Quantification of chronic aortic regurgitation by vector flow mapping: a novel echocardiographic method

Quantification of aortic regurgitation (AR) using echocardiography is challenging. A newly established echocardiographic method, vector flow mapping (VFM), can directly measure blood flow volume (FV) regardless of rheological characteristics. We intended to assess the accuracy of VFM in the quantification of chronic AR.

Twenty-one patients with chronic AR, along with 21 healthy volunteers selected as controls, underwent conventional echocardiography and estimation of aortic blood flow using quantitative Doppler and VFM. The regurgitation ratio (RegR), derived as the quotient of backward and forward aortic FV in the ascending aorta measured by VFM, increased with AR severity: 1.1 +/- 1.5% (normal), 11.4 +/- 3.8% (mild AR), 31.2 +/- 8.0% (moderate AR), and 59.3 +/- 4.7% (severe AR). In a linear regression model, RegR closely correlated with the VC width (r = 0.932) and regurgitation fraction and effective regurgitant orifice measured by the quantitative Doppler method (r = 0.929 and 0.891, respectively). The intra- and interobserver variability of RegR was 4.2 and 6.7%, respectively. There was no difference between RegR measured in the apical five-chamber view and in that in apical three-chamber view using the paired t-test (P = 0.751).

RegR measured by VFM, a new Doppler method allowing quantitative analysis of FV in spite of the presence of turbulent flow, is a highly reproducible parameter with good accuracy for AR quantification.