Native nephrectomy prior to pediatric kidney transplantation: biological and clinical aspects

Abstract

Background: Pre-transplant nephrectomy is performed to reduce risks to graft and recipient. The aims of this study were to evaluate (1) indications, surgical approach, and morbidity of native nephrectomy and (2) the effects of kidney removal on clinical and biological parameters.

Methods: This study was designed as a single-center retrospective cohort study in which 49 consecutive patients with uni- or bilateral native nephrectomies were identified from a total of 126 consecutive graft recipients in our pediatric kidney transplantation database between 1992 and 2011. Demographic, clinical, and laboratory details were extracted from charts and electronic records, including operation reports and pre- and post-operative clinic notes.

Results: Of the 49 nephrectomized patients, 47% had anomalies of the kidneys and urinary tract, 22% had cystinosis, 12% had focal segmental glomerulosclerosis, and 6% had congenital nephrotic syndrome. Nephrectomy decisions were based on clinical judgment, taking physiological and psychosocial aspects into consideration. Nephrectomy was performed in patients with polyuria (>2.5 ml/kg/h) and/or large proteinuria (>40 mg/m(2)/h), recurrent urinary tract infection or (rarely) hypertension. Urine output decreased from (median) 3.79 to 2.32 ml/kg/h (-34%), and proteinuria from 157 to 100 mg/m(2)/h (-40%) after unilateral nephrectomy (p=0.005). After bilateral nephrectomy, serum albumin, protein and fibrinogen concentrations normalized in 93, 73, and 55% of nephrectomized patients, respectively. Clinically relevant procedure-related complications (peritoneal laceration, hematoma) occurred in five patients.

Conclusion: In summary, we demonstrate quantitatively that native nephrectomy prior to transplantation improved serum protein levels and anticipated post-transplant fluid intake needs in select children, reducing the risk of graft hypoperfusion and its postulated consequences for graft outcome.

Fig. 1

Summary of patients and nephrectomy procedures. ^aOne patient each had the first kidney removed previously for non-kidney transplant-related reasons, ^bnative kidneys removed 4 and 19 months post-kidney transplant (KT) because of frequent urinary tract infection

Fig. 2

Gradual decrease of urine output following unilateral nephrectomy (in months; median 36%, range −10 to −70%). Depicted are all patients for whom data on serial, post-nephrectomy urine collections were available. 0 Time of nephrectomy. Subjects showed no appreciable decline of urine output following its stabilization after the initiation of dialysis 1–3 years prior to nephrectomy. Asterisk Analysis was performed with bivariate linear regression: effect of time on urine output (r ² = 0.97)

Fig. 3

Serum albumin (a), total protein (b), and fibrinogen (c) concentrations, and urine protein excretion (d) pre- and post-unilateral and bilateral nephrectomy. Horizontal Lower reference ranges for serum tgroupalbumin and total protein (31 and 61 g/l, respectively), upper range for fibrinogen (4.0 g/L), and definition of nephrotic range proteinuria (40 mg/m²/h). Analyses were performed with Wilcoxon signed-rank test. In cases of sequential nephrectomies, an asterisk indicates measurements before/after the first (unilateral) and before/after the second procedure (bilateral nephrectomy). Note that the majority of patients undergoing unilateral nephrectomy had large proteinuria, but also polyuria or other risk factors leading to kidney removal