Overview
Identify clinically significant portal hypertension, prevent first decompensation and select safe beta-blocker or endoscopic prophylaxis for variceal bleeding.
Normal portal venous pressure depends on low-resistance flow through hepatic sinusoids. Cirrhotic scar, nodules, endothelial dysfunction and active vasoconstriction raise resistance, while splanchnic vasodilatation increases flow. The resulting collaterals decompress the portal system but create oesophageal, gastric, rectal and abdominal-wall varices. Portal hypertensive gastropathy, hypersplenism, ascites, hepatorenal physiology and encephalopathy are related consequences. Portal vein thrombosis, schistosomiasis, Budd-Chiari syndrome and right-heart disease require different causal treatment despite similar signs.
A hepatic venous pressure gradient of at least 10 mmHg defines CSPH in sinusoidal cirrhosis, but invasive measurement is usually confined to specialist indications or research. Transient elastography with platelet count can rule in or rule out risk in selected aetiologies, while grey-zone results need imaging, endoscopy or expert review. Collaterals or varices themselves are conclusive clinical evidence. Cut-offs depend on technique, obesity, inflammation and disease, so the BSG position statement adds UK caveats to international thresholds.