Evaluation of aortic regurgitation severity using flow convergence from the parasternal window: comparison with cardiac magnetic resonance and traditional Doppler parameters.

AIMS: To assess whether two-dimensional measurements of flow convergence (FC) from the standard parasternal long-axis (PLA) window relate to aortic regurgitation (AR) severity.

METHODS AND RESULTS: Patients with chronic AR who underwent transthoracic echocardiography and cardiac magnetic resonance imaging (CMR) within 4 h were included. FCPLA was assessed using 3 parameters: the maximum length (Lmax), width (Dmax), and hemispheric area. Traditional echo/Doppler parameters of AR severity were measured per guidelines. FC and other echo/Doppler results were compared to CMR-derived regurgitant volume (RegV). A total of 80 patients were evaluated. AR was significant by CMR (RegV > 45 mL) in 41% of patients. FCPLA parameters were measurable in 83% of patients whereas apical PISA quantitation was feasible in only 39%. FCPLA measurements correlated well with CMR RegV: Spearman ρ = 0.75 for Lmax, ρ = 0.65 for Dmax, and ρ = 0.78 for area. The AUC values of Lmax = 0.55 cm, Dmax = 0.65 cm, and FCPLA area = 0.35 cm2 for identifying significant AR were 0.98, 0.84, and 0.94, respectively, with Lmax and FC area demonstrating significantly higher AUCs. They were comparable to those of vena contracta width (AUC = 0.94) and left ventricular end-diastolic volume index (AUC = 0.91) and superior to those of jet width/LVOT diameter (AUC = 0.80), descending aorta end-diastolic velocity (AUC = 0.74), and pressure half-time (AUC = 0.71).

CONCLUSION: In chronic AR, flow convergence is more identifiable from the parasternal long axis window compared to traditional PISA measured from the apical window. FCPLA nonvolumetric parameters relate well to AR severity by CMR and are comparable to conventional echo/Doppler parameters.