Impact of donating the larger kidney by CT volumetry on the kidney function, 5-years after living donation.

PURPOSE

Removing the smaller kidney for donor nephrectomy has been advocated if there is a size difference of ≥ 10% after other anatomical considerations. This study reports the difference in long-term renal function in patients who have their larger kidney removed for donor nephrectomy.

METHODS

Data of 104 donors were prospectively collected. They were divided into 2 groups depending on donated kidney being ≥ 10% larger (Group-1) or < 10% larger (Group-2) than the remaining kidney. Baseline characteristics (age, gender, BMI, surgical details, co-morbidities), estimated Glomerular Filtration Rate (eGFR, calculated using CKD-EPI formula) before and up to 5-years after surgery were collected.

RESULTS

Group 1 (n = 28) and Group 2 (n = 76) had similar baseline characteristics. The split renal volume (SRV) of donated kidney was 53.4% (52.5-58.7%) for Group 1 and 49.9% (44.3-52.5%) for Group 2 eGFR between 2 groups were similar (110.7 ± 20.8 vs 103.4 ± 22.5, p = 0.14). eGFR was not different at 6-months, 1-, 3- and 5-year post-operation. Patients with eGFR < 60 was also not significantly different between the 2 groups 23.1% vs 31.4% (p = 0.42). Group-1 had significantly greater absolute reduction in eGFR than Group-2 (45.5 ± 17.8 vs 37.6 ± 14.5, p = 0.02) at 6-months post op. After which, there was a steady improvement in eGFR up to 5-years; which was most significant from the 6-months to 1-year (p = 0.02, 0.001). The absolute and relative recovery in eGFR beyond 6-months does not differ significantly.

CONCLUSION

Despite an initial greater decrease in eGFR at 6 months, removing the larger kidney (> 10% absolute difference within the SRV limits of this study) for donor nephrectomy did not result in a significant difference in kidney function at 5 years due to similar rates of eGFR recovery after nadir levels at 6 months.