Quantitative assessment of aortic regurgitation by Doppler echocardiography: Usefulness of the comparison of aortic and pulmonary flows

Aims Patients with significant (3+/4+) aortic regurgitation ( AR ) require careful monitoring or valve surgery. We sought to evaluate the diagnostic performance of aortic and pulmonary flow comparison in identifying patients with significant AR , by echocardiography. Method Two hundred forty‐six patients with more than trivial AR were prospectively enrolled from three centers. Aortic regurgitation ( AR ) severity was assessed by an expert using the currently recommended integrative approach. Aortic and pulmonary flows were independently assessed by another investigator to calculate the regurgitant fraction ( RF ), the aortic to pulmonary flow ratio (Qao/Qp) and the aortic to pulmonary velocity‐time integral ( VTI ao/ VTI p) ratio. The control group consisted of 195 patients without AR . Results A significant correlation was observed between AR grading and RF ( r  = .82, P  < .0001) and Qao/Qp ( r  = .81, P  < .0001), but the correlation was modest for VTI ao/ VTI p ratio ( r  = .63; P  < .0001). The accuracy of RF and Qao/Qp ratio to identify patients with significant AR was excellent (0.96 and 0.95, respectively), but was significantly lower for VTI ao/ VTI p ratio at 0.82. A RF  > 40% indicated grade 3 or 4 AR with a sensitivity of 83% and a specificity of 93%. A Qao/Qp ratio > 1.6 indicated grade 3 or 4 AR with a sensitivity of 88% and a specificity of 89%. The VTI ao/ VTI p ratio was not helpful in identifying patients with significant AR , as a wide overlap was found between 1+/2+ and 3+/4+ patients. Conclusion Regurgitant fraction ( RF ) and Qao/Qp are helpful in identifying significant AR . The assessment of Doppler aortic/pulmonary flow should be incorporated in the comprehensive evaluation of AR .