PERCUTANEOUS TRANSHEPATIC MEASUREMENT OF THE PRESSURE-GRADIENT BETWEEN THE PORTAL AND HEPATIC VEINS

Background. Knowledge of the portal pressure may be of value in the assessment of patients with chronic liver disease but its measurement is problematic. Aims: To evaluate the ease and safety of percutaneous transhepatic measurement of the pressure gradient between the portal and hepatic veins and to determine directly the need for an internal zero. Methods: Sixty-one patients undergoing liver biopsy for suspected liver disease had pressures in branches of portal and hepatic veins measured using a flexible 22G (Chiba) needle. Results: The procedure was successful in all patients, took less than ten minutes in most, and was associated with minimal discomfort. Post-procedure morbidity was similar to that of liver biopsy. Portal pressure using an external zero (either puncture site or sternal angle) was inaccurate compared with pressures obtained using the generally accepted gold standard internal zero, hepatic venous pressure, and led to incorrect classification of the presence or absence of portal hypertension in at least 100% of patients. Variations in hepatic venous pressure were not predictable on clinical grounds. The only histopathological feature predictive of portal hypertension was cirrhosis, 20 of 25 patients with and four of 36 patients without cirrhosis having portal hypertension. Of routine biochemical and haematological tests, only plasma albumin and platelet count jointly (and negatively) predicted hepatic venous pressure gradient on multiple regression analysis (R2 = 0.40). Conclusions: The use of an internal zero is essential for accurate measurement of portal pressure and this can be achieved safely using the percutaneous, transhepatic route in patients with well compensated liver disease.