1003-6 Doppler Assessment of Pulmonary Artery Diastolic Pressure in Patients with Tricuspid Regurgitation

Abstract

A reliable Doppler echo method to assess pulmonary artery diastolic pressure (PAD) would be clinically useful. By applying the Bernoulli equation, ΔP = 4(V) 2 , an indirect estimate of RV pressure can be obtained from tricuspid regurgitant velocity (TV), if right atrial pressure is not significantly elevated. Since PAD and RV pressures equilibrate at the time of pulmonic valve opening (PVO), 4(TV) 2 measured at pva should approximate PAD. To test this hypothesis, we studied pts undergoing Swan Ganz monitoring who had tricuspid regurgitation detected by color flow Doppler. To avoid pts with marked elevation of right atrial pressure, we excluded pts with severe tricuspid regurgitation or evidence of right heart failure. The study group consisted of 20 pts. In each pt, TV was obtained by continuous wave Doppler. The time of PVO was determined by pulsed wave Doppler as the onset of systolic flow in the pulmonary artery, and the interval between the onset of the ORS and pva was measured. This interval was then used to determine the point on the TV envelope that corresponded to the time of PVO. TV was measured at this point and 4(TV) 2 was calculated using the Bernoulli equation. We compared 4(TV) 2 at PVO obtained by Doppler with PAD measured invasively. PAD by cath ranged from 9 to 36 mmHg (mean 20). Measurement of 4(TV) 2 at PVO ranged from 9 to 27 mmHg (mean 17) and showed an excellent correlation with cath PAD (r = 0.91, Y = 4.4 + 0.68x, SEE = 1.8). Doppler estimation of tricuspid regurgitant gradient at PVO is a reliable new method for estimation of PAD.