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

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 ¼ 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.

Critical analysis of pyeloplasty role in adults with late diagnosis of ureteropelvic junction obstruction-a comparative study

PURPOSE

Due to the data paucity about the functional outcomes post pyeloplasty for patients diagnosed with ureteropelvic junction obstruction (UPJO) with a preoperative age above the age of 45 years and according to the elderly definition (age ≥ 65 years), we conducted this study to clarify the different outcomes in adults presented with late hydronephrosis.

METHODS

We included patients who were managed by pyeloplasty with a preoperative age ≥ 45 years. We further subdivided those patients into; group (A) patient's age ≥ 65 years and group (B) patient's age ≥ 45 and < 65 years. Split renal function (SRF) difference was evaluated by the changes between the last follow-up and the baseline renogram, where 5% change was considered a significant change. Functional outcomes and factors predicting the functional recoverability post pyeloplasty were evaluated.

RESULTS

A total of 119 patients were included. The mean age was 62.3 ± 16.4 years. Group (A) and group (B) included 47 and 72 patients, respectively. After 24 months, GFR and SRF were increased at the last follow-up (P = 0.32 and 0.57, respectively). No significant functional changes were noted between both groups. Sixty two, 7 and 13 patients showed static, decreased and improved renal function. Lower preoperative SRF was the only predictor for poor functional recoverability in patients with age ≥ 45 years who were managed by pyeloplasty.

CONCLUSION

Elderly patients should not be excluded from the corrective surgery for UPJO. Lower preoperative SRF was the only predictor for renal function deterioration post pyeloplasty.