| Abstract: | ![]()
A noninvasive and quantitative evaluation of pulmonary regurgitation (PR) using pulsed Doppler echocardiography (PDE) was performed in 25 patients with tetralogy of Fallot (TOF) after corrective surgery. Considering a possibility of the presence of the difference in regurgitant flow velocity in pulmonary artery, four sampling points for detecting the pulmonary regurgitant flow were designed as follows: point 0 was positioned at the right ventricular outflow tract; point 1, at the pulmonary annulus; point 2, at mid-portion of the pulmonary trunk; point 3, at bifurcation of the pulmonary artery. The values of maximum Doppler shift determined by analysing the sonograms recorded at point 1, 2 and 3 were examined in comparison with the grades of PR estimated by pulmonary arteriography and the results obtained were as follows. In a retrospective study in 18 patients with PR, the values of maximum Doppler shift were highest at point 1, and followed by point 2 and point 3 in order (p less than 0.005), indicating that the velocity gradient of regurgitant flow existed in the pulmonary artery. The values of maximum Doppler shift were highest in the group of PR grade III estimated by pulmonary arteriography, and followed by the group of PR grade II and grade I in order. At point 2, the group of grade III-PR showed significantly higher Doppler shift than the group of grade I-PR (p less than 0.05). Following above data, a new criteria for estimating the severity of PR by PDE according to the velocity gradient of regurgitant flow in the pulmonary artery was proposed. In a prospective study in a separate group of other 7 patients, the grade of PR estimated by PDE corresponded well with these of pulmonary arteriography, with a significant Spearman rank correlation coefficient (rs = 0.90, p less than 0.01). An experimental study using a dog with surgically induced PR of different grades confirmed the presence of higher Doppler shift in pulmonary artery corresponding to the grade of PR. These results indicated the usefulness of a newly proposed method evaluating PR by PDE applying a concept of Windkessel model for PR regurgitant flow. |
