#2287 Impact of renal reserve before donation in post-transplant renal function of donors and recipients

Abstract

Abstract Background and Aims The influence of Renal Reserve (RR), i.e. its presence or absence, in post-transplant renal function both in living kidney donors and recipients is unknown. The presence of RR in donors may be beneficial in terms of better renal function both for the donor and recipient after transplantation. In the other hand, the absence of RR in donors might indicate a lower renal endowment and so predispose to lower GFR post-transplantation in donors and recipients. However, little evidence is available in this field. Method In a previous study (ERA Abstract 2023, #3737) we described in a group of 52 potential living kidney donors, the presence (24-46%), absence (13-25%) or use (15-29%) of RR before donation. The latter was defined as the lack of increase in GFR after stimulation in patients with basal GFR > 100 mL/min. GFR was measured before and after transplantation by the clearance of iohexol with dried blood spots. Presence of RR was defined as an increase >10% of basal GFR after IV amino acid infusion. GFR was unadjusted to body surface area (BSA). In this follow-up study we investigated the impact of the presence, absence or use of RR before donation in GFR 12 months after transplantation, both in donors and recipients. Results Of the 52 pairs of donors and recipients, renal transplantation was performed in 21 who also had 12 months of follow-up. Before transplantation 9 donors had RR, 4 did not and 8 had RR in use. Pre-transplant GFR was 95 ± 15 ml/min, 89 ± 6 ml/min and 127 ± 16 ml/min in donors with RR, without RR and with RR in use, respectively. At 12 months after kidney donation, GFR was higher in donors who had RR in use before donation: 79 ± 12 ml/min, compared with those with RR: 65 ± 9 ml/min (p = 0.048) and those without RR 59 ± 10 (p = 0.03). In recipients, GFR was comparable between those who had a donor with RR or RR in use: 72 ± 19 ml/min vs 68 ± 12 ml/min (p = ns), whereas both groups had higher GFR than those recipients whose donors had no RR before donation 53 ± 5 ml/min, although of borderline signification (p = 0.07). Non parametric tests were used. No major complications after transplantations such as rejections or surgical complications, etc, that could alter GFR were observed. Conclusion The presence or use of RR may determine a better renal function 12 months after donation both for donors and recipients. This is a preliminary study and we acknowledge that the low number of cases is a limitation and so, these results require further studies.