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Biomedical subjects

John C Bucuvalas

Publications and source records attributed to John C Bucuvalas.

At least 19 recordsLinked to original sources
PubMed2006

High prevalence of renal dysfunction in long-term survivors after pediatric liver transplantation.

OBJECTIVE: To determine the prevalence and identify variables associated with renal dysfunction in long-term survivors of pediatric liver transplantation. STUDY DESIGN: Data from 117 patients who survived>or=3 years after liver transplantation were analyzed. Demographic and clinical information was obtained from chart review and from a clinical care database. The dependent variable was renal function as determined by measured glomerular filtration rate (mGFR). Univariate and multivariate analyses were performed to identify independent variables associated with renal dysfunction (mGFR<70 mL/min per 1.73 m2). RESULTS: The average time since liver transplant was 7.6+/-3.4 years (range, 3 to 14.6 years). When the last available mGFR for all patients was analyzed, renal dysfunction was present in 32%. In the univariate analysis, mGFR at 1 year after transplant, cyclosporine immunosuppression, and time since transplant were significant; the second two were strongly collinear. Using multiple logistic regression modeling excluding time since transplant, cyclosporine and mGFR at 1 year after transplant were strongly associated with renal dysfunction. CONCLUSIONS: Renal dysfunction is a common complication in children who survive liver transplantation. Our observations are of critical importance because children may live long enough to move from a stage of renal insufficiency characterized by asymptomatic decreased GFR to symptomatic end-stage renal disease.

Adolescent↗
PubMed2006

Outcomes after liver transplantation: keep the end in mind.

Since the advent of transplantation as a life-saving procedure for patients with end-stage liver disease, more than 15,000 children and adolescents have received liver transplants. With the improvements in long-term posttransplant survival offered by advances in medical and surgical therapy, the concept of transplantation outcome has expanded beyond simple patient and graft survival rates. The quality of the life years restored, the long-term complications of transplant immunosuppression, and the overall cost of care have been increasingly recognized as important components of liver transplantation outcome. This review focuses on the efforts of a single pediatric transplant center to examine the incidence of, and risk factors for, common posttransplantation complications, to characterize posttransplantation health-related quality of life, to describe the cost of posttransplant care, and to implement novel programs to improve health care delivery. Together, these projects set the future course for research and care improvement initiatives in this population and encourage us to "keep the end in mind" when considering pediatric liver transplantation.

Adolescent↗
PubMed2005

Low-dose chemotherapy for Epstein-Barr virus-positive post-transplantation lymphoproliferative disease in children after solid organ transplantation.

PURPOSE: To evaluate the efficacy of a low-dose chemotherapy regimen in children with Epstein-Barr virus (EBV) -positive, post-transplantation lymphoproliferative disease (PTLD) after organ transplantation who have experienced failure with front-line therapy for PTLD. PATIENTS AND METHODS: Eligible patients received cyclophosphamide (600 mg/m2 intravenous for 1 day) and prednisone (2 mg/kg orally for 5 days) every 3 weeks for six cycles. RESULTS: Thirty-six patients treated on study were assessable for analyses. Front-line therapies for PTLD before study entry included immune suppression reduction or withdrawal (n = 36), antiviral therapy (n = 33), surgical resection (n = 8), rituximab (n = 2), and interferon alfa (n = 1). Reasons for failure of front-line therapy included progressive disease (PD; n = 33) and persistent disease with concurrent allograft rejection (n = 3). Thirty patients (83%) had stage III to IV disease, 92% had extranodal disease, and 75% had > or = three sites of disease. The overall response rate was 83% (75% complete response + 8% partial response). The relapse rate was 19%, with only one of five relapsed patients alive and disease-free. Four patients presented with fulminant, disseminated PTLD; only one of these four patients achieved a response, and all four died of PD. Two patients died of treatment-related toxicity. Three patients (8%) experienced allograft loss, but two of the three patients are alive and disease-free after a second transplantation. The 2-year overall, relapse-free, and failure-free (without PTLD and with functioning original allograft) survival rates were 73%, 69%, and 67%, respectively. CONCLUSION: This low-dose chemotherapy regimen is effective for children with EBV-positive, nonfulminant PTLD who have experienced treatment failure with front-line therapy, and this study represents the largest series of PTLD patients treated prospectively with a uniform chemotherapy regimen.

Adolescent↗
PubMed2005

A novel approach to managing variation: outpatient therapeutic monitoring of calcineurin inhibitor blood levels in liver transplant recipients.

OBJECTIVE: To apply the principles of statistical process control (SPC) to manage calcineurin inhibitor (CNI) blood levels. We hypothesized that the use of SPC would increase the proportion of CNI blood levels in the target range. STUDY DESIGN: The study population consisted of 217 patients more than 3 months after liver transplantation. After demonstration of proof of concept using the rapid cycle improvement process, SPC was applied to the entire population. The change package included definition of target ranges for CNI, implementation of a web-based tool that displayed CNI blood levels on a control chart, and implementation of a protocol and a checklist for management of CNI blood levels. The principal outcome measure was the proportion of CNI blood levels in the target range. RESULTS: In the pilot study, the proportion of CNI blood levels in the target range increased from 50% to 85%. When the protocol was spread to the entire population, the proportion of drug levels in the target range increased to 77% from 50% (P < .001), whereas the range of CNI levels decreased. The rate of allograft rejection did not change. CONCLUSIONS: Utilization of SPC increased the proportion of CNI blood levels in target range. These observations may be applicable to the care of other chronic healthcare problems.

Ambulatory Care↗
PubMed2004

Predictors of length of stay for pediatric liver transplant recipients.

The resources that are directed towards the care of liver transplant recipients are substantial. Approximately 100 million dollars are spent on the hospitalization of the 400-500 children in the United States who undergo liver transplantation each year. Using length of stay as a surrogate marker for hospital resource use, we sought to identify factors that impact length of stay and assess the trends of hospitalization after liver transplantation for a representative population of pediatric liver transplant recipients. The study population was comprised of 956 patients who underwent primary liver transplantation between 1995 and 2003 and survived at least 90 days. Data were retrieved from the Studies of Pediatric Liver Transplantation data registry. The primary outcome was the length of initial hospitalization after liver transplantation. Independent variables were age, gender, race, pediatric end-stage liver disease score (PELD), year of transplantation, organ type, primary disease, length of operation, and insurance status. The mean and standard deviation of length of stay after liver transplantation was 24.0 +/- 24.5 days. Multivariate analyses showed that increased hospital stay was associated with infants less than 1 year of age, fulminant liver failure, receiving a technical variant organ from a cadaveric donor, government insurance, and transplant era (before 1999 vs. 1999 or later). Decreasing height z-scores and increasing length of operation were also associated with increased hospital stay. In conclusion, these parameters accounted for only 11% of the total variance, suggesting that post-transplant complications and course account for much of the variability of resource use in the immediate post-transplant period.

Cadaver↗
PubMed2004

Outcome after pediatric liver transplantation impact of living donor transplantation on cost.

OBJECTIVE: To compare the direct health care cost of living donor liver transplantation (LDLT) with that of cadaver donor liver transplantation (CDLT) in children and identify predictors of cost. STUDY DESIGN: All 16 children who underwent LDLT from January 1997 through January 2002 at Cincinnati Children's Hospital Medical Center comprised the study population. They were matched for age, diagnosis, and nutritional status with 31 children who received CDLT during the same era. A historic cohort analysis was performed. RESULTS: There was no difference in the 1-year mortality rates between both groups. Costs associated with graft retrieval contributed 15.3% and 31% of the initial transplant cost for LDLT and CDLT, respectively. Mean cost of care in the first year was 60.3% higher for LDLT than CDLT (P=.01). Multivariate analysis identified biliary complications and insurance status as predictors of cost for initial transplantation (R(2)=0.57), whereas biliary complications and pediatric end stage liver disease scores were identified as predictors of cost of care in the first year after transplantation (R(2)=0.77). CONCLUSIONS: The comprehensive cost of LDLT in the first year after transplantation is higher than cadaveric transplantation. This must be balanced against the time spent and care needs of patients on the waiting list.

Cadaver↗
PubMed2004

Impact of liver transplantation on HRQOL in children less than 5 years old.

Our primary goal was to assess health related quality of life (HRQOL) at transplantation and 1 yr after transplantation in pediatric liver transplant patients aged less than 5 years. We conducted a prospective longitudinal study of HRQOL in pediatric liver transplant recipients, aged less than 5 years to define the impact of liver transplantation on HRQOL and identify factors that predict HRQOL after transplantation. The infant toddler health status questionnaire (ITHQ) was completed at the time of listing for liver transplantation and at 6 and 12 months after liver transplantation. The primary outcome measures were the subscale scores that comprise ITHQ. The mean age (+/-s.e.m.) of the enrolled patients (n = 45) at transplantation was 1.4 (+/-1.2) yr. Thirty-eight (84%) of the enrolled patients completed the study. The highest mean baseline scores of 78.6 (+/-3.3) were for global mental health (GlobalMH). ITHQ subscale scores increased steadily after transplantation. The greatest increase was in the first 6 months after transplant. At 1 yr after transplantation, there were significant increases in all of the ITHQ subscale scores except for GlobalMH. ITHQ subscales were similar for patients who received LDLT compared with those who received cadaver donor liver transplantation (CDLT) at baseline and a year after transplant. Time elapsed as transplantation was a significant predictor of functional health in all of the models generated. Scores for general health (GH), global health (GGH), parental time-impact (PT) and parental time-emotion (PE) were higher for male children. Family cohesion (FC) improved with time elapsed since transplant and increased number of inpatient days. HRQOL improves after transplantation in all of our patients irrespective of the donor type. Functional health scores were higher in patients with normal serum bilirubin at 1 yr post-transplant. Assessment of HRQOL should be an integral part of care for liver transplant patients and their caregivers.

Bilirubin↗
PubMed2004

Pediatric transplantation of the kidney, liver and heart: summary report.

The following is a summary report of an extensive review of the literature from 1966 to 2001 on growth and development in children receiving kidney, liver and heart transplants. The literature was assessed for relevancy to current clinical practice and for reliability and generalizability of the inferences based on the study design, controls, sample size, age distribution, confounding factors, use of standardized instruments, and consistency with other findings. While studies on growth are included in the review, the main emphasis is on research in cognitive and psychosocial development since these areas have been far less thoroughly studied and contain various methodological deficiencies. On the basis of the literature review both general methodological recommendations and specific recommendations for future research studies are made. Access to the full is provided on the World Wide Web at http://light.emmes.com/pedstransplantation/.

Child↗
PubMed2004

Pediatric transplantation.

Analysis of the OPTN/SRTR database demonstrates that, in 2002, pediatric recipients accounted for 7% of all recipients, while pediatric individuals accounted for 14% of deceased organ donors. For children fortunate enough to receive a transplant, there has been continued improvement in outcomes following all forms of transplantation. Current 1-year graft survival is generally excellent, with survival rates following transplantation in many cases equaling or exceeding those of all other recipients. In renal transplantation, despite excellent early graft survival, there is evidence that long-term graft survival for adolescent recipients is well below that of other recipients. A causative role for noncompliance is possible. While the significant improvements in graft and patient survival are laudable, waiting list mortality remains excessive. Pediatric candidates awaiting liver, intestine, and thoracic transplantation face mortality rates generally greater than those of their adult counterparts. This finding is particularly pronounced in patients aged 5 years and younger. While mortality awaiting transplantation is an important consideration in refining organ allocation strategies, it is important to realize that other issues, in addition to mortality, are critical for children. Consideration of the impact of end-stage organ disease on growth and development is often equally important, both while awaiting and after transplantation.

Age Distribution↗
PubMed2003

Determination of risk factors for Epstein-Barr virus-associated posttransplant lymphoproliferative disorder in pediatric liver transplant recipients using objective case ascertainment.

BACKGROUND: Previous studies have suggested an increased risk of Epstein-Barr virus-associated posttransplant lymphoproliferative disorder (EBV-PTLD) in patients receiving tacrolimus for immunosuppression. We hypothesized that after correction for confounding variables, immunosuppression with tacrolimus is not associated with an increased risk of EBV-PTLD. METHODS: Potential cases of EBV-PTLD, identified by chart review, were independently ascertained by three clinicians and defined using published criteria. Agreement in diagnosing EBV-PTLD was measured using Kappa coefficients. Unadjusted and adjusted relative risk estimates were determined using proportional hazards regression. RESULTS: Twenty-three cases of EBV-PTLD were identified in 221 patients, a proportion of 10.4% (95% confidence interval [CI]: 6.4%-14.4%). Multivariable analysis revealed that immunosuppression with tacrolimus was associated with an increased risk of EBV-PTLD (relative risk 3.10: 95% CI: 1.21-7.92), as was age at transplantation as a continuous variable (parameter estimate -0.15, P=0.03). Kappa coefficients in diagnosing EBV-PTLD and subclassifying as neoplastic and non-neoplastic EBV-PTLD were 0.73 (95% CI: 0.54-0.93) and 0.54 (95% CI: 0.40-0.68), respectively. Patients with neoplastic PTLD demonstrated a lower probability of survival than patients with non-neoplastic PTLD and non-cases. CONCLUSIONS: Immunosuppression with tacrolimus and young age at transplantation are associated with an increased risk of EBV-PTLD in children undergoing liver transplantation, although we cannot exclude detection bias as an explanation for this observed increase. Good agreement between observers can be achieved using previously published criteria for defining EBV-PTLD. Patients with neoplastic EBV-PTLD may have a worse prognosis, and thus identification of risk factors for the development of this subtype of the disorder may be more important.

Aging↗
PubMed2003

Risk of hearing impairment in pediatric liver transplant recipients: a single center study.

As survival rates following liver transplantation have increased, health care providers must assess the impact of transplantation on dimensions other than traditional medical measures. Hearing impairment may adversely impact social, emotional, cognitive, academic, and speech and language development. We hypothesized that children who undergo liver transplantation are at risk for hearing impairment due to exposure to ototoxic drugs. We conducted a review of 74 children who had undergone liver transplantation between December 1996 and September 2000 at Cincinnati Children's Hospital Medical Center. Hearing was assessed at discharge by an audiologist using age and developmentally appropriate techniques. The principal outcome measure was sensorineural hearing impairment. Independent variables were age at transplantation, United Network for Organ Sharing (UNOS) status at transplantation, primary diagnosis, post-transplant length of hospital stay, days of treatment with aminoglycosides, and days of treatment with loop diuretics. Eleven of 74 children (15%) had sensorineural hearing loss, of whom four had severe to profound hearing loss. Multivariate analyses showed that the adjusted relative risk for hearing loss in patients with hepatoblastoma was 66 and that there was a 5% increase risk for hearing loss for each additional day of hospitalization. Age at transplantation, UNOS status, and days of treatment with loop diuretics or aminoglycosides did not achieve significance in the model. Sensorineural hearing impairment occurs in a subset of pediatric patients following liver transplantation. Patients with hepatoblastoma or those who experience prolonged hospitalization after transplantation are at increased risk. Our observations are of particular importance for pediatric liver transplant recipients since the median age at transplantation is 12-18 months, a critical period for language acquisition.

Biliary Atresia↗
PubMed2003

Health-related quality of life in pediatric liver transplant recipients: A single-center study.

The goals of the present study were (1) to measure health-related quality of life (HRQOL) in pediatric liver transplantation (LT), (2) to identify demographic and clinical factors that correlate with HRQOL, and (3) to compare two instruments that have been used to measure HRQOL in children and adolescents. We conducted a single-center cross-sectional study of 77 pediatric LT recipients ages 5 to 18 years, all of whom had had LT at least 6 months previously. We used the Child Health Questionnaire Parent Form 50 (CHQPF50) and the PedsQL4.0 to determine measured dimensions of physical and psychosocial health from the parents' perspective. Individual scale scores range from 0 to 100, with higher scores reflecting better health. Data on demographics, clinical status at transplantation, posttransplantation clinical course, and graft function were collected to identify predictors of posttransplantation HRQOL. Fifty-three percent of the liver transplant recipients had biliary atresia, 78% were white, and 61% were female. The mean age at LT was 3.8 +/- 3.6 years, and the range of time since LT was 1 to 15 years. HRQOL in pediatric liver transplant recipients was lower than that reported for healthy children but similar to that for children with other chronic illness. Age at transplantation, the time elapsed since transplantation, hospitalizations within the previous year, maternal education, and race were significant predictors of physical health. Age at transplantation and maternal education predicted psychosocial function. HRQOL was decreased in a population of pediatric liver transplant recipients compared with the general population and similar to that for children with chronic illness. Prospective longitudinal studies will permit us to define predictors of HRQOL at different periods of time after transplantation. The information gained from this study will help us to better define expectations and the clinical course after liver transplantation to patients and their families.

Adolescent↗
PubMed2003

Bone mineral density in long-term survivors following pediatric liver transplantation.

We sought to estimate the prevalence of reduced bone mass, defined by lumbar spine bone mineral density (LS-BMD) (z-score < -2.0), and to determine the factors associated with LS-BMD after liver transplantation in children and adolescents. LS-BMD z-scores were measured in a sample of subjects who had undergone liver transplantation in childhood or adolescence using dual energy x-ray absorptiometry (DXA). One hundred nine patients underwent DXA. The mean age at transplantation was 4.3 years (median, 1.8 years), and mean duration since transplantation was 6.2 years (median, 5.8 years). The mean weight z-score was -0.130 (SD, 1.26). The mean LS-BMD z-score was -0.243 (SD, 1.27). Eight patients, or 7.3% (95% confidence interval [CI], 2.4% to 12.2%), had reduced bone mass. Compared with those without reduced bone mass, subjects with reduced bone mass were more likely to have been treated for rejection at least once (87.5% versus 51.5%; P =.07), and had greater cumulative exposure to prednisone during the year before DXA (92.3 versus 26.2 mg/kg/y; P =.001). Multiple linear regression determined that LS-BMD z-score was positively associated with time since transplantation and weight z-score and negatively associated with cumulative prednisone exposure. Serum 25-OH vitamin D was measured and reduced (< 15 ng/mL) in 5 of 87 patients, one of whom had reduced bone mass. In conclusion, the prevalence of reduced bone mass was 7.3% in our population. Only certain patients appear to be at risk for low BMD, including those with a history of rejection. Screening for reduced bone mass may be appropriate for these patients.

Absorptiometry, Photon↗
PubMed2002

Long-term outcome after liver transplantation in children.

Children (defined as under 18 yr of age) account for approximately 12.5% of all liver transplants in the United States. Even though the annual number of liver transplantation procedures remains relatively constant, the population of long-term survivors of liver transplantation has grown. Presently, the population of long-term survivors of liver transplantation is 10-fold greater then the number of transplantations carried out each year. For long-term survivors of liver transplantation, the goal is to maintain graft function and wellness while decreasing the morbidity associated with long-term immunosuppression. The primary diagnosis leading to liver transplantation in children do not recur in the allograft. Consequently, many of the complications of liver transplantation, both early and long term, relate to the need for immunosuppression. Children may be at increased risk to develop significant end-organ damage as a result of increased serum lipid levels, elevated blood pressure, altered glucose metabolism, decreased renal function, cancer, and diminished bone accretion that occur as a result of immunosuppressive therapy or complications of therapy. As survival rates have increased, health care providers have begun to assess health-related quality of life. We will review our current knowledge of long-term outcome following pediatric liver transplantation in children.

Adaptation, Physiological↗