Robert S. Venick

Natural History of Pediatric Intestinal Failure: Initial Report from the Pediatric Intestinal Failure Consortium

OBJECTIVEnTo characterize the natural history of intestinal failure (IF) among 14 pediatric centers during the intestinal transplantation era.nnnSTUDY DESIGNnThe Pediatric Intestinal Failure Consortium performed a retrospective analysis of clinical and outcome data for a multicenter cohort of infants with IF. Entry criteria included infants <12 months receiving parenteral nutrition (PN) for >60 continuous days. Enteral autonomy was defined as discontinuation of PN for >3 consecutive months. Values are presented as median (25th, 75th percentiles) or as number (%).nnnRESULTSn272 infants with a gestational age of 34 weeks (30, 36) and birth weight of 2.1 kg (1.2, 2.7) were followed for 25.7 months (11.2, 40.9). Residual small bowel length in 144 patients was 41 cm (25.0, 65.5). Diagnoses were necrotizing enterocolitis (71, 26%), gastroschisis (44, 16%), atresia (27, 10%), volvulus (24, 9%), combinations of these diagnoses (46, 17%), aganglionosis (11, 4%), and other single or multiple diagnoses (48, 18%). Prescribed medications included oral antibiotics (207, 76%), H2 blockers (187, 69%), and proton pump inhibitors (156, 57%). Enteral feeding approaches varied among centers; 19% of the cohort received human milk. The cohort experienced 8.9 new catheter-related blood stream infections per 1000 catheter days. The cumulative incidences for enteral autonomy, death, and intestinal transplantation were 47%, 27%, and 26%, respectively. Enteral autonomy continued into the fifth year after study entry.nnnCONCLUSIONSnChildren with IF endure significant mortality and morbidity. Enteral autonomy may require years to achieve. Improved medical, nutritional, and surgical management may reduce time on PN, mortality, and need for transplantation.

Pretransplant Predictors of Survival After Intestinal Transplantation: Analysis of a Single-center Experience of More Than 100 Transplants

Introduction. Outcomes after intestinal transplantation (ITx) have steadily improved. There are few studies that assess factors associated with these enhanced results. The purpose of this study was to examine peri-ITx variables and survival. Methods. A review of a prospectively maintained database was undertaken and included all patients undergoing ITx from 1991 to 2010. The study endpoints were patient and graft survival. Data collection included 44 variables. Survival was computed using Kaplan-Meier methods. Univariate analysis was conducted (log-rank test) with significance set at P less than or equal to 0.20. Multivariate analysis of significant variables was conducted using model reduction by backward elimination variable selection method with significance set at P less than 0.05. Results. Eighty-eight patients received 106 ITx. The majority of recipients were male, Latino, and children. The leading causes of intestinal and liver failure were gastroschisis and parenteral nutrition. Grafts transplanted were isolated intestine (24%), liver-intestine (62%), and multivisceral (14%). Overall 1- and 5-year patient and graft survival were 80% and 65%, and 74% and 64%, respectively. Significant univariate survival predictors were weight less than 20 kg, children, liver-inclusive allograft, panel reactive antibody less than 20%, absence of donor-specific antibody, negative crossmatch, warm ischemia time less than 60 min, absence of recipient splenectomy, interleukin-2 receptor antagonist induction, and era. Significant multivariate survival predictors were absence of donor-specific antibody, absence of recipient splenectomy, and liver-inclusive graft type. Conclusion. This large, single-center ITx experience confirms a marked improvement in outcome over time. Several important factors were associated with survival, and these factors can potentially be adjusted before ITx. These findings should refocus future efforts on strategies to improve treatment and prevent graft loss.

Predictors of Enteral Autonomy in Children with Intestinal Failure: A Multicenter Cohort Study

OBJECTIVESnIn a large cohort of children with intestinal failure (IF), we sought to determine the cumulative incidence of achieving enteral autonomy and identify patient and institutional characteristics associated with enteral autonomy.nnnSTUDY DESIGNnA multicenter, retrospective cohort analysis from the Pediatric Intestinal Failure Consortium was performed. IF was defined as severe congenital or acquired gastrointestinal diseases during infancy with dependence on parenteral nutrition (PN) >60 days. Enteral autonomy was defined as PN discontinuation >3 months.nnnRESULTSnA total of 272 infants were followed for a median (IQR) of 33.5 (16.2-51.5) months. Enteral autonomy was achieved in 118 (43%); 36 (13%) remained PN dependent and 118 (43%) patients died or underwent transplantation. Multivariable analysis identified necrotizing enterocolitis (NEC; OR 2.42, 95% CI 1.33-4.47), care at an IF site without an associated intestinal transplantation program (OR 2.73, 95% CI 1.56-4.78), and an intact ileocecal valve (OR 2.80, 95% CI 1.63-4.83) as independent risk factors for enteral autonomy. A second model (n = 144) that included only patients with intraoperatively measured residual small bowel length found NEC (OR 3.44, 95% CI 1.36-8.71), care at a nonintestinal transplantation center (OR 6.56, 95% CI 2.53-16.98), and residual small bowel length (OR 1.04 cm, 95% CI 1.02-1.06 cm) to be independently associated with enteral autonomy.nnnCONCLUSIONSnA substantial proportion of infants with IF can achieve enteral autonomy. Underlying NEC, preserved ileocecal valve, and longer bowel length are associated with achieving enteral autonomy. It is likely that variations in institutional practices and referral patterns also affect outcomes in children with IF.

Renal function impacts outcomes after intestinal transplantation.

Background. Although renal dysfunction (RD) has been commonly associated with poor outcome after other solid organ transplants, it has not been studied in detail after intestinal transplantation (ITx). Here we provide a detailed analysis of renal function after ITx, and identify predictors of post-ITx RD. Methods. A retrospective analysis of patients undergoing ITx from 1991 to 2006 was performed. For each patient, the estimated glomerular filtration rate (eGFR) was compared with the normal GFR for age and gender to obtain the percent of normal eGFR. Chi-square analysis and log-rank tests were used to identify categorical variables associated with RD (eGFR <75% of normal) and to determine if RD was predictive of post-ITx survival. Results. Sixty-eight transplantations were performed in 62 patients. Overall patient survival at 1 and 5 years was 78% and 56%, respectively. Renal dysfunction was observed in 16% of patients post-ITx. The most frequent predictors of post-ITx RD were preoperative eGFR less than 75% of normal, pre-ITx location in the intensive care unit, and high-dose tacrolimus immunotherapy. An eGFR less than 75% of normal at days 7, 28, and 365 was predictive of poor patient survival (P<0.05). Conclusions. This study provides the first detailed analysis of renal function after ITx. We identified specific risk factors for the development of RD in the first year post-ITx and found a significant association of RD with decreased long-term survival. Given the strong correlation of RD with poor outcome, preserving renal function may be key to improving long-term outcomes in ITx recipients.

Donor-specific HLA Antibodies Are Associated with Late Allograft Dysfunction after Pediatric Liver Transplantation

Background The role of donor-specific HLA antibodies (DSA) after pediatric liver transplantation (LTx) is not clearly established. We completed a cross-sectional study to characterize DSA in long-term survivors of pediatric LTx and assess the impact of C1q-binding DSA on allograft outcomes. Methods Serum samples were collected at routine clinic visits from 50 pediatric LTx recipients classified into 3 clinical phenotypes: nontolerant (n = 18) with de novo autoimmune hepatitis (DAIH) and/or late acute cellular rejection (ACR); stable (n = 25) on maintenance tacrolimus; operationally tolerant (n = 7). Samples were blinded, and antibody detection was performed using Luminex single antigen class I and II beads. Patients with positive DSA were tested for C1q-binding DSA. Results DSA were detected in 54% (n = 27) of the patients, with the majority directed at HLA class II antigens (DR, 41%; DQ, 53%). Patients with DSA were younger at the time of LTx (P = 0.016) and time of study (P = 0.024). Mean aspartate aminotransferase, alanine aminotransferase, total bilirubin, and gamma glutamyl transferase were higher in DSA-positive patients, though did not reach statistical significance. Nontolerant patients were significantly more likely to have DQ DSA (61%) compared to stable (20%) and tolerant (29%) patients (P = 0.021). The nontolerant phenotype was associated with DSA and C1q-binding DSA, with odds ratios of 13 (P = 0.015) and 8.6 (P = 0.006), respectively. The presence of DQ DSA was associated with DAIH and late ACR, with odds ratios of 12.5 (P = 0.004) and 10.8 (P = 0.006), respectively. Conclusions Allograft dysfunction is not always evident in patients with DSA, but DQ DSA are strongly associated with DAIH, late ACR, and chronic rejection.

Fulminant hepatic failure in children: superior and durable outcomes with liver transplantation over 25 years at a single center.

Objective(s):Death occurs in half of all children with fulminant hepatic failure (FHF). Although liver transplantation (LT) is potentially life-saving, there are only a few published series with limited experience. The aim was to examine predictors of survival after LT for FHF. Methods:Between 1984 and 2008, all LT for FHF performed in recipients less than or equal to 18 years of age were analyzed from a prospectively maintained database using 35 demographic, laboratory, and operative variables. Unique calculated variables included creatinine clearance (cCrCl) and Pediatric End-Stage Liver Disease score (PELD). Study end-points were patient and death censored graft survival. Median follow-up was 98 months. Statistical analysis involved the log-rank test and Cox proportional hazards model. Results:A total of 122 children underwent 159 LTx. Cryptogenic was the primary etiology (70%) and the median age was 53 months. The significant (P < 0.05) univariate predictors of worse graft survival were: recipient age <24 months, cCrCl <60 mL/min/1.73m2, PELD >25 points, and warm ischemia time >60 minutes. The significant (P < 0.05) univariate predictors of worse patient survival were: recipient African-American and Asian race, recipient age <24 months, cCrCl <60 mL/min/1.73m2, and time from onset jaundice to encephalopathy <7 days. On multivariate analysis, survival was significantly impacted by 4 variables: cCrCl <60 mL/min/1.73m2 (GRAFT and PATIENT), PELD >25 points (GRAFT), recipient age <24 months (GRAFT), and time from onset jaundice to encephalopathy <7 days (PATIENT). While overall 5- and 10-year survival was 73% and 72% (GRAFT) and 77% and 73% (PATIENT), these were significantly worse when a combination of multivariate risk-factors were present. Conclusions:This data from a large, single-center experience demonstrates that LT is the treatment of choice for FHF and results in durable survival. Analysis revealed 4 novel outcome predictors. Young children with rapid onset acute liver failure are a high-risk subpopulation. Unique to this study, cCrCl and PELD accurately predicted the end-points. This analysis identifies patient subpopulations requiring early aggressive intervention with LT.

Pediatric health-related quality of life after intestinal transplantation

Ngo KD, Farmer DG, McDiarmid SV, Artavia K, Ament ME, Vargas J, Busuttil RW, Colangelo J, Esmailian Y, Gordon‐Burroughs S, Duffy J, Venick RS. Pediatric health‐related quality of life after intestinal transplantation. u2028Pediatr Transplantation 2011: 15: 849–854.

Pediatric Intestinal Failure–Associated Liver Disease Is Reversed With 6 Months of Intravenous Fish Oil

BACKGROUNDnStudies have suggested that when intravenous (IV) soybean oil (SO) is replaced with fish oil (FO), direct hyperbilirubinemia is more likely to resolve. The necessary duration of FO has not been established. This study seeks to determine if 24 weeks of FO is an effective and safe therapy for intestinal failure-associated liver disease (IFALD).nnnMATERIALS AND METHODSnThis is a clinical trial using patients with IFALD between the ages of 2 weeks and 18 years. SO was replaced with FO (1 g/kg/d) in 10 patients who were receiving most of their calories from parenteral nutrition (PN). Patients were compared with 20 historic controls receiving SO. SO for both groups was prescribed by the primary medical team at variable doses. The primary outcome was time to reversal of cholestasis. Secondary outcomes were death, transplant, and full enteral feeds. Safety measurements included growth, essential fatty acid deficiency, and laboratory markers to assess bleeding risk.nnnRESULTSnThe Kaplan-Meier method estimated that 75% in the FO group would experience resolution of cholestasis by 17 weeks vs 6% in the SO group (P < .0001). When compared with the SO group, the FO group had decreased serum direct bilirubin concentrations at weeks 8 (P = .03) and 12, 16, 20, and 24 weeks (P < .0001). Although length z score at the end of the study increased in the FO group compared with baseline (P = .03), there were no significant differences in other outcomes.nnnCONCLUSIONSnA limited duration of FO appears to be safe and effective in reversing IFALD.

Long-term nutrition and predictors of growth and weight gain following pediatric intestinal transplantation.

Background. Advances in intestinal transplantation (ITx) have resulted in improved survival and the opportunity to examine nutritional outcomes. The aim of this study was to describe detailed, long-term nutritional results and identify positive predictors of growth and weight gain following pediatric ITx. Methods. A single-center retrospective, Institutional Review Board-approved review of a prospective database was conducted. Inclusion criteria were ITx recipients 18 years or younger with survival of 6 months or more. Outcomes included anthropometric measurements and biochemical markers at 6, 12, 24, 36, and 48 months post-ITx. More than 25 ITx-related variables were analyzed as potential predictors of growth and weight gain. Statistical analysis was performed using chi-square test, t test, and analysis of variance. Results. Between November 1991 and April 2007, 50 children received 55 ITx; 33 patients met eligibility criteria. Median age at ITx was 2.2 years, follow-up time was 3.8 years, and time from ITx to cessation of total parenteral nutrition was 31 days. The most common micronutrient deficiencies post-ITx were zinc, iron, and copper. Serum protein levels improved significantly over time. Weight gain occurred within 6 months and vertical growth within 12 months, although limited catch-up growth was seen. Early predictors of weight gain and growth included shorter hospitalization and absence of rejection. Long-term predictors were low steroid dosage, infrequent hospitalization, and the use of peptide-based formulas. Conclusions. This represents one of the largest and most comprehensive long-term studies on nutritional outcomes in pediatric ITx. Overall, positive growth and weight gain were seen as were micronutrient deficiencies. Numerous long-term nutritional challenges exist which require a multidisciplinary approach and future prospective studies.

Exome sequencing finds a novel PCSK1 mutation in a child with generalized malabsorptive diarrhea and diabetes insipidus.

Objectives: Congenital diarrhea disorders are a group of genetically diverse and typically autosomal recessive disorders that have yet to be well characterized phenotypically or molecularly. Diagnostic assessments are generally limited to nutritional challenges and histologic evaluation, and many subjects eventually require a prolonged course of intravenous nutrition. Here we describe next-generation sequencing techniques to investigate a child with perplexing congenital malabsorptive diarrhea and other presumably unrelated clinical problems; this method provides an alternative approach to molecular diagnosis. Methods: We screened the diploid genome of an affected individual, using exome sequencing, for uncommon variants that have observed protein-coding consequences. We assessed the functional activity of the mutant protein, as well as its lack of expression using immunohistochemistry. Results: Among several rare variants detected was a homozygous nonsense mutation in the catalytic domain of the proprotein convertase subtilisin/kexin type 1 gene. The mutation abolishes prohormone convertase 1/3 endoprotease activity as well as expression in the intestine. These primary genetic findings prompted a careful endocrine reevaluation of the child at 4.5 years of age, and multiple significant problems were subsequently identified consistent with the known phenotypic consequences of proprotein convertase subtilisin/kexin type 1 (PCSK1) gene mutations. Based on the molecular diagnosis, alternate medical and dietary management was implemented for diabetes insipidus, polyphagia, and micropenis. Conclusions: Whole-exome sequencing provides a powerful diagnostic tool to clinicians managing rare genetic disorders with multiple perplexing clinical manifestations.