Foetal aortic flow velocity waveforms in healthy and hypertensive pregnant women

Abstract

BackgroundThe foetal aortic Doppler frequency spectrum is influenced by cardiac output and contractility of the foetal heart as well as vascular compliance, blood viscosity and impedance of the arterial vascular system. The present study aimed at comparing Doppler flow pulsatility (PI) and resistance (RI) indexes of foetal proximal descending aorta (AoF) in the first, second and third trimesters of pregnancy, in low risk women and in those with chronic arterial hypertension, who had normal pregnancy outcomes.MethodsA longitudinal and prospective study was carried out in 101 singleton pregnancies (71 low-risk pregnancies and 30 with essential hypertension). Multivariate regression had to be considered due to the experiment’s nature: two different indexes were read on the same set of individuals, once at each trimester of the pregnancy [1st (11–14 weeks), 2nd (19–22 weeks) and 3rd (28–32 weeks) trimesters]. The response variable was denoted as index d, in a subject with hypertensive status h (hypertensive or normotensive), at continuous time t.ResultsIn both groups, AoF-PI and AoF-RI showed a small, but significant increase from the first to the second (1.850 ± 0.339 vs 2.110 ± 0.242 for PI, and 0.829 ± 0.068 vs 0.857 ± 0.038 for RI; p < 0.001) and the first to the third (1.850 ± 0.339 vs 2.163 ± 0.282 for PI, and 0.829 ± 0.068 vs 0.864 ± 0.037 for RI; p < 0.001) trimesters of pregnancy. The global model showed that while AoF-RI trends were converging as time progressed, the AoF-PI values exhibited a divergent trend (p < 0.05).ConclusionsChronic stable hypertension in pregnancies with normal outcome, evidences an upward regular trend of foetal descending aorta pulsatility index that is similar to the normotensive condition.

Characterization of Cardiac Dynamics in an Acute Myocardial Infarction Model by Four-Dimensional Optoacoustic and Magnetic Resonance Imaging

“…The high temporal resolution of the introduced OA system enables high contrast deep tissue imaging of volumetric contrast agent perfusion, allowing for an accurate quantification of the PTT during initial passage of the concentrated ICG bolus through the heart, before it gets significantly diluted in the bloodstream. The PTT values then serve as an indicator of bi-ventricular dysfunction, and can be further used to estimate the pulmonary vascular resistance 24 . Significant changes in the PTT (50-100%) were observed based on a beat-by-beat analysis of the volumetric OA image sequences.…”

Quantification of carotid artery plaque stability with multiple region of interest based ultrasound strain indices and relationship with cognition

“…Recently, shear wave elastography has been applied to generate quantitative characteristics using shear modulus maps for assessing unstable plaque (Garrard et al , 2015; Ramnarine et al , 2014). Li et al (Li et al , 2016) measured the shear modulus to characterize arterial stiffness in the common carotid for patients diagnosed with an acute ischemic stroke and found it to be elevated when compared to age and sex matched controls.…”

Sex differences in fetal Doppler parameters during gestation

“…The UA PI, DAo PI, DV PVIV, and PIV data were analyzed using a linear mixed effects model with gestational age (in completed weeks), fetal heart rate, race (Asian, Black or African American, White, other), and fetal sex (female, male) as the fixed effects and a heteroscedastic random effect where inter-subject variation varied linearly with gestational age. Linear models were chosen based on previous studies of UA PI [ 5 , 11 ], DAo PI [ 6 , 9 ], and DV PIV [ 7 , 10 ] throughout gestation. A linear mixed effects model using a second-order polynomial function was used to determine if the MCA PI and CPR depended on gestational age (in completed weeks), fetal heart rate, race, and fetal sex.…”