#4776 RENAL RESERVE ASSESSMENT IN PATIENTS WHO UNDERWENT DONOR NEPHRECTOMY OVER A 15-YEAR FOLLOW-UP PERIOD AND COMPARISON WITH 2 OTHER PATIENTS
Authors: Tadic Jelena , Rancic Nemanja , Obrencevic Katarina , Radojevic Milorad , Marić Predrag , Tomić Aleksandar , Mijuskovic Mirjana , Vavic Neven 
Published: June 2023

Abstract

Background and Aims
Since the beginning of living related/non-related transplantation programs, the long-term risks for kidney donors after donor nephrectomy have not been given enough significance. Initially, the emphasis was only on the good health of the living donor at the time of donation, but there was no monitoring of the donor's health and life quality post-op. In recent years, special attention has been given to kidney donors after living transplantation, as a result of a long-term follow-up and the fact that they are more susceptible to develop certain diseases, e.g. an increased risk of chronic kidney disease (CKD) and terminal renal failure (ESRD).

Method
The study was conducted as a retrospective case-control study. In our study, 243 patients, who were divided into three groups, were analysed. The case group consisted of patients who underwent donor nephrectomy (108 patients), the first control group consisted of patients who were being monitored because of simplex or parapelvic cysts with preserved renal function parameters (40 renal cyst patients with Bosniak classification ≤2) of similar age and sex, while the second control group consisted of patients who underwent a unilateral radical nephrectomy due to kidney cancer in T1bNoMo clinical stage (95 patients).

Results
The kidney donors from the case group were mainly females (60.2%) with the average age of 55.87 years at the time of transplantation. In comparison to the control groups, we observed a statistically significant difference in the radical nephrectomy group of patients, who were, on average, younger Caucasian males, with the average age of 46.84 years. The renal reserve recovery (GFR) was faster in the donor nephrectomy group (85%) than in the radical nephrectomy group, whose recovery was 76.67% of the initial values. Also, the values of serum creatinine (sCre) in the donor nephrectomy group after only one month were very similar to the values of sCre after ten years of follow-up (median was approximately 83 μmol/l). GFR according to the CKD EPI formula was initially the best in the group of patients with cysts, and this trend continued over the 15-year follow-up. After one year, eGFR CKD EPI corresponded to the second degree of renal impairment in both the donor and radical nephrectomy groups, bearing in mind the fact that in the group with radical nephrectomy it was lower than 65 ml/min/1.73m² after one year, and that the trend of declining kidney function was maintained even after 15 years of follow-up. On the other hand, in the donor nephrectomy group, after 10 years of follow-up, eGFR CKD EPI was above 65 ml/min/1.73m², i.e. above 60 ml/min/1.73m² after 15 years of follow-up. In contrast, in the group of patients with renal cysts, a reduced kidney function was verified only after 10 years of follow-up - less than 90 ml/min/1.73m², while it was maintained above 80 ml/min/1.73m² even after 15 years of follow-up.

Conclusion
Comparing these three groups, only in the donor nephrectomy group, one patient ended up on chronic hemodialysis treatment (0.92%), while in the other two groups there were no patients with terminal kidney failure. The values of serum creatinine - the median, were the same after 6 months and after 5 years post-op in the donor nephrectomy group (79 μmol/l). The aforementioned findings can help us predict the expected values of serum creatinine after donor nephrectomy in the future. In donors as well as in patients with renal cysts, the reason for higher mortality was not ESRD, but more often it was a sudden cardiac death or a cardiovascular disease. The well-being of the giver must be ensured both in the short and long term, but the potential harmful consequences for the recipient must be determined as well.