Developmental changes in flow-wave propagation velocity in embryonic chick vascular system.
We analyzed flow-wave propagation velocity in the early embryonic vascular system and its responses to acute alterations in circulating blood volume. Two 20-MHz pulsed Doppler velocimeters were positioned along the arterial system in stage 18 (n = 12), 21 (n = 10), and 24 (n = 11) chick embryos. Distance between the two measurement sites was measured by video-microscopy. Phase velocity was calculated using Fourier transform up to the fourth harmonics. Wave-front velocity was also calculated by threshold technique. In a subset of embryos at stage 24 (n = 10), circulating blood volume was acutely altered to change stroke volume. Mean phase velocity increased from 42.9 +/- 3.3 to 95.8 +/- 7.5 cm/s from stage 18 to 24 (P < 0.05 by analysis of variance), whereas wave-front velocity increased from 52.8 +/- 2.4 to 72.2 +/- 5.2 cm/s. Stroke volume and mean aortic pressure paralleled the changes in mean phase velocity and wave-front velocity in normal development and in response to changes in circulating blood volume. Thus developmental changes in wave-propagation velocity were consistent with changes in the size of the vascular system, pressure range, and elastic properties of the arterial wall during systemic vasculogenesis in the embryo.
Yoshigi
M
M
Strong Children's Research Center, Department of Pediatrics, University of Rochester School of Medicine and Dentistry, New York 14642, USA.
Ettel
J M
JM
Keller
B B
BB
D000818:Animals; D001158:Arteries / Q000000981:diagnostic imaging / Q000196:embryology* / Q000502:physiology; D001783:Blood Flow Velocity; D001794:Blood Pressure; D001810:Blood Volume; D002302:Cardiac Output; D002642:Chick Embryo; D005583:Fourier Analysis; D006321:Heart / Q000196:embryology* / Q000502:physiology; D006439:Hemodynamics; D013318:Stroke Volume; D013997:Time Factors; D018617:Ultrasonography, Doppler, Pulsed