HVPG

Q: Hepatic venous pressure gradient (HVPG) is calculated by subtracting hepatic vein pressure from? (select one)

A) Central venous pressure (CVP)

B) Right atrial (RA) pressure

C) Pulmonary Artery Occlusion Pressure (PAOP)

D) Inferior vena caval (IVC) pressure 

Answer: D

HVPG is a gradient of pressures between the portal vein and the inferior vena cava (IVC). 

Clinical significance: It is a reliable quantification of the degree of portal hypertension. Once it goes above 5 mmHg, the risk of portal hypertension progressively varies goes up - like once HVPG is ≥12 mmHg, the risk for variceal bleeding and the development of ascites is almost universal.

How to measure: WHVP is usually measured in an interventional radiology suite. A balloon-tipped catheter is introduced via the right jugular (R-IJ) vein under ultrasound (like a central line or swan-ganz catheter) and advanced through the right atrium into the IVC and the right hepatic vein. Fluoroscopic guidance is required. If R0IJ is not available, femoral or antecubital veins can be used. The catheter is maintained in the hepatic vein 2 to 4 cm from its takeoff from IVC. The hepatic vein is occluded by inflating the balloon. An operator may introduce a little contrast to confirm occlusion (no reflux) or wash-out.

In contrast to Pulmonary Artery Occlusion/wedge pressure, the pressure may take up to 60 seconds to record a reliable HVPG. Experts can simultaneously calculate free hepatic venous pressure (FHVP) and wedged hepatic venous pressure (WHVP). This further pressure management details pre-sinusoidal, sinusoidal, and post-sinusoidal sites of resistance to portal blood flow.

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References:

1. Berzigotti A, Seijo S, Reverter E, Bosch J. Assessing portal hypertension in liver diseases. Expert Rev Gastroenterol Hepatol 2013; 7:141.

2. Groszmann RJ, Wongcharatrawee S. The hepatic venous pressure gradient: anything worth doing should be done right. Hepatology 2004; 39:280.

3. Leung JC, Loong TC, Pang J, et al. Invasive and non-invasive assessment of portal hypertension. Hepatol Int 2018; 12:44.