Publications by authors named "Evgenia Preka"

7 Publications

  • Page 1 of 1

Update on the creation and maintenance of arteriovenous fistulas for haemodialysis in children.

Pediatr Nephrol 2020 Oct 15. Epub 2020 Oct 15.

"Mitera" Children's Hospital, Maroussi, Athens, Greece.

Arteriovenous fistulas (AVFs) are widely used for haemodialysis (HD) in adults with stage 5 chronic kidney disease (CKD 5) and are generally considered the best form of vascular access (VA). The 'Fistula First' initiative in 2003 helped to change the culture of VA in adults. However, this cultural change has not yet been adopted in children despite the fact that a functioning AVF is associated with lower complication rates and longer access survival than a central venous line (CVL). For children with CKD 5, especially when kidney failure starts early in life, there is a risk that all VA options will be exhausted. Therefore, it is essential to develop long-term strategies for optimal VA creation and maintenance. Whilst AVFs are the preferred VA in the paediatric population on chronic HD, they may not be suitable for every child. Recent guidelines and observational data in the paediatric CKD 5 population recommend switching from a 'Catheter First' to 'Catheter Last' approach. In this review, recent evidence is summarized in order to promote change in current practices.
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http://dx.doi.org/10.1007/s00467-020-04746-6DOI Listing
October 2020

Cell-Free DNA in Pediatric Solid Organ Transplantation Using a New Detection Method of Separating Donor-Derived from Recipient Cell-Free DNA.

Clin Chem 2020 Oct;66(10):1300-1309

Department of Paediatric Nephrology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK.

Background: The use of cell-free DNA (cfDNA) as a noninvasive biomarker to detect allograft damage is expanding rapidly. However, quantifying the low fraction of donor-derived cfDNA (ddcfDNA) is challenging and requires a highly sensitive technique. ddcfDNA detection through unique donor single nucleotide polymorphisms (SNPs) is a recent new approach, however there are limited data in pediatric solid organ transplant (SOT) recipients.

Methods: We developed an assay using a combination of 61 SNPs to quantify the ddcfDNA accurately using a custom R script to model for both the patient and donor genotypes requiring only a single sample from the allograft recipient. Performance of the assay was validated using genomic DNA (gDNA), cfDNA and donor samples where available.

Results: The R "genotype-free" method gave results comparable to when using the known donor genotype. applicable to both related and unrelated pairs and can reliably measure ddcfDNA (limit of blank, below 0.12%; limit of detection, above 0.25%; limit of quantification 0.5% resulting in 84% accuracy). 159 pediatric SOT recipients (kidney, heart, and lung) were tested without the need for donor genotyping. Serial sampling was obtained from 82 patients.

Conclusion: We have developed and validated a new assay to measure the fraction of ddcfDNA in the plasma of pediatric SOT recipients. Our method can be applicable in any donor-recipient pair without the need for donor genotyping and can provide results in 48 h at a low cost. Additional prospective studies are required to demonstrate its clinical validity in a large cohort of pediatric SOT recipients.
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http://dx.doi.org/10.1093/clinchem/hvaa173DOI Listing
October 2020

Free 25-hydroxyvitamin-D concentrations are lower in children with renal transplant compared with chronic kidney disease.

Pediatr Nephrol 2020 06 22;35(6):1069-1079. Epub 2020 Jan 22.

Renal Unit, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK.

Background: Total serum 25-hydroxyvitamin D [25(OH)D] is considered the best marker of vitamin D status and used routinely in clinical practice. However, 25(OH)D is predominantly bound to vitamin D-binding protein (VDBP), and it has been reported that the free-25(OH)D and 25(OH)D loosely bound to albumin fraction correlates better with clinical outcomes.

Methods: We assessed total-25(OH)D, measured free-25(OH)D, and calculated free-25(OH)D and their relationship with VDBP and biomarkers of mineral metabolism in 61 children (22 CKD 2-3, 18 dialysis, and 21 post-transplant).

Results: Total-25(OH)D concentrations were comparable across the three groups (p = 0.09), but free- and bioavailable-25(OH)D (free- and albumin-25(OH)D) were significantly lower in the transplant group (both: p = 0.01). Compared to CKD and dialysis patients, the transplant group had significantly higher VDBP concentrations (p = 0.03). In all three groups, total-25(OH)D concentrations were positively associated with measured free-, calculated free-, and bioavailable-25(OH)D. Multivariable regression analysis showed that total-25(OH)D was the only predictor of measured free-25(OH)D concentrations in the dialysis group (β = 0.9; R = 90%). In the transplant group, measured free-25(OH)D concentrations were predicted by both total-25(OH)D and VDBP concentrations (β = 0.6, - 0.6, respectively; R = 80%). Correlations between parathyroid hormone with total-25(OH)D and measured and calculated free-25(OH)D were only observed in the transplant group (all: p < 0.001).

Conclusions: In transplanted patients, VDBP concentrations were significantly higher compared to CKD and dialysis patients, and consequently, free-25(OH)D concentrations were lower, despite a comparable total-25(OH)D concentration. We suggest that free-25(OH)D measures may be required in children with CKD, dialysis, and transplant, with further research required to understand its association with markers of mineral metabolism.
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http://dx.doi.org/10.1007/s00467-020-04472-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7184055PMC
June 2020

Think Twice before Postponing Chronic Dialysis in Children.

J Am Soc Nephrol 2019 12 24;30(12):2473-2474. Epub 2019 Oct 24.

Department of Medical Informatics, Amsterdam Public Health Research Institute, European Society of Paediatric Nephrology/European Renal Association and European Dialysis and Transplant Association (ESPN/ERA-EDTA) Registry, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands; and.

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http://dx.doi.org/10.1681/ASN.2019090895DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6900805PMC
December 2019

Should we abandon GFR in the decision to initiate chronic dialysis?

Pediatr Nephrol 2020 09 15;35(9):1593-1600. Epub 2019 Aug 15.

Department of Paediatric Nephrology, Great Ormond Street Hospital for Children NHS foundation Trust, Great Ormond Street, London, WC1N 3JH, UK.

The best time to start chronic dialysis during the course of CKD stage 5 is controversial. The first randomised control trial of dialysis initiation either in early or late CKD stage 5 in adults (IDEAL study), and 3 studies from the two largest paediatric registries, the U.S. Renal Data System (USRDS) and the European Society of Paediatric Nephrology (ESPN) Registry, have now provided us with evidence to guide us in this important decision-making process. The message 'no benefit from early start of dialysis' is the conclusion from all four studies. However, what are the limitations of these studies? Can GFR be assessed at CKD stages 4 and 5? What are the factors used to assess the benefit of early or late start? These issues are discussed in this review.
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http://dx.doi.org/10.1007/s00467-019-04333-4DOI Listing
September 2020

Association between timing of dialysis initiation and clinical outcomes in the paediatric population: an ESPN/ERA-EDTA registry study.

Nephrol Dial Transplant 2019 11;34(11):1932-1940

Department of Pediatric Nephrology, Gazi University, Ankara, Turkey.

Background: There is no consensus regarding the timing of dialysis therapy initiation for end-stage kidney disease (ESKD) in children. As studies investigating the association between timing of dialysis initiation and clinical outcomes are lacking, we aimed to study this relationship in a cohort of European children who started maintenance dialysis treatment.

Methods: We used data on 2963 children from 21 different countries included in the European Society of Pediatric Nephrology/European Renal Association-European Dialysis and Transplant Association Registry who started renal replacement therapy before 18 years of age between 2000 and 2014. We compared two groups according to the estimated glomerular filtration rate (eGFR) at start: eGFR ≥8 mL/min/1.73 m2 (early starters) and eGFR <8 mL/min/1.73 m2 (late starters). The primary outcomes were patient survival and access to transplantation. Secondary outcomes were growth and cardiovascular risk factors. Sensitivity analyses were performed to account for selection- and lead time-bias.

Results: The median eGFR at the start of dialysis was 6.1 for late versus 10.5 mL/min/1.73 m2 for early starters. Early starters were older [median: 11.0, interquartile range (IQR): 5.7-14.5 versus 9.4, IQR: 2.6-14.1 years]. There were no differences observed between the two groups in mortality and access to transplantation at 1, 2 and 5 years of follow-up. One-year evolution of height standard deviation scores was similar among the groups, whereas hypertension was more prevalent among late initiators. Sensitivity analyses resulted in similar findings.

Conclusions: We found no evidence for a clinically relevant benefit of early start of dialysis in children with ESKD. Presence of cardiovascular risk factors, such as high blood pressure, should be taken into account when deciding to initiate or postpone dialysis in children with ESKD, as this affects the survival.
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http://dx.doi.org/10.1093/ndt/gfz069DOI Listing
November 2019

The interplay between bone and vessels in pediatric CKD: lessons from a single-center study.

Pediatr Nephrol 2018 09 5;33(9):1565-1575. Epub 2018 Jun 5.

Centre de Référence des Maladies Rénales Rares, Centre de Référence des Maladies Rares du Calcium et du Phosphore, Hôpital Femme Mère Enfant, Boulevard Pinel, 69677, Bron, France.

Objective: Mineral and bone disorders associated to chronic kidney disease (CKD-MBD) are a daily challenge for pediatric nephrologists, with a significant risk of long-term bone and vascular comorbidities.

Methods: This single-center study is a prospective transversal evaluation of pediatric CKD patients of our center, part of the European 4C study. In addition to clinical and biochemical data, vascular and bone evaluation was performed: 24-h blood pressure assessment, carotid intima-media thickness (cIMT), pulse wave velocity (PWV), and high-resolution peripheral quantitative computed tomography (HR-pQCT) at the ultra-distal tibia. Results are presented as median (range).

Results: At a median age of 12.9 years (10.2-17.9), SDS height of - 1.0 (- 3.3-1.2) and estimated glomerular filtration rate (eGFR) of 33 mL/min/1.73m (11-72), 32 patients (8 girls) were evaluated. Median calcium, phosphate, parathyroid hormone (PTH), and 25 OHD3 levels were 2.44 mmol/L (2.24-2.78), 1.43 mmol/L (1.0-2.7), 80 pg/mL (9-359), and 70 nmol/L (32-116), respectively. Bivariate Spearman and backward multivariable analyses showed that calcium and bone trabecular thickness (Tb.Th), were positively associated with diastolic and mean arterial blood pressure (both for the 24 h, day and night assessment), whereas PTH and vitamin D did not predict blood pressure.

Conclusions: We show that the greater the serum levels of calcium, the greater the (diastolic and mean) blood pressure; moreover, the greater the Tb. Th, the greater the (diastolic and mean) blood pressure. The role of calcium supplements to explain such findings in early pediatric CKD can be discussed.
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http://dx.doi.org/10.1007/s00467-018-3978-3DOI Listing
September 2018