67 74 Hepatoportal blood flow

Hepatoportal blood flow: dual blood supply of the liver, the hepatic arterial buffer response and portal hypertension.

Hepatoportal (splanchnic) blood flow supplies the liver and the abdominal organs: stomach, intestines, pancreas and spleen. Together they receive about a quarter of cardiac output at rest, roughly 1.2–1.5 L/min. The liver has a dual blood supply: about three quarters arrives through the portal vein, which collects blood rich in absorbed nutrients from the gut and spleen, and about a quarter through the hepatic artery, which brings oxygen-rich blood. Blood flow to the gut rises after meals.

LiverPortal circulationSplanchnic flow

Share of cardiac output≈ 24–25%

At rest≈ 1.2–1.5 L/min

Portal vein≈ 75% of liver inflow

Hepatic artery≈ 25% of liver inflow

Figure 1. Resting distribution of a cardiac output of about 5 L/min (after Chapman and Mitchell, 1965). The highlighted bar shows abdominal (hepatoportal) blood flow.

This application estimates regional blood flow as a percentage of cardiac output and converts it into mL/min from the calculated cardiac output. In clinical practice, organ blood flow is measured invasively or with imaging (for example indicator dilution, Doppler ultrasound, PET or MRI perfusion).

Regulation

The liver cannot control portal venous flow, which depends on the gut and spleen. Instead, the hepatic arterial buffer response compensates: when portal flow falls, adenosine accumulates around the hepatic arterioles and dilates the hepatic artery within seconds, keeping total liver flow relatively stable. The splanchnic vessels also act as a blood reservoir: in bleeding and shock they constrict strongly to shift blood to the heart and brain.

Clinical significance

Liver cirrhosis: scarring increases resistance to portal flow, causing portal hypertension, varices, ascites and an enlarged spleen
Portal or hepatic vein thrombosis (Budd–Chiari syndrome)
Heart failure: congestion of the liver (congestive hepatopathy) and reduced splanchnic flow
Shock: prolonged splanchnic vasoconstriction can damage the gut lining and liver ("shock liver")
Mesenteric ischaemia: blockage of the intestinal arteries, causing severe abdominal pain out of proportion to findings

Seek emergency care

for sudden severe abdominal pain, vomiting blood, black stools, rapidly increasing abdominal swelling, jaundice or confusion in a person with liver disease.

References

Lautt WW. Hepatic Circulation: Physiology and Pathophysiology. San Rafael (CA): Morgan & Claypool Life Sciences; 2009. ncbi.nlm.nih.gov/books/NBK53069
Vander A, Sherman J, Luciano D. Human Physiology: The Mechanisms of Body Function. 8th ed. Boston: McGraw-Hill; 2001. Fig. 14-9 (after Chapman CB, Mitchell JH. Sci Am. 1965). Data: BioNumbers BNID 109465

This article is for general information and does not replace a consultation with a doctor. Measurements must be interpreted by a physician together with symptoms and other tests.

Published on 30 April 2024