Portal venous pressure
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Portal venous pressure is the
blood pressure Blood pressure (BP) is the pressure of circulating blood against the walls of blood vessels. Most of this pressure results from the heart pumping blood through the circulatory system. When used without qualification, the term "blood pressure" r ...
in the
hepatic portal vein The portal vein or hepatic portal vein (HPV) is a blood vessel that carries blood from the gastrointestinal tract, gallbladder, pancreas and spleen to the liver. This blood contains nutrients and toxins extracted from digested contents. Approxima ...
, and is normally between 5-10 mmHg. Raised portal venous pressure is termed
portal hypertension Portal hypertension is abnormally increased portal venous pressure – blood pressure in the portal vein and its branches, that drain from most of the intestine to the liver. Portal hypertension is defined as a hepatic venous pressure gradient gr ...
, and has numerous sequelae such as
ascites Ascites is the abnormal build-up of fluid in the abdomen. Technically, it is more than 25 ml of fluid in the peritoneal cavity, although volumes greater than one liter may occur. Symptoms may include increased abdominal size, increased weight, ab ...
and
hepatic encephalopathy Hepatic encephalopathy (HE) is an altered level of consciousness as a result of liver failure. Its onset may be gradual or sudden. Other symptoms may include movement problems, changes in mood, or changes in personality. In the advanced stages ...
.


Wedged hepatic venous pressure (WHVP)

WHVP is used to estimate the portal venous pressure by reflecting not the actual hepatic portal vein pressure but the hepatic
sinusoidal A sine wave, sinusoidal wave, or just sinusoid is a mathematical curve defined in terms of the '' sine'' trigonometric function, of which it is the graph. It is a type of continuous wave and also a smooth periodic function. It occurs often in m ...
pressure. It is determined by wedging a catheter in a
hepatic vein In human anatomy, the hepatic veins are the veins that drain venous blood from the liver into the inferior vena cava (as opposed to the hepatic portal vein which conveys blood from the gastrointestinal organs to the liver). There are usually thr ...
, to occlude it, and then measuring the pressure of proximal static blood (which is reflective of pressure in the sinusoids). WHVP in fact slightly underestimates portal pressure due to sinusoidal equilibration in patients without
cirrhosis Cirrhosis, also known as liver cirrhosis or hepatic cirrhosis, and end-stage liver disease, is the impaired liver function caused by the formation of scar tissue known as fibrosis due to damage caused by liver disease. Damage causes tissue repai ...
, but the difference between the two is clinically insignificant. In patients with cirrhotic livers intersinusoidal communication is disrupted such that sinusoidal pressure equilibrium cannot be maintained, and so WHVP becomes a far more accurate measure of portal venous pressure.


Hepatic venous pressure gradient (HVPG)

HVPG is a clinical measurement of the pressure gradient between the WHVP and the free hepatic venous pressures (FHPV), and thus is an estimate of the pressure gradient between the portal vein and the inferior vena cava. An HVPG of ≥5 mmHg defines portal hypertension, and if the measurement exceeds 10 mmHg it is called clinically significant portal hypertension. Above 12 mm Hg, variceal haemorrhage may occur. While not widely performed, its assessment in people with chronic liver disease is recommended to monitor response to treatment.


References


External links

* {{Cardiovascular physiology Blood pressure