Portal Vein Flow

• Use the phased array probe in cardiac presets.
• Anterior axillary line with the pointer towards the patient’s head.
• Identify the portal vein by the hyperechoic walls (Figure 1).
• Place the color Doppler over the portal vein to identify flow.
• Place the pulse wave Doppler over the portal vein.
• Reduce the gate as low as possible.
• Acquire PW signal.
• Adjust the scale to optimize waveform.

Interpretation

Waveform (Figure 2)

Normal portal flow is continuous. (Figure 3)

Elevated right atrial pressure (RAP) will cause pulsatility in the vein (Figure 4).

As it increases elevated RAP will cause a to-and-fro pattern (Figure 5).

Tips

It is important to differentiate hepatic veins from portal veins. Hepatic veins have hypoechoic thin walls.

Pulsatile flow is also a sign of portal hypertension, and cannot be used as a measure of right atrial pressure elevation in cirrhosis.

Figure 1 - Portal vein

Figure 2 - Portal flow patterns with RAP

Figure 3 - Normal portal flow

Figure 4 - Pulsatile portal flow

Figure 5 - To and fro flow

Clip 1 - Portal Vein Doppler

Beaubien-Souligny, William, et al. “Extracardiac signs of fluid overload in the critically ill cardiac patient: a focused evaluation using bedside ultrasound.” Canadian Journal of Cardiology 33.1 (2017): 88-100.

Beaubien-Souligny, William, et al. “The association between pulsatile portal flow and acute kidney injury after cardiac surgery: a retrospective cohort study.” Journal of cardiothoracic and vascular anesthesia 32.4 (2018): 1780-1787.