Association of renal volumetry and histological features with marginal donors: risks for donors and recipients in living donor kidney transplantation.

Background: We investigated the roles of renal volumetry and histological features in the assessment of preoperative and postoperative renal function in living kidney donors (LKDs) including high-risk marginal donors (MDs).

Methods: We included 128 LKDs who underwent donor nephrectomy at our institution between 2006 and 2022. Clinical and radiographic data were retrospectively obtained from medical charts. Renal volume parameters were calculated using preoperative computed tomography images. Tissues obtained from allograft biopsies were examined. MDs were defined according to the Japanese guidelines and compared with standard donors (SDs).

Results: LKDs were divided into 89 SDs and 39 MDs. Renal volumetry parameters did not differ significantly between the two groups, while interstitial inflammation and interstitial fibrosis/tubular atrophy were significantly higher in MDs (P = 0.031 and P = 0.041). In the multivariate analysis, age < 60 years (P = 0.036), body mass index > 25 (P = 0.031), and residual kidney volume/body surface area (RKV/BSA; P = 0.002) were independent factors for poor preservation of renal function. Subgroup analysis of the MDs revealed that RKV/BSA (P = 0.0096), residual measured glomerular filtration rate (GFR) (P = 0.0005), and arteriosclerosis (P = 0.045) were associated with poor preservation of renal function. Furthermore, the risk of graft loss was significantly higher for kidneys donated from MDs (P = 0.0019).

Conclusions: RKV/BSA can be a reliable screening and prognostic tool for selection of LKDs, including MDs, and RKV/BSA, measured GFR, and histological findings such as arteriosclerosis can be used to establish clearer MD criteria for optimal personalized follow-up after surgery.