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The purpose of this study is to determine the incidence of reverse aortic arch flow in newborn infants with pulmonary hypertension, and no other identifiable cause for flow reversal, being considered for extracorporeal membrane oxygenation (ECMO) 2) compare the left ventricular output, and 3) outcomes, of these infants, with those in the group of patients with normal arch flow. We reviewed the medical records and echocardiograms of all infants referred to our institution for extracorporeal membrane oxygenation support for pulmonary hypertension, between August 1994 and April 1996. Neonates with pulmonary hypertension and reverse aortic arch flow had significantly lower left ventricular output (p = 0.005), and had significantly higher mortality (p = 0.04), than those with normal aortic arch flow. They required significantly higher ventilatory support (p = 0.01) and tended to need more inotropic support. Reverse aortic arch flow in newborn infants with pulmonary hypertension, and no other cause for the reverse flow, indicates significantly decreased left ventricular output, and may be a marker for a more difficult clinical course and poor prognosis. In this group of patients with pulmonary hypertension, the survival was significantly higher in infants with no PDA or with pure left to right shunt across a PDA.

Tetralogy of Fallot has increased in incidence during the past decade. Although abnormalities of the four-chamber screening examination of the fetal heart identifies structural anomalies associated with semilunar and atrioventricular valve hypoplasias, the anomalies associated with tetralogy of Fallot are not as readily identifiable from the four-chamber view alone. This study was designed to determine whether aortic root dilatation, commonly observed in the newborn with tetralogy of Fallot, is a marker for tetralogy of Fallot diagnosed in utero. In 45 normal (control) fetuses the biparietal diameter, head circumference, abdominal circumference, and femur length were measured and M-mode measurements were made of the biventricular outer dimension and aortic root dimension. The aortic root dimension from seven fetuses (18, 19, 20, 23, 32, 33, and 34 weeks' gestation) with tetralogy of Fallot was increased in dimension when compared with cardiac (biventricular outer dimension) and noncardiac biparietal diameter, head and abdomen circumferences, and femur length parameters. In conclusion, incorporation of aortic root imaging with the four-chamber view of the fetal heart during a routine screening examination allows for identification of fetuses with tetralogy of Fallot.

Aortic root diameter measurements were obtained during the first week of life by M-mode echocardiography using leading edge methodology during early diastole in 172 preterm and 228 term neonates. At least 40 newborns were included in each 500-g birth-weight subgroup from 750 to 4750 g. The aortic root diameter increased linearly from 0.63 +/- 0.04 cm in newborns with birth weights of 750-1249 g to 1.06 +/- 0.06 cm in newborns of 4250-4750 g.

The aortic root dimension and aortic valve excursion of 43 normal fetuses were recorded with M-mode echocardiography and the measured dimensions correlated with noncardiac measurements (biparietal diameter, head circumference, abdominal circumference, and femur length) and cardiac measurements (diastolic biventricular inner dimension, diastolic left ventricular internal dimension, and mitral valve excursion). The correlation coefficients for the aortic root dimension ranged between 0.87 and 0.95, while those for the aortic valve excursion ranged between 0.78 and 0.87. Regression analysis demonstrated that the best fit of the data was a linear model from which the 5% and 95% confidence limits were computed for individual predictions of aortic root dimension and aortic valve excursion from noncardiac and cardiac measurements.

The combination of 2-dimensional real-time and pulsed Doppler echocardiography provides a noninvasive method of measuring blood flow and has been used to study blood flow at the lower thoracic level in the descending aorta of the human fetus. Using these techniques, we evaluated the proportion of cardiac output distributed through the descending aorta in 20 healthy term newborn infants at 1-6 days of age. Blood flow in the ascending aorta was 759 +/- 135 ml/min (mean +/- S.D.) and in the descending aorta 482 +/- 92 ml/min indicating that 63.8% of the left ventricular output is distributed through the descending aorta. Peak systolic and mean blood flow velocities were comparable at the two sites, whereas the diameter of the descending aorta was 19% smaller than that of the ascending aorta. The changes in aortic blood flow were correlated with the changes in aortic diameter.