Normal and abnormal diameter pulse waveforms in the fetal inferior vena cava

Area of Science:

• Cardiology
• Fetal Medicine
• Medical Imaging

Background:

• Noninvasive assessment of fetal cardiac function is crucial for prenatal care.
• Diameter pulse waveforms (DPWs) offer a potential window into fetal cardiovascular dynamics.
• The inferior vena cava (IVC) is a key vessel for evaluating fetal hemodynamics.

Purpose of the Study:

• To investigate the characteristics of fetal IVC DPWs in normal and abnormal human fetuses.
• To correlate DPW patterns with fetal cardiac structure and rhythm abnormalities.
• To determine the clinical significance of DPW findings in fetal well-being.

Main Methods:

• Utilized a paired ultrasonic phase-locked echo tracking system for noninvasive DPW recording.
• Analyzed DPWs from 90 normal fetuses (20-40 weeks gestation).
• Examined DPWs in 17 fetuses with cardiac structural abnormalities or arrhythmias.

Main Results:

• Successfully identified four distinct waves (A, X, V, Y) in fetal IVC DPWs.
• Observed increased depth of X and Y nadirs in normal fetuses.
• Distinguished two abnormal DPW patterns: high pulsatility (associated with intraatrial pressure changes in pulmonary stenosis/arrhythmia) and low pulsatility (linked to tricuspid regurgitation).
• Found significantly worse clinical outcomes in fetuses with low pulsatility waveforms.

Conclusions:

• Fetal IVC DPW analysis is a simple, noninvasive method for assessing fetal cardiac performance.
• Low pulsatility DPWs may serve as an indicator of depressed fetal myocardial function.
• DPW patterns provide valuable insights into fetal cardiovascular health and clinical prognosis.