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Hemodynamic factors affecting uterine artery Doppler waveform pulsatility in sheep.
Author(s) -
Saunders H M,
Burns P N,
Needleman L,
Liu J B,
Boston R,
Wortman J A,
Chan L
Publication year - 1998
Publication title -
journal of ultrasound in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 91
eISSN - 1550-9613
pISSN - 0278-4297
DOI - 10.7863/jum.1998.17.6.357
Subject(s) - medicine , vascular resistance , umbilical artery , hemodynamics , cardiology , waveform , circulatory system , blood pressure , uterine artery , blood flow , angiotensin ii , pulsatility index , biology , pregnancy , fetus , physics , gestation , quantum mechanics , voltage , genetics
Quantitative analysis of vascular resistance from the Doppler time‐velocity waveform relies on measuring arterial pulsatility. However, input pressure waveform pulsatility, impedance, and resistance have all been found to effect artery flow waveform pulsatility in circulatory mathematic models and in umbilical sheep preparations in vivo. The present study used an in vivo sheep preparation to determine that embolization of the uteroplacental circulation and maternal angiotensin II administration caused changes in the uterine Doppler time‐velocity waveform pulsatility that were dependent on input pressure waveform pulsatility, fundamental impedance, and resistance changes. Uteroplacental vascular embolization increased vascular resistance and the uterine artery Doppler waveform resistive index; the mean component of flow (mean pressure/resistance) decreased. Decreased uterine artery Doppler resistive index occurred despite angiotensin II‐induced vasoconstriction and increased vascular resistance because the pulse component of flow (pulse pressure/impedance) decreased.