Outcomes of prenatally diagnosed solitary functioning kidney during early life

Glomerular hyperfiltration: part 2-clinical significance in children

Glomerular hyperfiltration (GHF) is a phenomenon that can occur in various clinical conditions affecting the kidneys such as sickle cell disease, diabetes mellitus, autosomal dominant polycystic kidney disease, and solitary functioning kidney. Yet, the pathophysiological mechanisms vary from one disease to another and are not well understood. More so, it has been demonstrated that GHF may occur at the single-nephron in some clinical conditions while in others at the whole-kidney level. In this review, we explore the pathophysiological mechanisms of GHF in relation to various clinical conditions in the pediatric population. In addition, we discuss the role and mechanism of action of important factors such as gender, low birth weight, and race in the pathogenesis of GHF. Finally, in this current review, we further highlight the consequences of GHF in the progression of kidney disease.

Is the prognosis of congenital single functioning kidney benign? A population-based study

BACKGROUND

We investigated the risk of kidney injury among adolescents with and without a congenital single functioning kidney (SFK).

METHODS

This retrospective study is based on a medical evaluation database of 17-year-old Israeli conscripts, born during 1989-1999. Those with congenital SFK diagnosis, verified by a pediatric nephrologist's review of the original military medical committee classifications, were compared to the rest of the cohort. Kidney injury (KI) was defined as proteinuria, high blood pressure (BP), or estimated glomerular filtration rate (eGFR) < 90 ml/min/1.73 m² prior to army recruitment. Risk factors for KI were examined using logistic regression.

RESULTS

Of 979,630 screened candidates, 353 were diagnosed with SFK. The yearly incidence of SFK gradually increased in the first years of the study, reaching a plateau in 1995 (5.5 ± 1.2/10,000 births/year). The male to female ratio was 2.7:1. Concomitant genital malformations were documented in 5.5% of those with SFK. KI was more prevalent in the SFK than the control group (42.2% vs. 23.5%, p < 0.001). All three components of KI were more common in the SFK than the control group: high BP (31.7% vs. 23.1%, p < 0.001), proteinuria (18.2% vs. 0.4%, p < 0.001), and eGFR <90 ml/min/1.73m² (12.0% vs 0.1%, p < 0.001). Multivariate analysis of the SFK group revealed associations of higher mean BMI, male sex, and smaller ultrasonographic kidney length with KI.

CONCLUSIONS

This large population-based study documents a significant risk for KI among adolescents with SFK. Obesity represents a major modifiable risk factor for KI, implicating the need for closer follow-up in this group during childhood.

Renal function in children with a congenital solitary functioning kidney: A systematic review

INTRODUCTION

Abnormal renal development that results in lack of function or development of one of two kidneys is known as congenital solitary functioning kidney (CSFK). Two well characterized sub-categories of CFSK are unilateral renal agenesis (URA) and multicystic dysplastic kidney (MCDK). This systematic review sought to evaluate the change in renal function in children ≤18 years old with a CSFK as a result of URA or MCDK.

METHODS

A literature search in MEDLINE and Embase was conducted (1946 to July 13, 2020). All relevant articles were retrieved and evaluated based on pre-selected criteria by two independent researchers. Data was then extracted from variables of interest and conflicts were resolved by a third researcher. The primary outcome was renal function, and the secondary outcomes were proteinuria and hypertension.

RESULTS

Forty-five studies were included, of which 49% (n = 22) were retrospective and/or 58% (n = 26) were cohort studies. A combined total of 2148 and 885 patients were diagnosed with MCDK or URA, respectively. The proportion of children with worsened renal function at follow-up was found to be 8.4% (95% CI: 5.2%-13.4%). Among the studies reporting renal function as a group mean or median at follow-up, 84% (21/25) had a GFR/CrCl above 90 (mL/min/1.73  m²/ml/min). In terms of secondary outcomes, the proportion of children with proteinuria and hypertension was found to be 10.1% (95% CI: 6.9%-14.6%) and 7.4% (95% CI: 5.0%-10.9%), respectively.

CONCLUSION

The risk of developing proteinuria (10.1%), hypertension (7.4%), and/or worsened renal function (8.4%) for children with CFSK as a result of MCDK or URA is low. However, the level of evidence in the literature is weak. Further research is needed to identify the predisposing factors that may differentiate the small subset of children with CSFK at a higher risk of developing adverse renal outcomes.

Outcomes of fenestrated-branched endovascular aortic repair in patients with a solitary functional kidney

OBJECTIVE

The aim of this study was to evaluate outcomes of fenestrated-branched endovascular aortic repair (F-BEVAR) of pararenal abdominal aortic aneurysms or thoracoabdominal aortic aneurysms (TAAAs) in patients with a solitary functional kidney (SFK).

METHODS

We analyzed the outcomes of 287 consecutive patients (206 male; mean age, 74 ± 8 years old) enrolled in a prospective nonrandomized study to investigate use of F-BEVAR for treatment of patients with pararenal abdominal aortic aneurysms or TAAAs between 2013 and 2018. Outcomes were analyzed in patients with solitary kidney (functional or congenital) and compared with control patients who had two functioning kidneys. Acute kidney injury (AKI) was defined using Risk, Injury, Failure, Loss of kidney function, and End-stage renal disease criteria, and renal function deterioration (RFD) was defined by a decline in estimated glomerular filtration the estimated glomerular filtration rate of more than 30% from baseline. End points included 30-day mortality and major adverse events, AKI, freedom from RFD, and patient survival.

RESULTS

There where 30 patients (10%) with a SFK and 257 patients with two functioning kidneys. Patients with a SFK were younger and had significantly (P < .05) higher baseline creatinine (+0.3 mg/dL), lower estimated glomerular filtration rate (-16 mL/minute/1.73 m²) and more often had stage III to V chronic kidney disease (73% vs 43%). There were no differences in cardiovascular risk factors and aneurysm extent. Technical success was achieved in 98.9% of patients with SFK and in 99.8% of controls (P = .10). At 30 days, there was no significant differences in mortality (0% vs 1%) and major adverse events (40% vs 24%; P = .08), including rates of AKI (20% vs 12%) and new-onset dialysis (3% vs 1%) between patients with a SFK and the control group, respectively. Mean follow-up was 18 ± 15 months. At 2 years, there was no difference (P = .36) in patient survival (92 ± 5% vs 84 ± 3%) and freedom from RFD (100 ± 0% vs 84 ± 3%) for patients with SFK and controls, respectively. Presence of a SFK was not a predictor for AKI or RFD. By multivariable analysis, estimated blood loss of more than 1 L (odds ratio [OR], 2.9; P = .04) and total fluoroscopy time (OR, 1.8; P = .05) were predictors for AKI, and postoperative AKI (OR, 4.9; P < .001), renal branch occlusion/stenosis (OR, 3.1; P = .001), and Crawford extent II TAAA (OR, 2.4; P = .007) were predictors for RFD.

CONCLUSIONS

Despite the worse baseline renal function, F-BEVAR is safe and effective with nearly identical outcomes in patients with a SFK as compared with patients with two functioning kidneys. Development of postoperative AKI is the most important predictor for RFD.