Fetal aortic distension waveforms for evaluating cardiac function and changes in blood pressure: fetal lamb...

Area of Science:

• Cardiovascular Physiology
• Fetal Medicine
• Biomedical Engineering

Background:

• Assessing fetal cardiovascular health is crucial for managing high-risk pregnancies.
• Non-invasive methods are preferred for monitoring fetal well-being.
• Aortic distension waveforms offer potential for indirect physiological measurements.

Purpose of the Study:

• To determine which fetal aortic distension waveform parameters correlate with fetal cardiac contractility.
• To identify which aortic distension waveform parameters reflect fetal aortic blood pressure.

Main Methods:

• Aortic distension waveforms were recorded using an echo-tracking system in fetal lambs.
• Left ventricular pressure and aortic pressure were measured invasively.
• Infusions of dobutamine and angiotensin II altered cardiac contractility and blood pressure.
• Linear regression analysis correlated waveform parameters with pressure measurements (Max dP/dt).

Main Results:

• The maximum first derivative of the systolic rising slope of the aortic distension waveform strongly correlated with cardiac contractility (Max dP/dt, r = 0.93).
• Aortic distension waveform amplitude and its increase from end-diastole correlated with aortic blood pressure amplitude (r = 0.60 and r = 0.61).

Conclusions:

• The systolic rising slope of the fetal aortic distension waveform can serve as a non-invasive indicator of cardiac contractility.
• The amplitude of the fetal aortic distension waveform can non-invasively estimate aortic blood pressure amplitude.