Clinical usefulness of intravenous albunex for the Doppler assessment of aortic stenosis.

Optimal Doppler recordings of stenotic aortic flow are not always easy to obtain. Therefore, the present study investigated how useful intravenous Albunex injections were for improving the Doppler assessment of pressure gradients for aortic stenosis in 20 consecutive patients who underwent Doppler and left-heart catheterization studies within a 1-week period. Continuous-wave Doppler echocardiography was performed using both a 2.5 MHz duplex and a 1.9MHz independent transducer before and after Albunex injections. The maximum and mean pressure gradients were calculated from the highest Doppler velocity tracings using the simplified Bernoulli equation. Pullback catheterization pressure tracings from the left ventricle to the ascending aorta were superimposed for determination of the maximum instantaneous and mean pressure gradients. The Doppler-derived peak and mean pressure gradients showed significant underestimation compared with the catheterization gradients (23+/-17 mmHg and 11+/-7 mmHg, respectively). However, this underestimation disappeared with Albunex injection (-2+/-7 mmHg and -1+/-4mmHg, respectively). Although the Doppler-derived instantaneous and mean pressure gradients correlated well with the catheterization gradients (r=0.909 and r=0.879, respectively), they became much closer with Albunex (r=0.987 and r=0.963, respectively). The improvements in the Doppler-derived peak pressure gradients were significant from an apical window (n=12, 84-120mmHg, p<0.001). but less so from non-apical windows (n=8, 84-91 mmHg, p=0.0146). Accordingly, Albunex is most useful for Doppler recordings of stenotic aortic flow available from the apical window, but not less so from other acoustic windows.