Comparison of Doppler-Based and Three-Dimensional Methods for Fetal Cardiac Output Measurement

Abstract

Objective: Fetal cardiac output is conventionally measured using two-dimensional (2D) and Doppler ultrasound (Doppler). New methods based on 3D measurements of ventricular size in systole and diastole have been proposed. Our aim was to validate these tools against the conventional Doppler-based methods. Methods: Fetal combined cardiac output was prospectively measured at 16, 20, and 24 weeks of gestation in 15 uncomplicated pregnancies using Doppler and three different 3D algorithms [virtual organ computer-aided analysis (VOCAL), sonographic automatic volume calculation (SonoAVC), and inversion mode]. We determined the inter- and intraobserver variability of the 3D techniques and assessed the correlation between Doppler and 3D. Results: The 3D techniques showed adequate inter- and intraobserver reproducibility (intraclass correlation coefficient 0.69–0.98), with the best reproducibility for SonoAVC and inversion mode. Bland-Altman analysis revealed low bias and relatively good correlations when comparing the 3D methods among each other, albeit with wide 95% confidence intervals. Doppler measurement of fetal weight-adjusted combined cardiac output (349.0 ml·min^–1·kg^–1) yielded significantly higher results than 3D CO measurements (177.2, 160.7, and 174.0 ml·min^–1·kg^–1 for VOCAL, SonoAVC, and inversion mode, respectively; p < 0.0001) and correlated poorly with the 3D methods. Conclusions: Although 3D volume-based cardiac output measurements are reproducible, results obtained with different methods are not interchangeable. SonoAVC and inversion have the highest intra- and interobserver reproducibility. Results of cardiac output measurement by 3D and Doppler cannot be interchanged.

Functional echocardiography in the fetus with non-cardiac disease

“…Cardiac output measurements reflect the volume of blood flowing through the heart per unit of time. When measured using Doppler ultrasound of the outflow valves, combined left and right ventricular outputs per fetal weight stay stable throughout gestation at around 400–450 ml/kg/min Cardiac output is a crude estimate of the cardiac global ‘pump’ function and is influenced by heart rate, preload, afterload, ventricular volume, and myocardial contractility.…”

Real-Time 3-Dimensional Echocardiographic Assessment of Ventricular Volume, Mass, and Function in Human Fetuses

“…Accurate and reliable methods for assessing ventricular volumes, mass, stroke volume (SV), cardiac output (CO), and ejection fraction (EF) will provide information to guide medical and surgical management of fetuses with structural and functional abnormalities. Conventional quantitative assessments of these indices in fetuses using 2-dimensional echocardiography (2DE) and pulse-wave Doppler have intrinsic technical limitations in terms of accuracy and have not gained wide acceptance [1]. A spatiotemporal image correlation (STIC) technique and virtual organ computer-aided analysis (VOCAL) have recently been used to assess fetal cardiac volume [2]–[6].…”

Z Score Reference Ranges of Fetal Cardiac Output From 12 to 40 Weeks of Pregnancy

“…We observed that our Doppler‐based technique yielded much more measurement values of CO, either the RCO, LCO, or CCO, compared to those derived from the VOCAL method reported by Hamil et al and DeKoninck et al, as presented in Table . Our observation was in agreement with that reported by DeKoninck et al, who found that VOCAL‐based CO measurements gave fewer values than those obtained from a Doppler‐based technique, and they concluded that fetal COs obtained by different methods cannot be interchanged. Accordingly, actual measurement values in clinical practice must be evaluated by reference ranges based on the same technique.…”

“…The stroke volume is calculated from the valve area, usually obtained by 2‐dimensional (2D) US measurement of the ventricular outflows, and cardiac spectral Doppler analysis of the velocity‐time integral (VTI) over the aortic/pulmonary valve area, which is automatically derived by the built‐in software . Recently, with the innovation of a virtual cardiac cycle, reconstructed by 4‐dimensional spatiotemporal image correlation (STIC), the stroke volume can be measured by the Virtual Organ computer‐aided analysis (VOCAL; GE Healthcare, Milwaukee, WI) function together with US automatic volume calculation . However, the 4‐dimensional method is relatively new, not extensively used, and not available for worldwide use.…”