Hepatic inflow disorders: artery, portal vein, sinusoids
- Lesion
The liver has two blood supplies, so blocking one rarely kills tissue; blocking flow inside the liver causes congestion and necrosis.
What it is
The liver receives blood from the portal vein (most of the flow) and the hepatic artery (much of the oxygen). Because of this dual supply, infarcts are rare. Blockage of the portal vein before the liver causes portal hypertension with a usually normal liver. Inside the liver, flow can be impeded by cirrhosis, by sinusoids plugged with cells (sickle cells, tumour cells, DIC) and by blood-filled cavities (peliosis hepatis).
Step by step
- Flow into the liver is blocked at the portal vein or its branches, or the sinusoids are plugged.
- The dual supply keeps most hepatocytes alive, but pressure rises upstream.
- Portal hypertension develops with varices and splenomegaly.
- Where sinusoids are blocked, zone 3 hepatocytes downstream suffer most and may die.
- Organized thrombus may be replaced by a network of collaterals (cavernous transformation).
Disorders of blood flow into and through the liver
| Disorder | Mechanism | Result |
|---|---|---|
| Hepatic artery occlusion | Embolism, vasculitis, surgery, transplant thrombosis | Usually tolerated; ischemic cholangiopathy in grafts |
| Portal vein thrombosis | Stasis, infection, tumour, hypercoagulability | Prehepatic portal hypertension, varices, splenomegaly |
| Intrahepatic portal branch occlusion | Small thrombi or emboli | Infarct of Zahn (congested, atrophic wedge) |
| Sinusoidal plugging | Sickle cells, malaria, tumour cells, DIC microthrombi | Pericentral congestion and necrosis |
| Peliosis hepatis | Sinusoidal wall damage | Blood-filled cysts; risk of rupture and bleeding |
Test yourself
Think of the answer, then tap the question to see it.
Why are hepatic infarcts uncommon?
The liver has a dual blood supply from the portal vein and the hepatic artery, so one can compensate for the other.
What is an infarct of Zahn?
A wedge-shaped area of congestion and hepatocyte atrophy after occlusion of an intrahepatic portal vein branch; there is no necrosis.
What is peliosis hepatis and which drugs cause it?
Blood-filled cystic spaces in the liver; anabolic steroids and oral contraceptives are classic causes, and Bartonella in immunosuppressed people.
Elsewhere in DurgiPedia
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Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Hepatic ischemia: MedlinePlus Medical Encyclopedia (MedlinePlus, US National Library of Medicine, 2026); Portal Hypertension (StatPearls (NCBI Bookshelf), 2025).
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Representative model, for educational purposes only.