Long term renal outcome and risk of elevated blood pressure in children undergoing complete primary repair of bladder exstrophy (CPRE)

Introduction Since the initiation of staged reconstruction for bladder exstrophy (BE), hypertension has been a known complication of the procedure. Hypertension is a well-established risk factor for chronic kidney disease (CKD) progression and associated with cardiovascular/cerebrovascular morbidity and mortality. Few studies exist evaluating the risk of developing hypertension among patients with bladder exstrophy who underwent CPRE. We hypothesized that long-term blood pressure levels may be elevated in males vs females, and may be correlated with presence of hydronephrosis, bladder neck reconstruction, or continence status. Objective We sought to revisit our long-term experience with CPRE and determine factors associated with incidence of elevated blood pressures.Methods We reviewed all BE patients undergoing CPRE at our institution from 1999 to 2019. Patients were considered eligible for inclusion if last renal ultrasound was obtained at least 5 years after repair. Upper tract outcomes based on imaging, history of pyelonephritis and renal function tests measured by serum creatinine and estimated glomerular filtration rate (eGFR, Schwartz formula) were reviewed. Systolic/diastolic blood pressures (SBP/DBP) from all encounters were captured. All blood pressure values were age adjusted by percentile.Results A total of 36 patients were considered eligible for review. Median follow-up of this cohort was 10.01 (5.16-21.47) years. The mean creatinine for the patients available was 0.58 mg/dL (SD = 0.20), at mean age of 8.90 years Neither SBP or DBP were significantly elevated in males vs females, but had lower odds of elevation >90th percentile for those with higher eGFR, lower renal length, and reimplantation. Pyelonephritis incidence was 38% (n = 14) with first episode at mean age of 8.8 years, and mean of 3.7 episodes per patient.Discussion At long term follow up, blood pressures following CPRE were not significantly elevated, despite the relatively frequent occurrence of CKD, and hydronephrosis. Male gender does appear to suggest higher risk for long-term deterioration in this regard. Higher eGFR, higher renal length, and presence of ureteral reimplantation were associated with lower likelihood of systolic/diastolic blood pressure elevation. Continence status and bladder neck reconstruction were not associated with likelihood of blood pressure elevation.Conclusions Blood pressure and upper-tract outcomes for patients undergoing CPRE at birth are positive for the majority of patients. To avoid complications from hypertension, patients should be closely evaluated as the risks associated with elevated blood pressure are significant. Ultimately, larger-scale prospective and multi-institutional studies are further needed to characterize risks of hypertension in this complex patient population.