent deviation of the theoretical coefficient 4 is determined. The Bernoulli verification test is one aspect in heart valve approval testing according to the FDA Standard.

Method

The Bernoulli verification test is performed in the CVE pulse duplicator.

The pressure gradient of the aortic test prosthesis is calculated from pressure sensor data acquired at two different locations. The pressure data is acquired in the apex region of ventricle and at two positions inside the ascending aortic root, approximately 3 cm und 10 cm downstream the test prosthesis. Simultaneously the velocities proximal and distal the test prosthesis are measured with Echo-Doppler. From this velocity data a “new” appropriate coefficient C for the simplified Bernoulli equation C (vd˛-vp˛) is calculated by linear regression of the plotted pressure gradients versus the Difference of the Echo-Doppler velocities. The slope of the regression line corresponds to the new coefficient C.