Immunosuppressive Therapy of Antibody-Mediated aHUS and TTP.

The recent classification of pediatric thrombotic microangiopathies (TMA) takes into consideration mechanisms of disease for guidance to targeted therapies. We present our experience with seven patients with antibody mediated atypical hemolytic uremic syndrome (aHUS) and thrombotic thrombocytopenic purpura (TTP). Five children had aHUS with antibodies against complement factor H (CFH-ab) and two with TTP with antibodies against metalloproteinase ADAMTS13. In the aHUS cases diagnosed and treated before the eculizumab era, CFH-ab was detected using the ELISA assay. Mutational analysis of selected complement genes was performed. TTP was diagnosed if, in addition to microangiopathic hemolytic anemia and thrombocytopenia, ischemic organ involvement and severe deficiency in ADAMTS13 activity were present. Treatment protocol consisted of plasma exchanges (PE) and steroid pulses, followed by the combination of cyclophosphamide and rituximab to achieve long-term immunosuppression. Four patients with CFH-ab and the TTP patients with ADAMTS13 antibodies came into sustained remission. After a median follow-up of 11.7 (range 7.7-12.9) years without maintenance therapy, no disease recurrence was observed; nevertheless, six patients, two had hypertension and two had proteinuria as a late consequence. One patient, with late diagnosis of CFH-ab and additional genetic risk factors who was treated only with PE and plasma substitution, reached end-stage renal disease and was later successfully transplanted using eculizumab prophylaxis. In the cases of antibody-mediated TMAs, PE and early immunosuppressive treatment may result in sustained remission with preserved kidney function. Further data are needed to establish optimal treatment of anti-FH antibody-associated HUS.

Subclinical cardiac dysfunction in pediatric kidney transplant recipients identified by speckle-tracking echocardiography.

BACKGROUND: Kidney transplantation (KTx) improves prognosis in children with kidney failure; still, these patients are prone to cardiovascular damage due to multiple risk factors. Our aim was to assess myocardial structure and function in pediatric KTx by conventional and speckle-tracking echocardiography (STE) in association with established cardiovascular risk factors. METHODS: Forty-two KTx and 39 healthy age- and gender-matched children were evaluated. KTx recipients were further categorized according to the control of hypertension assessed by 24-h ambulatory blood pressure monitoring (ABPM). Subjects underwent pulse wave velocity (PWV) measurement, conventional echocardiography, and 2-dimensional STE. Left and right ventricular (LV, RV) global longitudinal strain (GLS), and LV circumferential strain (GCS) were measured. Glomerular filtration rate (eGFR) was calculated according to the Schwartz formula. RESULTS: KTx patients had increased blood pressure and arterial stiffness. LV ejection fraction (EF) was preserved along with elevated LV mass index (LVMi) while LVGLS was significantly lower, whereas LVGCS and RVGLS were increased in KTx. Uncontrolled hypertensives had lower LVGLS compared to those with controlled hypertension. Using multiple forward stepwise regression analysis, 24-h SBP and relative wall thickness (RWT) were independent determinants of LVMi, whereas antihypertensive therapy, eGFR, and HOMA-IR were independent determinants of LVGLS. CONCLUSIONS: Cardiac morphology and function show distinct changes after KTx. Along with comparable ventricular volumes, LV hypertrophy and subclinical myocardial dysfunction are present. Control of hypertension and kidney graft function are major factors of LV performance. STE may be useful to reveal early myocardial dysfunction in pediatric KTx. A higher resolution version of the Graphical abstract is available as Supplementary information.

Cardiovascular Risk Assessment in Pediatric Liver Transplant Patients.

OBJECTIVES: Cardiovascular (CV) diseases play a leading role in the mortality of adult liver transplant (LT) recipients. However, data regarding CV risk factors in children after LT remain sparse. The present study assessed the presence of CV risk factors and signs of CV impairment in LT children. METHODS: A total of 42 LT recipients (21 men, age 9.93 ±â€Š3.57 years) were studied. Body composition [body mass index standard deviation score, percentage of body fat (by bioimpedance analysis)], lipid profiles, glycemic control, blood pressure, and arterial stiffness [assessed by aortic pulse wave velocity (PWV)] were evaluated. The effect of different treatment modalities [tacrolimus (TAC) (n = 30) or cyclosporine (CyA) (n = 11)] was also analyzed. RESULTS: Almost 18% of children were overweight or obese. Patients on TAC had a significantly higher body fat mass and percentage of body fat compared with the CyA group (P < 0.02). Borderline to high lipid values were present in 40% of patients. Children on CyA had higher serum cholesterol levels compared to TAC (P < 0.004). Nineteen percent of patients had hypertension. Half of the patients had glomerular filtration rate values <90 mL/min/1.73 m, whereas PWV values were above the 95th percentile in 12%. CONCLUSIONS: Increased body fat, chronic kidney disease, high lipid content, hypertension, and increased arterial stiffness are already present and are in part related to the type of immunosuppression regimen in LT children >5 years following transplantation. Long-term follow-up is needed to evaluate their impact on CV health and survival.

Cardiac Magnetic Resonance Imaging of the Myocardium in Chronic Kidney Disease.

Early stages of chronic kidney disease (CKD) are often underdiagnosed, while their deleterious effects on the cardiovascular (CV) system are already at work. Thus, the assessment of early CV damage is of crucial importance in preventing major CV events. Myocardial fibrosis is one of the major consequences of progressive CKD, as it may lead to reentry arrhythmias and long-term myocardial dysfunction predisposing to sudden death and/or congestive heart failure. Subclinical myocardial fibrosis, with a potential key role in the development of uraemic cardiac disease, can be measured and characterised by appropriate cardiac magnetic resonance (CMR) techniques. Fibrosis detection was initially based on the contrast agent gadolinium, due to the superiority in sensitivity and accuracy of contrast-based methods in fibrosis assessment relative to native techniques. However, the severe consequences of gadolinium administration in uraemia (nephrogenic systemic fibrosis) have forced practitioners to re-evaluate the methodology. In the present overview, we review the possible contrast-based and contrast agent-free CMR techniques, including native T1 relaxation time, extracellular volume and global longitudinal strain measurement. The review also summarises their potential clinical relevance in CKD patients based on recently published studies.

Bone metabolism and arterial stiffness after renal transplantation.

BACKGROUND/AIMS: To assess the relationship between bone and vascular disease and its changes over time after renal transplantation. Metabolic bone disease (MBD) is common in chronic kidney disease (CKD) and is associated with cardiovascular (CV) disease. Following transplantation (Tx), improvement in CV disease has been reported; however, data regarding changes in bone disease remain controversial. METHODS: Bone turnover and arterial stiffness (pulse wave velocity (PWV)) were assessed in 47 Tx patients (38 (3-191) months after Tx). RESULTS: Bone alkaline phosphatase (BALP), osteocalcin (OC) and beta-crosslaps were significantly higher in Tx patients, and decreased significantly after one year. There was a negative correlation between BALP, OC and steroid administered (r = -0.35; r = -0.36 respectively). PWV increased in the Tx group (1.15 SD). In patients with a follow up of <24 months, PWV was correlated with BALP and beta-crosslaps (r=0.53; r = 0.69 respectively) while in the ≥24 months group, PWV was correlated with cholesterol (r=0.38). CONCLUSIONS: Increased bone turnover and arterial stiffness are present following kidney transplantation. While bone turnover decreases with time, arterial stiffness correlates initially with bone turnover, after which the influence of cholesterol becomes significant. Non-invasive estimation of bone metabolism and arterial stiffness may help to assess CKD-MBD following renal transplantation.

Extracellular Vesicles of Patients on Peritoneal Dialysis Inhibit the TGF-ß- and PDGF-B-Mediated Fibrotic Processes.

Among patients on peritoneal dialysis (PD), 50-80% will develop peritoneal fibrosis, and 0.5-4.4% will develop life-threatening encapsulating peritoneal sclerosis (EPS). Here, we investigated the role of extracellular vesicles (EVs) on the TGF-ß- and PDGF-B-driven processes of peritoneal fibrosis. EVs were isolated from the peritoneal dialysis effluent (PDE) of children receiving continuous ambulatory PD. The impact of PDE-EVs on the epithelial-mesenchymal transition (EMT) and collagen production of the peritoneal mesothelial cells and fibroblasts were investigated in vitro and in vivo in the chlorhexidine digluconate (CG)-induced mice model of peritoneal fibrosis. PDE-EVs showed spherical morphology in the 100 nm size range, and their spectral features, CD63, and annexin positivity were characteristic of EVs. PDE-EVs penetrated into the peritoneal mesothelial cells and fibroblasts and reduced their PDE- or PDGF-B-induced proliferation. Furthermore, PDE-EVs inhibited the PDE- or TGF-ß-induced EMT and collagen production of the investigated cell types. PDE-EVs contributed to the mesothelial layer integrity and decreased the submesothelial thickening of CG-treated mice. We demonstrated that PDE-EVs significantly inhibit the PDGF-B- or TGF-ß-induced fibrotic processes in vitro and in vivo, suggesting that EVs may contribute to new therapeutic strategies to treat peritoneal fibrosis and other fibroproliferative diseases.

The role of complement in Streptococcus pneumoniae-associated haemolytic uraemic syndrome.

BACKGROUND: Atypical forms of haemolytic uraemic syndrome (aHUS) include HUS caused by defects in the regulation of alternative complement pathway and HUS linked to neuraminidase-producing pathogens, such as Streptococcus pneumoniae. Increasing data support a pathogenic role of neuraminidase in the development of S. pneumoniae-associated haemolytic uraemic syndrome (SP-HUS), but the role of complement has never been clarified in detail. Therefore, we aimed to investigate whether the pathologic complement profile and genetic risk factors of aHUS are present in patients with SP-HUS. METHODS: Enrolling five patients with SP-HUS classical and alternative pathway activity, besides C3, C4, factors H, B, I and anti-factor H autoantibody levels were determined. The coding regions of CFH, CFI, CD46 (MCP), THBD, C3 and CFB genes were sequenced and the copy number of CFI, CD46, CFH and related genes were also analyzed. RESULTS: We found that in the acute phase samples of SP-HUS patients, complement components C4, C3 and activity of the classical and alternative pathways were decreased, indicating severe activation and complement consumption, but most of these alterations normalized later in remission. Three of the patients carried mutations and risk haplotypes in complement-mediated aHUS associated genes. The identified mutations include a previously published CFI variant (P50A) and two novel ones in CFH (R1149X) and THBD (T44I) genes. CONCLUSIONS: Our results suggest that severe complement dysregulation and consumption accompany the progress of invasive pneumococcal disease (IPD)-associated SP-HUS and genetic variations of complement genes may contribute to the development of this complication in a proportion of the affected patients.

Prevalence and predictors of the sub-target Hb level in children on dialysis.

BACKGROUND: Anaemia is a common and potentially treatable co-morbidity of end-stage renal disease. We aimed to determine the prevalence of the sub-target haemoglobin (Hb) level among European children on dialysis and to identify factors associated with a low Hb level. METHODS: From the European Society for Paediatric Nephrology (ESPN)/European Renal Association-European Dialysis Transplant Association (ERA-EDTA) registry, data were available on 2351 children between 1 month and 18 years of age, totalling 5546 measurements from 19 countries. RESULTS: The mean Hb level was 10.8 g/dL (5th-95th percentiles, 7.4-13.9). Among those above 2 years of age, the mean Hb level was 10.9 g/dL (11.4% below 8.5 g/dL), while it was 10.3 g/dL among those below 2 years (11.2% below 8.0 g/dL). A total of 91.2% of the patients were on an erythropoiesis-stimulating agent (ESA). Hb levels increased with age and were higher in peritoneal dialysis compared with haemodialysis patients. Patients with congenital anomalies of the kidney and urinary tract showed the highest Hb levels, and those with cystic kidney diseases or metabolic disorders the lowest ones. Ferritin levels between 25 and 50 ng/mL were associated with the highest Hb levels. We found a weak inverse association between parathyroid hormone (PTH) and Hb. Whereas standardized blood pressure (BP) was not elevated in patients with above-target Hb, elevated systolic BP z-score was noted in those with sub-target Hb levels. CONCLUSIONS: Sub-target Hb levels remain common in children on dialysis, in spite of virtually all children being treated with ESA; although we cannot exclude under-dosing. Optimal ferritin levels seemed to be slightly lower in children (25-50 ng/mL) than those in adults. Other risk factors for sub-target Hb are dialysis modality and a high PTH level.

Cardiac magnetic resonance imaging in children with chronic kidney disease and renal transplantation.

CV disease is the major cause of death in patients with CKD. Recently, CMR imaging emerges as a complementary method providing advantages in cardiac assessment; however, data on CMR in pediatric CKD are scarce. We performed CMR in 15 children: two with CKD, six on peritoneal dialysis, seven on hemodialysis, and in 18 children 5.1 (0.4-15.4) yr after kidney Tx. Eight children underwent CMR six months before and after Tx. Results are presented as mean z score ± SD. LV EF was higher and in the normal range in Tx patients compared with CKD (-0.3 ± 1 vs. -2.1 ± 1.6, respectively, p < 0.05), whereas RV EF was similar (-0.9 ± 1.4 vs. -0.9 ± 1.8, p = n.s.). End-diastolic and end-systolic LV volume index (0 ± 1.7 vs. 2.1 ± 3.1; 0.2 ± 1.2 vs. 3.1 ± 3.7, both p < 0.05) and LV mass index (1.4 ± 1.5 vs. 3.4 ± 2.9, p < 0.05) were lower in Tx children. All parameters improved in the eight children after Tx. In conclusion, our CMR analysis suggests marked improvement of cardiac function and morphology in children after kidney Tx. CMR might be an appropriate complementary method for measuring detailed cardiac status in children with CKD.

Assessment of Quality of Life in Children With Pulmonary Hypertension Using Parent and Self-report Questionnaires.

Pulmonary arterial hypertension (PAH) is a progressive disease characterized by elevation of pulmonary vascular resistance and right ventricular failure. By using advanced therapies to reduce mortality, clinicians focus on improving functional status and quality of life (QOL). The aim of our study was to assess health-related QOL of pediatric patients with PAH. Parents of all children (aged 2-18 years) and patients aged 5-18 years with an appropriate level of intellectual development completed general and cardiac-specific validated surveys (Pediatric Quality of Life Inventory 4.0 and Pediatric Quality of Life Inventory 3.0, respectively). Demographic and clinical information was collected to grade disease severity. Twenty-five children were enrolled, yielding 25 parent reports and 15 patient self-reports. The PAH group had significantly lower scores than healthy children in all domains. Patients with World Health Organization Functional Class I had significantly higher parent proxy scores in School Functioning (P = .029) and in Heart Problems and Symptoms domain (P = .014) Patients with tricuspid annular plane systolic excursion below -2 z score showed impairment in each parent proxy general domain and in the Cognitive Problems score of the Cardiac module (P = .006). In conclusion the QOL of patients with PAH was impaired in every domain compared with healthy children. Patients with reduced right ventricle systolic function showed significantly lower QOL in all core domains. These results point to the need for psychosocial rehabilitation in addition to somatic care to improve the QOL in this severely ill population.

Prognostic Value of Early Risk Stratification in Pediatric Pulmonary Arterial Hypertension.

BACKGROUND: Pulmonary arterial hypertension (PAH) is a life-threatening disease with risk stratification-based treatment strategy in adults. Although the risk factors have been studied individually in children, effective risk stratification is still lacking. We have tested the prognostic accuracy of pediatric PAH risk factors in our patient group. PATIENTS AND METHODS: Records of 58 PAH patients treated between 1995 and 2019 were reviewed retrospectively. Median age at diagnosis was 4.2 years (range, 0.1-16.1 years), and follow-up was 5.4 years (range, 0.01-24.1 years). Data collected at diagnosis were demographics, World Health Organization functional class, evidence of right ventricular failure, and parameters of echocardiography and cardiac catheterization. RESULTS: Mortality was 29% and 33% reached the composite endpoint. Patients with idiopathic PAH (n = 12) had increased risk of mortality compared with the congenital heart disease-associated PAH group (n = 32) (P = .0024). Neither the initial World Health Organization functional class staging nor the echocardiographic parameters significantly predicted the prognosis. The number of risk factors had no significant prognostic value either. In contrast, patients with higher pulmonary vascular resistance index (PVRI) had significantly increased risk (each 10 Wood units ⋅ m2 increase in PVRI being associated with 49.1% higher hazard, P = .0048). CONCLUSIONS: Survival analysis showed that PAH etiology might be an important determinant in pediatric PAH risk stratification. We confirmed that PVRI has predictive value in prognostic assessment. We could not establish the prognostic value of nonweighted single risk factors or their combination to predict pediatric PAH outcome due to the low sample size, but these results indicate that such studies are warranted.

Follow-Up of Blood Pressure, Arterial Stiffness, and GFR in Pediatric Kidney Transplant Recipients.

Pediatric renal transplant recipients (RTx) were studied for longitudinal changes in blood pressure (BP), arterial stiffness by pulse wave velocity (PWV), and graft function. Patients and Methods: 52 RTx patients (22 males) were included; office BP (OBP) and 24 h BP monitoring (ABPM) as well as PWV were assessed together with glycemic and lipid parameters and glomerular filtration rate (GFR) at 2.4[1.0-4.7] (T1) and 9.3[6.3-11.8] years (T2) after transplantation (median [range]). Results: Hypertension was present in 67 and 75% of patients at T1 and T2, respectively. Controlled hypertension was documented in 37 and 44% by OBP and 40 and 43% by ABPM. Nocturnal hypertension was present in 35 and 30% at T1 and T2; 24 and 32% of the patients had masked hypertension, while white coat hypertension was present in 16 and 21% at T1 and T2, respectively. Blood pressure by ABPM correlated significantly with GFR and PWV at T2, while PWV also correlated significantly with T2 cholesterol levels. Patients with uncontrolled hypertension by ABPM had a significant decrease in GFR, although not significant with OBP. Anemia and increased HOMAi were present in ~20% of patients at T1 and T2. Conclusion: Pediatric RTx patients harbor risk factors that may affect their cardiovascular health. While we were unable to predict the evolution of renal function based on PWV and ABPM at T1, these risk factors correlated closely with GFR at follow-up suggesting that control of hypertension may have an impact on the evolution of GFR.

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.

Distance measurement for pulse wave velocity estimation in pediatric age: Comparison with intra-arterial path length.

BACKGROUND AND AIMS: Central pulse wave velocity (PWV) is a marker of arterial stiffness and is calculated by dividing the pulse wave travel distance by the transit time. However, there is no consensus as to the ideal distance measurement in children. The aim of our study was to identify the more reliable method to assess the distance measurement in the pediatric age. METHODS: Carotid-femoral PWV was measured by applanation tonometry in 988 healthy children aged 6.5-19.9 years. Two different surface distances were assessed: the subtraction method, representing the distance from the suprasternal notch to the femoral artery minus the distance from the carotid artery to the suprasternal notch, and the direct method, consisting of 80% of the distance from the carotid artery to the femoral artery. Both these methods were compared with the actual path length determined by magnetic resonance imaging (MRI) in 31 children. RESULTS: Subtraction and direct methods were significantly correlated in patients aged <14 years and the corresponding PWV values showed a good agreement. In children aged ≥14 years, a significant difference between the two methods was found: subtraction - direct distance = -45 ± 28 mm, with a significant difference in the resulting PWV values = -0.57 ± 0.35 m/s (p < 0.0001). This result was confirmed by MRI, showing a 10% overestimation in distance measurement by the direct method in subjects aged ≥14 years, resulting in a significantly higher PWV. CONCLUSIONS: These data suggest a greater reliability of the subtractive method of distance measurement compared to the direct method in children.

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.

Renal ultrafiltration changes induced by focused US.

PURPOSE: To determine if focused ultrasonography (US) combined with a diagnostic microbubble-based US contrast agent can be used to modulate glomerular ultrafiltration and size selectivity. MATERIALS AND METHODS: The experiments were approved by the animal care committee. The left kidney of 17 healthy rabbits was sonicated by using a 260-kHz focused US transducer in the presence of a microbubble-based US contrast agent. The right kidney served as the control. Three acoustic power levels were applied: 0.4 W (six rabbits), 0.9 W (six rabbits), and 1.7 W (five rabbits). Three rabbits were not treated with focused US and served as control animals. The authors evaluated changes in glomerular size selectivity by measuring the clearance rates of 3000- and 70,000-Da fluorescence-neutral dextrans. The creatinine clearance was calculated for estimation of the glomerular filtration rate. The urinary protein-creatinine ratio was monitored during the experiments. The authors assessed tubular function by evaluating the fractional sodium excretion, tubular reabsorption of phosphate, and gamma-glutamyltransferase-creatinine ratio. Whole-kidney histologic analysis was performed. For each measurement, the values obtained before and after sonication were compared by using the paired t test. RESULTS: Significant (P < .05) increases in the relative (ratio of treated kidney value/nontreated kidney value) clearance of small- and large-molecule agents and the urine flow rates that resulted from the focused US treatments were observed. Overall, 1.23-, 1.23-, 1.61-, and 1.47-fold enhancement of creatinine clearance, 3000-Da dextran clearance, 70 000-Da dextran clearance, and urine flow rate, respectively, were observed. Focal tubular hemorrhage and transient functional tubular alterations were observed at only the highest (1.7-W) acoustic power level tested. CONCLUSION: Glomerular ultrafiltration and size selectivity can be temporarily modified with simultaneous application of US and microbubbles. This method could offer new opportunities for treatment of renal disease.

Pulse wave velocity in children following renal transplantation.

BACKGROUND: Arterial stiffness (ASt) increases with age, a process accelerated by uraemia and reversed by transplantation (Tx). Increased ASt results in an elevated pulse wave velocity (PWV). METHODS: To compare the PWV of Tx patients (n = 25, age = 15.1/95% CI = 13.5-16.7/year) and healthy controls, three control groups were formed: matched for age (A), for height and weight (H/W) and for age and height (A/H), respectively. To avoid bias from the growth deficit of Tx, firstly Z-scores of PWV were calculated (PWV-Z). Second, the PWV/height (PWV/h) ratio was assessed. Pre-Tx serum Ca, P, PTH and the cumulative dose of calcitriol (cCTL) were also analysed. Finally, Tx patients were compared to ESRD patients (n = 11). PWV was measured by applanation tonometry. RESULTS: Tx were smaller than A and older than H/W. The PWV of Tx differed only from H/W and A/H. PWV-Z and PWV/h of Tx were increased compared to all control groups. They correlated with the CaxP and cCTL before Tx and were independent of age. Patients with creatinine clearance >90 ml/min/1.73 m(2) or <1 year on dialysis had lower PWV-Z and PWV/h than ESRD. CONCLUSION: Controls that matched for both age and height should be used to assess PWV in children with growth failure. PWV-Z is a universal age-independent parameter of PWV in cases of growth retardation; PWV/h is a simple alternative of PWV-Z. CaxP and cCTL are major determinants of ASt after Tx. PWV may be reduced after Tx suggesting that the uraemia-induced cardiovascular changes might be reversible.