Accurate quantification of chronic aortic regurgitation (AR) using 2D-TTE is sometimes challenging. Cardiac magnetic resonance imaging (CMR) is increasingly used to refine this assessment by estimating measurement of regurgitation fraction (RF), but remains not widely available. 3D echocardiography (3D-ETT) allows a non-invasive approach of right ventricular (RV) and left ventricular (LV) volumes with a good correlation with CMR measurements. The 3D-TTE volume method is based on the comparison of RV and LV stroke volumes, which is then used to calculate the RF of the aortic valve in isolated AR.The primary objective of this study was to investigate the ability of 3D-TTE to assess the severity of chronic AR based on the criterion of regurgitation fraction (RF) obtained by the volume method in comparison to PC-CMR.

We enrolled 42 patients with isolated AR who underwent ASE algorithm-guided 2D echocardiography (2D-TTE), 3D echocardiography and CMR. Regurgitation fraction (RF) was calculated by 3D-TTE using the formula [(LV Stroke Volume–RV Stroke Volume)/LV Stroke Volume]×100. Correlation and concordance between 3D-TTE-RF and PC-CMR-RF were analyzed. Reproducibility of 3D-TTE-RF measurement was evaluated.

Seven (17%) had mild AR, 27 (64%) moderate AR, and 8 (19%) severe AR in PC-CMR. Mean RF was 32.7±13.9% by 3D-TTE and 30,7±14,9% by PC-CMR-RF (P<0,05). 3D-TTE-RF and PC-CMR-RF had a good correlation (r=0.90, P<0,05). We found a good intra-operator (r:0.95, P<0.05) and inter-operator (r:0.87, P<0.05) reproductibility. The final gradation of AR was concordant between 3D TTE and PC-CMR in 88% of the cases.

The assessment of isolated aortic regurgitation fraction in 3D-TTE by the volumetric method is a feasible and reproducible method in daily clinical practice, with a good correlation to PC-CMR. Estimation of the aortic regurgitation fraction in (Figure 1).