Closure of the ductus venosus in premature infants: Findings on real time gray-scale, color-flow Doppler, and duplex Doppler sonography

OBJECTIVE. Our objective was to use gray-scale, color-flow, and duplex Dopp ler sonography to study the anatomy, flow pattern, and time of closure of t he ductus venosus in healthy premature infants. SUBJECTS AND METHODS. We prospectively examined the ductus venosus in 130 p remature infants whom we divided into two groups: Group I comprised 27 neon ates of gestational age 28-32 weeks, and group II comprised 103 neonates of gestational age 33-36 weeks. Neonates who had undergone umbilical vessel m anipulation were excluded from the study. All examinations included gray-sc ale, color-flow, and duplex Doppler sonography. Patency, length, color flow , and Doppler characteristics of the ductus venosus were recorded. Neonates were examined 1-2 days after birth, 6-7 days after birth, and subsequently every 3-4 days until ductus closure was observed. The time of closure of t he ductus for the two groups was compared using the chi-square test. RESULTS. The ductus venosus was patent during the initial examination in 12 8 of the 130 neonates. Doppler waveform was venous with little variation in velocity. Ductus length slightly exceeded I cm in both groups. We found a statistically significant difference in the percentage of infants having a patent ductus venosus after the initial examination: At 1 week after birth, ductus patency was shown in 85% of the infants in group I and in 56% of th e infants in group II; at 2 weeks, the respective percentages were 42% and 14%; and at 3 weeks, 27% and 0%. CONCLUSION. The ductus venosus is patent 1-2 days after birth in virtually all premature infants. From 6 days after birth and onward, a significantly greater percentage of smaller premature infants (i.e., 28-32 weeks' gestati onal age) have a patent ductus venosus than do larger premature infants (i. e., 33-36 weeks' gestational age).