Giovanna Leozappa

A ten-year experience of Brescia-Cimino arteriovenous fistula in children: Technical evolution and refinements

PURPOSE The arteriovenous fistula (AVF) of Brescia-Cimino fulfills nearly all of the criteria for an optimal access for chronic hemodialysis, such as long-term patency rate, low complication rate, and respect of vascular morphologic features. Alternative dialytic methods (i.e., external shunts and vascular grafts) cannot easily be applied to pediatric patients, and in addition, these methods are responsible for higher complication rates. METHODS From January 1985 to December 1994, 112 Brescia-Cimino AVFs were performed in 90 children (average age, 5.5 years; range, 5 months to 18 years). The average weight of the children was 28 kg (range, 6.5 to 54 kg); 16% of AVFs were performed in children who were less than 5 years old, and 18% in children who were less than 15 kg in body weight. RESULTS Chronic renal failure was caused by a nephropathy in 53 cases (14 with a nephrotic syndrome), and 37 cases had a uropathy. In all cases a phlebography was performed before the microsurgical treatment. Since 1994 an inflatable tourniquet has been placed on the selected upper arm because of an optimal exsanguination of the operating field. The primary patency rate was obtained in all but six of the children; 35% of AVFs had either immediate or late complications. Thrombosis was the most frequent complication that we observed. In comparison with 79% of late thrombosis, 60% of early thrombosis was cured. Of the 80 AVFs, 63.5% with a 4-year follow-up are still patent. CONCLUSION We emphasize the following two conclusions: first, microsurgery is essential to create AVFs with good results in children as well as in adult patients; and second, the results improved after the adoption of an upper-arm exsanguination and ischemia (pressure range, 400 mm Hg to 600 mm Hg) that avoided spasm of the vessels with a final 35% reduction in surgical time.

Growth in Very Young Children Undergoing Chronic Peritoneal Dialysis

Very young children with chronic kidney disease often have difficulty maintaining adequate nutrition, which contributes to the high prevalence of short stature in this population. Characteristics of the dialysis prescription and supplemental feeding via a nasogastric (NG) tube or gastrostomy may improve growth, but this is not well understood. Here, we analyzed data from 153 children in 18 countries who commenced chronic peritoneal dialysis at <24 months of age. From diagnosis to last observation, 57 patients were fed on demand, 54 by NG tube, and 10 by gastrostomy; 26 switched from NG to gastrostomy; and 6 returned from NG to demand feeding. North American and European centers accounted for nearly all feeding by gastrostomy. Standardized body mass index (BMI) uniformly decreased during periods of demand feeding and increased during NG and gastrostomy feeding. Changes in BMI demonstrated significant regional variation: 26% of North American children were obese and 50% of Turkish children were malnourished at last observation (P < 0.005). Body length decreased sharply during the first 6 to 12 months of life and then tended to stabilize. Time fed by gastrostomy significantly associated with higher lengths over time (P < 0.001), but adjustment for baseline length attenuated this effect. In addition, the use of biocompatible peritoneal dialysate and administration of growth hormone independently associated with improved length, even after adjusting for regional factors. In summary, growth and nutritional status vary regionally in very young children treated with chronic peritoneal dialysis. The use of gastrostomy feeding, biocompatible dialysis fluid, and growth hormone therapy associate with improved linear growth.

Phenotypic variability in Bartter syndrome type I

Abstract Limited phenotypic variability has been reported in patients with Bartter syndrome type I, with mutations in the Na-K-2Cl cotransporter gene (BSC). The diagnosis of this hereditary renal tubular disorder is usually made in the antenatal-neonatal period, due to the presence of polyhydramnios, premature delivery, hypokalemia, metabolic alkalosis, hypercalciuria, and nephrocalcinosis. Among nine children with hypercalciuria and nephrocalcinosis, we identified new mutations consistent with a loss of function of the mutant allele of the BSC gene in five. Three of the five cases with BSC gene mutations were unusual due to the absence of hypokalemia and metabolic alkalosis in the first years of life. The diagnosis of incomplete distal renal tubular acidosis was considered before molecular evaluation. Three additional patients with hypokalemia and hypercalciuria, but without nephrocalcinosis in the first two and with metabolic acidosis instead of alkalosis in the third, were studied. Two demonstrated the same missense mutation A555T in the BSC gene as one patient of the previous group, suggesting a single common ancestor. The third patient presented with severe hypernatremia and hyperchloremia for about 2 months, and a diagnosis of nephrogenic diabetes insipidus was hypothesized until the diagnosis of Bartter syndrome type I was established by molecular evaluation. We conclude that in some patients with Bartter syndrome type I, hypokalemia and/or metabolic alkalosis may be absent in the first years of life and persistent metabolic acidosis or hypernatremia and hyperchloremia may also be present. Molecular evaluation can definitely establish the diagnosis of atypical cases of this complex hereditary tubular disorder, which, in our experience, may exhibit phenotypic variability.

Peritoneal dialysis in infants: the experience of the Italian Registry of Paediatric Chronic Dialysis

BACKGROUND Although chronic peritoneal dialysis (CPD) is considered the replacement therapy of choice for infants with end-stage renal failure, many questions persist about treatment risks and outcomes. METHODS We present data on 84 infants who started CPD at <1 year of age; these patients represent 12% of the total population of the Italian Registry of Paediatric Chronic Dialysis. We analysed patient records from all children consecutively treated with CPD between 1995 and 2007 in Italy. Growth data analysis was performed only in infants with complete auxological parameters at 0, 6 and 12 months of follow-up. RESULTS Median age at the start of CPD was 6.9 months, weight was 6.1 kg and length 63.6 cm. In one-half of the study population diagnosis leading to renal failure was congenital nephrouropathy. Twenty-eight per cent of the children had at least one pre-existing comorbidity. The mean height standard deviation score was -1.65 at the start of CPD, -1.82 after 12 months and -1.53 after 24 months. Catch-up growth was documented in 50% of patients during dialysis. A positive correlation was observed between longitudinal growth and both exchange volume (R(2) = 0.36) and dialysis session length (R(2) = 0.35), while a negative association was found with the number of peritonitis cases (P = 0.003). Peritonitis incidence was 1:20.7 episode:CPD-months (1:28.3 in the older children from the same registry) and was significantly higher in children with oligoanuria (1:15.5 episode:CPD-months) compared to infants with residual renal function (1:37.4 episode:CPD-months). Catheter survival rate was 70% at 12 months and 51% at 24 months. Catheter-related complications were similar in infants and older children (1:20.5 versus 1:19.8 episode:CPD-months), while clinical complications were more frequent in children under 1 year of age (1:18.3 versus 1:25.2 episode:CPD-months; P < 0.05). During the follow-up period, 33 patients were transplanted (39.3%), 18 were shifted to haemodialysis (21.4%) and 8 died (9.5%). The mortality rate was 4-fold greater than in older children (2.3%). CONCLUSIONS Our data confirm that infants on CPD represent a high-risk group; however, our experience demonstrated that growth was acceptable and a large portion was successfully transplanted. Increased efforts should be aimed at optimizing dialysis efficiency and preventing peritonitis. The higher mortality rate in infants was largely caused by comorbidities.

Encapsulating peritoneal sclerosis in paediatric peritoneal dialysis patients: the experience of the Italian Registry of Pediatric Chronic Dialysis

BACKGROUND Paediatric literature about encapsulating peritoneal sclerosis (EPS) is limited and comes primarily from anecdotic experiences. In this study, we described the incidence and characteristics of EPS in a large paediatric chronic peritoneal dialysis (CPD) patient population. METHODS We reviewed files of patients starting CPD at <16 years of age, recorded from January 1986 to December 2011 by the Italian Registry of Pediatric Chronic Dialysis (n = 712). Moreover, in December 2011, a survey was performed involving all the Italian Pediatric Nephrology Units to report such EPS cases that occurred after CPD withdrawal. RESULTS Fourteen EPS cases were reported, resulting in a prevalence of 1.9%. The median age of EPS cases was 4.8 years (range 0.6-14.4) at the start of CPD and 14.3 years (6.5-26.8) at EPS diagnosis. Eleven EPS cases received CPD for longer than 5 years. At diagnosis, nine patients were still on CPD, two were on haemodialysis and three were transplanted. In eight patients, the primary renal disease was represented by glomerulopathy, mainly focal segmental glomerulosclerosis (n = 5). In the last 6 months prior to CPD discontinuation, 10 patients were treated with solutions containing more than 2.27% glucose. Peritonitis incidence was 1:26.8 CPD-months, similar to that calculated in children >12 months of age from the same registry (1:28.3 CPD-months). The mortality rate was 43%. A more aggressive course and an association with calcineurin inhibitors were observed in transplanted patients. CONCLUSIONS Surveillance for EPS should be maintained in high-risk children who received long-term PD even after years from CPD withdrawal.

Peritoneal Dialysis Access Revision in Children: Causes, Interventions, and Outcomes

BACKGROUND AND OBJECTIVES Little published information is available about access failure in children undergoing chronic peritoneal dialysis. Our objectives were to evaluate frequency, risk factors, interventions, and outcome of peritoneal dialysis access revision. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Data were derived from 824 incident and 1629 prevalent patients from 105 pediatric nephrology centers enrolled in the International Pediatric Peritoneal Dialysis Network Registry between 2007 and 2015. RESULTS In total, 452 access revisions were recorded in 321 (13%) of 2453 patients over 3134 patient-years of follow-up, resulting in an overall access revision rate of 0.14 per treatment year. Among 824 incident patients, 186 (22.6%) underwent 188 access revisions over 1066 patient-years, yielding an access revision rate of 0.17 per treatment year; 83% of access revisions in incident patients were reported within the first year of peritoneal dialysis treatment. Catheter survival rates in incident patients were 84%, 80%, 77%, and 73% at 12, 24, 36, and 48 months, respectively. By multivariate logistic regression analysis, risk of access revision was associated with younger age (odds ratio, 0.93; 95% confidence interval, 0.92 to 0.95; P<0.001), diagnosis of congenital anomalies of the kidney and urinary tract (odds ratio, 1.28; 95% confidence interval, 1.03 to 1.59; P=0.02), coexisting ostomies (odds ratio, 1.42; 95% confidence interval, 1.07 to 1.87; P=0.01), presence of swan neck tunnel with curled intraperitoneal portion (odds ratio, 1.30; 95% confidence interval, 1.04 to 1.63; P=0.02), and high gross national income (odds ratio, 1.10; 95% confidence interval, 1.02 to 1.19; P=0.01). Main reasons for access revisions included mechanical malfunction (60%), peritonitis (16%), exit site infection (12%), and leakage (6%). Need for access revision increased the risk of peritoneal dialysis technique failure or death (hazard ratio, 1.35; 95% confidence interval, 1.10 to 1.65; P=0.003). Access dysfunction due to mechanical causes doubled the risk of technique failure compared with infectious causes (hazard ratio, 1.95; 95% confidence interval, 1.20 to 2.30; P=0.03). CONCLUSIONS Peritoneal dialysis catheter revisions are common in pediatric patients on peritoneal dialysis and complicate provision of chronic peritoneal dialysis. Attention to potentially modifiable risk factors by pediatric nephrologists and pediatric surgeons should be encouraged.

Anterior Ischemic Optical Neuropathy in Children on Chronic Peritoneal Dialysis: Report of 7 Cases

♦ Background: Anterior ischemic optic neuropathy (AION) is characterized by infarction of the optic nerve head due to hypoperfusion of the posterior ciliary arteries and causes sudden blindness in adults on chronic dialysis, but has rarely been described in children. Unlike adults, children do not have comorbidities related to aging. ♦ Methods: We retrospectively analyzed data of 7 children on nocturnal continuous cycling peritoneal dialysis (CCPD) who developed AION identified within the Italian Registry of Pediatric Chronic Dialysis. We also summarized data from 10 cases reported in the literature. ♦ Results: Our 7 patients suffered from acute onset bilateral blindness. Their mean age was 3.2 years and chronic hypotension had been observed prior the AION in 3 of the 7 children. Low systolic blood pressure (SBP) was associated with higher risk of developing AION according to statistical analysis. None recovered completely. In total, 11 out of 16 experienced a partial recovery and no clear evidence emerged favoring specific treatments. ♦ Conclusions: Hypotensive children treated with CCPD are at increased risk of developing AION, which often results in irreversible blindness.