Doppler echocardiographic differentiation of functional from anatomical pulmonary atresia: analysis using quantitative parameters.

Functional pulmonary atresia must be distinguished from anatomical atresia, which has an intact ventricular septum, to avoid inappropriate treatment, but there is a paucity of data regarding the echocardiographic features that differentiate these conditions. Echocardiographic findings in 5 neonates with functional atresia were compared to those in 5 with anatomical atresia. The left and right ventricular end-diastolic dimensions (LVDd, RVDd), percent of normal predicted LVDd, RVDd/LVDd, tricuspid valve ring diameter (TVD), percent of normal predicted TVD, grade of tricuspid regurgitation (TR), peak TR velocity, pulmonary valve ring diameter (PVD), percent of normal predicted PVD, the minimum diameter of the ductus and the peak velocity through it (PDA velocity) were measured. In addition, systolic pulmonary (PAp) and right ventricular pressure (RVp) from either PDA velocity or TR velocity, and calculated PAp/RVp were also estimated. There were significant differences in RVDd/LVDd, %TVD, and peak TR velocity between the 2 groups. All functional patients showed RVDd/LVDd >0.6, %TVD >100%, estimated RVp <50mmHg, PAp/RVp >0.85, and peak TR velocity <4m/s, whereas the findings in anatomical atresia patients were completely the opposite. In conclusion, a large RVDd/LVDd, TVD, PAp/RVp, low RVp and small TR velocity all suggest functional rather than anatomical pulmonary atresia, although there may be some exceptions such as severe Ebstein anomaly.