What causes the hepatic vein flow to have a triphasic waveform?
The waveforms were considered triphasic when there were two hepatofugal or antegrade phases (related to atrial and ventricular diastole) and a short phase of hepatopetal or retrograde flow (caused by the pressure increase in the right atrium at atrial systole) (Fig. 1).
Are hepatic veins triphasic?
The normal hepatic vein waveform, despite commonly being described as triphasic, has four components: a retrograde A wave, an antegrade S wave, a transitional V wave (which may be ante-grade, retrograde, or neutral), and an antegrade D wave (13).
What would you expect the hepatic vein waveforms to look like in a patient with chronic cirrhosis?
Normal hepatic venous waveform shows a triphasic pattern. In cirrhosis, this pattern changes to a biphasic or monophasic pattern.
What is phasic waveform?
Phasic blood flow has velocity and acceleration fluctuations that are generated by cyclic (phasic) pressure fluctuations, which are in turn generated by the cardiac cycle (cardiac phasicity). When phasic blood flow is sampled at spectral Doppler US, it is displayed as a phasic waveform.
What does triphasic waveforms mean?
Duplex scanners The normal (“triphasic”) Doppler velocity waveform is made up of three components which correspond to different phases of arterial flow: rapid antegrade flow reaching a peak during systole, transient reversal of flow during early diastole, and slow antegrade flow during late diastole.
What are hepatic veins?
Hepatic veins are blood vessels that return low-oxygen blood from your liver back to the heart. The veins are key players in the supply chain that moves the blood that delivers nutrients and oxygen to every cell in your body.
Is triphasic flow normal?
Triphasic arterial flow is considered normal in peripheral arteries and monophasic flow is considered abnormal 7. Due to the controversy surrounding the definition of biphasic, there is disagreement about whether biphasic flow is normal 2.
Is monophasic waveform bad?
The presence of a poor monophasic waveform, encountered in 91 (24.3%) of 375 segments, was a reliable sign of significant aortoiliac disease, with a positive predictive value of 92%. Other waveforms were nondiagnostic for aortoiliac obstructive disease.
What does high resistance waveform mean?
High-resistance spectral waveforms are characterized by velocities that increase sharply with systole, decrease rapidly with the cessation of ventricular contraction, and show little or no forward flow during diastole (Fig.
What are the waveforms of the hepatic vein?
The normal hepatic vein waveform, despite commonly being described as triphasic, has four components: a retrograde A wave, an antegrade S wave, a transitional V wave (which may be ante-grade, retrograde, or neutral), and an antegrade D wave (13).
Why are normal waveforms absent in hepatic disease?
In hepatic and cardiac disease, these normal waves may be absent, a finding indicative of flow in a nonphysiologic manner. In addition, transient patient factors such as phase of the respiratory cycle may influence the appearance of the spectral tracing.
How is the shape of the hepatic vein Doppler determined?
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”.
Where is the probe located in the hepatic veins?
The hepatic veins are interro- gated by placing the probe along the anterior or right lateral aspect of the abdomen or lower thorax. Introduction Duplex Doppler sonography of the liver plays an