Ventriculoperitoneal shunts in children on peritoneal dialysis: a survey of the International Pediatric Peritoneal Dialysis Network.

OBJECTIVE: The aim of this study was to inform best evidence-based practice by collating and disseminating the experiences of members of the International Pediatric Peritoneal Dialysis Network with children having concurrent ventriculoperitoneal shunts (VPS) and peritoneal dialysis catheters (PDC). METHODS: An online questionnaire was created and distributed to all 135 centers participating in the International Pediatric Peritoneal Dialysis Network; the overall response rate was 56 %. RESULTS: A total of 18 patients with a concurrent VPS and PDC were reported. The children were 0-12 (mean 6.8) years old at the time of placement of the second indwelling device (PDC or VPS). In 15 cases, the PDC was inserted post-VPS. On average, the two catheters were present concurrently for 23 (range 1-60) months. There were 20 episodes of peritonitis observed in 11 of the 18 patients during a period of 392 months at risk, which is a peritonitis rate of 1/19.6 months. Only one patient developed both a VPS infection and an episode of peritonitis, and these events were temporally unrelated. No episodes of an ascending shunt infection or meningitis occurred in association with any episode of peritonitis, and no other complications of catheter dysfunction were described. CONCLUSIONS: The rate of peritonitis, the absence of any documented ascending or descending infections and the lack of catheter dysfunction during the period of observation suggests that the presence of, or need for, a VPS should not preclude PD as a safe option for children requiring renal replacement therapy.

Survival advantage of pediatric recipients of a first kidney transplant among children awaiting kidney transplantation.

The mortality rate in children with ESRD is substantially lower than the rate experienced by adults. However, the risk of death while awaiting kidney transplantation and the impact of transplantation on long-term survival has not been well characterized in the pediatric population. We performed a longitudinal study of 5961 patients under age 19 who were placed on the kidney transplant waiting list in the United States. Of these, 5270 received their first kidney transplant between 1990 and 2003. Survival was assessed via a time-varying nonproportional hazards model adjusted for potential confounders. Transplanted children had a lower mortality rate (13.1 deaths/1000 patient-years) compared to patients on the waiting list (17.6 deaths/1000 patient-years). Within the first 6 months of transplant, there was no significant excess in mortality compared to patients remaining on the waiting list (adjusted Relative Risk (aRR) = 1.01; p = 0.93). After 6 months, the risk of death was significantly lower: at 6-12 months (aRR = 0.37; p < 0.001) and at 30 months (aRR 0.26; p < 0.001). Compared to children who remain on the kidney transplant waiting list, those who receive a transplant have a long-term survival advantage. With the potential for unmeasured bias in this observational data, the results of the analysis should be interpreted conservatively.

Pharmacokinetics, Pharmacodynamics, and Safety of Lisinopril in Pediatric Kidney Transplant Patients: Implications for Starting Dose Selection.

Hypertension in pediatric kidney transplant recipients contributes to long-term graft loss, yet treatment options--including angiotensin-converting enzyme inhibitors--are poorly characterized in this vulnerable population. We conducted a multicenter, open-label pharmacokinetic (PK) study of daily oral lisinopril in 22 children (ages 7-17 years) with stable kidney transplant function. Standard noncompartmental PK analyses were performed at steady state. Effects on blood pressure were examined in lisinopril-naïve patients (n = 13). Oral clearance declined in proportion to underlying kidney function; however, in patients with low estimated glomerular filtration rate (30-59 ml/min per 1.73m(2)), exposure (standardized to 0.1 mg/kg/day dose) was within the range reported previously in children without a kidney transplant. In lisinopril-naïve patients, 85% and 77% had a ≥ 6 mmHg reduction in systolic and diastolic blood pressure, respectively. Lisinopril was well tolerated. Our study provides initial insight on lisinopril use in children with a kidney transplant, including starting dose considerations.

Vitamin status of pediatric patients receiving long-term peritoneal dialysis.

The oral vitamin intakes and concentrations of vitamins in blood of eight children on long-term peritoneal dialysis and six control children were measured. All patients received a daily supplement containing water-soluble vitamins. Serum concentrations of vitamin A, vitamin B-12, ascorbic acid, and folic acid and dialysate concentrations of ascorbic acid were determined. Thiamin and riboflavin were assessed by measuring erythrocyte enzyme activities. Vitamin B-6 was measured as plasma pyridoxal phosphate. Dietary vitamin intake was determined with weighed 3-d food records. The dialysis patients had significantly greater stores of vitamin A, thiamin, riboflavin, pyridoxal phosphate, and folic acid than did the control population (P less than or equal to 0.01). The patients' combined dietary and supplemental intake of all vitamins except ascorbic acid was also significantly greater than the intake of the control group (P less than 0.01). Vitamin supplementation is associated with normal or greater-than-normal values of water-soluble vitamins in pediatric patients receiving long-term peritoneal dialysis.

Detection of HLA IgG antibodies by two enzyme-linked immunoassays, solubilized HLA class I and PRA-STAT. Comparison with the AHG PRA.

HLA class I-directed IgG antibodies have traditionally been detected with a complement-dependent lymphocytotoxicity (CDL) technique. We have evaluated two solid-phase enzyme-linked immunoassays (EIA) and compared them with the CDL antihuman globulin (AHG) dithiothreitol-treated (DTT) PRA in their ability to discriminate between the presence or absence of HLA class I-directed IgG antibodies in serum from patients awaiting transplantation. The EIA were: (1) an EIA that uses solubilized HLA class I antigens (sHLA-I) isolated from a 240-member platelet donor pool, and (2) the PRA-STAT ELISA kit. For the first comparison, we used 691 serum samples from 272 patients taken before they had been transplanted. The data show a significant (P < 0.0001) linear correlation (r = 0.77 between the AHG DTT PRA and the sHLA EIA. They also demonstrate that the mean sHLA-I EIA ratio significantly increases (P < 0.01) above background levels with each stepwise increase in AHG DTT PRA level. Discordant results were 1.0% (7/691) for sHLA-I EIA+ PRA- and 6.3% (44/691) for PRA+ sHLA-I EIA-. However, a lower correlation was noted between the AHG DTT PRA and the PRA-STAT (Nextran) PRA results (n = 230; r = 0.42). The sHLA-I EIA is able to determine whether or not HLA Class I IgG antibodies are present in serum from transplant candidates and is an appropriate adjunct to the traditional CDL PRA assay, whereas the PRA-STAT is not.

HLA-DR and DQ typing by polymerase chain reaction using sequence-specific primer mixes reduces the incidence of phenotypic homozygosity (blanks) over serology.

Because of the inherent difficulties in allele assignment with HLA-DR serological typing, in 1993 our organ procurement organization-based HLA laboratory replaced serology with the molecular method of polymerase chain reaction using sequence-specific primer mixes (PCR-SSP) to type for DR and DQ at a resolution level equivalent to that of serologically defined antigens. In this study, we compared the incidence of DR blanks, where allocative homozygosity occurred, and graft outcome during our serology epoch (1987-1993) with that of our molecular epoch (1993-1996). The incidence of DR blanks by PCR-SSP (17.0%; 138/1101) was significantly lower (P<0.005) than in the serology epoch (21.5%; 569/2647). Although DQ is not a component of the allocation algorithm, the incidence of blanks in the molecular era (21.9%; 196/895) was 46% lower (P<0.001) than in the serology epoch (40.8%; 931/2277). Graft survival in 163 cadaveric renal transplant recipients for whom molecular DR allocation occurred (patient and donor were molecularly typed) showed that PCR-SSP typing had no significant effect on 2.5-year graft survival for patients mismatched for 0 (97%), 1 (90%), or 2 (94%) HLA-DR antigens (P=0.4; log-rank). In conclusion, molecular typing lowered the rate of DR and DQ blanks, but molecular matching for HLA DR and DQ did not influence graft outcome at 2.5 years.

Long-term graft survival is improved in cadaveric renal retransplantation by flow cytometric crossmatching.

BACKGROUND: Cadaveric renal retransplantation is associated with a higher risk of early graft failure than primary grafts. A large proportion of those graft losses is likely attributable to donor-directed HLA class I antibodies, detectable by flow cytometry cross-matching but not by conventional crossmatching techniques. METHODS: Long-term graft survival in a group of 106 recipients of consecutive cadaveric renal regrafts between 1990 and 1997, in whom a negative flow T-cell IgG crossmatch was required for transplantation, was compared with two other groups of cadaveric transplant recipients. The first group consisted of 174 cadaveric regrafts transplanted between 1985 and 1995 using only a negative anti-human globulin (AHG) T-cell IgG crossmatch. The second group was primary cadaveric transplants done concurrently with the flow group (1990 to 1997) using only the AHG T-cell IgG crossmatch. RESULTS: The long-term (7 year) graft survival rate of flow crossmatch-selected regraft recipients (68%; n= 106) was significantly improved over that of regraft recipients who were selected for transplantation by only the AHG crossmatch technique (45%; n=174; log-rank=0.001; censored for patients dying with a functioning graft). Graft outcome for the flow cross-matched regraft recipients was not significantly different from that of primary cadaveric patients (72%; n=889; log-rank=0.2; censored for patients dying with a functioning graft). Finally, a positive B-cell IgG flow cytometric crossmatch had no influence on long-term regraft outcome. CONCLUSIONS: The use of the flow T-cell IgG cross-match as the exclusion criterion for cadaveric renal retransplantation yields an improved long-term graft outcome over that obtained when only the AHG cross-match is used and has improved survival of regraft recipients to the level of our primary cadaveric renal transplant population.

Cold ischemia time: an independent predictor of increased HLA class I antibody production after rejection of a primary cadaveric renal allograft.

BACKGROUND: Cadaveric kidneys experiencing longer cold ischemia time (CIT) are associated with higher levels of delayed graft function, acute rejection, and early graft loss. One mechanism to explain these results is that ischemia/reperfusion (I/R) injury makes the allograft more immunogenic by upregulating molecules involved in the immune response (e.g., HLA Class I/II). METHODS: We evaluated the influence of CIT on the production of HLA Class I antibody level, measured by an antihuman globulin panel reactive antibody (AHG PRA) level, in 90 unsensitized recipients of primary cadaveric renal transplants (from a total of 1442 between 1985 and 1997) who rejected their kidneys. RESULTS: By multivariate analysis, a CIT of 15 hr or more (vs. < 15 hr) independently increased the risk of the AHG Class I PRA level being > or = 20% after unsensitized patients rejected their first kidneys (relative risk=3.57; 95% confidence interval=1.26 to 10.14; P=0.01), despite the same degree of Class I/II mismatch between the two CIT groups. The overall mean peak PRA level after primary kidney rejection was significantly lower for the CIT < 15 hr group (25.9%+/-33.9; n=24) compared with the CIT > or = 15 hr group (46.3%+/-36.5; n=66) (P<0.001). CONCLUSION: Longer CIT induces a humorally more immunogenic kidney.

Influence of the Rh (D) blood group system on graft survival in renal transplantation.

BACKGROUND: The Rh (D) blood group system has not traditionally been considered to be a clinically relevant histocompatibility barrier in transplantation since conflicting results of its clinical importance have been reported. METHODS: We analyzed 786 consecutive primary cadaveric renal transplants performed by transplant centers in our Organ Procurement Organization (OPO) between 1990 and 1997. We also analyzed United Network for Organ Sharing (UNOS) data on 26,469 kidney transplants done from April 1994 to June 1996. RESULTS: Multivariate analysis revealed that Rh identity between the recipient and donor was significantly related to better graft outcome (risk ratio, 0.43; 95% confidence interval, 0.30 to 0.61; P=0.0001). Multivariate analysis of the UNOS data revealed that the Rh -/- group may have a positive influence on graft survival with a risk ratio of 0.43 (P=0.14). CONCLUSION: Multivariate analysis of primary cadaveric renal allografts performed within the Midwest Organ Bank OPO indicates that Rh (D) is a clinically relevant histocompatibility barrier that influences 7-year graft survival.

Transplantation rate of the blood group B waiting list is increased by using A2 and A2B kidneys.

BACKGROUND: We have increased the transplantation rate for blood group B cadaveric waiting list candidates by transplanting them with A2 and A2B kidneys. METHODS: Since 1991, five of the seven renal transplant programs in our organ procurement organization service area have preferentially transplanted blood group A2 and A2B cadaveric kidneys to B blood group waiting list candidates with histories of low anti-A isoagglutinin titers. RESULTS: Between 1991 and 1997, these five centers performed transplantations on 71 patients from the B cadaveric waiting list. Of those 71 patients, 29% (21 of 71) underwent transplantation with either A2 (n=18) or A2B (n=3) cadaveric kidneys. In 1997 alone, 48% (11 of 23) of the B patient transplant recipients received A2 or A2B kidneys. CONCLUSIONS: Transplantation of A2 and A2B kidneys into B waiting list patients has successfully increased access of B patients to kidneys. Such an allocation algorithm implemented nationally may similarly increase the transplantation rate of B waiting list candidates.

Ten-year experience in transplantation of A2 kidneys into B and O recipients.

BACKGROUND: This article summarizes our 10-year multicenter experience with transplantation of 50 blood group A2 and A2B kidneys into B and O patients. METHODS: Since 1986, we have transplanted kidneys from 46 cadaver donors and 4 living donors who were blood group A2 (47 donors) or A2B (3 donors) into 19 B and 31 O patients. In 1991, we began allocating these kidneys preferentially to B and O recipients who were selected based on a history of low (< or =4) anti-A IgG isoagglutinin titers. Immunosuppression was no different from that used in ABO-compatible grafts. RESULTS: The 1-month function rate before thus selecting the patients was 68% (19/28), but is now 94% (17/18). Two-year cadaver-donor graft survival with this selection method is 94%, compared with 88% for 640 concurrent and consecutive ABO-compatible transplants (log-rank, 0.15). All four living-related transplants are still functioning, with a mean follow-up of 71 months. Since we began allocating A2 kidneys preferentially to B and O recipients, the percentage of the B patients who received A2 or A2B kidneys has increased from 29% (8/28) to 55% (10/18). CONCLUSIONS: Transplantation of A2 or A2B kidneys into B and O patients is clinically equivalent to that of ABO-compatible transplantation when recipients are selected by low pretransplant anti-A titer histories. This approach increases access of blood group B recipients to kidneys.

Aluminum intoxication in a child: treatment with intraperitoneal desferrioxamine.

We report the successful chelation of aluminum and the clinical resolution of severe aluminum intoxication in an infant receiving chronic peritoneal dialysis through the use of intraperitoneal desferrioxamine. Following the introduction of desferrioxamine, urine and dialysate fluid aluminum levels exceeded those noted without the chelating agent, thus demonstrating enhanced removal of aluminum. As a result of therapy, plasma and bone aluminum levels decreased markedly, and previously noted histomorphometric abnormalities on bone biopsy resolved. Clinically, the aluminum-associated osteomalacia and microcytic hypochromic anemia completely reversed. Moderate developmental delay has also improved slightly but persists. Our experience suggests that intraperitoneal chelation therapy with desferrioxamine may be helpful to reverse aluminum intoxication in children with chronic renal failure. However, limited exposure to aluminum should remain a primary goal.

Tenckhoff catheters prove superior to cook catheters in pediatric acute peritoneal dialysis.

Peritoneal dialysis (PD) is the most common form of renal replacement therapy in infants and young children with acute renal failure (ARF). The two most commonly used catheters for performing acute PD are the Cook catheter (CC), placed at the bedside, and the surgically placed Tenckhoff catheter (TC). In the present study, we compared the complications and survival rates of the two catheters. The records of 59 children (age, 1 day to 16.7 years) who underwent PD for ARF from March 1989 through June 1999 in our hospital were reviewed. The initial (primary) catheter was a TC in 22 patients and a CC in 37 patients. The age of the patients who received a primary TC (2.8 +/- 4.5 years) was no different than the age of those with a primary CC (1.4 +/- 2.0 years; P = not significant). The duration of use (mean +/- SD) of TCs (16.5 +/- 14.2 days) was significantly greater than the duration of CC use (4.9 +/- 4.2 days; P < 0.001). Only two patients with a TC (9%) developed complications, whereas 18 patients with a CC (49%) developed complications, 13 of whom required catheter replacement (P < 0.01). Thirty-five patients (59%) recovered renal function after undergoing dialysis for 11.5 +/- 8.0 days. Twenty-three of those patients (66%) required dialysis for more than 5 days. Only 4 patients with a primary CC had successful completion of dialysis without catheter-associated complications compared with 15 patients with a primary TC. Kaplan-Meier survival analysis showed that by day 6 of dialysis, only 46% of primary CCs were functioning without complications compared with 90% of TCs that were free of complications. We conclude that the use of a CC is associated with significantly more complications than a TC, and nearly one half of the CCs are likely to be nonfunctional beyond 5 days of dialysis, at a time when two thirds of the patients are still expected to be undergoing dialysis. Therefore, when possible, a TC should be the catheter of choice when initiating acute PD in children. In those patients for whom a CC is chosen as the initial catheter, an elective change to a TC should be considered once dialysis is expected to extend beyond 5 days.

Risk factors for mortality in infants and young children on dialysis.

The factors associated with a greater mortality risk in infants and young children undergoing dialysis have not been clearly determined. We report the results of a North American Pediatric Renal Transplant Cooperative Study designed to assess risk factors in patients aged younger than 6 years at initiation of dialysis therapy. Sixty-four nonsurvivors were matched with 110 survivors for age at dialysis initiation, primary renal disease, and year of entry onto the database. Questionnaires on 137 patients (51 nonsurvivors, 86 survivors) were completed by participating centers. Seventy-five percent (103 of 137 patients) of the patients were aged younger than 2 years at dialysis initiation; 42% (58 of 137 patients) had renal aplasia, dysplasia, and/or hypoplasia or obstructive uropathy; 62% were boys; and 62% were white. One-year patient survival rates were 83% in infants beginning dialysis at younger than 3 months of age, 89% in 3- to 23-month-olds, and 95% in 2- to 5-year-olds (P = 0.001). Comorbid nonrenal disease occurred in 37 of 51 nonsurvivors (74%) versus 46 of 84 survivors (55%; P = 0.027). Nonsurvivors had pulmonary disease and/or hypoplasia more often (14 of 37 nonsurvivors; 37.8% versus 8 of 46 survivors; 17.4%; P = 0.04). Oliguria or anuria was present in 23 of 33 nonsurvivors (70%) aged younger than 2 years versus 26 of 64 survivors (41%; P = 0.007). Infection accounted for 15 of 51 deaths (29.4%). In summary, these results suggest that age at dialysis initiation; presence of nonrenal disease, particularly pulmonary disease and/or hypoplasia; and oliguria or anuria in children aged younger than 2 years are identifiable as risk factors for mortality in these young patients.

What are the clinical correlates of adequate peritoneal dialysis?

The efficacy of peritoneal dialysis in terms of the clearance of small molecules such as urea and creatinine is referred to as "adequacy." Treatment guidelines and adequacy targets have been developed and distributed by the National Kidney Foundation-Dialysis Outcomes Quality Initiative (NKF-DOQI) in an effort to reduce variations in end-stage renal disease (ESRD) treatment. Much effort has been made to determine the correlation between dialysis dose and various clinical outcome measures (eg, hospitalization, mortality) in adults in an attempt to define the optimal dialysis dose. The delineation of this issue in the pediatric ESRD population is more complex because of the small number of patients and the need to define sensitive outcome measures that are unique to children. The review addresses the possible clinical correlates of dialysis adequacy in children that exist today and the additional data on the topic that needs to be collected in the future.

Lessons from the peritoneal dialysis patient database: a report of the North American Pediatric Renal Transplant Cooperative Study.

Data derived from 1383 independent courses of peritoneal dialysis have been recorded in the database of the North American Pediatric Renal Transplant Cooperative Study (NAPRTCS). Automated peritoneal dialysis (APD) continues to be the preferred modality. Peritoneal access is most commonly achieved with a Tenckhoff curled catheter with a single-cuff and straight tunnel. Overall, the peritonitis rate is 1 infection every 13.3 months, the frequency of infection being greatest in the youngest patients. Two-cuffed catheters and exit-sites directed down positively influence this rate. Excessive infection is the primary reason for modality termination in surviving patients not transplanted. A total of 64 deaths have occurred in the peritoneal dialysis population. The 12-month and 24-month mortality probabilities in children < two years of age are significantly greater than comparable data in the older children.

New hormones in the therapeutic arsenal of chronic renal failure. Growth hormone and erythropoietin.

Although the benefits of rhGH and r-HuEPO therapy in children with CRF and on dialysis are already significant, further study of these new additions to the therapeutic arsenal remains necessary. Data on the final adult height achieved in patients who receive rhGH are extremely important information that is as yet unavailable. The risks and benefits of raising the target hematocrit to a "normal" value in patients receiving r-HuEPO remains under study. Only when these and other issues are soundly evaluated will the full impact of these medications be understood.

Early onset hyperkalemia in extremely low birth weight infants.

The incidence of hyperkalemia and associated clinical features in extremely preterm infants were determined by reviewing medical records of 32 infants with birth weights of less than or equal to 800 g born during a 1-year period. Hyperkalemia, defined as serum potassium concentration of greater than 6.5 mEq/L, occurred in 12 infants on the first day of life and in four others on the second day. Six infants (38%) had electrocardiographic abnormalities associated with hyperkalemia. Infants with hyperkalemia were less mature than infants with normal potassium levels. All infants of less than 25 weeks' gestation developed hyperkalemia. Fluid intakes and urine flow rates were lower and body weight loss greater during the first 24 hours of hospitalization for hyperkalemic infants. Hyperkalemia frequently occurs within the first 48 hours of life in extremely immature infants. Serum potassium should be monitored closely to avoid life-threatening cardiac arrhythmias in these infants.

Peritoneal dialysis in the neonatal period: outcome data.

Scant information exists on the prognosis of infants with renal failure who receive peritoneal dialysis in the first month of life. We reviewed the outcome of 23 such patients 1 year after the onset of renal failure. Diagnoses included acute tubular necrosis (11 infants), renal dysplasia (5), obstructive uropathy (4), polycystic kidney disease (1), renal vein thrombosis (1), and renal artery thrombosis (1). Seven of the eleven patients with acute tubular necrosis had had cardiac surgery. At 1 year, eight (35%) of the patients had died, six (26%) had a full recovery, seven (30%) were receiving long-term dialysis awaiting a transplant, and two (9%) had chronic renal failure. Effective dialysis, characterized by the reversal of metabolic disturbances or attainment of fluid balance, was accomplished in all patients. The mean duration of dialysis was 4.5 months (range, 0.1 to 12 months). The most common complications of dialysis were peritonitis and catheter exit site infection. Despite the provision of supplemental calories via nasogastric tube, the majority of patients receiving long-term dialysis showed impaired growth and mild developmental abnormalities. Peritoneal dialysis is an effective means of renal replacement therapy in the neonatal period; however, the morbidity and mortality rate for this population remains high.