Flow Velocity Wave Forms in the Human Fetal Ductus Arteriosus during the Normal Second Half of Pregnancy

Abstract

ABSTRACT. Maximum flow velocity wave forms in the breathing movements (5). There is a significant reduction in ductus arteriosus were studied longitudinally in 40 fetuses ductal peak flow velocity during inspiration as compared with from 18 to 38 wk of gestation at 3-to 4-wk intervals. expiration, and this difference in peak flow velocity increases Median maternal age was 29 y (range 18-41 y), median exponentially with advancing gestational age, reflecting the deparity was 1 (range 0-6). All flow velocity wave forms were veloping pulmonary vascular bed (5). obtained using a mechanical sector scanner with a continTo our knowledge, a detailed analysis of normal fetal ductal uous Doppler system (carrier frequency 3.5 MHz). The wave forms has never been canied out in a longitudinal setting. flow velocity parameters studied were peak-systolic, peak-The objective of the present study was 2-fold: 1 ) to establish the diastolic, and time-averaged velocity and acceleration time. distribution of peak-systolic, peak-diastolic, and time-averaged There was considerable variability in measurements be-velocities as well as acceleration time in the fetal ductus arteriosus tween fetuses at any particular gestational age. An increase between 18 and 38 wk of pregnancy; and 2) to determine whether of ductal flow parameters with advancing gestational age there is fetal heart rate dependency for one or more of the was found. They showed no correlation with heart rate. aforementioned parameters within the physiologic fetal heart These results suggest that the normal second half of preg-rate range (i.e. 1 10-160 bpm) and, if so, to establish the relationnancy is characterized by a reduction in right ventricular ship between fetal period time (the reciprocal of heart rate) and afterload. This may be a result of decreased placental the parameter concerned. vascular resistance or increased pulmonary vascular flow. Acceleration time in ductal flow velocity wave forms was PATIENTS AND METHODS significantly higher than that observed in the pulmonary artery and ascending aorta, suggesting a lower afterload in A total of 40 women with normal singleton pregnancies conthe ductus arteriosus compared with the other two outflow sented to participate in the study. The study protocol was aptract vessels. (Pediatr Res 30: [487][488][489][490] 1991) proved by the Hospital Ethics Committee. Fetal ductal Doppler examinations were carried out at 3-to 4-wk intervals between Abbreviations 18 and 38 wk of gestation. The first examination was performed between 18 and 22 wk of gestation. PSI, prostaglandin synthetase inhibitorsNormal pregnancy was defined by a normal fetal biparietal diameter and birth weight between the 5th and 95th percentile according to Kloosterman's tables, corrected for maternal parity and fetal sex (6). The pregnancy duration was determined from ~h~ ductus arte,.josus is a large vessel that connects the pul-the last menstrual period and confirmed by ultrasonic measuremonary trunk with the descending aorta during fetal life. Thus, men...

Blood flow velocity waveforms of the fetal pulmonary artery and the ductus arteriosus: reference ranges from 13 weeks to term

“…Similar results have been published by Brezinka et al 14 . in fetuses from 11 to 25 weeks of gestation and by van der Mooren et al 13 . from 18 to 38 weeks.…”

“…Reproducibility of velocimetry of the peak systolic velocity and the time velocity integral in the DA has been demonstrated 20,26 . As in a previous study 13 , there were no associations between fetal heart rate and peak systolic and peak diastolic velocity, respectively, but a significant increase of end‐diastolic velocity with increasing fetal rate due to the shortened diastolic phase of the cardiac cycle was found.…”

“…Angle correction was not used. Doppler tracings were recorded with the sample volume positioned just distal to the pulmonary valve in the centre of the vessel 8–12 , for Doppler recordings in the DA the sample volume was placed in the distal ductal part 13,14 . The sample volume was set at 1–3 mm and the high‐pass filter at 100–200 Hz 8,15 , 16 .…”

Utility of Cardiac Monitoring in Fetuses at Risk for Congenital Heart Block

“…[23][24][25][26][27][28][29] The studies were recorded on VHS videotape or DVD/optical disk by the pediatric cardiologist or obstetrician caring for the patient. The videotapes were then sent to the core fetal echocardiographic laboratory where the studies were read and quantified as recorded on the fetal echocardiographic data abstraction forms (by D.M.F.).…”

Prenatal Diagnosis of Idopathic Stenosis of the Ductus arteriosus Associated with Fetal Atrial Flutter

“…At this point, peak systolic flow velocity of 2.29 m/s was recorded ( fig. 4) which is markedly increased [10,11]. Peak diastolic flow velocity was 0.4 m/s, enddiastolic flow velocities varied between 0 Fetal Ductus arteriosus and 0.22 m/s during sinus rhythm and up to 0.4 m/s during tachycar dia.…”