hepatic vein
Summary
Hepatic veins are the terminal branches of the venous drainage of the liver, carrying deoxygenated blood from hepatic sinusoids into the inferior vena cava (IVC). There are typically three major hepatic veins (right, middle, left) that drain into the IVC just below the diaphragm. They are the site of thrombosis in Budd-Chiari syndrome.
Detail
The hepatic veins arise from the central veins of hepatic lobules, which collect blood from sinusoids after it has passed through the portal triad (portal vein and hepatic artery blood mix in sinusoids). Central veins converge into progressively larger hepatic veins, ultimately forming three main hepatic veins (right, middle, and left) that drain directly into the IVC near its junction with the right atrium, close to the diaphragm. Unlike most other veins, hepatic veins lack valves.
Clinically, hepatic vein anatomy is important for liver segmentation (Couinaud classification) used in hepatic surgery and transplantation, as the hepatic veins along with the portal vein branches define the vascular segments of the liver.
Hepatic vein thrombosis causes Budd-Chiari syndrome, characterized by the classic triad of abdominal pain, ascites, and hepatomegaly due to outflow obstruction leading to hepatic congestion, sinusoidal dilation, and eventually centrilobular necrosis and fibrosis (nutmeg liver on gross/microscopic exam). Causes include hypercoagulable states (polycythemia vera, other myeloproliferative disorders, factor V Leiden, antiphospholipid syndrome), hepatocellular carcinoma invasion, and pregnancy/OCP use. Diagnosis is typically via Doppler ultrasound showing absent or reversed flow in hepatic veins.
Hepatic vein pressure is also relevant to hepatic venous pressure gradient (HVPG) measurement, which assesses portal hypertension severity by comparing wedged hepatic venous pressure to free hepatic venous pressure; a gradient >10 mmHg indicates clinically significant portal hypertension with risk of variceal bleeding.
Right-sided heart failure can cause passive hepatic congestion via backup through the hepatic veins and IVC, producing a similar nutmeg liver appearance but from a different (cardiac) mechanism.
Sources
- Robbins and Cotran Pathologic Basis of Disease
- Moore's Clinically Oriented Anatomy
- First Aid for the USMLE Step 1
- Sabiston Textbook of Surgery
Reviewed by AnkiBoss editorial — medical student review. Information here is for study reference only and is not medical advice. Spotted an error? Let us know.