Indocyanine green intrinsic hepatic clearance as a prognostic index of survival in patients with cirrhosis

Abstract

The prognostic value of quantitative liver function tests in patients with cirrhosis is not clearly established. Indocyanine green intrinsic hepatic clearance (ICG-IHC) is a quantitative liver function parameter independent of liver blood flow, which was shown to correlate strictly with the Child-Turcotte-Pugh (CTP) classification of severity of liver disease. Few data are available on its prognostic value. One hundred and five patients with cirrhosis were studied. ICG-IHC was measured according to the ‘sinusoidal perfusion’ model. Median ICG-IHC in the whole series was 374 ml/min (interquartile range: 214–496 ml/min). During follow-up (mean 31 months; max. 48 months) 38 patients died. The probability of survival was lower in patients with ICG-IHC lower than 300 ml/min (35% at 48 months) than in patients with ICG-IHC between 300 and 1000 ml/min (70%), or with ICG-IHC over 1000 ml/min (80%) ( P = 0.02). Also s-albumin ( P < 0.01), ascites ( P = 0.001) and CTP class ( P < 0.001) were significant predictors of survival. On incorporation of age, sex, etiology of cirrhosis, ICG-IHC, s-albumin, s-bilirubin, prothrombin index, ascites and encephalopathy, into a multiple regression analysis according to the Cox's model, the results showed only ascites and s-albumin to be independent significant predictors of survival, while ICG-IHC was not among the covariates independently predictive of survival. When CTP class was added to the investigated covariates, the results showed it as the only independent predictor of survival. It is concluded that ICG-IHC is a significant predictor of survival in cirrhosis, but does not further improve the prognostic accuracy once the common liver tests and the clinical data are taken into account.