Screening and prognostic roles of renal volumetry and scintigraphy in the assessment of living kidney transplant donors, considering the early recovery of the residual renal function.

Background: The existing criteria for living kidney donors (LKDs)in Japan are controversial. We evaluated the roles of computed tomography volumetry (CTV) and 99 m Tc-diethylenetriamine penta-acetic acid (DTPA) scintigraphy in assessing preoperative and postoperative renal function and predicting early recovery of residual renal function.

Methods: We retrospectively reviewed the medical charts of 175 consecutive LKDs who underwent donor nephrectomy (DN) at our institution between 2006 and 2022. Preoperative renal volume was assessed using enhanced CTV, and screening of renal functions was performed using 99 m Tc-DTPA scintigraphy. We evaluated the estimated glomerular filtration rate (eGFR), single-kidney eGFR (skeGFR), and recovery rate three months after DN.

Results: We included 55 men and 81 women (median age, 59 years; median follow-up period, 73 months). Age > 60 years, hypertension, and total kidney volume/body surface area (TKV/BSA) < 170 mL/m independently predicted preoperative eGFR < 80 mL/min/1.73 m, whereas total measured GFR < 80 mL/min/1.73 m independently predicted preoperative eGFR < 70 mL/min/1.73 m. Regarding postoperative renal function, residual KV/BSA < 85 mL/m and ΔskeGFR ≤ 9 mL/min/1.73 m independently predicted postoperative eGFR < 60% of preoperative eGFR, and TKV/BSA < 170 mL/m independently predicted early recovery of skeGFR.

Conclusions: CTV may be used as a reliable prognostic screening tool to select LKDs and assess their split renal functions before DN, and renal scintigraphy may help select the optimal LKD.