Single time point measurement by C2 or C3 is highly predictive in cyclosporine area under the curve estimation immediately after lung transplantation

Abstract

The two h post-dose cyclosporine (CsA) concentration has been advocated as the optimal time point measurement for CsA area under the curve (AUC) estimation after solid organ transplantation. The aim of the study was to investigate whether intensified CsA monitoring is necessary, or if a single time point measurement is accurate to estimate the AUC in the very early period following lung transplantation (LuTX). Within the first two wk following transplantation, daily AUCs were calculated by serial CsA measurements at zero, one, two, three, four, and six h (C0-C6) in 12 consecutive lung transplant recipients. Correlation of single CsA measurements and AUC as well as linear regression analysis was performed to evaluate the most predictive single CsA blood level regarding the AUC. A total of 606 CsA concentration measurements were performed and the 101 corresponding AUCs were calculated for each patient. Mean AUC was 3443 +/- 1451 microg/L. C0: 361 +/- 118 microg/L, C1: 481 +/- 231 microg/L, C2: 682 +/- 314 microg/L, C3: 715 +/- 347 microg/L, C4: 658 +/- 271 microg/L, C6: 571 +/- 260 microg/L. The correlation of CsA serum levels with AUC was the lowest at trough levels (C0) with a correlation coefficient (r = 0.31) and highest at three h (C3: r = 0.89) and two h (C2: r = 0.88). Similar to a stable post-transplant period, CsA trough levels turned out to have poor correlation with the corresponding AUC early after LuTX. The highest correlation of C3 with the AUC may be explained by delayed intestinal resorption immediately post-operative, however C2 is a peer parameter. Optimum AUCs and corresponding C2 or C3 levels in the immediate post-operative phase however remain to be determined.