Zero-Fluoroscopy Catheter Ablation of Supraventricular Tachycardias in the Pediatric Population.

Catheter ablation (CA) of supraventricular tachycardias (SVTs) is conventionally performed with the aid of X-ray fluoroscopy. Usage of a three-dimensional (3D) electro-anatomical mapping (EAM) system and intracardiac echocardiography (ICE) enables zero-fluoroscopy ablation, eliminating the harmful effects of radiation. We retrospectively analyzed the feasibility, effectiveness and safety of zero-fluoroscopy radiofrequency and cryoablation of various types of SVTs in pediatric patients. Overall, in 171 consecutive patients (12.5 ± 3.9 years), 175 SVTs were diagnosed and 201 procedures were performed. The procedural success rate was 98% (193/197), or more precisely, 100% (86/86) for AVNRT, 95.8% (91/95) for AVRT, 94.1% (16/17) for AT and 100% (2/2) for AFL. No complications were recorded. Follow-up was complete in 100% (171/171) of patients. During the mean follow-up period of 488.4 ± 409.5 days, 98.2% of patients were arrhythmia-free with long-term success rates of 98.7% (78/79), 97.5% (78/80), 100% (13/13) and 100% (2/2) for AVNRT, AVRT, AT and AFL, respectively. Zero-fluoroscopy CA of various types of SVTs in the pediatric population is a feasible, effective and safe treatment option.

Clinical and genetic characteristics of a patient with phosphoribosyl pyrophosphate synthetase 1 deficiency and a systematic literature review.

Phosphoribosylpyrophosphate synthetase 1 (PRS-I) is an enzyme involved in nucleotide metabolism. Pathogenic variants in the PRPS1 are rare and PRS-I deficiency can manifest as three clinical syndromes: X-linked non-syndromic sensorineural deafness (DFN2), X-linked Charcot-Marie-Tooth neuropathy type 5 (CMTX5) and Arts syndrome. We present a Slovenian patient with PRS-I enzyme deficiency due to a novel pathogenic variant - c.424G > A (p.Val142Ile) in the PRPS1 gene, who presented with gross motor impairment, severe sensorineural deafness, balance issues, ataxia, and frequent respiratory infections. In addition, we report the findings of a systemic literature review of all described male cases of Arts syndrome and CMTX5 as well as intermediate phenotypes. As already proposed by other authors, our results confirm PRS-I deficiency should be viewed as a phenotypic continuum rather than three separate syndromes because there are multiple reports of patients with an intermediary clinical presentation.

Systolic and diastolic left ventricular function in children with primary hypertension: a systematic review and meta-analysis.

OBJECTIVE: Evaluation of left ventricular function provides early evidence of target-organ damage in children with primary hypertension. We performed a systematic review and meta-analysis of left ventricular systolic and diastolic function in children and adolescents with primary hypertension. METHODS: Literature search was performed in PubMed database and out of 718 articles (published between 2000 and 2021) 22 studies providing comparison of left ventricular function parameters between children with primary hypertension and normotensive controls were selected. RESULTS: Overall, 3460 children (5-21 years) with primary hypertension were analyzed. Meta-analysis showed that hypertensive patients when compared with normotensives, had an increased heart rate (mean difference [MD] 5.59; 95% confidence interval [CI] 3.28, 7.89; 10 studies) and increased fractional shortening (MD 1.04; 95% CI 0.48, 1.60; 9 studies) but did not differ in ejection fraction (MD -0.03; 95% CI -1.07, 1.02; 12 studies). Stroke volume was higher in one out of three studies, whereas no differences in cardiac output were found in two studies with available data. Hypertensive children had also lower E/A values (MD -0.21; -0.33, -0.09; 14 studies), greater values of E/e' (MD 0.59; 0.36, 0.82; 8 studies) and greater global longitudinal stress (MD 2.50; 2.03, 2.96; 4 studies) when compared to those with normotension. CONCLUSION: Our results indicate that hypertensive children and adolescents present with signs of hyperkinetic function of the left ventricle, demonstrate evidence of increased left ventricular strain and impaired diastolic function compared to normotensive controls.

Knowledge gaps and future directions in cognitive functions in children and adolescents with primary arterial hypertension: A systematic review.

Arterial hypertension (AH) among adults is known to be associated with worse cognitive outcomes. Similarly, children and adolescents with AH could be expected to underperform during neuropsychological evaluations when compared with healthy peers. Our aims were to review the existing literature on cognitive functioning among children and adolescents with primary AH and to identify what additional evidence may be needed to substantiate the impact of hypertension on poor cognitive outcomes in this population. We conducted a systematic review of articles in PubMed and Web of Science published before 17 January 2022, reporting on cognitive testing among children and adolescents with primary AH. From 1,316 records, 13 were included in the review-7 used battery-testing while other employed indirect measures of cognitive functions. Most of the studies reported worse results among individuals with AH. Results of two prospective trials suggested that cognitive functioning may improve after starting antihypertensive treatment. Ambulatory blood pressure monitoring was shown to be more strongly related to cognitive testing results than office measures of blood pressure. Significant confounders, namely obesity and sleep apnea, were identified throughout the studies. Our review indicates that evidence relating AH with poor cognitive functioning among youth is usually based on indirect measures of executive functions (e.g., questionnaires) rather than objective neuropsychological tests. Future prospective trials set to test different cognitive domains in children and adolescents undergoing treatment for AH are endorsed and should consider using standardized neuropsychological batteries as well as adjust the assessing results for obesity and sleep disorders.

Phenotypic Variability in Siblings With Autosomal Recessive Polycystic Kidney Disease.

Introduction: Autosomal recessive polycystic kidney disease (ARPKD) is a rare monogenic disorder characterized by early onset fibrocystic hepatorenal changes. Previous reports have documented pronounced phenotypic variability even among siblings in terms of patient survival. The underlying causes for this clinical variability are incompletely understood. Methods: We present the longitudinal clinical courses of 35 sibling pairs included in the ARPKD registry study ARegPKD, encompassing data on primary manifestation, prenatal and perinatal findings, genetic testing, and family history, including kidney function, liver involvement, and radiological findings. Results: We identified 70 siblings from 35 families with a median age of 0.7 (interquartile range 0.1-6.0) years at initial diagnosis and a median follow-up time of 3.5 (0.2-6.2) years. Data on PKHD1 variants were available for 37 patients from 21 families. There were 8 patients from 7 families who required kidney replacement therapy (KRT) during follow-up. For 44 patients from 26 families, antihypertensive therapy was documented. Furthermore, 37 patients from 24 families had signs of portal hypertension with 9 patients from 6 families having substantial hepatic complications. Interestingly, pronounced variability in the clinical course of functional kidney disease was documented in only 3 sibling pairs. In 17 of 20 families of our cohort of neonatal survivors, siblings had only minor differences of kidney function at a comparable age. Conclusion: In patients surviving the neonatal period, our longitudinal follow-up of 70 ARPKD siblings from 35 families revealed comparable clinical courses of kidney and liver diseases in most families. The data suggest a strong impact of the underlying genotype.

Early childhood height-adjusted total kidney volume as a risk marker of kidney survival in ARPKD.

Autosomal recessive polycystic kidney disease (ARPKD) is characterized by bilateral fibrocystic changes resulting in pronounced kidney enlargement. Impairment of kidney function is highly variable and widely available prognostic markers are urgently needed as a base for clinical decision-making and future clinical trials. In this observational study we analyzed the longitudinal development of sonographic kidney measurements in a cohort of 456 ARPKD patients from the international registry study ARegPKD. We furthermore evaluated correlations of sonomorphometric findings and functional kidney disease with the aim to describe the natural disease course and to identify potential prognostic markers. Kidney pole-to-pole (PTP) length and estimated total kidney volume (eTKV) increase with growth throughout childhood and adolescence despite individual variability. Height-adjusted PTP length decreases over time, but such a trend cannot be seen for height-adjusted eTKV (haeTKV) where we even observed a slight mean linear increase of 4.5 ml/m per year during childhood and adolescence for the overall cohort. Patients with two null PKHD1 variants had larger first documented haeTKV values than children with missense variants (median (IQR) haeTKV 793 (450-1098) ml/m in Null/null, 403 (260-538) ml/m in Null/mis, 230 (169-357) ml/m in Mis/mis). In the overall cohort, estimated glomerular filtration rate decreases with increasing haeTKV (median (IQR) haeTKV 210 (150-267) ml/m in CKD stage 1, 472 (266-880) ml/m in stage 5 without kidney replacement therapy). Strikingly, there is a clear correlation between haeTKV in the first eighteen months of life and kidney survival in childhood and adolescence with ten-year kidney survival rates ranging from 20% in patients of the highest to 94% in the lowest quartile. Early childhood haeTKV may become an easily obtainable prognostic marker of kidney disease in ARPKD, e.g. for the identification of patients for clinical studies.

Clinical characteristics of Slovenian pediatric patients with autosomal recessive polycystic kidney disease.

AIMS: Autosomal recessive polycystic kidney disease (ARPKD) is a rare inherited disease. We reviewed the clinical characteristics, management, and outcomes in Slovenian pediatric patients with ARPKD. MATERIALS AND METHODS: All patients with ARPKD who were treated at the Pediatric Nephrology Department of the University Children's Hospital in Ljubljana between 1980 and 2020 were included in the study. The data were assessed retrospectively by reviewing the patients' medical records and analyzed using descriptive statistics. RESULTS: We included 13 patients, 6 boys and 7 girls. A prenatal diagnosis was established in 3 (23%) patients. In 4 (31%) patients, the diagnosis was confirmed within the first few days of life, while in 6 (46%) patients the disease manifested later during childhood. Four babies (31%) needed ventilatory support after birth. Arterial hypertension developed in all patients. Liver function was affected in 12 (92%) patients and was the predominant clinical concern in 2 of them. Two (15%) patients presented with end-stage renal disease (ESRD). Portal hypertension was found in 7 (54%) patients. Initial sonography revealed enlarged kidneys in 12 (92%) patients, hyperechoic kidneys or poor cortico-medullary differentiation in 10 (77%), and liver abnormalities in 5 (38%) patients. Unilateral nephrectomy was necessary before dialysis in 1 patient. Six (46%) patients started maintenance dialysis at an average age of 15.3 years. Kidney transplantation was performed in 2 (15%) and liver transplantation in 1 (8%) patient. Two (15%) patients died because of sepsis or respiratory failure. CONCLUSION: ARPKD is a progressive disease leading to ESRD and renal replacement treatment in almost half of our patients. Our data confirm the phenotypic variability of ARPKD in Slovenian patients.

FHR-5 Serum Levels and CFHR5 Genetic Variations in Patients With Immune Complex-Mediated Membranoproliferative Glomerulonephritis and C3-Glomerulopathy.

Background: Factor H-related protein 5 (FHR-5) is a member of the complement Factor H protein family. Due to the homology to Factor H, the main complement regulator of the alternative pathway, it may also be implicated in the pathomechanism of kidney diseases where Factor H and alternative pathway dysregulation play a role. Here, we report the first observational study on CFHR5 variations along with serum FHR-5 levels in immune complex-mediated membranoproliferative glomerulonephritis (IC-MPGN) and C3 glomerulopathy (C3G) patients together with the clinical, genetic, complement, and follow-up data. Methods: A total of 120 patients with a histologically proven diagnosis of IC-MPGN/C3G were enrolled in the study. FHR-5 serum levels were measured in ELISA, the CFHR5 gene was analyzed by Sanger sequencing, and selected variants were studied as recombinant proteins in ELISA and surface plasmon resonance (SPR). Results: Eight exonic CFHR5 variations in 14 patients (12.6%) were observed. Serum FHR-5 levels were lower in patients compared to controls. Low serum FHR-5 concentration at presentation associated with better renal survival during the follow-up period; furthermore, it showed clear association with signs of complement overactivation and clinically meaningful clusters. Conclusions: Our observations raise the possibility that the FHR-5 protein plays a fine-tuning role in the pathogenesis of IC-MPGN/C3G.

Aetiology, course and treatment of acute tubulointerstitial nephritis in paediatric patients: a cross-sectional web-based survey.

BACKGROUND: Acute tubulointerstitial nephritis (TIN) is a significant cause of acute renal failure in paediatric and adult patients. There are no large paediatric series focusing on the aetiology, treatment and courses of acute TIN. PATIENTS, DESIGN AND SETTING: We collected retrospective clinical data from paediatric patients with acute biopsy-proven TIN by means of an online survey. Members of four professional societies were invited to participate. RESULTS: Thirty-nine physicians from 18 countries responded. 171 patients with acute TIN were included (54% female, median age 12 years). The most frequent causes were tubulointerstitial nephritis and uveitis syndrome in 31% and drug-induced TIN in 30% (the majority of these caused by non-steroidal anti-inflammatory drugs). In 28% of patients, no initiating noxae were identified (idiopathic TIN). Median estimated glomerular filtration rate (eGFR) rose significantly from 31 at time of renal biopsy to 86 mL/min/1.73 m2 3-6 months later (p<0.001). After 3-6 months, eGFR normalised in 41% of patients (eGFR ≥90 mL/min/1.73 m2), with only 3% having severe or end-stage impairment of renal function (<30 mL/min/1.73 m2). 80% of patients received corticosteroid therapy. Median eGFR after 3-6 months did not differ between steroid-treated and steroid-untreated patients. Other immunosuppressants were used in 18% (n=31) of patients, 21 of whom received mycophenolate mofetil. CONCLUSIONS: Despite different aetiologies, acute paediatric TIN had a favourable outcome overall with 88% of patients showing no or mild impairment of eGFR after 3-6 months. Prospective randomised controlled trials are needed to evaluate the efficacy of glucocorticoid treatment in paediatric patients with acute TIN.

A novel mutation of congenital nephrotic syndrome in a Slovenian child eventually receiving a renal transplant.

Congenital nephrotic syndrome (CNS) is a rare disease defined as heavy proteinuria, hypoalbuminemia, hyperlipidemia, and edema presenting in the first three months of life. It is most commonly caused by mutations in the NPHS1 gene associated with nephrotic syndrome type 1, also known as Finnish-type CNS, which is inherited in an autosomal recessive manner. Symptomatic treatment with intravenous albumins, vitamins, minerals, nutritional, and hormonal supplementation and treatment of complications are mandatory. Children refractory to the symptomatic treatment are recommended to undergo nephrectomy and renal replacement therapy, preferably renal transplantation. We report on a child with Finnish type CNS with a NPHS1 mutation, which is the first case confirmed by genetic study in Slovenia. We showed for the first time that homozygous mutation c.2928-3del in the NPHS1 gene caused exon 22 skipping, leading to a truncated protein and Fin-minor phenotype.

Validation of distinct pathogenic patterns in a cohort of membranoproliferative glomerulonephritis patients by cluster analysis.

BACKGROUND: A novel data-driven cluster analysis identified distinct pathogenic patterns in C3-glomerulopathies and immune complex-mediated membranoproliferative glomerulonephritis. Our aim was to replicate these observations in an independent cohort and elucidate disease pathophysiology with detailed analysis of functional complement markers. METHODS: A total of 92 patients with clinical, histological, complement and genetic data were involved in the study, and hierarchical cluster analysis was done by Ward method, where four clusters were generated. RESULTS: High levels of sC5b-9 (soluble membrane attack complex), low serum C3 levels and young age at onset (13 years) were characteristic for Cluster 1 with a high prevalence of likely pathogenic variations (LPVs) and C3 nephritic factor, whereas for Cluster 2-which is not reliable because of the small number of cases-strong immunoglobulin G staining, low C3 levels and high prevalence of nephritic syndrome at disease onset were observed. Low plasma sC5b-9 levels, decreased C3 levels and high prevalence of LPV and sclerotic glomeruli were present in Cluster 3, and patients with late onset of the disease (median: 39.5 years) and near-normal C3 levels in Cluster 4. A significant difference was observed in the incidence of end-stage renal disease during follow-up between the different clusters. Patients in Clusters 3-4 had worse renal survival than patients in Clusters 1-2. CONCLUSIONS: Our results confirm the main findings of the original cluster analysis and indicate that the observed, distinct pathogenic patterns are replicated in our cohort. Further investigations are necessary to analyse the distinct biological and pathogenic processes in these patient groups.

C4 nephritic factor in patients with immune-complex-mediated membranoproliferative glomerulonephritis and C3-glomerulopathy.

BACKGROUND: Acquired or genetic abnormalities of the complement alternative pathway are the primary cause of C3glomerulopathy(C3G) but may occur in immune-complex-mediated membranoproliferative glomerulonephritis (IC-MPGN) as well. Less is known about the presence and role of C4nephritic factor(C4NeF) which may stabilize the classical pathway C3-convertase. Our aim was to examine the presence of C4NeF and its connection with clinical features and with other pathogenic factors. RESULTS: One hunfe IC-MPGN/C3G patients were enrolled in the study. C4NeF activity was determined by hemolytic assay utilizing sensitized sheep erythrocytes. Seventeen patients were positive for C4NeF with lower prevalence of renal impairment and lower C4d level, and higher C3 nephritic factor (C3NeF) prevalence at time of diagnosis compared to C4NeF negative patients. Patients positive for both C3NeF and C4NeF had the lowest C3 levels and highest terminal pathway activation. End-stage renal disease did not develop in any of the C4NeF positive patients during follow-up period. Positivity to other complement autoantibodies (anti-C1q, anti-C3) was also linked to the presence of nephritic factors. Unsupervised, data-driven cluster analysis identified a group of patients with high prevalence of multiple complement autoantibodies, including C4NeF. CONCLUSIONS: In conclusion, C4NeF may be a possible cause of complement dysregulation in approximately 10-15% of IC-MPGN/C3G patients.

Is renal scintigraphy really a necessity in the routine diagnosis of congenital solitary kidney?

BACKGROUND: For a definitive diagnosis of congenital solitary kidney, renal scintigraphy is suggested as being the gold standard of ruling out ectopic functioning renal tissue, possibly missed by ultrasound. The aim of our study was to test ultrasonography precision in comparison with renal scintigraphy on a larger cohort of congenital solitary kidneys. METHODS: We performed a retrospective unicenter study of children with congenital solitary kidney with no contralateral tissue, who were treated in the period from 1980 to 2017. The findings in children who underwent both abdominopelvic ultrasound and nuclear renal scintigraphy were compared and the accuracy of ultrasound was assessed. RESULTS: 99 children met the inclusion criteria of congenital solitary kidney confirmed with abdominopelvic ultrasound and nuclear renal scintigraphy. The children were predominantly male (61.6%), and the congenital solitary kidney was largely right-sided (55.5%). In 97 cases (98%), ultrasound correctly predicted the absence of functional renal tissue on one side in the renal fossa or in an ectopic location (pelvis or ipsilateral side). The calculated accuracy of abdominopelvic ultrasound in diagnosing congenital solitary kidney was therefore 98%. CONCLUSIONS: Our findings confirm that abdominopelvic ultrasound alone is accurate enough to diagnose congenital solitary kidney. It gives enough information for consideration if further radiological evaluation is still needed.

Long-term renal outcome in children with OCRL mutations: retrospective analysis of a large international cohort.

Background: Lowe syndrome (LS) and Dent-2 disease (DD2) are disorders associated with mutations in the OCRL gene and characterized by progressive chronic kidney disease (CKD). Here, we aimed to investigate the long-term renal outcome and identify potential determinants of CKD and its progression in children with these tubulopathies. Methods: Retrospective analyses were conducted of clinical and genetic data in a cohort of 106 boys (LS: 88 and DD2: 18). For genotype-phenotype analysis, we grouped mutations according to their type and localization. To investigate progression of CKD we used survival analysis by Kaplan-Meier method using stage 3 CKD as the end-point. Results: Median estimated glomerular filtration rate (eGFR) was lower in the LS group compared with DD2 (58.8 versus 87.4 mL/min/1.73 m2, P < 0.01). CKD stage II-V was found in 82% of patients, of these 58% and 28% had moderate-to-severe CKD in LS and DD2, respectively. Three patients (3%), all with LS, developed stage 5 of CKD. Survival analysis showed that LS was also associated with a faster CKD progression than DD2 (P < 0.01). On multivariate analysis, eGFR was dependent only on age (b = -0.46, P < 0.001). Localization, but not type of mutations, tended to correlate with eGFR. There was also no significant association between presence of nephrocalcinosis, hypercalciuria, proteinuria and number of adverse clinical events and CKD. Conclusions: CKD is commonly found in children with OCRL mutations. CKD progression was strongly related to the underlying diagnosis but did not associate with clinical parameters, such as nephrocalcinosis or proteinuria.

Does Guidewire Exchange Influence Infection Rate Related to Catheters Used for Vascular Access in Children on Chronic Hemodialysis?

A central venous catheter (CVC) can either be inserted "de novo" or placed by guidewire exchange (GWE). From September 1998 to September 2015, 32 children (19 boys, 13 girls) were hemodialyzed in our unit by using a CVC. The mean age at CVC insertion was 12.6 ± 0.5 years. A total of 121 uncuffed catheters were placed, either "de novo" or by GWE in 64 (52.9%) and 57 (47.1%) cases, respectively. The most frequent cause for line revision was catheter dysfunction in 40/121 (33.1%) patients. The overall incidence of bacteremia was 1.5/1000 catheter-days. The incidence in newly inserted and GWE catheters was 1.4 and 1.7/1000 catheter-days, respectively. The difference did not reach statistical significance (P = 0.939). The infection rate correlated with patient age, and was higher in younger children (P = 0.006). GWE is an effective option of line revision, and did not influence the infection rate in our study.

Acute rheumatic fever outbreak in southern central European country.

A decline in the incidence of acute rheumatic fever (ARF) in developed countries over the past century can be attributed to the improved public hygiene and to widespread use of antibiotics. ARF seemed to be a rare disease in southern central European country, Slovenia, up to 2010 when we noticed an increase in the number of patients with ARF. In order to assess the current incidence of ARF, we performed a retrospective study of all patients with ARF treated at the University Children's Hospital Ljubljana from January 2008 until the end of December 2014. In a period of 7 years, 19 patients with ARF were identified. The estimated annual incidence of ARF during the study period was 1.25 cases per 100,000 children. Carditis was present in all patients, arthritis in 37 % and Sydenham chorea in 32 %. CONCLUSION: Recent ARF outbreak in Slovenia revealed that this disease is still present in southern central Europe with an estimated annual incidence of 1.25 cases per 100,000 children. Unrecognized or inadequately treated ARF could be the cause of acquired heart disease and must be even nowadays included among the differential diagnoses in a febrile child with arthritis, heart murmur or movement disorder. What is Known: • Acute rheumatic fever (ARF) is diagnosed based on the major and minor Jones Criteria. • A decline in the incidence of ARF in developed countries over the past century can be attributed to the improved public hygiene and to widespread use of antibiotics. What is New: • In the last decade, an increase in the incidence of ARF was observed in Slovenia which has a central European geographic position. • Our paper highlights the importance of including ARF in the differential diagnosis of a febrile child with arthritis/arthralgia and/or heart murmur and/or acute chorea.

Chronic Hemodialysis in Small Children.

When peritoneal dialysis is inapplicable, chronic hemodialysis (HD) becomes the only available treatment option in small children. Due to small patient size, central venous catheters (CVC) are mainly used for vascular access. Over the past 4 years, four children weighing less than 15 kg received chronic HD in our unit. A total of 848 dialysis sessions were performed. Altogether, 21 catheters were inserted. In all but one occasion, uncuffed catheters were used. Catheter revision was performed 15 times during the study period, either due to infection or catheter malfunction. The median number of catheter revisions and the median line survival was 3.0/patient-year and 53 days (range; 6-373 days), respectively. There were 14 episodes of catheter related infections requiring 11 CVC revisions (78.6%). The median rate of line infections was 2.8/patient-year. Chronic HD in small children is demanding and labor intensive. Issues pertain mainly to CVCs and limit its long-term use.

Fate of Central Venous Catheters Used for Acute Extracorporeal Treatment in Critically Ill Pediatric Patients: A Single Center Experience.

Renal replacement treatment (RRT) is required in severe acute kidney injury, and a functioning central venous catheter (CVC) is crucial. Twenty-eight children younger than 16 years have been treated at the University Medical Centre Ljubljana between 2003 and 2012 with either acute hemodialysis (HD) and/or plasma exchange (PE), and were included in our study. The age of the patients ranged from 2 days to 14.1 years. Sixty-six CVCs were inserted (52% de novo, 48% guide wire). The sites of insertion were the jugular vein in 20% and the femoral vein in 80%. Catheters were in function from 1 day to 27 days. The most common cause for CVC removal or exchange was catheter dysfunction (50%). CVCs were mostly inserted in the femoral vein, which is the preferred site of insertion in acute HD/PE because of the smaller number of complications.