Portal hypertension occurs when pressure in the portal venous system rises, usually due to liver cirrhosis or scarring impeding blood flow into the liver. Ultrasound can detect signs of portal hypertension like ascites, splenomegaly, dilated portal veins and collateral vessels that form around the liver. Specific findings include thrombosed or narrowed portal veins, enlarged arteries supplying the liver, and reversed blood flow away from the liver.

2. PORTAL HYPERTENSION
Subject:
Applied Doppler, Vascular Doppler.

3. TOPICS:
Definition.
Anatomy.
Causes
Ultrasound Finding.
References.

4. DEFINITION OF PORTAL HYPERTENSION.
Portal hypertension occurs when the pressure in the portal venous
system is raised. This may happen as a result of chronic liver
disease, particularly in the cirrhotic stage, when the nodular and
fibrosed nature of the parenchyma impedes the flow of blood into
the liver.

5. ANATOMY

6. • The portal venous system extends from
the intestinal capillaries to the hepatic
sinusoids. This venous system carries the
blood from the abdominal gastrointestinal
tract, the pancreas, gallbladder, and
spleen back to the heart (coursing
through the liver).
• The portal vein supplies 70% of the blood
flow to the liver, but only 40% of the liver
oxygen supply. The remainder of the
blood comes from the hepatic artery,
and blood from both of these vessels
mixes in the sinusoids.
• The liver receives a tremendous volume of
blood, on the order of 1.5 liters per
minute.

7. CAUSES:
Normal portal vein pressures range from 5–10 mm Hg.
Portal hypertension is present when the portal vein pressure exceeds 12 mmHg.
1) Prehepatic or Infrahepatic Causes.
2) Intrahepatic or Hepatic Causes .
3) Posthepatic or Suprahepatic Causes.

8. 1. PREHEPATIC OR INFRAHEPATIC CAUSES
i. Congenital Atresia Or Stenosis.
ii. Thrombosis Of Portal Vein.
iii. Thrombosis Of Splenic Vein.
iv. Extrinsic compression (e.g , tumor). Portal Vein
Thrombosis

9. 2. INTRAHEPATIC OR HEPATIC CAUSES .
i. liver cirrhosis
ii. hepatic fibrosis (e.g. due to Wilson's
disease,hemochromatosis, or
congenital fibrosis)
iii. less commonly noncirrhotic causes
such as schistosomiasis, massive
fatty change and diffuse
granulomatous diseases.

10. 3. POSTHEPATIC OR SUPRAHEPATIC CAUSES.
i. Budd-chiari Syndrome ( Hepatic
Vein Thrombosis )
ii. IVC thrombosis.
iii. Cardiac Disease:
a. Constrictive Pericarditis.
b. Valvuar Heart Disease.
c. Right Heart Failure.

11. • Ascites (free fluid in the peritoneal
cavity) & Cirrhotic liver
Transabdominal ultrasound shows loops of
small bowel with thickened walls floating
within ascitic fluid due to portal hypertension
Cirrhotic right hepatic lobe
with the surrounding ascites.

12. • Splenomegaly.
Splenomegaly in portal hypertension. The
inferior splenic margin is blunted, descending
below and medial to the left kidney.
Varices at the splenic hilum
in portal hypertension.

13. • Dilated portal veins
The Normal Portal Vein is < 1.3 cm,
> 20% change in caliber with respiration

14. • Ligamentum Teres
Para-umbilical channel running along the ligamentum teres to the anterior abdominal
wall in a patient with end-stage chronic liver disease and portal hypertension.

15. • Porto System Collaterals
Splenic Vein Occlusion
Longitudinal color Doppler ultrasound shows
an umbilical vein collateral extending
anteriorly from left portal vein branch

16. • Dilated Hepatic Arteries

17. • Portal vein thrombosis
A, Longitudinal view ofthe main portal
vein (arrow) shows hypoechoic
thrombus throughout the venous
lumen.
B, Transverse view ofthe left portal vein
shows focal isoechoic thrombus (arrow)
within thelumen.
C, Longitudinal view of the main portal
vein shows focal hyperechoic thrombus
(arrows) within the lumen.
D, Transverse view of the main portal
vein shows a large hyperechoic
thrombus (arrow) near the splenic vein
confluence.
Portal vein thrombosis in different patients.

18. • Hepatofugal (reversed) portal flow
Reversed PV flow in portal hypertension. Note the increased velocity of hepatic arterial flow indicated.

19. REFERENCES: