Incidental kidney stones: a single center experience with kidney donor selection

The presence of kidney stones has been a relative contraindication for living donation. With the widespread use of more sensitive imaging techniques as part of the routine living donor workup, kidney stones are more frequently detected, and their clinical significance in this setting is largely unknown. Records from 325 potential kidney donors who underwent MRA or CT-angiography were reviewed; 294 proceeded to donation. The prevalence of kidney stones found incidentally during donor evaluation was 7.4% (24 of 325). Sixteen donors with stones proceeded with kidney donation. All incidental calculi were nonobstructing and small (median 2 mm; range 1-9 mm). Eleven recipients were transplanted with allografts containing stones. One recipient developed symptomatic nephrolithasis after transplantation. This recipient was found to have newly formed stones secondary to hyperoxaluria, suggesting a recipient-driven propensity for stone formation. The remaining ten recipients have stable graft function, postoperative ultrasound negative for nephrolithiasis, and no sequelae from stones. No donor developed symptomatic nephrolithiasis following donation. Judicious use of allografts with small stones in donors with normal metabolic studies may be acceptable, and careful follow-up in recipients of such allografts is warranted.