Cardiology Commons^™

A Population Pharmacokinetic Model For Simvastatin And Its Metabolites In Children And Adolescents., Kayode Ogungbenro, Jonathan B. Wagner, Susan M. Abdel-Rahman, J Steven Leeder, Aleksandra Galetin

Manuscripts, Articles, Book Chapters and Other Papers

PURPOSE: Poor adherence to dietary/behaviour modifications as interventions for hypercholesterolemia in paediatric patients often necessitates the initiation of statin therapy. The aim of this study was to develop a joint population pharmacokinetic model for simvastatin and four metabolites in children and adolescents to investigate sources of variability in simvastatin acid exposure in this patient population, in addition to SLCO1B1 genotype status.

METHODS: Plasma concentrations of simvastatin and its four metabolites, demographic and polymorphism data for OATP1B1 and CYP3A5 were analysed utilising a population pharmacokinetic modelling approach from an existing single oral dose (10 mg < 17 years and 20 mg ≥ 18 years) pharmacokinetic dataset of 32 children and adolescents.

RESULTS: The population PK model included …

Longitudinal Measures Of Deformation Are Associated With A Composite Measure Of Contractility Derived From Pressure-Volume Loop Analysis In Children., Shahryar M. Chowdhury, Ryan J. Butts, Carolyn L. Taylor, Varsha M. Bandisode, Karen S. Chessa, Anthony M. Hlavacek, Arni Nutting, Girish S. Shirali, G Hamilton Baker

Manuscripts, Articles, Book Chapters and Other Papers

Aims: The relationship between echocardiographic measures of left ventricular (LV) systolic function and reference-standard measures have not been assessed in children. The objective of this study was to assess the validity of echocardiographic indices of LV systolic function via direct comparison to a novel composite measure of contractility derived from pressure-volume loop (PVL) analysis.

Methods and results: Children with normal loading conditions undergoing routine left heart catheterization were prospectively enrolled. PVLs were obtained via conductance catheters. A composite invasive composite contractility index (ICCI) was developed using data reduction strategies to combine four measures of contractility derived from PVL analysis. Echocardiograms …

Echocardiographic Detection Of Increased Ventricular Diastolic Stiffness In Pediatric Heart Transplant Recipients: A Pilot Study., Shahryar M. Chowdhury, Ryan J. Butts, Anthony M. Hlavacek, Carolyn L. Taylor, Karen S. Chessa, Varsha M. Bandisode, Girish S. Shirali, Arni Nutting, G Hamilton Baker

Manuscripts, Articles, Book Chapters and Other Papers

Background: Pediatric heart transplant recipients are at risk for increased left ventricular (LV) diastolic stiffness. However, the noninvasive evaluation of LV stiffness has remained elusive in this population. The objective of this study was to compare novel echocardiographic measures of LV diastolic stiffness versus gold-standard measures derived from pressure-volume loop (PVL) analysis in pediatric heart transplant recipients.

Methods: Patients undergoing left heart catheterization were prospectively enrolled. PVLs were obtained via conductance. The end-diastolic pressure-volume relationship was obtained via balloon occlusion. The stiffness constant, β, was calculated. Echocardiographic measures of diastolic function were derived from spectral and tissue Doppler and two-dimensional …

Validation Of Noninvasive Measures Of Left Ventricular Mechanics In Children: A Simultaneous Echocardiographic And Conductance Catheterization Study., Shahryar M. Chowdhury, Ryan J. Butts, Carolyn L. Taylor, Varsha M. Bandisode, Karen S. Chessa, Anthony M. Hlavacek, Girish S. Shirali, G Hamilton Baker

Manuscripts, Articles, Book Chapters and Other Papers

BACKGROUND: The accuracy of echocardiography in evaluating left ventricular contractility has not been validated in children. The objective of this study was to compare echocardiographic measures of contractility with those derived from pressure-volume loop (PVL) analysis in children.

METHODS: Patients with relatively normal loading conditions undergoing routine left heart catheterization were prospectively enrolled. PVLs were obtained via conductance catheters. The gold-standard measure of contractility, end-systolic elastance (Ees), was obtained via balloon occlusion of one or both vena cavae. Echocardiograms were performed immediately after PVL analysis under the same anesthetic conditions. Single-beat estimations of echocardiographic Ees were calculated using four different …

The Reproducibility And Absolute Values Of Echocardiographic Measurements Of Left Ventricular Size And Function In Children Are Algorithm Dependent., Renee Margossian, Shan Chen, Lynn A. Sleeper, Lloyd Y. Tani, Girish S. Shirali, Fraser Golding, Elif Seda Selamet Tierney, Karen Altmann, Michael J. Campbell, Anita Szwast, Angela Sharkey, Elizabeth Radojewski, Steven D. Colan, Pediatric Heart Network Investigators

Manuscripts, Articles, Book Chapters and Other Papers

BACKGROUND: Several quantification algorithms for measuring left ventricular (LV) size and function are used in clinical and research settings. The aims of this study were to investigate the effects of measurement algorithm and beat averaging on the reproducibility of measurements of the left ventricle and to assess the magnitude of agreement among the algorithms in children with dilated cardiomyopathy.

METHODS: Echocardiograms were obtained in 169 children from eight clinical centers. Inter- and intrareader reproducibility was assessed on measurements of LV volumes using the biplane Simpson, modified Simpson, and 5/6 × area × length (5/6AL) algorithms. Percentage error was calculated as …

Functional Health Status In Children And Adolescents After Fontan: Comparison Of Generic And Disease-Specific Assessments., Brian W. Mccrindle, Victor Zak, Victoria L. Pemberton, Linda M. Lambert, Victoria L. Vetter, Wyman W. Lai, Karen Uzark, Renee Margossian, Andrew M. Atz, Amanda Cook, Jane W. Newburger, Pediatric Heart Network Investigators, Girish S. Shirali

Manuscripts, Articles, Book Chapters and Other Papers

PURPOSE: The aim of this study was to compare associations between generic versus disease-specific functional health status assessments and patient and clinical characteristics for patients with severe congenital heart disease.

METHODS: This was a cross-sectional observational study involving 325 single ventricle patients, aged 10-18 years, after Fontan procedure. Enrolled patients underwent a medical history review, laboratory testing, and assessment of the functional health status by completion of the generic Child Report Child Health Questionnaire and the disease-specific Congenital Heart Adolescent and Teenage questionnaire. Correlated conceptually equivalent domains from both questionnaires were identified and their associations with patient and clinical variables …

Lean Body Mass May Explain Apparent Racial Differences In Carotid Intima-Media Thickness In Obese Children., Shahryar M. Chowdhury, Melissa H. Henshaw, Brad Friedman, J Philip Saul, Girish S. Shirali, Janet Carter, Bryana M. Levitan, Tom Hulsey

Manuscripts, Articles, Book Chapters and Other Papers

Background: Racial differences in carotid intima-media thickness (cIMT) have been suggested to be associated with the disproportionally high prevalence of cardiovascular disease in black adults. The objective of this study was to evaluate the effects of cardiovascular risk factors on the racial differences seen in cIMT in obese children.

Methods: Obese subjects aged 4 to 21 years were recruited prospectively. Height, weight, blood pressure, fasting insulin, glucose, lipid panel, high-sensitivity C-reactive protein, and body composition by dual-energy x-ray absorptiometry were obtained. B-mode carotid imaging was analyzed by a single blinded physician.

Results: A total of 120 subjects (46 white, 74 …

Predictors Of Disease Progression In Pediatric Dilated Cardiomyopathy., Kimberly M. Molina, Peter Shrader, Steven D. Colan, Seema Mital, Renee Margossian, Lynn A. Sleeper, Girish S. Shirali, Piers Barker, Charles E. Canter, Karen Altmann, Elizabeth Radojewski, Elif Seda Selamet Tierney, Jack Rychik, Lloyd Y. Tani, Pediatric Heart Network Investigators

Manuscripts, Articles, Book Chapters and Other Papers

Background: Despite medical advances, children with dilated cardiomyopathy (DCM) remain at high risk of death or need for cardiac transplantation. We sought to identify predictors of disease progression in pediatric DCM.

Methods and results: The Pediatric Heart Network evaluated chronic DCM patients with prospective echocardiographic and clinical data collection during an 18-month follow-up. Inclusion criteria were age <22 years and DCM disease duration >2 months. Patients requiring intravenous inotropic/mechanical support or listed status 1A/1B for transplant were excluded. Disease progression was defined as an increase in transplant listing status, hospitalization for heart failure, intravenous inotropes, mechanical support, or death. Predictors of disease progression were identified using …

Pediatric Pharmacogenomics: A Systematic Assessment Of Ontogeny And Genetic Variation To Guide The Design Of Statin Studies In Children., Jonathan B. Wagner, J Steven Leeder

Manuscripts, Articles, Book Chapters and Other Papers

The dose-exposure-response relationship for drugs may differ in pediatric patients compared with adults. Many clinical studies have established drug dose-exposure relationships across the pediatric age spectrum; however, genetic variation was seldom included. This article applies a systematic approach to determine the relative contribution of development and genetic variation on drug disposition and response using HMG-CoA reductase inhibitors as a model. Application of the approach drives the collection of information relevant to understanding the potential contribution of ontogeny and genetic variation to statin dose-exposure-response in children, and identifies important knowledge deficits to be addressed through the design of future studies.

The Ventricular Volume Variability Study Of The Pediatric Heart Network: Study Design And Impact Of Beat Averaging And Variable Type On The Reproducibility Of Echocardiographic Measurements In Children With Chronic Dilated Cardiomyopathy., Steven D. Colan, Girish S. Shirali, Renee Margossian, Dianne Gallagher, Karen Altmann, Charles Canter, Shan Chen, Fraser Golding, Elizabeth Radojewski, Michael Camitta, Michael Carboni, Jack Rychik, Mario Stylianou, Lloyd Y. Tani, Elif Seda Selamet Tierney, Yanli Wang, Lynn A. Sleeper, Pediatric Heart Network Investigators

Manuscripts, Articles, Book Chapters and Other Papers

BACKGROUND: Clinical trials often rely on echocardiographic measures of left ventricular size and function as surrogate end points. However, the quantitative impact of factors that affect the reproducibility of these measures is unknown. To address this issue, the National Heart, Lung, and Blood Institute-funded Pediatric Heart Network designed a longitudinal observational study of children with known or suspected dilated cardiomyopathy aged 0 to 22 years from eight pediatric clinical centers.

METHODS: Clinical data were collected together with 150 echocardiographic indices of left ventricular size and function. Separate observers performed duplicate echocardiographic imaging. Multiple observers performed measurements from three cardiac cycles …