Recipient Selection and Outcome Comparison Between Single and Dual Kidney Transplantation

Background: The persistent shortage of donor kidneys has stimulated broader utilization of kidneys from expanded criteria donors (ECDs), older donors, and marginal grafts. Dual kidney transplantation (DKT) was developed to maximize the use of organs that might otherwise be discarded, particularly when nephron mass from a single donor kidney is considered insufficient to ensure adequate post-transplant renal function. However, the optimal criteria for recipient selection and the comparative outcomes of single kidney transplantation (SKT) and DKT remain subjects of ongoing debate.

Methods: This narrative review summarizes current evidence regarding recipient selection strategies, donor assessment methods, surgical considerations, graft function, patient survival, and long-term outcomes associated with SKT and DKT. Particular emphasis is placed on studies published during the last two decades
evaluating outcomes from marginal and expanded criteria donors.

Results: DKT has emerged as a valuable strategy for utilizing kidneys from elderly and marginal donors. Evidence indicates that carefully selected recipients undergoing DKT achieve graft and patient survival rates comparable to those observed with SKT from standard criteria donors. DKT recipients generally demonstrate lower rates of delayed graft failure than would be expected from transplantation of a single marginal kidney, while exhibiting superior long-term renal function owing to greater nephron mass. Histological evaluation, donor age, estimated glomerular filtration rate (eGFR), Kidney Donor Profile Index (KDPI), and Remuzzi scoring systems are the principal tools guiding allocation decisions. Nonetheless, DKT is associated with increased operative complexity and longer surgical times.

Conclusions: DKT represents an effective organ-preservation strategy that safely expands the donor pool and reduces organ discard rates. Appropriate donor-recipient matching remains essential to optimize outcomes. Future allocation systems integrating histological, functional, and machine-learning predictive models may further refine the decision between SKT and DKT.

Keywords: Dual Kidney Transplantation, Single Kidney Transplantation, Expanded Criteria Donor, Marginal Donor, Kidney Transplant, Recipient Selection, Graft Survival, Delayed Graft Function, Organ Allocation, Nephron Mass.