[Echocardiographic evaluation of the aortic and pulmonary valve areas in the newborn infant. Normal patterns].

Objectives: To determine normal values of the aortic and pulmonary functional valve areas in healthy newborn children.
Material and Methods: We prospectively studied 32 newborns (17 boys) who were included in the following criteria: healthy parents, normal pregnancy, eutocic delivery, Apgar index 10 at 5 minutes weight between 2.500 and 4.000 kg, normal physical and echocardiographical examinations. The echocardiographical examination was executed during the first 48 hours of life. We used the continuity equation to calculate the aortic and pulmonary functional valve areas. As a reference we used the anatomic (pi r2) aortic and pulmonary valve areas, calculated in the bidimensional images from the distance measured between the two insertion points of the sigmoid valves.
Results: We had echocardiographic images and Doppler registrations of excellent quality, in all the newborn children. The functional pulmonary valve area ranged between 0.30 and 0.50 cm2 (mean +/- SD = 0.41 +/- 0.06) and the anatomical one ranged between 0.29 and 0.49 cm2 (mean +/- SD = 0.49 +/- 0.05), without statistical significance and with a correlation index 0.92. The functional aortic valve area ranged between 0.20 and 0.40 cm2 (mean +/- SD = 0.31 +/- 0.05) and the anatomical ranged between 0.21 and 0.36 cm2 (mean +/- SD = 0.29 +/- 0.05), without statistical significance and with a correlation index 0.91.
Conclusion: There is a good correlation between the functional aortic and pulmonary valve areas, calculated from the continuity equation, and the anatomical ones. These values will be useful in characterizing the critical stenosis of the newborn child with decreased ventricular function, where the transvalvular gradient is inaccurate in the quantification of the obstruction.