Twenty adult patients undergoing orthotopic liver transplantation (OLT) were enrolled in this study, with the noninvasive indocyanine green plasma disappearance rate (ICG-PDR) measured both during and after OLT to assess the relationship between ICG-PDR and the ability of patients to achieve therapeutic postoperative tacrolimus immunosuppressant blood levels. Liver function was determined at both 2 and 18 hours post reperfusion with the ICG-PDR k value (1/min). Postoperative standard serum measures of liver function as well as liver biopsies were also collected and analyzed. The median ICG-PDR k value for the study group at 2 hours post reperfusion was 0.20 (0.16, 0.27), whereas at 18 hours post reperfusion, it was 0.22 (0.18, 0.35). The median change in the k value between the two ICG-PDR measurements was 0.05 (-0.02, 0.07) with P = 0.02. There was an interaction between the postoperative day 1 (18 hours post reperfusion) ICG-PDR k value and the linear increase in the tacrolimus blood level, such that the greater the k value was, the more gradual the observed rise was in tacrolimus over time [that is, the longer it took to achieve a therapeutic blood level (>12 ng/mL), P = 0.003]. Of the 16 patients that received tacrolimus, comparable dosing on a per kilogram body weight basis was observed. Also, no significant association between ICG-PDR k values and postoperative liver biopsy results was seen. This study demonstrates that the ICG-PDR measurement is a modality with the potential to assist in achieving adequate blood levels of tacrolimus following OLT.
(c) 2007 AASLD.