Pop-off mechanisms protecting long-term renal function in posterior urethral valve

Abstract

Objective To explore the pop-off mechanisms protecting renal long-term function in posterior urethral valves (PUV) after value ablation.Methods A total of 24 hospitalized PUV patients aged under 3 months at our institute from 2003 to 2013 were retrospectively analyzed.The parameters of serum creatinine,effective renal plasma flow (ERPF),voiding cystourethrogram (VCUG) and urodynamics were analyzed through medical history,questionnaires and outpatient visits.Renal function was evaluated in pop-off and nopop-off groups by comparing serum creatinine at admission and discharge and Year 2 post-ablation.Bladder function was evaluated by clinical symptoms and urodynamic study.Results The inter-group difference of serum creatinine at admission was significant (28.6 ± 9.0 vs 62.3 ± 44.3,P＜0.05).However discharge serum creatinine (29.4 ± 7.7 vs 34.1 ± 9.8,P＞0.05) and serum creatinine at Year 2 post-ablation (27.7 ± 5.4 vs 28.2 ± 6.5,P＞ 0.05) were insignificant.During long-term follow-ups,1 case died of chronic renal insufficiency complication and another with chronic renal insufficiency underwent renal dialysis in nopop-off group.There were 3 cases with urinary retention undergoing clean intermittent catheterization (CIC) and overnight bladder drainage.One case received α blockers,CIC and overnight bladder drainage.But urodynamics indicated poor compliance and poor renal function.And bladder augmentation was required.The inter-group differences in Pded.max (86.1 ± 20.4 vs 67.5 ± 16.8) and MBC (78.2 ± 18.2 vs 92.4 ± 13.3) were significant (P＜0.05).Conclusions The pop-off mechanism acts as a pressure pop-off for protecting bladder and long-term renal function. Key words: Urethral obstruction; Kidney; Bladder; Radionuclide imaging; Urodynamics