Quantitative evaluation of pulmonary regurgitation after repair of tetralogy of Fallot using real-time flow imaging system

Real-time flow imaging of pulmonary regurgitation (PR) by two-dimensional pulsed Doppler echocardiography was performed in 34 patients after repair of tetralogy of Fallot. The right ventricle and pulmonary artery were demonstrated in the parasternal short axis view and PR flow was visualized. The image was frozen when the velocity of regurgitant flow was maximum at the level of the pulmonary valve. Pulmonary regurgitant area index (PRAI) was calculated from planimetric measurement of the area where PR flow was expressed. Grading of PR (1 to 3) was independently attempted according to the extension of PR flow detected in pulmonary artery by a range-gated pulsed Doppler echocardiography. PRAI (cm2/m2) was 0.36 +/- 0.29 (mean +/- standard deviation) in grade 1, 1.48 +/- 0.46 in grade 2, and 2.80 +/- 0.94 in grade 3. Severity of PR (grade 1 to 3) was also rated on the basis of the pulmonary arteriography and compared with PRAI. PRAI was 0.64 +/- 0.60 in grade 1, 1.07 +/- 0.63 in grade 2, and 2.21 +/- 1.67 in grade 3, respectively. RPAI showed strong correlation with pulmonary regurgitant fraction measured by videodensitometric study of right ventriculography (r = 0.84). Quantitative evaluation of PR using real-time flow imaging system is a reliable and useful method.