The sequence of intervention determines the risk of early postoperative acute kidney injury in infants with bilateral ureteropelvic junction obstruction.

INTRODUCTION AND OBJECTIVES: The management of bilateral ureteropelvic junction obstruction (UPJO) is greatly debated. We aim to identify the risk of early postoperative acute kidney injury (AKI) in relation to the sequence of intervention in children with bilateral UPJO managed in a sequential manner. METHODS: A single center database was retrospectively reviewed for children ≤2 years who underwent bilateral pyeloplasty. According to the differential renal function on the preoperative renograms, patients were categorized into group A: pyeloplasty on the poorer functioning kidney first and group B: pyeloplasty on the better functioning side first. Serum creatinine and eGFR, using the modified Schwartz formula, were evaluated at four time points (I): before the first intervention (II): within 48 h of the first intervention (III): before the second intervention and (IV): within 48 h of the second intervention. Preoperative and postoperative values were compared. The incidence of early postoperative AKI in both groups was defined according to the Acute Kidney Injury Network (AKIN) criteria. RESULTS: The study comprised 46 children treated by staged pyeloplasty, 28 of them underwent pyeloplasty on the poorer functioning side first. Baseline serum creatinine and eGFR were not significantly different between both groups. Patients who underwent pyeloplasty on the poorer functioning side first, had a significant decline of eGFR after the first intervention (p = 0.006). Conversely, no significant eGFR changes were observed after the first or second interventions in the other group (figure). Overall, 64.3% and 33.3% of patients developed some degrees of AKI when intervention was started on the poorer and better functioning renal units, respectively (p = 0.04). DISCUSSION: Bilaterality is seen in approximately » of patients with UPJO. Oftentimes, both renal units are asymmetrically affected with little data to guide surgeons on the optimal sequence of intervention. Following pyeloplasty, 52.2% of the evaluated children with bilateral UPJO had early postoperative AKI, mostly of low stage. Our data suggest that intervening first on the better functioning side allows for better recovery of the renal functional reserve and lowers the risk of postoperative AKI. CONCLUSION: In children with bilateral UPJO, starting intervention on the poorer functioning kidney is associated with increased risk of postoperative AKI. Long-term prospective studies are needed to confirm our findings.

Functional outcomes after pyeloplasty in solitary kidneys: structured analysis with the implication of Acute Kidney Injury Network (AKIN) staging criteria to predict long-term renal function recoverability.

OBJECTIVES: To assess the long-term functional outcomes after pyeloplasty in solitary kidney (SK) models and to define factors affecting postoperative renal function recoverability in adults. PATIENTS AND METHODS: We retrospectively evaluated all adult patients who underwent pyeloplasty for pelvi-ureteric junction obstruction (PUJO) in SK. Long-term renal function was assessed by diuretic scintigraphy and morphological changes were also determined, e.g. renal parenchymal volume (RPV) and parenchymal thickness (PT). We considered a >20% increase in glomerular filtration rate (GFR) as improvement, >20% decrease as deterioration, and changes within 20% as stationary renal function. Univariate and multivariate analysis for factors affecting renal function recoverability, including the Acute Kidney Injury Network (AKIN) Staging System postoperatively, were performed. RESULTS: The study included 62 patients with a mean (SD) age of 29 (10.5) years. At a median of 48 months, the mean (SD) GFR increased from 41.3 (17) to 48.5 (20.1) mL/min (P < 0.001), with a significant increase in RPV and PT (P = 0.02 and P = 0.001, respectively). Follow-up renal function was static, improved and decreased in 39 (63.4%), 17 (27%) and six (9.6%) patients, respectively. Functional success was achieved in 90.4%. Patient's age ≥39 years, PT ≤0.75 cm and higher early postoperative AKIN staging were predictors associated with a 4.8-, 3.2- and 2.7-fold deterioration in renal function. CONCLUSION: Pyeloplasty in SK preserved renal function in 90.4% of the present patients. Pyeloplasty in SK when associated with older age, decreased PT preoperatively, and early higher AKIN staging postoperatively was associated with poor renal function recoverability.

Long-term outcomes after pyeloplasty for pelvi-ureteric junction obstruction in adults associated with renal congenital anomalies: Age, sex and renal function matched analysis.

Objective: To assess the long-term outcomes after pyeloplasty for pelvi-ureteric junction obstruction (PUJO) associated with renal anomalies. Patients and methods: Data were collected for patients after pyeloplasty for PUJO associated with renal anomalies and analysed retrospectively. Long-term functional success was evaluated by comparing the renographic split renal function (SRF) and glomerular filtration rate (GFR) at last follow-up with baseline values. A change of 5% in SRF was considered significant. Factors affecting functional outcome were assessed. The outcomes were compared to an age, sex and renal function matched group with PUJO in otherwise normal kidneys (Group 2) to evaluate the pattern of difference in functional recoverability in both groups. This was assessed using repeated-measures analysis of variance. Results: The study initially included 70 adult patients, with a mean age of 31.8 years. At a median of 44 months, 55 patients completed follow-up (Group 1) and no statistically significant changes in GFR (P = 0.7) and SRF (P = 0.06) were found. In all, 17, four and 34 patients showed a decrease, increase and static SRF (functional success rate was 69%). Higher preoperative SRF (P = 0.02) and Anderson-Hynes (A-H) pyeloplasty (P = 0.003) were associated with functional preservation. In the comparison with the other matched group (Group 2), the patients in Group 2 had better functional recoverability after pyeloplasty than patients with associated anomalies [GFR (P = 0.001), SRF (P = 0.002) and functional success (P = 0.001)]. Conclusion: Functional preservation after pyeloplasty in associated renal anomalies could be achieved in 69% of patients, which was significantly lower than those with otherwise normal kidneys. A-H pyeloplasty and higher preoperative SRF were associated with better functional outcomes. Abbreviations: A-H: Anderson-Hynes; HSK: horseshoe kidneys; OR: odds ratio; PUJO: PUJ obstruction; SRF: split renal function; T1/2, half-time.