Some Problems in Estimating ICGRmax and lts Clinical Significance

Toshihiro Katoh, Naoki Yamanaka, Eizo Okamoto

First Department of Surgery, Hyogo College of Medicine

Values of the ICG maximal removal rate (Rmax) of a total of 405 patients with chronic liver diseases during the 12 years from January 1976 through December 1987 were retrospectively analyzed and evaluated. In the early period before April 1983 when Rmax was obtained from ICG K_0.5, K_1.0 and K_3.0, the incidence of unevaluable Rmax, not provided by an inequality formula of ICG K₁>K₂>K₃, was 46% (92/201). In the current period since April 1983, when Rmax was obtained from ICG K_0.5, K_2.0 and K_4.0, the incidence fell to l4% (28/204). The evaluable Rmax values provided by the inequality formula remained within 5 mg/kg/min without exception in both of the two periods so that Rmax exceeding 5 mg/kg/min was considered an unevaluable value. The unevaluable Rmax values were frequently encountered in the patients with ICG K_0.5<0.05 or ≥0.15, indicating that the patients with either extremely poor or very good hepatic reserve were not suitable candidates for Rmax estimation. In terms of clinical significance of evaluable Rmax as an index of hepatic reserve, Rmax correlated well with the histopathological severity as well as the morphometrically estimated collagen content. The patients with Rmax lower than 0.47 mg/kg/min without exception had an associated B type cirrhosis. Those, in whom Rmax values were relatively low for the ICG clearance rate had a higher degree of hepatic fibrosis and a higher incidence of esophageal varices as compared with Rmax corresponding to the ICG clearance rate.

Key words
ICG maximal removal rate, ICG clearance rate, functional reserve of the liver, liver fibrotic index

Reprint requests
Toshihiro Katoh First Department of Surgery, Hyogo College of Medicine
1-1 Mukogawa-cho, Nishinomiya, 633 JAPAN

Accepted
November 11, 1992

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