understanding portal hypertension

Portal Hypertension: Learn from the start

Pratap Sagar Tiwari, Lecturer, NGMC

What does Portal HTN mean ?

• In simpler terms. It means Hypertension or increased blood pressure in the Hepatic portal system.

• Note: this isnt an standard definition

What is hepatic portal System ????

Hepatic portal system

• The hepatic portal system is the system of veins that consists of the hepatic portal vein and its tributaries.

• It is also called the portal venous system.

Pic taken from : http://imageradiology.blogspot.com/2010/10/hepatic-portal-vein.html

It is one of the two portal system in the body and the other being is the Hypophyseal portal system is a blood system of vessels in the brain that connects the hypothalamus with the anterior pituitary.

Portal circulation

Hepatic Artery Proper

Hepatic portal vein

25%

75%

Hepatic vein

IVC

IMV

Splenic vein

SMV

Cystic vein

Gastric vein

GI tract

Spleen

Portal circulation

• The liver receives about 75% of its blood through the hepatic portal vein, with the remainder coming from the hepatic artery proper.

• The hepatic portal vein is a blood vessel that conducts blood from the gastrointestinal tract and spleen to the liver.

• The blood leaves the liver to the heart in the hepatic veins.• The hepatic portal vein is usually formed by the confluence

of the superior mesenteric and splenic veins and also receives blood from the inferior mesenteric, gastric, and cystic veins.

Portal triad

Pic taken from : https://cms.webstudy.com/WebstudyFileSystem/testovaci/GetFile/293875/Ch%2022/Ch22b/index.html

Portal triad

A portal triad (a component of the hepatic lobule) It consists of the following five structures:1. proper hepatic artery2. hepatic portal vein3. common bile duct4. lymphatic vessels5. branch of the vagus nerve

Portal vein & tributaries

HEART

IVC

Bile canaliculi & sinusoids Hepatic vein

Systemic cirulation

PreHepatic IntraHepatic

PostHepatic

Occulsion↑ resistance↑ pressure hypertension

Portal HTN :causes

Ref: HEMODYNAMIC PRINCIPLES OF PORTAL HYPERTENSION. Sleisenger-2010. http://www.uptomed.ir

Portal HTN : manifestations

Understanding HVPG

Ref: http://www.ias.ac.in/meetings/annmeet/71am_talks/sksarin/img46.html

Portal hypertension

• PHTN is hypertension (high BP) in the portal vein system, which is composed by the portal vein, and its branches.

• Portal venous pressure is the blood pressure in the hepatic portal vein, and is normally between 5-10 mmHg.

• NOTE: Wedged hepatic venous pressure (WHVP)= hepatic sinusoidal pressure• hepatic venous pressure gradient HVPG= WHVP- FHVP• Normal HVPG = < 5 mmhg

• Portal hypertension is defined as elevation of hepatic venous pressure gradient to >5mmHg.

Summary

• Normal portal venous pressure is generally considered to be between 5 -10 mm Hg.

• Once the portal venous pressure rises to 12 mm Hg or greater, complications can arise, such as varices ,ascites etc.

• Portal hypertension is defined as elevation of hepatic venous pressure gradient to >5mmHg.

Prognostic value of HPVG in CLDMeasurement(mmhg) Significance

1-5 normal

6-10 Preclinical sinusoidal portal htn

≥10 Clinically significant phtn

≥12 Increase risk of rupture of varices

≥16 Increase risk of mortality

≥20 Treatment failure and mortality in acute variceal bleeding

Ref: Iris W. Liou, MD. Screening for Varices and Prevention of Bleeding http://hepatitisc.uw.edu/

Portal hypertension is defined as elevation of hepatic venous pressure gradient to >5mmHg.

An HPVG of ≥10 mmHg defines clinically significant portal hypertension

Differentiating Sinusoidal from preSinusoidal portal HTN

Intrahepatic PVP WHVP FHVP HVPGPresinusoidal ↑ N N NSInusoidal ↑ ↑↑ ↑ ↑

WHVP = sinusoidal pressureHVPG = WHVP – FHVP

Portal venous pressure is increased ,so portal hypertensionBut WHVP increases in Sinusoidal ,so Ascites is common in Sinusoidal causes of portal htn(increased Sinusoidal pressure= transudation of fluid )

Schematic dig showing blood flow

Normal Portal HTNSource: emedicine

Overall Manifestations: PHTN

• Ascites• Varices• Hepatic encephalopathy• Splenomegaly

Next Part :• Investigation & Management of portal

hypertension

• Thankyou