Continuous wave doppler pre-attenuation velocity envelope: a promising tool for the echocardiographic assessment of aortic stenosis

Background: In this study, we evaluated the utility of the continuous wave (CW) Doppler pre-attenuation velocity envelope as a potential surrogate for pulsed-wave (PW) Doppler-based interrogation of left ventricular outflow tract (LVOT) flow in patients with moderate or severe aortic stenosis. Methods: In a retrospective analysis, we examined 92 patients with moderate or severe aortic stenosis. Pulsed-wave Doppler was employed to acquire LVOT velocity and velocity time integral (VTI) in the 5-chamber view. CW Doppler recordings were scrutinized across multiple views with a specific focus on identifying a discernible pre-attenuation velocity envelope. Through manual tracing, we extracted peak velocity and VTI across the aortic valve as well as the pre attenuated velocity, which was used as a surrogate for LVOT assessment and substitute in the continuity equation in the evaluation of aortic valve stenosis. Results: The pre-attenuation velocity envelope was distinctly discernible in 83 (90%) of patients. PW Doppler of the LVOT velocity significantly correlated with pre-attenuation velocity from the 5-chamber view (r = 0.75, p-value < 0.001) but showed a weaker correlation when obtained from other windows (r = 0.46, p-value < 0.001). Bland-Altman analyses indicated high levels of agreement between pre-attenuation velocities from the 5-chamber view and PW Doppler derived LVOT velocities, while weaker levels of agreement were observed between pre-attenuation velocities from other windows and PW Doppler derived LVOT velocities. Conclusions: The pre-attenuation velocity envelope is attainable in the majority of patients with aortic stenosis. The pre-attenuation velocity envelope recorded from the 5-chamber view exhibits a noteworthy correlation and agreement with PW Doppler LVOT velocity. This observation positions pre-attenuation velocity envelope as a promising alternative and plausibility check for hemodynamic assessment in patients with aortic stenosis.