Normal hepatic vein Doppler

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Normal hepatic vein Doppler

The hepatic veins have a characteristic spectral Doppler waveform. Alterations in the normal hepatic vein waveform may reveal or confirm abnormalities in the heart or liver.

Terminology

The shape of the hepatic vein spectral Doppler waveform is primarily determined by pressure changes in the right atrium, or more exactly the blood flow resulting from the resultant pressure gradients. Multiple terms have been used to describe the hepatic vein waveform, including "phasic", "triphasic", "tetrainflectional", and "periodic". Some prefer the term "periodic" since the term "triphasic" already has a specific application in arterial spectral Doppler waveforms and since "periodic" suggests that the waveform is transmitted by cardiac motion rather than systolic flow.

Radiographic features

The normal periodic hepatic vein waveform is typically described in four parts:

  • a wave: atrial contraction
    • coinciding with the "p wave" on the electrocardiogram, contraction elevates pressure within the right atrium creating a gradient for late diastolic filling of the right ventricle
    • this also creates a pressure gradient favoring a lesser degree of retrograde flow into the IVC and hepatic veins
    • the small reversal of flow typically results in a small wave above the baseline, reversed from the overall net flow back to the heart
       
  • s wave: ventricular systole
    • as systole commences, right ventricle contraction results in longitudinal, apically oriented traction on the tricuspid annulus
    • the resultant "stretching" of the right atrium results in a drop in pressure, creating a gradient for anterograde flow from the inferior vena cava and hepatic veins, most pronounced at mid-systole
    • this typically forms the highest velocity deflection seen in the waveform
       
  • v wave: atrial overfilling
    • a transitional inflection point
    • as blood fills the right atrium, the flow from the hepatic veins and IVC slows, resulting in the s wave returning back to baseline
      • if the atrium fills to capacity then there may be a small amount of flow "recoil" backward, resulting in a v wave that rises above the baseline
         
  • d wave: tricuspid valve opening
    • as the tricuspid valve opens, blood flows from the right atrium into the right ventricle, resulting in a net flow of blood away from the liver and the waveform again dives back down below the baseline
    • this wave is almost always lower in magnitude than the s wave

Sometimes a c wave occurs as a second small inflection above the baseline, right after the a wave, reflecting the effect of the tricuspid valve bulging into the right atrium.

Differential diagnosis

Alterations in the normal hepatic venous Doppler waveform often indicate cardiac dysfunction, although it may also reflect disease of the hepatic parenchyma and/or vasculature. The consequent hemodynamic perturbations may manifest as: