Prediction of early graft function after living donor kidney transplantation by quantifying the "nephron mass" using CT-volumetric software

Kazuhiro Takahashi; Kinji Furuya; Masahiko Gosho; Joichi Usui; Tomokazu Kimura; Akio Hoshi; Shinji Hashimoto; Hiroyuki Nishiyama; Tatsuya Oda; Kenji Yuzawa; Kunihiro Yamagata

doi:10.3389/fmed.2022.1007175

Prediction of early graft function after living donor kidney transplantation by quantifying the "nephron mass" using CT-volumetric software

Front Med (Lausanne). 2022 Oct 28:9:1007175. doi: 10.3389/fmed.2022.1007175. eCollection 2022.

Authors

Affiliations

¹ Department of Gastrointestinal and Hepato-Biliary-Pancreatic Surgery, University of Tsukuba, Tsukuba, Japan.
² Department of Biostatistics, University of Tsukuba, Tsukuba, Japan.
³ Department of Nephrology, University of Tsukuba, Tsukuba, Japan.
⁴ Department of Urology, University of Tsukuba, Tsukuba, Japan.
⁵ Department of Transplant Surgery, Mito Medical Center, Mito, Japan.

Abstract

Early renal function after living-donor kidney transplantation (LDKT) depends on the "nephron mass" in the renal graft. In this study, as a possible donor-recipient size mismatch parameter that directly reflects the "nephron mass," the cortex to recipient weight ratio (CRWR) was calculated by CT-volumetric software, and its ability to predict early graft function was examined. One hundred patients who underwent LDKT were enrolled. Patients were classified into a developmental cohort (n = 79) and a validation cohort (n = 21). Using the developmental cohort, the correlation coefficients between size mismatch parameters, including CRWR, and the posttransplantation estimated glomerular filtration rate (eGFR) were calculated. Multiple regression analysis was conducted to define a formula to predict eGFR 1-month posttransplantation. Using the validation cohort, the validity of the formula was examined. The correlation coefficient was the highest for CRWR (1-month r = 0.66, p < 0.001). By multiple regression analysis, eGFR at 1-month was predicted using the linear model: 0.23 × donor preoperative eGFR + 17.03 × CRWR + 8.96 × preemptive transplantation + 5.10 (adjusted coefficient of determination = 0.54). In most patients in the validation cohort, the observed eGFR was within a 10 ml/min/1.73 m² margin of the predicted eGFR. CRWR was the strongest parameter to predict early graft function. Predicting renal function using this formula could be useful in clinical application to select proper donors and to avoid unnecessary postoperative medical interventions.

Keywords: cortex weight recipient weight ratio; estimated glomerular filtration rate (eGFR); living-donor kidney transplantation (LDKT); multidetector raw CT (MDCT); weight ratio (WR).