Small donors for small recipients - excellent growth and long-term function of single kidney grafts

Small-donor kidneys (<= 20 kg donor weight, SDK) are preferably transplanted en bloc in adults. Concerns about thrombotic complications or hyperfiltration hinder their use in children, particularly as single grafts. Low centre experience and donor-to-recipient size are rated critical regarding outcomes. We evaluated SDK transplantation (SDTx) in paediatric recipients at a specialized transplant centre. Between 2008 and 2018, SDTx was performed in 40 children (mean age 5.4 +/- 1.4 years, single grafts n = 38, donor weight <= 10 kg: n = 10). Perioperative complications were rare (n = 3), mainly thromboses despite immediate heparinization and resulted in graft loss in one patient. Overall, early and long-term GFR were excellent (76 +/- 21 and 100 +/- 11 ml/min/1.73 m(2), first month and year 5, respectively). Three patients presented with delayed graft function. Graft volume increased significantly (69 +/- 38 vs. 111 +/- 33 ml within 5 years; P < 0.0001). Patients showed catch-up growth to normal range (SDS for height -2.06 +/- 1.6 to -1.60 +/- 1.5). Stratification by recipient age and donor weight revealed superior results in young recipients (<= 3 years) and <= 10 kg donors, respectively. Outcome of single SDK grafts was excellent. Gain of GFR and graft volume was even higher in patients with very small donor or recipient size, regardless of a reduced donor-to-recipient weight ratio. Therefore, SDTx should be considered favouring small paediatric recipients.