Clinical course and new renal scar development in children with high-grade vesicoureteral reflux

Abstract

Purpose: to define the resolution rate of high-grade vesicoureteral reflux (VUR) in on-to-three-year follow-up, and determine the new renal scar development. Methods: This longitudinal study was performed in children < 18 years with high-grade VUR from March 2003 to 2022. Patients who underwent radionuclide cystography 12-36 months after the diagnosis of VUR enrolled in the study and the resolution rate of VUR was calculated. Those who performed technetium-99m dimercaptosuccinic acid scans as baseline and follow-up were evaluated for new renal scarring. In the third part of the investigation, the role of different confounders was evaluated in the resolution rate of VUR and the appearance of new renal scarring. In addition, renal scarring at initial evaluation was calculated in total eligible cases who underwent a Tc-99m DMSA scan. Results: Of 216 eligible cases, 68 (31.5%) and 43 (19.9%) patients entered the study's first and second parts, respectively. They included 50% girls, with a median age at diagnosis of 31 months. Surgical interventions were performed at follow-up in 18 patients (26.5 %). Total, spontaneous, and surgical resolution rates of VUR per person at one –three-year follow-ups were 19.1% (n=13), 16 % (n=8), and 27.8 % (n=5), respectively. Renal scars and severe renal scarring were found in 135 (80.8%) and 86 (51.5%) out of 167 eligible cases, respectively. New renal scars appeared in 46.5% of patients. Resolution or downgrading of VUR did not correlate with age at presentation, gender, type and laterality of VUR, pyelonephritis at follow-up, and presentation as prenatal hydronephrosis (P> 0.05 for all). Lack of appearance of new renal scar significantly was more frequent in-group not presented compared to those presented by prenatal hydronephrosis (67.7% compared to 16.7%, respectively; P=0.005). Resolution of VUR was significantly more common in KUUs with VUR grade V than IV (26.5% compared to 7.8%, respectively; P = 0.026). Spontaneous resolution of VUR was reported in five patients (38.5%) presented with prenatal hydronephrosis, and three cases (5.5%) by other clinical presentations (P=0.005). Conclusions: High-grade VUR persists in the majority of cases after one-three-year follow-ups and about half of patients develop new renal scars. The resolution of VUR is significantly more common in KUUs with VUR grade V than in IV. In addition, spontaneous resolution happened more frequently in cases presented by prenatal hydronephrosis than in other manifestations. Further investigations need to determine cases who are at risk for developing new renal scar and persistent VUR.