Correlation between hypertrophy and risk of hypertension in congenital solitary functioning kidney.

Purpose: Solitary functioning kidney (SFK) may be associated to hypertrophy, hypertension and chronic kidney disease. We evaluated blood pressure (BP) of children with congenital SFK comparing agenesis to multicystic dysplastic kidney (MCDK) and correlated BP profiles with renal dimensions of affected and contralateral kidney.

Methods: We compared 40 patients with MCDK, grouped for either treatment options (A: conservative vs B: nephrectomy) or involution time (A1: before 4 years-of-age vs A2: persistence-of-MCDK), to 10 unilateral agenesis (C). Patients were evaluated with ultrasound, scintigraphy, office-ambulatory BP monitoring.

Results: Compensatory hypertrophy was demonstrated in most of the subjects, without differences between subgroups, with an increase over time (p < 0.001). A1-C showed an overall percentage of hypertrophy significantly higher than A2-B (83%-88% vs 70%-73%, respectively; p = 0.03); moreover, cumulative risk to develop hypertension in A1-C is significantly higher compared to A2-B in office and ambulatory BP monitoring (p = 0.03). Insufficient dipping in systolic and/or diastolic BP was found in 82% children, without differences between subtypes.

Conclusions: Patients with a small/absent dysplastic kidney have an increased risk to develop hypertrophy and hypertension compared to patients with a large residual, regardless of nephrectomy. ABPM revealed absent dipping in most patients with SFK, warning further investigations in apparently not symptomatic patients.