Indocyanine green retention test in cirrhosis and portal hypertension: Accuracy and relation to severity of disease

Background and Aims: Patients with cirrhosis and portal hypertension often develop complications relating to hepatic excretory dysfunction. The standard measurement of the hepatic excretion is the constant infusion indocyanine green clearance (ICG) technique. The ICG 15-min retention test (ICG-r15) is faster, more patient friendly, and cheaper. The aims were to compare the ICG-r15 test with the standard method, to assess relations to patient characteristics and survival, and to assess the ICG-r15 level in healthy control subjects. Methods: This study included 68 patients with cirrhosis and portal hypertension (Child class A/B/C:17/37/14). All patients underwent a full liver vein catheterization and hemodynamic evaluation with determination of ICG-r15 and ICG as the reference in a subset of 38 patients. Sixteen healthy control subjects were included for compiling a reference interval. Results: The ICG-r15 was increased in the cirrhotic patients with increasing values in parallel with liver dysfunction (15/41/58%) in Child class A/B/C compared with 7% in the controls (P < 0.001). ICG-r15 correlated highly significantly with the ICG (r = −0.96, P < 0.0001) and in a multivariate regression analysis with hepatic venous pressure gradient, markers of liver dysfunction and hyperdynamic circulation (P < 0.05–0.005). In the control group, normal reference values ranged from 0% to 13%. In addition, ICG-r15 was significantly related to mortality in the patient group (P = 0.02). Conclusions: Indocyanine green-r15 reflects portal hypertension, the degree of hepatic failure, and survival and may replace the standard ICG. A more elaborated reference interval needs to be compiled, and the prognostic value of ICG-r15 should be validated.