Association of Plasma Uremic Solute Levels with Residual Kidney Function in Children on Peritoneal Dialysis.

BACKGROUND AND OBJECTIVES: Residual native kidney function confers health benefits in patients on dialysis. It can facilitate control of extracellular volume and inorganic ion concentrations. Residual kidney function can also limit the accumulation of uremic solutes. This study assessed whether lower plasma concentrations of uremic solutes were associated with residual kidney function in pediatric patients on peritoneal dialysis. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Samples were analyzed from 29 pediatric patients on peritoneal dialysis, including 13 without residual kidney function and ten with residual kidney function. Metabolomic analysis by untargeted mass spectrometry compared plasma solute levels in patients with and without residual kidney function. Dialytic and residual clearances of selected solutes were also measured by assays using chemical standards. RESULTS: Metabolomic analysis showed that plasma levels of 256 uremic solutes in patients with residual kidney function averaged 64% (interquartile range, 51%-81%) of the values in patients without residual kidney function who had similar total Kt/Vurea. The plasma levels were significantly lower for 59 of the 256 solutes in the patients with residual kidney function and significantly higher for none. Assays using chemical standards showed that residual kidney function provides a higher portion of the total clearance for nonurea solutes than it does for urea. CONCLUSIONS: Concentrations of many uremic solutes are lower in patients on peritoneal dialysis with residual kidney function than in those without residual kidney function receiving similar treatment as assessed by Kt/Vurea.

Inpatient citrate-based hemodialysis in pediatric patients.

BACKGROUND: Citrate-based dialysate is an effective method of hemodialysis (HD) anticoagulation in adults. The objective of this study was to evaluate this therapy as an alternative to heparin anticoagulation in pediatric patients in the inpatient setting requiring HD. METHODS: We performed a prospective, non-randomized study of citrate-based dialysate HD treatments (N = 119) over a 9-month period in 18 pediatric patients (age range 0-18 years) admitted to hospital. Primary outcome measures were thrombosis incidence rates that resulted in circuit loss, catheter loss or early dialysis termination. Secondary outcome measures were hypocalcemia incidence and heparin use. Data analysis was performed using descriptive and comparative statistics. RESULTS: There was a thrombosis incidence rate of 2.5 % circuit loss, 2.5 % catheter loss and 5.9 % early dialysis termination due to the thrombosis risk. In 64 % of treatments a circuit clot developed but with no circuit loss, and mild asymptomatic hypocalcemia deveoped in 58 % of the monitored HD sessions . No patient required additional heparin during the citrate-based HD treatments, but 11.1 % were subsequently converted to heparin anticoagulation. CONCLUSIONS: Our study showed a low percentage of thrombotic episodes resulting in catheter or circuit loss. Hypocalcemia was common but remained mild and asymptomatic. Citrate-based dialysate was well tolerated by our patients. We therefore conclude that citrate-based dialysate is a safe alternative to heparin-based hemodialysis anticoagulation.

The duration of hepatitis B vaccine immunity in pediatric dialysis patients.

BACKGROUND: Dialysis patients are at risk for hepatitis B infection, a serious but preventable disease. Long-term hepatitis B protection has not been defined in pediatric patients with chronic kidney disease stage 5 on dialysis (CKD 5D) who were vaccinated as infants or children. METHODS: Annual hepatitis B antibody surveillance data were collected retrospectively on a cohort of pediatric CKD 5D patients (n = 202) at a single institution and analyzed by survival analysis to assess hepatitis B immunity duration. RESULTS: Median duration of immunity by Kaplan-Meier analysis since primary vaccination was 106.3 [95 % confidence interval (CI) 93.9, 124.4] months. After the initiation of dialysis, the median duration of hepatitis B immunity was 37.1 (95 % CI 24.2, 72.3) months. Multivariate adjusted analysis showed that there was a significant difference in the duration of hepatitis immunity based on the timing of hepatitis B vaccination (p < 0.001). Patients immunized after starting dialysis had a hazard ratio of 6.13 (95 % CI 2.87, 13.08) for hepatitis B immunity loss compared to patients immunized as infants (p < 0.001). CONCLUSIONS: After dialysis initiation, protective hepatitis B antibody levels wane rapidly, with a shortened duration of immunity. In our cohort of pediatric patients with CKD 5D, this decline was more pronounced in children who were immunized after starting dialysis than in those who received hepatitis B immunizations during childhood. Both groups of patients should be monitored with serial antibody titers.

Comparison of 1-84 and intact parathyroid hormone assay in pediatric dialysis patients.

The non-invasive diagnosis of renal osteodystrophy (ROD) in patients with end-stage renal disease (ESRD) remains dependent on the determination of an accurate parathyroid hormone (PTH) level. Older assays that determine the "intact" PTH molecule are known to cross react with various PTH fragments, resulting in overestimation of PTH levels. Recently, assays that determine the whole 1-84 PTH molecule have been made available. Monthly PTH values in chronic dialysis patients at our institution were compared using the Nichols Bio-Intact PTH (BiPTH, 1-84 PTH) and the intact PTH (iPTH) assay over 3 consecutive months. One hundred twenty-four samples were obtained from 51 (29 male) pediatric dialysis patients (27 HD). The mean patient age was 14.2+/-5.6 years (1.8-25.7 years), with 12 patients<10 years and 15 patients <30 kg. The mean 1-84 PTH/iPTH ratio was 0.48+/-0.11. While BiPTH values correlated closely with iPTH values ( r =0.98, P <0.05), we observed significant intra-patient (16.4+/-15.4%; range: -73.9 to 67.7%, total % error: 47.2%) and inter-patient (17.2+/-18.9%; range: -73.9 to 129.9%, total % error: 55%) variability in the 1-84 PTH/iPTH ratio over the 3-month study period. Thus, our findings suggest that ROD management based on prior associations between iPTH levels and bone biopsy findings should not be extrapolated using the newer 1-84 PTH assay.

Acute and chronic inflammation in pediatric patients receiving hemodialysis.

OBJECTIVES: To assess chronic and acute inflammation in children receiving maintenance hemodialysis. STUDY DESIGN: To assess markers of acute inflammation, serum levels (ELISA) of the cytokines tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, IL-10, and IL-6, 3 to 5 mL of serum was obtained from 13 pediatric patients (mean patient weight, 37.0+/-15.2 kg; mean age, 14.6+/-4.6 years) before and 30 minutes and 24 hours after a routine midweek hemodialysis treatment session. Chronic inflammation was assessed by serum C-reactive protein (CRP) levels. RESULTS: Early-response cytokines TNF-alpha at 30 minutes (5.84+/-0.94 to 9.67+/-0.92 pg/mL; P=.002) and 24 hours (5.84+/-0.94 to 9.54+/-1.05 pg/mL; P=.008) and IL-1beta at 30 minutes (17.19+/-2.00 to 26.17+/-1.12 pg/mL; P=.001) and 24 hours (17.19+/-2.00 to 23.01+/-1.13 pg/mL; P=.02) increased significantly after hemodialysis. Later-response cytokines IL-10 and IL-6 activation was not significant. CRP levels were elevated in 10 of 13 patients (mean, 14.7+/-9.5mg/L; range, 7.2-38.8 mg/L) and correlated with dialysis vintage. Baseline IL-6 and IL-10 levels correlated with dialysis vintage and correlated negatively with eqKt/V. CONCLUSIONS: We observed a chronic inflammatory state in pediatric hemodialysis patients not related to the hemodialysis treatment but rather dialysis vintage and hemodialysis adequacy. We suggest that either more frequent dialysis or enhanced cytokine clearance may ameliorate the chronic inflammatory state observed in pediatric patients receiving hemodialysis.

Cardiovascular calcifications in pediatric patients receiving maintenance dialysis.

Cardiovascular disease is a major cause of morbidity and mortality in adult patients with end-stage renal disease receiving maintenance dialysis. Coronary artery calcifications (CAC) contribute to the high prevalence of cardiac disease and are associated with hyperphosphatemia, an elevated calcium-phosphorus product (CaxP), and prolonged time on dialysis. Chronic inflammation and malnutrition are also associated with an increased risk for development of cardiac calcifications. Young adults receiving maintenance dialysis develop cardiac calcifications at a degree out of proportion to healthy adults of the same age and gender. Many of these young adults initiated dialysis as children or teenagers. Risk factors associated with the development of CAC are also seen in the pediatric dialysis population. To date, reports of cardiac calcifications in pediatric patients receiving maintenance dialysis are limited to post-mortem studies. We present two pediatric patients with ANCA-positive vasculitis diagnosed with cardiac calcifications while receiving maintenance dialysis. Hyperphosphatemia and an elevated CaxP product were seen in both patients and probably contributed to the development of extraskeletal calcifications. In addition, both patients had an underlying systemic inflammatory disease and significant weight loss/malnutrition that may have contributed to the early and rapid onset of cardiac calcifications.

Permanent hemodialysis vascular access survival in children and adolescents with end-stage renal disease.

BACKGROUND: Transplantation is the optimal therapy for pediatric end-stage renal disease (ESRD) patients, but in a subset of patients with peritoneal membrane failure, failed transplants or poor social situations, chronic hemodialysis (HD) remains the only option. Long-term survival of arteriovenous fistulas (AVFs) and arteriovenous grafts (AVGs) in pediatric patients has not been well described. METHODS: We studied the survival of permanent vascular access in 34 pediatric ESRD patients treated with chronic HD at our institution between 1/1/89 and 12/1/95 and followed to 12/31/2000. RESULTS: Twenty-four AVFs and 28 AVGs were created in 19 and 23 patients, respectively. Mean age and weight at insertion were 15.1 years (range 7.1 to 20.9) and 46 kg (18 to 81) for AVFs and 13.3 years (3.8 to 21.1) and 41.5 kg (10.5 to 145) for AVGs. Fifteen patients weighed <35 kg at the time of access creation (7 AVFs in 5 patients, 14 AVGs in 13 patients). Excluding primary failures, one-year, three-year and five-year patency rates for AVFs (74%, 59%, 59%) and AVGs (96%, 69%, 40%) were not significantly different. Patency did not correlate with patient weight or age at access creation. Primary access failure occurred more often (P < 0.01) in AVFs (8/24) compared to AVGs (1/28). Access thrombosis, stenosis and infection occurred more frequently in AVG (P = 0.02). CONCLUSIONS: Both AVF and AVG function well even in small pediatric patients and have survival rates equivalent to adult series and longer than cuffed venous catheters in pediatric patients. Both AVFs and AVGs are preferable for long-term HD access in pediatrics.