Transcription Factor ß-Catenin Plays a Key Role in Fluid Flow Shear Stress-Mediated Glomerular Injury in Solitary Kidney.

Increased fluid flow shear stress (FFSS) in solitary kidney alters podocyte function in vivo. FFSS-treated cultured podocytes show upregulated AKT-GSK3ß-ß-catenin signaling. The present study was undertaken to confirm (i) the activation of ß-catenin signaling in podocytes in vivo using unilaterally nephrectomized (UNX) TOPGAL mice with the ß-galactosidase reporter gene for ß-catenin activation, (ii) ß-catenin translocation in FFSS-treated mouse podocytes, and (iii) ß-catenin signaling using publicly available data from UNX mice. The UNX of TOPGAL mice resulted in glomerular hypertrophy and increased the mesangial matrix consistent with hemodynamic adaptation. Uninephrectomized TOPGAL mice showed an increased ß-galactosidase expression at 4 weeks but not at 12 weeks, as assessed using immunofluorescence microscopy (p < 0.001 at 4 weeks; p = 0.16 at 12 weeks) and X-gal staining (p = 0.008 at 4 weeks; p = 0.65 at 12 weeks). Immunofluorescence microscopy showed a significant increase in phospho-ß-catenin (Ser552, p = 0.005) at 4 weeks but not at 12 weeks (p = 0.935) following UNX, and the levels of phospho-ß-catenin (Ser675) did not change. In vitro FFSS caused a sustained increase in the nuclear translocation of phospho-ß-catenin (Ser552) but not phospho-ß-catenin (Ser675) in podocytes. The bioinformatic analysis of the GEO dataset, #GSE53996, also identified ß-catenin as a key upstream regulator. We conclude that transcription factor ß-catenin mediates FFSS-induced podocyte (glomerular) injury in solitary kidney.

Organ-Specific Monitoring of Solitary Kidney after Living Donation by Using Markers of Glomerular Filtration Rate and Urinary Proteins.

BACKGROUND: Effective follow-up after living kidney donation is important for maintaining the renal function of the donor. We investigated whether the estimated glomerular filtration rate (eGFR) and urinary protein and enzyme levels can provide important information regarding the state of the remaining kidney after donor nephrectomy. METHODS: Seventy-five living donations were included (prospective/retrospective) in the study. The following parameters were measured up to 1 year after donor nephrectomy: serum creatinine and cystatin C as markers of the GFR; the high-molecular-weight urinary proteins as markers of glomerular injury; and the low-molecular-weight urinary proteins and urinary enzymes as markers of tubular function. RESULTS: One year after kidney donation, the creatinine and cystatin C values were 1.38-fold increased than their initial values, while the eGFR was 32% lower. At that time, 38% of donors had a moderate or high risk of CKD progression. The biochemical urinary glomerular and tubular kidney markers examined showed different behaviors. After a transient increase, the glomerular proteins normalized. Conversely, the detection of low-molecular-weight urinary proteins and enzymes reflected mild tubular damage at the end of the study period. CONCLUSIONS: Our findings suggest that for the evaluation of mild tubular damage, low-molecular-weight marker proteins should be included in the urine diagnostic of a personalized living kidney donor follow-up.

The feasibility of one-stage flexible ureteroscopy lithotripsy in solitary kidney patients with 1-3 cm renal stones and risk factors of renal function changes.

PURPOSE: To compare perioperative outcomes and long-term renal function changes between prior stenting (PS) and not prior stenting (NPS) before flexible ureteroscopy lithotripsy (f-URS) for solitary kidney patients. METHODS: Solitary kidney patients with 10-30 mm renal stones were enrolled in this historical control study. Perioperative parameters and complications were compared. Stone-free was defined as the absence of any residual stones on a CT scan. Renal function changes were evaluated by estimated glomerular filtration rate (eGFR) and adjusted for body surface area. A decrease in the eGFR over 20% was identified as 'deterioration' in renal function. The follow-up period was at least 6 months. Logistic regression was used to identify risk factors of renal function deterioration. RESULTS: Of the 76 patients included, 40 cases experienced prior stenting before f-URS. The average stone diameter was 16.8 ± 4.7 mm, ranging from 10.0 to 28.4 mm. Initial SFR was 85.0 and 83.3% in the PS and NPS groups, respectively (p = 0.842), while SFR after the second procedure was 97.5 and 94.4% (p = 0.926). Seven PS and 5 NPS patients developed complications (p = 0.666). At the postoperative 6 months, seven patients showed a deteriorated renal function. Surgical time in minutes was identified as a risk factor for renal function deterioration after the operation (OR = 1.061, 95% CI: 1.015-1.109, p = 0.009, per minute). CONCLUSION: It appears that one-stage f-URS without PS could be feasible for 10-30 mm renal stones in solitary kidney patients, and less surgical time might be beneficial to protect renal function.

Functional and molecular evaluation of using aliskiren during acute and chronic partial ureteral obstruction in rat solitary kidney.

AIMS: To study the effect of direct renin inhibitor (aliskiren) on the renal function during acute and chronic partial ureteral obstruction (PUO) in rat solitary kidney. MAIN METHODS: Sixty male Sprague-Dawley rats were randomly allocated into three groups (20 rats each); sham, PUO and aliskiren groups. Right nephrectomy was performed in all groups. Rats in PUO and aliskiren groups were subjected to left PUO and received no treatment and aliskiren (10 mg/kg, orally, once per day till sacrification), respectively. Blood samples were then collected for biochemical measurements. Ten rats from each group were sacrificed after two weeks, while the remaining rats were sacrificed after four weeks. Left kidneys were harvested for histopathological examination, BCL-2, interleukin (IL)-6, transforming growth factor (TGF)-ß1, collagen I and fibronectin relative gene expression and assessment of glutathione (GSH), superoxide dismutase (SOD), malondialdehyde (MDA) and nitric oxide (NO) activity. KEY FINDINGS: After two and four weeks of PUO, aliskiren significantly recompensed the rise of serum creatinine (Scr) and blood urea nitrogen (BUN). Aliskiren also revealed significantly better histopathological results regarding cortical and medullary necrosis, regeneration and inflammatory cell infiltration. Aliskiren group showed statistically significant up-regulation of BCL-2 and down-regulation of IL-6, TGF-ß1, collagen I and fibronectin relative gene expression. Aliskiren significantly increased GSH and SOD activity and reduced MDA and NO activity. Moreover, aliskiren administration for four weeks after PUO significantly yielded more renoprotective effect compared to its administration for two weeks. SIGNIFICANCE: Aliskiren ameliorates the deterioration of the renal function during acute and chronic PUO in a solitary kidney.

Congenital Solitary Kidney from Birth to Adulthood.

PURPOSE: To evaluate the course of prenatally diagnosed and early-enrolled congenital solitary functioning kidney patients followed until adulthood and to identify risk factors for kidney injury. MATERIALS AND METHODS: Among all congenital solitary functioning kidney patients followed (1993-2018), we recalled 56 patients with prenatal diagnosis and congenital solitary functioning kidney confirmation at 1-3 months of life reaching at least 18 years of age. Serum uric acid, heavy smoking (≥25 cigarettes/day) and overweight/obesity were clustered as modifiable risk factors. Kidney injury was defined by estimated glomerular filtration rate <90 ml/minute/1.73 m2 and/or 24-hour ambulatory blood pressure monitoring confirmed hypertension and/or proteinuria. Modifiable risk factors and congenital anomalies of the kidney and urinary tract (CAKUT) of congenital solitary functioning kidney were evaluated as risk factors for kidney injury. RESULTS: The mean followup period was 21.1 years (range 18-33 years). Mild kidney injury was found in 15 out of 56 patients (26.8%). The mean age at proteinuria, reduced estimated glomerular filtration rate and hypertension onset was 19.7 years (1.2 SDS), 20.7 years (2.7 SDS), and 22 years (5.6 SDS), respectively. Patients with CAKUT of congenital solitary functioning kidney and with both CAKUT of congenital solitary functioning kidney and modifiable risk factors presented survival free from kidney injury of 0% at 22.2 and 24.2 years of age, respectively. Patients with modifiable risk factors presented 42.4% of survival at 30 years. Patients without CAKUT of congenital solitary functioning kidney nor modifiable risk factors presented 100% of survival at 30 years of age (p=0.002). The presence of CAKUT of congenital solitary functioning kidney was the only significant risk factor (HR 4.9; 95% CI 1.8-14.2; p=0.003). CONCLUSIONS: The outcomes of congenital solitary functioning kidney in early adulthood appear better than previously reported. Prompt diagnosis of congenital solitary functioning kidney, healthy lifestyle promotion and monitoring of serum uric acid may improve the prognosis of congenital solitary functioning kidney patients.

Functional outcomes after pyeloplasty in solitary kidneys: structured analysis with the implication of Acute Kidney Injury Network (AKIN) staging criteria to predict long-term renal function recoverability.

OBJECTIVES: To assess the long-term functional outcomes after pyeloplasty in solitary kidney (SK) models and to define factors affecting postoperative renal function recoverability in adults. PATIENTS AND METHODS: We retrospectively evaluated all adult patients who underwent pyeloplasty for pelvi-ureteric junction obstruction (PUJO) in SK. Long-term renal function was assessed by diuretic scintigraphy and morphological changes were also determined, e.g. renal parenchymal volume (RPV) and parenchymal thickness (PT). We considered a >20% increase in glomerular filtration rate (GFR) as improvement, >20% decrease as deterioration, and changes within 20% as stationary renal function. Univariate and multivariate analysis for factors affecting renal function recoverability, including the Acute Kidney Injury Network (AKIN) Staging System postoperatively, were performed. RESULTS: The study included 62 patients with a mean (SD) age of 29 (10.5) years. At a median of 48 months, the mean (SD) GFR increased from 41.3 (17) to 48.5 (20.1) mL/min (P < 0.001), with a significant increase in RPV and PT (P = 0.02 and P = 0.001, respectively). Follow-up renal function was static, improved and decreased in 39 (63.4%), 17 (27%) and six (9.6%) patients, respectively. Functional success was achieved in 90.4%. Patient's age ≥39 years, PT ≤0.75 cm and higher early postoperative AKIN staging were predictors associated with a 4.8-, 3.2- and 2.7-fold deterioration in renal function. CONCLUSION: Pyeloplasty in SK preserved renal function in 90.4% of the present patients. Pyeloplasty in SK when associated with older age, decreased PT preoperatively, and early higher AKIN staging postoperatively was associated with poor renal function recoverability.

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.

The natural history of solitary post-nephrectomy kidney in a pediatric population.

INTRODUCTION: Children with a solitary post-nephrectomy kidney (SNK) are at potential risk of developing kidney disease later in life. In response to the global decline in the number of nephrons, adaptive mechanisms lead to renal injury. The aim of this study was to determine the prevalence and time of onset of high blood pressure (HBP), proteinuria, glomerular filtration rate (GFR) disruption and renal tubular acidosis (RTA) in children with SNK. MATERIALS AND METHODS: After obtaining the approval from our institution's ethics committee, we reviewed the medical records of patients under 18 years of age who underwent unilateral nephrectomy between January 2005 and December 2015 in three university hospitals. RESULTS: We identifi ed 43 patients, 35 (81.4%) cases of unilateral nephrectomy (UNP) were due to a non-oncologic pathology and Wilm's tumor was identified in 8 (18.6%) cases. In patients with non-oncologic disease, 9.3% developed de novo hypertension, with an average time of onset of 7.1 years, 25% developed proteinuria de novo, with an average time of onset of 2.2 years. For GFR, 21.8% presented deterioration of the GFR in an average time of 3.4 years. Ten (43.5%) patients developed some type of de novo renal injury after UNP. Patients with oncolo-gic disease developed the conditions slowly and none of them developed proteinuria. CONCLUSIONS: Taking into account the high rate of long term postoperative renal injury, it can be considered that nephrectomy does not prevent this disease. The follow-up of children with SNK requires a multidisciplinary approach and long-term surveillance to detect renal injury.

The natural history of solitary post-nephrectomy kidney in a pediatric population

ABSTRACT Introduction: Children with a solitary post-nephrectomy kidney (SNK) are at potential risk of developing kidney disease later in life. In response to the global decline in the number of nephrons, adaptive mechanisms lead to renal injury. The aim of this study was to determine the prevalence and time of onset of high blood pressure (HBP), proteinuria, glomerular filtration rate (GFR) disruption and renal tubular acidosis (RTA) in children with SNK. Materials and methods: After obtaining the approval from our institution's ethics committee, we reviewed the medical records of patients under 18 years of age who underwent unilateral nephrectomy between January 2005 and December 2015 in three university hospitals. Results: We identified 43 patients, 35 (81.4%) cases of unilateral nephrectomy (UNP) were due to a non-oncologic pathology and Wilm's tumor was identified in 8 (18.6%) cases. In patients with non-oncologic disease, 9.3% developed de novo hypertension, with an average time of onset of 7.1 years, 25% developed proteinuria de novo, with an average time of onset of 2.2 years. For GFR, 21.8% presented deterioration of the GFR in an average time of 3.4 years. Ten (43.5%) patients developed some type of de novo renal injury after UNP. Patients with oncologic disease developed the conditions slowly and none of them developed proteinuria. Conclusions: Taking into account the high rate of long term postoperative renal injury, it can be considered that nephrectomy does not prevent this disease. The follow-up of children with SNK requires a multidisciplinary approach and long-term surveillance to detect renal injury.

Extra Hepatic Portal Vein Obstruction with Solitary Left Kidney: A Case Report.

Extra Hepatic Portal Vein Obstruction in individual with solitary left kidney is rare occurence. Though there is no etiological association between Extra Hepatic Portal Vein Obstruction and solitary left kidney but the solitary left kidney decides the modality of treatment. Eighteen year lady referred to our institute with menorrhagia for 5 years and ultrasonography finding of splenomegaly and atretic right kidney. Investigations revealed Extra Hepatic Portal Vein Obstruction with multiple cavernoma formation with oesophagogastric varices with right renal agenesis. She successfully underwent splenectomy with devascularisation. Patient with Extra Hepatic Portal Vein Obstruction present mainly with recurrent episodes of variceal bleeding, splenomegaly and hypersplenism. Splenectomy and esophagogastric devascularisation is an effective modality of treatment for patient with Extra Hepatic Portal Vein Obstruction with solitary kidney. Keywords: cavernoma; modified Hassab's operation; Portal vein; unilateral renal agenesis.

Urinary procollagen III aminoterminal propeptide and ß-catenin - New diagnostic biomarkers in solitary functioning kidney?

PURPOSE: We aimed at evaluating urinary levels of procollagen III aminoterminal propeptide (PIIINP) and ß-catenin and the relationship between these markers and clinical and laboratory variables in children with a solitary functioning kidney (SFK). PATIENTS AND METHODS: The study group consisted of 98 (M/F: 62/36) children with an SFK with a median age of 8 years. An age-matched control group contained 54 healthy peers. Urinary levels of procollagen III aminoterminal propeptide and ß-catenin were measured using a commercially available immunoassay kit. RESULTS: The urinary values of PIIINP (UPIIINP) were significantly increased in patients with SFK versus controls (p < 0.01). Our analysis revealed no significant differences in urinary ß-catenin levels between the SFK patients and control subjects (p > 0.05). Only urinary PIIINP levels were correlated to renal function tests, such as serum creatinine, urea, uric acid, and estimated glomerular filtration rate (p<0.05). CONCLUSIONS: An increased urinary level of PIIINP may indicate early kidney impairment in children with SFK. Urinary ß-catenin does not seem to play any important role as a marker of renal function in children with SFK. Further long-term studies are required in order to evaluate the clinical usefulness of these markers and their predictive value of chronic kidney disease (CKD) progression.

Incidental finding of Zinner syndrome in a Greek military recruit: a case report of a rare clinical entity.

BACKGROUND: Zinner syndrome represents a rare congenital malformation of the urinary tract. It comprises a constellation of Wolffian duct anomalies and is almost exclusively encountered as a classic triad of seminal vesicle cysts, ejaculatory duct obstruction and renal agenesis. Patients can be either asymptomatic or symptomatic. Recently, minimally invasive surgical techniques have emerged, superseding traditional surgery for select symptomatic cases. Our case highlights the finding of a rare clinical syndrome that was incidentally detected during a routine mass screening of military recruits in the Greek Armed Forces. CASE PRESENTATION: Herein, we present a case of a 19-year-old male who reported having a solitary right kidney when examined in a military training center of Northern Greece. No additional clinical information was available; thus, referral to a tertiary urology department for further investigation ensued. Imaging studies, namely, computed tomography and magnetic resonance imaging, revealed left renal aplasia, multiple left seminal vesicle cysts, and ejaculatory duct obstruction. Laboratory values and urinalysis were within normal range. Semen analysis was significant for cryptozoospermia. Our patient remained asymptomatic during the entire hospitalization. Long-term follow-up was recommended. Nevertheless, he declined further investigation and sought treatment in a private practice setting. CONCLUSIONS: This article aims to present the incidental diagnosis of a rare syndrome in a military setting. Population screening conducted in the armed forces permits the identification of undiagnosed diseases that warrant further investigation. To the best of our knowledge, this was the first report of Zinner syndrome in a military recruit and the second case cited of a Greek patient in the published literature. Regular follow-up is the key to timely intervention in conservatively managed cases.

Management of Aortoiliac Aneurysms with Atypical Renal Artery Anatomy.

BACKGROUND: Renal artery anomalies occur at a rate of 1-2% and present a challenge to vascular surgeons performing aortic surgery. We describe adjuncts used to manage such anatomic variants. METHODS: A single surgeon registry of all abdominal aortic aneurysms repaired in an academic center was retrospectively reviewed. Patients with prior renal transplants, congenital pelvic kidneys, or horseshoe kidneys were included. Open repair was reserved for patients with no endovascular or hybrid repair options. RESULTS: Over an 8-year period, 18 patients were identified (renal transplant n = 9, horseshoe kidney n = 3, congenital pelvic kidney n = 6). All transplant patients were treated with endovascular repair. Four required cross-femoral bypasses, 1 for retrograde allograft perfusion after aorto-uni-iliac (AUI) procedure to the contralateral external iliac artery and 3 for contralateral limb perfusion after endograft extension into iliac artery ipsilateral to allograft. Three transplant patients required carotid access due to severe iliofemoral occlusive disease or allograft origin off the internal iliac artery. Two horseshoe kidney patients underwent open repair with direct reimplantation of accessory renal arteries, whereas 1 underwent endovascular repair with exclusion of an isthmus branch. Of the congenital single/pelvic kidney cohort, 2 underwent open repair with renal reimplantation, 2 underwent endovascular aneurysm repair, 1 was treated with AUI and cross-femoral bypass, and one was treated with a staged iliorenal bypass and subsequent fenestrated endovascular repair. Intravascular ultrasound was used to minimize contrast use in patients with chronic renal insufficiency (Cr > 1.5 mg/dL, n = 6). Over a mean follow-up of 31 months (range, 1-110), there were no aortic deaths or reintervention, no decline in renal function (measured by serum creatinine and glomerular filtration rate), and 100% patency of the preserved renal arteries. CONCLUSIONS: Atypical renal anatomy should not preclude repair of aortic aneurysms. Repair of such aneurysms is safe and achieves good long-term outcomes with the use of the described techniques.

Predicting Renal Function Outcomes After Partial and Radical Nephrectomy.

BACKGROUND: Partial nephrectomy (PN) is generally favored for cT1 tumors over radical nephrectomy (RN) when technically feasible. However, it can be unclear whether the additional risks of PN are worth the magnitude of renal function benefit. OBJECTIVE: To develop preoperative tools to predict long-term estimated glomerular filtration rate (eGFR) beyond 30d following PN and RN, separately. DESIGN, SETTING, AND PARTICIPANTS: In this retrospective cohort study, patients who underwent RN or PN for a single nonmetastatic renal tumor between 1997 and 2014 at our institution were identified. Exclusion criteria were venous tumor thrombus and preoperative eGFR <15ml/min/1.73m2. INTERVENTION: RN and PN. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Hierarchical generalized linear mixed-effect models with backward selection of candidate preoperative features were used to predict long-term eGFR following RN and PN, separately. Predictive ability was summarized using marginal RGLMM2, which ranges from 0 to 1, with higher values indicating increased predictive ability. RESULTS AND LIMITATIONS: The analysis included 1152 patients (13 206 eGFR observations) who underwent RN and 1920 patients (18 652 eGFR observations) who underwent PN, with mean preoperative eGFRs of 66ml/min/1.73m2 (standard deviation [SD]=18) and 72ml/min/1.73m2 (SD=20), respectively. The model to predict eGFR after RN included age, diabetes, preoperative eGFR, preoperative proteinuria, tumor size, time from surgery, and an interaction between time from surgery and age (marginal RGLMM2=0.41). The model to predict eGFR after PN included age, presence of a solitary kidney, diabetes, hypertension, preoperative eGFR, preoperative proteinuria, surgical approach, time from surgery, and interaction terms between time from surgery and age, diabetes, preoperative eGFR, and preoperative proteinuria (marginal RGLMM2). Limitations include the lack of data on renal tumor complexity and the single-center design; generalizability needs to be confirmed in external cohorts. CONCLUSIONS: We developed preoperative tools to predict renal function outcomes following RN and PN. Pending validation, these tools should be helpful for patient counseling and clinical decision-making. PATIENT SUMMARY: We developed models to predict kidney function outcomes after partial and radical nephrectomy based on preoperative features. This should help clinicians during patient counseling and decision-making in the management of kidney tumors.

A clinical predictive model of renal injury in children with congenital solitary functioning kidney.

BACKGROUND: Solitary functioning kidney (SFK) is an important condition in the spectrum of congenital anomalies of the kidney and urinary tract. The aim of this study was to describe the risk factors for renal injury in a cohort of patients with congenital SFK. METHODS: In this retrospective cohort study, 162 patients with SFK were systematically followed up (median, 8.5 years). The primary endpoint was time until the occurrence of a composite event of renal injury, which includes proteinuria, hypertension, and chronic kidney disease (CKD). A predictive model was developed using Cox proportional hazards model and evaluated by c statistics. RESULTS: Among 162 children with SFK included in the analysis, 132 (81.5%) presented multicystic dysplastic kidney, 20 (12.3%) renal hypodysplasia, and 10 (6.2%) unilateral renal agenesis. Of 162 patients included in the analysis, 10 (6.2%) presented persistent proteinuria, 11 (6.8%) had hypertension, 9 (5.6%) developed CKD stage ≥ 3, and 18 (11%) developed the composite outcome. After adjustment by the Cox model, three variables remained as independent predictors of the composite event: creatinine (HR, 3.93; P < 0.001), recurrent urinary tract infection (UTI) (HR, 5.05; P = 0.002), and contralateral renal length at admission (HR, 0.974; P = 0.002). The probability of the composite event at 10 years of age was estimated as 3%, 11%, and 56% for patients assigned to the low-risk, medium-risk, and high-risk groups, respectively (P < 0.001). CONCLUSION: Our findings have shown an overall low risk of renal injury for most of infants with congenital SFK. Nevertheless, our prediction model enabled the identification of a subgroup of patients with an increased risk of renal injury over time.

A multi-institutional report of peri-operative and functional outcomes after robot-assisted partial nephrectomy in patients with a solitary kidney.

To evaluate peri- and post-operative outcomes after robotic partial nephrectomy (RPN) in patients with a solitary kidney. A multi-institutional database of 1868 patients was used to identify 35 patients with a solitary kidney who underwent RPN at six different centers from 2007 to 2016. Peri-operative outcomes were summarized with descriptive statistics. We assessed the change in eGFR over time with a linear mixed-effects model. Median operative time, ischemia time, and estimated blood loss were 172 min, 16 min, and 113 mL, respectively. There were no positive surgical margins. The median length of stay was 1 day (range 1-7), and over half (54.3%) of patients were discharged one post-operative day 1. Seven post-operative complications occurred in six patients (17.1%); of which four were Clavien I, two were Clavien II, and one was Clavien III. The linear decline in eGFR up to 24 month post-RPN was marginal and not significant (ß = - 0.14; 95% CI = - 0.51, 0.23; p = 0.453), with predicted mean eGFR decreasing from 59.2 to 55.8 mL/min/1.73 m2 at 24 months. These results suggest that, in patients with a solitary kidney, RPN is a safe and feasible treatment option. In patients with a solitary kidney, RPN did not significantly compromise renal function for up to 2 years after surgery.

Towards adulthood with a solitary kidney.

Around 1/1000 people have a solitary kidney. Congenital conditions mainly include multicystic dysplastic kidney and unilateral renal aplasia/agenesis; acquired conditions are secondary to nephrectomy performed because of urologic structural abnormalities, severe parenchymal infection, renal trauma, and renal or pararenal tumors. Children born with congenital solitary kidney have a better long-term glomerular filtration rate than those with solitary kidney secondary to nephrectomy later in life. Acute and chronic adaptation processes lead to hyperfiltration followed by fibrosis in the remnant kidney, with further risk of albuminuria, arterial hypertension, and impaired renal function. Protective measures rely on non-pharmacological renoprotection (controlled protein and sodium intake, avoidance/limitation of nephrotoxic agents, keeping normal body mass index, and limitation of tobacco exposure). Lifelong monitoring should include blood pressure and albuminuria assessment, completed by glomerular filtration rate (GFR) estimation in case of abnormal values. In the absence of additional risk factors to solitary kidney, such assessment can be proposed every 5 years. There is no current consensus for indication and timing of pharmacological intervention.

Congenital solitary kidney size at birth could predict reduced eGFR levels later in life.

OBJECTIVES: To evaluate the impact of congenital solitary functioning kidney (CSFK) length, measured early in life, on the eGFR levels during the follow-up. STUDY DESIGN: We retrospectively selected 162 CSFK patients undergoing, within 60 days of life, renal length (RL) measurement by ultrasound. We divided the population in: Group 1 = RL ≥ 2 standard deviation score (SDS). Group 2 = RL < 2 SDS and showing RL ≥ 2 SDS during the follow-up. Group 3 = RL < 2 SDS and showing RL < 2 SDS during the follow-up. PRIMARY OUTCOME: development of eGFR below the range of normality. RESULTS: The median follow-up period of the overall population was 6.2 years (range 2-21.5 years). The cumulative proportion of patients free of primary outcome at 15 years of age was 96.4% in group 1, 64.6% in group 2, and 45.6% in group 3 (p = 0.03). The RL > 2 SDS within 60 days of life was a significant protective factor (hazard ratio = 0.13; 95% C.I. 0.02-0.97) against development of primary outcome. CONCLUSION: RL ≥ 2 SDS within 60 days of life could identify a population of CSFK with reduced risk of presenting reduced eGFR levels later in life.

Acute Kidney Injury after Partial Nephrectomy of Solitary Kidneys: Impact on Long-Term Stability of Renal Function.

PURPOSE: Acute kidney injury often leads to chronic kidney disease in the general population. The long-term functional impact of acute kidney injury observed after partial nephrectomy has not been adequately studied. MATERIALS AND METHODS: From 2004 to 2014 necessary studies for analysis were available for 90 solitary kidneys managed by partial nephrectomy. Functional data at 4 time points included preoperative serum creatinine, peak postoperative serum creatinine, new baseline serum creatinine 3 to 12 months postoperatively and long-term followup serum creatinine more than 12 months postoperatively. Adjusted acute kidney injury was defined by the ratio, observed peak postoperative serum creatinine/projected postoperative serum creatinine adjusted for parenchymal mass loss to reveal the true effect of ischemia. The long-term change in renal function (the long-term functional change ratio) was defined as the most recent glomerular filtration rate/the new baseline glomerular filtration rate. The relationship between the grade of the adjusted acute kidney injury and the long-term functional change was assessed by Spearman correlation analysis and multivariable regression. RESULTS: Median patient age was 64 years and median followup was 45 months. Median parenchymal mass preservation was 80%. Adjusted acute kidney injury occurred in 42% of patients, including grade 1 injury in 20 (22%) and grade 2/3 in 18 (20%). On univariable analysis the degree of the adjusted acute kidney injury did not correlate with the long-term glomerular filtration rate change (p = 0.55). On multivariable analysis adjusted acute kidney injury was not associated with a long-term functional change (p >0.05) while diabetes and warm ischemia were modestly associated with a long-term functional decline (each p <0.05). CONCLUSIONS: Acute kidney injury after partial nephrectomy was not a significant or independent predictor of long-term functional decline in our institutional cohort. A prospective study with larger sample sizes and longer followup is required to evaluate factors associated with long-term nephron stability.