Cerebral Artery Flow Velocity Acceleration and Deceleration Characteristics in Newborn Infants

Publisher Website
Google Scholar
Abstract
To evaluate maturational differences in the cerebral artery blood flow velocity characteristics, we measured the middle cerebral (MCA) and basilar artery blood flow velocity and time intervals using a real-time imaging pulsed Doppler system in 39 preterm and 25 term infants. Preterm MCA and basilar artery mean Doppler spectral ]area under the curve were 22 and 25% lower than the corresponding term values, with a significant increase during gestation as revealed by regression models. Paradoxically, the mean MCA systolic acceleration and deceleration slopes were U+2248 28 and 18% higher in preterm than in term infants: acceleration 701.2 ± 160 cm/s2 versus 546.4 ± 156.5/s2 (p2 versus 188.2 ± 52.2 cm/s2(ppppppp<0.02). However, the basilar artery acceleration and deceleration slopes were not significantly different between term and preterm groups, nor showed a significant gestational age effect in the multiple regression models. The results indicate that despite a lower volume flow, the rate of rise of MCA velocity is much higher in preterm than in the term infants; during maturation the velocity waveforms assume a smoother contour. These hemodynamic characteristics could in part reflect immature vessel wall viscoelastic properties, particularly lack of elastin which could result in a reduced windkessel phenomenon.