Does allograft size really matter in the long-term outcome of living donor kidney transplantation?

Background: Increased allograft mass in living donor kidney transplantation has been recognized as a predictor factor of better short-term allograft function. We evaluated whether donor kidney volume adjusted for recipient body weight is associated with long-term allograft function in living donor kidney transplantation.

Methods: We analyzed 67 living donors and their recipients who underwent transplantation between 2003 and 2007. Estimated glomerular filtration rate (eGFR) and serum creatinine levels at 1, 2, 3, 4, and 5 years post-transplantation were recorded for all recipients. Transplanted kidney volumes were measured using 3-D helical computed tomography scanning. A transplant kidney volume-recipient body weight (Vol/Wt) ratio was calculated for each donor-recipient pair. The subjects were divided into tertiles according to Vol/Wt ratios: low (<2.16), medium (2.16-2.88), and high (>2.88).

Results: Vol/Wt ratio significantly correlated with recipient eGFR and serum creatinine levels at 1, 2, 3, and 4 years post-transplantation (r = .48, P < .0001; r = .46, P < .0001; r = .47, P < .0001; r = .26, P = .037, respectively, for eGFR; r = -.53, P < .0001; r = -.50, P < .0001; r = -.44, P < .0001; r = -.37, P = .003, respectively, for serum creatinine) but not at 5 years (r = .12, P = .406 for eGFR; r = -.21, P = .110 for serum creatinine). Whereas recipient eGFR increased significantly in a graded fashion among low to high Vol/Wt ratio groups during 1 to 3 years post-transplantation, there was no difference in eGFR values between Vol/Wt ratio groups at 4 and 5 years (P = .21 and .71, respectively).

Conclusion: Vol/Wt ratio is not associated with long-term allograft function in living donor kidney transplantation.