Is the mode of occurrence of vesicoureteral reflux A prognostic factor for spontaneous resolution?

Abstract

Purpose Vesicoureteral reflux (VUR) may occur in response to increased pressure in the bladder either during filling or voiding, or it may be passive. In this study we investigate whether the mode of occurrence during infancy can be used as a predictor for spontaneous resolution of the reflux. Material and methods 103 infants with grade 4-5 reflux were included (70% bilateral). Investigations with videocystometry were performed at median 5, 20 and 42 months, and reflux was registered as occurring at unstable contraction during filling (UC), without change in pressure during filling (passive, P) or at micturition (M). Only the side with the highest grade of reflux was included when bilateral. Spontaneous resolution was 38% during the observation period. Results At the investigation during infancy reflux occurred in response to UC, P and M in 28%, 35% and 37%, respectively. VUR in response to UC was mainly seen in boys. Reflux that was still dilated at the latest follow-up, appeared in response to UC in 11% only and was P in 69%. This explains the significant correlation between high age and passive reflux when including all investigations (p=0.0002). High bladder capacity was also significant correlated to passive reflux at all follow-up investigations (p<0.001). Survival curves showed that those with M reflux at the first investigation, had a higher probability for spontaneous resolution than those with P reflux (at 20months 43% versus 23%), whereas UC reflux was in-between. Conclusions Reflux occurrence characteristics changed during the first years in boys, from a high proportion of pressure induced reflux during infancy to passive reflux. This change was correlated to a change in urodynamics, from high pressure to low pressure bladder pattern, but also to the higher spontaneous resolution rate in pressure induced reflux, most evident in the micturition reflux. Vesicoureteral reflux (VUR) may occur in response to increased pressure in the bladder either during filling or voiding, or it may be passive. In this study we investigate whether the mode of occurrence during infancy can be used as a predictor for spontaneous resolution of the reflux. 103 infants with grade 4-5 reflux were included (70% bilateral). Investigations with videocystometry were performed at median 5, 20 and 42 months, and reflux was registered as occurring at unstable contraction during filling (UC), without change in pressure during filling (passive, P) or at micturition (M). Only the side with the highest grade of reflux was included when bilateral. Spontaneous resolution was 38% during the observation period. At the investigation during infancy reflux occurred in response to UC, P and M in 28%, 35% and 37%, respectively. VUR in response to UC was mainly seen in boys. Reflux that was still dilated at the latest follow-up, appeared in response to UC in 11% only and was P in 69%. This explains the significant correlation between high age and passive reflux when including all investigations (p=0.0002). High bladder capacity was also significant correlated to passive reflux at all follow-up investigations (p<0.001). Survival curves showed that those with M reflux at the first investigation, had a higher probability for spontaneous resolution than those with P reflux (at 20months 43% versus 23%), whereas UC reflux was in-between. Reflux occurrence characteristics changed during the first years in boys, from a high proportion of pressure induced reflux during infancy to passive reflux. This change was correlated to a change in urodynamics, from high pressure to low pressure bladder pattern, but also to the higher spontaneous resolution rate in pressure induced reflux, most evident in the micturition reflux.