Application of the proximal flow convergence method to calculate the effective regurgitant orifice are in aortic regurgitation

Objectives. We sought to determine the reliability of the proximal isovelocity surface are (PISA) method for calculation of effective regurgitant orifice (ERO) of aortic regurgitation (AR). Background. The ERO are can be calculated by the PIS method, but this method has not been validated in AR. Methods. ERO calculation by the PIS method was undertaken prospectively in 71 consecutive patients with isolated AR and achieved in 64 and compared with two simultaneous reference methods (quantitative Doppler and quantitative two-dimensional echocardiography). In addition, this method was compared with angiography in 12 patients, with surgical assessment in 18 patients and with ventricular volumes in all patients. Results. Good correlations between PIS and reference methods were obtained (both r = 0.90, both p < 0.0001), but trend toward underestimation of the ERO by the PIS method was noted (24 ± 19 vs. 26 ± 22 mm2 and 27 ± 23 mm2, respectively, both p = 0.04). However, this trend was confined to five patients with an obtuse flow convergence angle (>220°), and on multivariate analysis this variable was the only independent determinant of underestimation of the ERO. In contrast, in 59 patients with flat flow convergence (≤220°), the PIS method, in comparison with reference methods, showed excellent correlations, with narrow standard error of the estimate (r = 0.95, SEE 5.4 mm2, and r = 0.95, SEE 5.8 mm2; all p < 0.0001) and no trend toward underestimation (22 ± 18 vs. 23 ± 16 mm2, p = 0.44, and vs. 23 ± 18 mm2, p = 0.34). Conclusions. In patients with AR, the PIS method can be used to measure the ERO with reasonable feasibility. Underestimation of the ERO by PIS may occur in patients with an obtuse flow convergence angle. However, in most patients with appropriate flow convergence, PIS provides reliable measurement of the ERO of AR.