The Clinical Significance of Routine Screening for the Renal Functional Asymmetry in Potential Live Kidney Donor

Abstract

Purpose: An insufficiently functioning nephron might fail to meet the metabolic demands of a kidney donor, as well as the recipient, and may lead to hyperfiltration. An extreme asymmetry of the functional capacity of donor’s bilateral kidneys might result in insufficiency to the recipient or donor. Methods: Since February 1996, 99mTc-DTPA renal scintigraphy has been routinely included in the evaluation of renal functional asymmetry of a donor. The functional ratio of each kidney, using 99mTc-DTPA, as well as the serum creatinine (Scr) and creatinine clearance (Ccr), were measured and calculated using the 24-hour urine from a hundred donors. Results: A hundred kidney donors were analyzed, including 62 male and 38 female donors. In the healthy donors, the average functional ratios of the left vs. the right kidneys were 52.5 vs. 47.5%. Seventy-three donors donated their left kidney and 27 their right. The Scr of the donors increased from 0.9±0.2 to 1.3±0.3 mg/dl after the nephrectomy. Both the Ccr in the 24 hour urine and the Ccr obtained using the Cockcroft and Gault formula of the remnant kidney after kidney donation increased from 54.5±11.4 to 68.0±14.3 ml/min/1.73 m2, and from 40.8±9.3 to 53.6±11.6 ml/ min/1.73 m2, respectively. Conclusion: Attention should be paid to the functional asymmetry of the kidney when choosing a kidney for donation. To protect the remnant kidney of a donor from hyperfiltration damage after donation, it is important to leave an adequate functioning nephron mass to meet the metabolic demands of the donor.