Fetal atrioventricular flow-velocity waveforms and their relation to arterial and venous flow-velocity waveforms at 8 to 20 weeks of gestation
Doppler ultrasonography was used to determine the nature and gestational age-related changes of human fetal AV flow-velocity waveforms and to establish their relationship with arterial impedance indexes and venous flow velocities in normal human fetuses between 8 and 20 weeks of gestation. Flow-velo...
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Veröffentlicht in: | Circulation (New York, N.Y.) N.Y.), 1996-09, Vol.94 (6), p.1372-1378 |
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Zusammenfassung: | Doppler ultrasonography was used to determine the nature and gestational age-related changes of human fetal AV flow-velocity waveforms and to establish their relationship with arterial impedance indexes and venous flow velocities in normal human fetuses between 8 and 20 weeks of gestation.
Flow-velocity waveform recordings were attempted in 318 singleton pregnancies. After the exclusion criteria were applied, data on 214 women were available for further analysis. Differentiation between E wave and A wave became possible at 9 weeks, whereas distinction between transmittal and transtricuspid valve flow velocities was first achieved at 10 to 11 weeks. A statistically significant nonlinear gestational age-dependent increase was established for all AV waveform parameters, which became linear when related to logarithmically estimated fetal crown-to-rump length. Transtricuspid valve flow velocities were significantly higher than transmittal valve flow velocities. Transmittal valve time-averaged flow velocities were positively correlated with peak diastolic velocities and time-velocity integral of late-diastolic reverse flow in the inferior vena cava. No correlation existed between AV time-averaged velocities and arterial impedance indexes.
Monophasic AV flow-velocity waveforms can be recorded as early as 8 weeks of gestation and become biphasic as early as 8 weeks. They demonstrate a linear increase relative to logarithmically estimated fetal crown-to-rump length, suggesting that fetal growth-related increase in volume flow plays a role in this velocity rise. Transtricuspid valve A-wave and E-wave velocities suggest right ventricular predominance as early as the late first trimester of pregnancy. AV flow velocities are not related to arterial downstream impedance. |
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ISSN: | 0009-7322 1524-4539 |
DOI: | 10.1161/01.CIR.94.6.1372 |