Role of hepatic vein catheterisation and transient elastography in the diagnosis of idiopathic portal hypertension.

BACKGROUND: Idiopathic portal hypertension is a rare cause of portal hypertension, frequently misdiagnosed as cryptogenic cirrhosis. This study evaluates specific findings at hepatic vein catheterisation or liver stiffness in idiopathic portal hypertension.

METHODS: 39 cases of idiopathic portal hypertension patients were retrospectively reviewed. Hepatic vein catheterisation and liver stiffness measurements were compared to matched patients with cirrhosis and portal hypertension, and non-cirrhotic portal vein thrombosis, included as controls.

RESULTS: Hepatic vein-to-vein communications were found in 49% idiopathic portal hypertension patients precluding adequate hepatic venous pressure gradient measurements in 12. In the remaining 27 patients, mean hepatic venous pressure gradient (HVPG) was 7.1 ± 3.1 mm Hg. Only 5 patients had HVPG≥10mmHg. HVPG was markedly lower than in cirrhosis (17 ± 3 mm Hg, p<0.001). Mean liver stiffness in idiopathic portal hypertension was 8.4 ± 3.3 kPa; significantly higher than in non-cirrhotic portal vein thrombosis (6.4 ± 2.2 kPa, p=0.009), but lower than in cirrhosis (40.9 ± 20.5 kPa, p=0.005). Only 2 idiopathic portal hypertension patients had liver stiffness >13.6 kPa.

CONCLUSIONS: Patients with idiopathic portal hypertension frequently have hepatic vein-to-vein communications and, despite unequivocal signs of portal hypertension, HVPG and liver stiffness values much lower than the cut-off for clinical significant portal hypertension in cirrhosis. These findings oblige to formally rule-out idiopathic portal hypertension in the presence of signs of portal hypertension.