Immediate extubation after pediatric liver transplantation: a single-center experience.

The care of pediatric liver transplant recipients has traditionally included postoperative mechanical ventilation. In 2005, we started extubating children undergoing liver transplantation in the operating room according to standard criteria for extubation used for general surgery cases. We reviewed our single-center experience to determine our rates of immediate extubation and practice since that time. The records of 84 children who underwent liver transplantation from 2005 to 2011 were retrospectively reviewed. The immediate extubation rate increased from 33% during 2005-2008 to 67% during 2009-2011. Immediate extubation did not result in an increased reintubation rate in comparison with delayed extubation in the intensive care unit (ICU). Patients undergoing immediate extubation had a trend toward a shorter mean ICU stay as well as a significantly decreased overall hospital length of stay. Our findings suggest that there is a learning curve for instituting immediate extubation in the operating room after liver transplantation and that the majority of pediatric liver recipients can safely undergo immediate extubation.

Frostbite of the liver: an unrecognized cause of primary non-function?

Appropriate hypothermic packaging techniques are an essential part of organ procurement. We present a case in which deviation from standard packaging practice may have caused sub-zero storage temperatures during transport, resulting in a clinical picture resembling PNF. An 18-month-old male with alpha-1-antitrypsin deficiency underwent liver transplant from a size-matched pediatric donor. Upon arrival at the recipient hospital, ice crystals were noted in the UW solution. The transplant proceeded uneventfully with short ischemia times. Surprisingly, transaminases, INR, and total bilirubin were markedly elevated in the postoperative period but returned to near normal by discharge. Follow-up of over five yr has demonstrated normal liver function. Upon review, it was discovered that organ packaging during recovery included storage in the first bag with only 400 mL of UW solution, and pure ice in the second bag instead of slush. This suggests that the postoperative delayed graft function was related to sub-zero storage of the graft during transport. This is the first report of sub-zero cold injury, or frostbite, following inappropriate packaging of an otherwise healthy donor liver. The clinical picture closely resembled PNF, perhaps implicating this mechanism in other unexpected cases of graft non-function.

Deceased donor liver transplantation in infants and small children: are partial grafts riskier than whole organs?

Infants have the highest wait-list mortality of all liver transplant candidates. Although previous studies have demonstrated that young children may be at increased risk when they receive partial grafts from adult and adolescent deceased donors (DDs), with few size-matched organs available, these grafts have increasingly been used to expand the pediatric donor pool. We aimed to determine the current adjusted risks of graft failure and mortality in young pediatric recipients of partial DD livers and to determine whether these risks have changed over time. We analyzed 2683 first-time recipients of DD livers alone under the age of 24 months in the United Network for Organ Sharing database (1995-2010), which included 1118 partial DD livers and 1565 whole DD organs. Transplant factors associated with graft loss in bivariate analyses (P < 0.1) were included in multivariate proportional hazards models of graft and patient survival. Interaction analysis was used to examine risks over time (1995-2000, 2001-2005, and 2006-2010). Although there were significant differences in crude graft survival by the graft type in 1995-2000 (P < 0.001), graft survival rates with partial and whole grafts were comparable in 2001-2005 (P = 0.43) and 2006-2010 (P = 0.36). Furthermore, although the adjusted hazards for partial graft failure and mortality were 1.40 [95% confidence interval (CI) = 1.05-1.89] and 1.41 (95% CI = 0.95-2.09), respectively, in 1995-2000, the adjusted risks of graft failure and mortality were comparable for partial and whole organs in 2006-2010 [hazard ratio (HR) for graft failure = 0.81, 95% CI = 0.56-1.18; HR for mortality = 1.02, 95% CI = 0.66-1.71]. In conclusion, partial DD liver transplantation has become less risky over time and now has outcomes comparable to those of whole liver transplantation for infants and young children. This study supports the use of partial DD liver grafts in young children in an attempt to significantly increase the pediatric organ pool.

Effect of CX516, an AMPA-modulating compound, on cognition and behavior in fragile X syndrome: a controlled trial.

A Phase II, 4-week randomized, double-blind, placebo-controlled clinical trial was conducted to evaluate the safety and efficacy of the Ampakine compound CX516 as a potential treatment for the underlying disorder in fragile X syndrome (FXS). After baseline screening, subjects with FXS (n = 49) underwent a 1-week placebo lead-in and then were randomized to study drug or placebo for a 4-week period. Cognitive and behavioral outcome measures were administered prior to treatment, at the end of treatment, and 2 weeks posttreatment. There were minimal side effects, no significant changes in safety parameters, and no serious adverse events. There was a 12.5% frequency of allergic rash in the CX516 group and 1 subject developed a substantial rash. There was also no significant improvement in memory, the primary outcome measure, or in secondary measures of language, attention/executive function, behavior, and overall functioning in CX516-treated subjects compared to placebo. This study did demonstrate that many outcome measures were reproducible in this test-retest setting for the FXS population, yet some were too difficult or variable. Adult subjects with FXS were able to complete an intensive clinical trial, and some valid outcome measures were identified for future FXS trial design. Problems with potency of CX516 in other studies have suggested dosing may have been inadequate for therapeutic effect and thus it remains unclear whether modulation of AMPA-mediated neurotransmission is a viable therapeutic strategy for the treatment of FXS.

Tissue expander stimulated lengthening of arteries (TESLA) induces early endothelial cell proliferation in a novel rodent model.

BACKGROUND: We examine the mechanism of aortic lengthening in a novel rodent model of tissue expander stimulated lengthening of arteries (TESLA). METHODS: A rat model of TESLA was examined with a single stretch stimulus applied at the time of tissue expander insertion with evaluation of the aorta at 2, 4 and 7day time points. Measurements as well as histology and proliferation assays were performed and compared to sham controls. RESULTS: The aortic length was increased at all time points without histologic signs of tissue injury. Nuclear density remained unchanged despite the increase in length suggesting cellular hyperplasia. Cellular proliferation was confirmed in endothelial cell layer by Ki-67 stain. CONCLUSIONS: Aortic lengthening may be achieved using TESLA. The increase in aortic length can be achieved without tissue injury and results at least partially from cellular hyperplasia. Further studies are required to define the mechanisms involved in the growth of arteries under increased longitudinal stress.

Strain induced esophageal growth in a novel rodent model.

PURPOSE: Longitudinal esophageal strain has been shown to increase esophageal length but the contribution of tissue hyperplasia to this growth is unknown. We used a novel model of esophageal stretch to determine the cellular response to the strain stimulus. METHODS: Male Sprague-Dawley rats underwent transection of the distal esophagus. The distal stump was ligated and stretched over a silicone tube. The proximal esophageal stump was anastomosed to the stomach to restore continuity. After two, four, or seven days, the silicone tube was removed and the esophageal segment was measured and compared to its initial length. Sham animals had only a thin piece of silicone tubing placed. Standardized histologic sections were evaluated for wall thickness. Immunofluorescence with DAPI, Ki-67, and Myogenin antibodies was used to assess nuclear density, proliferation indices, and myoblast differentiation indices. RESULTS: Experimental animals demonstrated a significant increase in esophageal length compared to sham controls at four and seven days with no difference at two days. There was significant lengthening between four and seven days among the experimental animals. There was no change in wall thickness between experimental and sham animals at any time point. Nuclear density was increased at all time points, although this only reached significance at day four. Proliferation indices were significantly increased relative to sham controls at all time points. Esophageal strain induced significantly increased myoblast differentiation. CONCLUSION: In this novel rat model of esophageal strain, lengthening is associated with stable esophageal wall thickness, increased nuclear density, increased cellular proliferation, and increased myogenin expression. These data suggest that true tissue hyperplasia may contribute to the increased length seen after esophageal strain.

The effect of graft type on mortality in liver transplantation for hepatocellular carcinoma.

BACKGROUND: Liver transplantation (LT) with living-donor (LD-P) and deceased-donor (DD-P) partial grafts for hepatocellular carcinoma (HCC) may be associated with worse outcomes. Using the United Network for Organ Sharing (UNOS), we aimed to: (1) examine the risk of mortality in LT for HCC, (2) to establish if this risk is affected by partial graft use, and (3) to determine if this effect is mitigated by improved tumor-associated risk stratification. MATERIAL AND METHODS: All first-time adult LT recipients were analyzed (3/2002-12/2012), including 2,353 LD-P, 727 DD-P, and 47,833 DD whole (DD-W) grafts. Cox proportional hazards models were used to examine the risk of mortality given HCC. Interaction/subset analyses were used to examine the effect of tumor-risk and graft-type on outcome. Presence of an HCC exception and low alpha-fetoprotein (AFP) level (<66 ng/mL) were considered favorable. RESULTS: Overall, HCC was associated with an increased mortality risk compared to the absence of HCC (HR 1.21 [1.15-1.27]), and the use of partial grafts was noted to further intensify this risk. However, HCC with a favorable risk profile had more comparable outcomes to patients without HCC and this finding was similar across all graft-types (Given LD-P: HR 1.14 [0.76-1.73]; Given DD-P: HR1.05 [0.71-1.56]; Given DD-W: HR1.08 [1.02-1.14]). On subset analysis, all graft types had similar outcomes given either favorable-risk HCC or the absence of HCC. CONCLUSIONS: There is no significant difference in outcomes between whole and partial grafts given (1) patients with HCC with a favorable risk-profile or (2) patients without HCC.

Pulmonary support on day of life 30 is a strong predictor of increased 1 and 5-year morbidity in survivors of congenital diaphragmatic hernia.

PURPOSE: Pulmonary support (PS) on day-of-life-30 (DOL-30) has been shown to be the strongest predictor of subsequent morbidity and in-patient mortality in congenital diaphragmatic hernia (CDH). We hypothesized that PS on DOL-30 can also predict long-term outcomes in CDH survivors. METHODS: We analyzed records of 201 CDH survivors followed by a single multidisciplinary clinic (1995-2010). Follow-up was 83 and 70% at 1 and 5years respectively. PS was defined as: (1) invasive support (n=44), (2) noninvasive support (n=54), or (3) room air (n=103). Logistic regression was used to estimate the adjusted association of PS on DOL-30 with outcomes at 1 and 5-years. RESULTS: Use of PS on DOL-30 was significantly associated with pulmonary and developmental morbidities at 1 and 5-years. Even after adjusting for defect-size and presence of ventilation/perfusion mismatch, greater PS on DOL-30 was associated with a significantly increased odds of requiring supplemental oxygen and developmental referral at 1-year, and asthma and developmental referral at 5-years. CONCLUSION: CDH survivors continue to have significant long-term pulmonary and developmental morbidities. PS on DOL-30 is a strong independent predictor of morbidity at 1 and 5-years and may be used as a simple prognostic tool to identify high-risk infants.

Deceased-donor split-liver transplantation in adult recipients: is the learning curve over?

BACKGROUND: Infants have the highest wait-list mortality of all liver transplantation candidates. Deceased-donor split-liver transplantation, a technique that provides both an adult and pediatric graft, might be the best way to decrease this disproportionate mortality. Yet concern for an increased risk to adult split recipients has discouraged its widespread adoption. We aimed to determine the current risk of graft failure in adult recipients after split-liver transplantation. STUDY DESIGN: United Network for Organ Sharing data from 62,190 first-time adult recipients of deceased-donor liver transplants (1995-2010) were analyzed (889 split grafts). Bivariate risk factors (p < 0.2) were included in Cox proportional hazards models of the effect of transplant type on graft failure. RESULTS: Split-liver recipients had an overall hazard ratio of graft failure of 1.26 (p < 0.001) compared with whole-liver recipients. The split-liver hazard ratio was 1.45 (p < 0.001) in the pre-Model for End-Stage Liver Disease era (1995-2002) and 1.10 (p = 0.28) in the Model for End-Stage Liver Disease era (2002-2010). Interaction analyses suggested an increased risk of split-graft failure in status 1 recipients and those given an exception for hepatocellular carcinoma. Excluding higher-risk recipients, split and whole grafts had similar outcomes (hazard ratio = 0.94; p = 0.59). CONCLUSIONS: The risk of graft failure is now similar between split and whole-liver recipients in the vast majority of cases, which demonstrates that the expansion of split-liver allocation might be possible without increasing the overall risk of long-term graft failure in adult recipients. Additional prospective analysis should examine if selection bias might account for the possible increase in risk for recipients with hepatocellular carcinoma or designated status 1.

Pulmonary support on day 30 as a predictor of morbidity and mortality in congenital diaphragmatic hernia.

PURPOSE: Congenital diaphragmatic hernia (CDH) is associated with significant in-hospital mortality, morbidity and length-of-stay (LOS). We hypothesized that the degree of pulmonary support on hospital day-30 may predict in-hospital mortality, LOS, and discharge oxygen needs and could be useful for risk prediction and counseling. METHODS: 862 patients in the CDH Study Group registry with a LOS ≥ 30 days were analyzed (2007-2010). Pulmonary support was defined as (1) room-air (n=320) (2) noninvasive supplementation (n=244) (3) mechanical ventilation (n=279) and (4) extracorporeal membrane oxygenation (ECMO, n=19). Cox Proportional hazards and logistic regression models were used to determine the case-mix adjusted association of oxygen requirements on day-30 with mortality and oxygen requirements at discharge. RESULTS: On multivariate analysis, use of ventilator (HR 5.1, p=.003) or ECMO (HR 19.6, p<.001) was a significant predictor of in-patient mortality. Need for non-invasive supplementation or ventilator on day-30 was associated with a respective 22-fold (p<.001) and 43-fold (p<.001) increased odds of oxygen use at discharge compared to those on room-air. CONCLUSIONS: Pulmonary support on Day-30 is a strong predictor of length of stay, oxygen requirements at discharge and in-patient mortality and may be used as a simple prognostic indicator for family counseling, discharge planning, and identification of high-risk infants.

Report of 111 consecutive patients enrolled in the International Serial Transverse Enteroplasty (STEP) Data Registry: a retrospective observational study.

BACKGROUND: The International Serial Transverse Enteroplasty (STEP) Data Registry is a voluntary online database created in 2004 to collect information on patients undergoing the STEP procedure. The aim of this study was to identify preoperative factors that are significantly associated with transplantation or death or attainment of enteral autonomy after STEP. STUDY DESIGN: Data were collected from September 2004 to January 2010. Univariate and multivariate logistic regression analyses were applied to determine the predictors of transplantation or death or enteral autonomy post-STEP. Time to reach full enteral nutrition was estimated using a Kaplan-Meier curve. RESULTS: Fourteen of the 111 patients in the Registry were excluded due to inadequate follow-up. Of the remaining 97 patients, 11 patients died and 5 progressed to intestinal transplantation. On multivariate analysis, higher direct bilirubin and shorter pre-STEP bowel length were independently predictive of progression to transplantation or death (p = 0.05 and p < 0.001, respectively). Of the 78 patients who were 7 days of age or older and required parenteral nutrition at the time of STEP, 37 (47%) achieved enteral autonomy after the first STEP. Longer pre-STEP bowel length was also independently associated with enteral autonomy (p = 0.002). Median time to reach enteral autonomy based on Kaplan-Meier analysis was 21 months (95% CI, 12-30). CONCLUSIONS: Overall mortality post-STEP was 11%. Pre-STEP risk factors for progressing to transplantation or death were higher direct bilirubin and shorter bowel length. Among patients who underwent STEP for short bowel syndrome, 47% attained full enteral nutrition post-STEP. Patients with longer pre-STEP bowel length were significantly more likely to achieve enteral autonomy.

Ductus venosus closure results in transient portal hypertension--is this the silent trigger for necrotizing enterocolitis?

INTRODUCTION: The etiology of necrotizing enterocolitis (NEC) remains elusive and no definite trigger has been identified. There are no studies to date examining the potential role of closure of the ductus venosus (DV), its effect on increasing portal venous pressure (PVP) and its association to mesenteric venous ischemia in the development of NEC. Our aim was to develop an animal model to examine this physiology. METHODS: Fifteen near-term lambs were used. The DV was occluded in experimental animals by a balloon tip catheter, while the sham controls underwent catheterization without DV occlusion. Vital signs and PVP were monitored for 4h, followed by intestinal biopsy. RESULTS: The experimental group (n=5) demonstrated a significant increase in PVP following DV occlusion (11.87 mm Hg [95% CI: 11.40-12.34]), compared to controls (8.95 mm Hg [95% CI: 8.34-9.56]) (F=12.16, p=0.001). Histology of the terminal ileum showed vacuolar degeneration, indicative of reversible cellular damage in the experimental group. CONCLUSIONS: We demonstrate that DV closure in the neonatal lamb leads to transient portal hypertension which is associated with cellular damage and inflammatory changes of the intestinal mucosa. Additional studies will be necessary to determine if the transient portal hypertension following DV closure leads to clinically apparent intestinal ischemia and NEC.

Fragile X-associated tremor/ataxia syndrome in sisters related to X-inactivation.

Fragile X tremor/ataxia syndrome (FXTAS) is a recently described condition consisting of tremor, ataxia, parkinsonism, and executive dysfunction, presenting predominantly in male carriers of a fragile X mental retardation 1 premutation. In this report, we present premutation carrier sisters in whom severity of clinical signs correlated with a molecular pattern of X-inactivation favoring higher expression of the premutation allele. In these women with a common genetic background, we suggest that symptom severity may be dictated by X-inactivation, and thus a higher percentage of cells producing the premutation-containing mRNA result in increased toxicity and disease.

Psychopharmacology in fragile X syndrome--present and future.

In addition to cognitive disability, fragile X syndrome (FXS) is associated with behavioral problems that are often functionally limiting. There are few controlled trials to guide treatment; however, available information does suggest that medications can be quite helpful for a number of categories of behavioral disturbance in FXS. Specifically, stimulants appear to be quite useful for management of distractibility, hyperactivity, and impulsive behavior; antidepressants help with anxiety, obsessive-compulsive behaviors and mood dysregulation; and antipsychotics can reduce aggression. These medications are supportive and help minimize dysfunctional behaviors and maximize functioning. As more is learned about the neural functions of FMRP, medications in the future will be expected to target specific synaptic mechanisms dysregulated in FXS brain and thus ameliorate the cognitive deficit with resultant behavioral improvements. This article summarizes knowledge about effectiveness and approaches to management of currently available psychopharmacology for behavior in FXS and discusses early leads to future treatments for cognition.