Quantification of valvular regurgitation by transthoracic 3D high pulse repetition frequency Doppler echocardiography

To improve quantification of valvular regurgitation, a 3D high-pulse repetition frequency Doppler (3D HPRFD) method was developed for regurgitant volume (RVol) estimation from transthoracic echocardiography (TTE). Although successfully applied in vitro and in selected clinical cases, a systematic clinical validation of 3D HPRFD has not been published. Hence, our aims were to investigate (i) feasibility of 3D HPRFD and (ii) correlation between 3D HPRFD and RVol estimates obtained by the 2D proximal isovelocity surface area (PISA) method and cardiac magnetic resonance (CMR) in patients with either aortic regurgitation (AR) or mitral regurgitation (MR).

We included 45 patients with AR (42% mild, 40% moderate, and 18% severe) and 45 with MR (67% mild, 24% moderate, and 9% severe). Median time between start of TTE and start of CMR was 1.5 h, minimizing changes in load. Overall feasibility of 3D HPRFD was 56% in AR and 44% in MR. Feasibility was only 25% in patients with severe regurgitation. In AR, estimated RVol from 3D HPRF did not correlate with estimated RVol from PISA or CMR [Spearman rho = 0.06 (P = 0.78) and 0.04 (P = 0.4), respectively]. In MR, RVol estimates from 3D HPRFD correlated with PISA (rho = 0.72, P < 0.001) but not with CMR (rho = 0.31, P = 0.43).

Regurgitant volume estimation by 3D HPRFD had a low feasibility, especially in severe regurgitation, and in general correlated poorly with PISA and CMR estimates. In its current state, 3D HPRFD is not ready for clinical use.