Carolyn L. Taylor

Relationship of Echocardiographic Z Scores Adjusted for Body Surface Area to Age, Sex, Race, and EthnicityCLINICAL PERSPECTIVE: The Pediatric Heart Network Normal Echocardiogram Database

Background— Published nomograms of pediatric echocardiographic measurements are limited by insufficient sample size to assess the effects of age, sex, race, and ethnicity. Variable methodologies have resulted in a wide range of Z scores for a single measurement. This multicenter study sought to determine Z scores for common measurements adjusted for body surface area (BSA) and stratified by age, sex, race, and ethnicity. Methods and Results— Data collected from healthy nonobese children ⩽18 years of age at 19 centers with a normal echocardiogram included age, sex, race, ethnicity, height, weight, echocardiographic images, and measurements performed at the Core Laboratory. Z score models involved indexed parameters (X/BSA&agr;) that were normally distributed without residual dependence on BSA. The models were tested for the effects of age, sex, race, and ethnicity. Raw measurements from models with and without these effects were compared, and <5% difference was considered clinically insignificant because interobserver variability for echocardiographic measurements are reported as ≥5% difference. Of the 3566 subjects, 90% had measurable images. Appropriate BSA transformations (BSA&agr;) were selected for each measurement. Multivariable regression revealed statistically significant effects by age, sex, race, and ethnicity for all outcomes, but all effects were clinically insignificant based on comparisons of models with and without the effects, resulting in Z scores independent of age, sex, race, and ethnicity for each measurement. Conclusions— Echocardiographic Z scores based on BSA were derived from a large, diverse, and healthy North American population. Age, sex, race, and ethnicity have small effects on the Z scores that are statistically significant but not clinically important.

Speckle-Tracking Echocardiography Improves Pre-operative Risk Stratification Before the Total Cavopulmonary Connection

Introduction: Single‐ventricle patients with elevated pulmonary vascular resistance (PVR) or end‐diastolic pressure (EDP) are excluded from undergoing total cavopulmonary connection (TCPC). However, a subset of patients deemed to be at acceptable risk experience prolonged length of stay (LOS) after TCPC. Routine assessment of ventricular function has been inadequate in identifying these high‐risk patients. Speckle‐tracking echocardiography (STE) is a novel method for assessment of myocardial deformation that may be useful in single‐ventricle patients. The aim of this study was to perform a contemporary preoperative risk assessment for prolonged LOS to determine whether STE improves risk stratification before TCPC. Methods: Our single institutions perioperative data were retrospectively collected. The primary outcome was postoperative LOS >14 days. Longitudinal and circumferential STE deformation measures were analyzed on echocardiograms obtained during preoperative catheterization. Patient‐specific, echocardiographic, and catheterization data were included in multivariable logistic regression. Receiver operating characteristic area under the curves (AUC) were analyzed. Results: From 2007 to 2014, 135 patients who underwent TCPC were included in the analysis. The median LOS was 11 (IQR 9‐14) days. The PVR (P < .01) and circumferential strain rate (CSR) (P < .01) were the only variables independently associated with LOS >14 days. For every 0.1 s−1 CSR increased, there was a 20% increased odds of prolonged LOS. The AUC for CSR was 0.70. The AUC for PVR and EDP combined was 0.68. The AUC for PVR, EDP, and CSR combined was 0.73. Conclusion: Preoperative CSR is independently associated with LOS >14 days and improves preoperative risk stratification in patients undergoing TCPC. HighlightsEchocardiography has had a limited role in risk stratifying patients undergoing total cavopulmonary connection.Our aim is to investigate the association between measures of myocardial deformation and postoperative length of stay after total cavopulmonary connection.Preoperative circumferential strain rate was associated with length of stay >14 days.Circumferential strain rate improved preoperative risk stratification in these patients.

Decline in ventricular function as a result of general anesthesia in pediatric heart transplant recipients

Echocardiography is frequently performed under anesthesia during procedures such as cardiac catheterization with EMB in pediatric HTx recipients. Anesthetic agents may depress ventricular function, resulting in concern for rejection. The aim of this study was to compare ventricular function as measured by echocardiography before and during GA in 17 pediatric HTx recipients. Nearly all markers of ventricular systolic function were significantly decreased under GA, including EF (−4.2% ±1.2, P < .01) and RV FAC (−0.05 ± 0.02, P = .04). Subjects in the first post‐transplant year (n = 9) trended toward a more significant decrease in EF vs those beyond the first post‐transplant year (n = 8; −6.0% ±1.2 vs −2.1 ± 2.0, P = .1). This information quantifies a decline in biventricular function that should be expected in pediatric HTx recipients while under GA and can assist the transplant clinician in avoiding unnecessary treatment of transient GA‐induced ventricular dysfunction.

Peak oxygen uptake (VO2peak) across childhood, adolescence and young adulthood in Barth syndrome: Data from cross-sectional and longitudinal studies

Barth syndrome (BTHS) is an ultra-rare, X-linked recessive disorder characterized by cardio-skeletal myopathy, exercise intolerance, and growth delay. Oxygen uptake during peak exercise (VO2peak) has been shown to be severely limited in individuals with BTHS however; the trajectory of VO2peak from childhood to young adulthood is unknown. The objective of this study was to describe VO2peak from childhood through young adulthood in BTHS. Methods and Materials: VO2peak over time was presented through cross-sectional (n = 33 participants) and a longitudinal analyses (n = 12 participants). Retrospective data were obtained through maximal exercise testing on a cycle ergometer from individuals with BTHS who were or are currently enrolled in a research study during July 2006-September 2017. Participants included in the cross-sectional analysis were divided into 3 groups for analysis: 1) children (n = 13), 2) adolescents (n = 8), and 3) young adults (n = 12). Participants in the longitudinal analysis had at least two exercise tests over a span of 2–9 years. Results: VO2peak relative to body weight (ml/kgBW/min), fat-free mass (FFM) and by percent of predicted VO2peak obtained were not significantly different between children, adolescents and young adults. VO2peak did not longitudinally change over a mean time of ~5 years in late adolescent and young adult participants with repeated tests. A model including both cardiac and skeletal muscle variables best predicted VO2peak. Conclusions: In conclusion, VO2peak relative to body weight and fat-free mass demonstrates short- and long-term stability from childhood to young adulthood in BTHS with some variability among individuals.

The Impact of the Left Ventricle on Right Ventricular Function and Clinical Outcomes in Infants with Single–Right Ventricle Anomalies up to 14 Months of Age

Background: Children with single–right ventricle anomalies such as hypoplastic left heart syndrome (HLHS) have left ventricles of variable size and function. The impact of the left ventricle on the performance of the right ventricle and on survival remains unclear. The aim of this study was to identify whether left ventricular (LV) size and function influence right ventricular (RV) function and clinical outcome after staged palliation for single–right ventricle anomalies. Methods: In the Single Ventricle Reconstruction trial, echocardiography‐derived measures of LV size and function were compared with measures of RV systolic and diastolic function, tricuspid regurgitation, and outcomes (death and/or heart transplantation) at baseline (preoperatively), early after Norwood palliation, before stage 2 palliation, and at 14 months of age. Results: Of the 522 subjects who met the study inclusion criteria, 381 (73%) had measurable left ventricles. The HLHS subtype of aortic atresia/mitral atresia was significantly less likely to have a measurable left ventricle (41%) compared with the other HLHS subtypes: aortic stenosis/mitral stenosis (100%), aortic atresia/mitral stenosis (96%), and those without HLHS (83%). RV end‐diastolic and end‐systolic volumes were significantly larger, while diastolic indices suggested better diastolic properties in those subjects with no left ventricles compared with those with measurable left ventricles. However, RV ejection fraction was not different on the basis of LV size and function after staged palliation. Moreover, there was no difference in transplantation‐free survival to Norwood discharge, through the interstage period, or at 14 months of age between those subjects who had measurable left ventricles compared with those who did not. Conclusions: LV size varies by anatomic subtype in infants with single–right ventricle anomalies. Although indices of RV size and diastolic function were influenced by the presence of a left ventricle, there was no difference in RV systolic function or transplantation‐free survival on the basis of LV measures. Highlights:In HLHS, the left ventricle can be of variable size.RV size is larger in patients with no measurable left ventricles.Diastolic indices are slightly better in patients with no measurable left ventricles.RV function and mortality are not affected by LV size.

Longitudinal measures of deformation are associated with a composite measure of contractility derived from pressure–volume loop analysis in children

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 were performed immediately after PVL analysis under the same anesthetic conditions. Conventional and speckle-tracking echocardiographic measures of systolic function were measured. Of 24 patients, 18 patients were heart transplant recipients, 6 patients had a small patent ductus arteriosus or small coronary fistula. Mean age was 9.1 ± 5.6 years. Upon multivariable regression, longitudinal strain was associated with ICCI (β = -0.54, P = 0.02) while controlling for indices of preload, afterload, heart rate, and LV mass under baseline conditions. Ejection fraction and shortening fraction were associated with LV mass and load indices, but not contractility. Conclusion Speckle-tracking derived longitudinal strain is associated ICCI in children with normal loading conditions. Longitudinal measures of deformation appear to accurately assess LV contractility in children.

DETECTION OF HEART FAILURE WITH PRESERVED EJECTION FRACTION IN SINGLE VENTRICLE PHYSIOLOGY: INSIGHTS FROM THE PEDIATRIC HEART NETWORK FONTAN CROSS-SECTIONAL STUDY PUBLIC USE DATASET

Introduction: Patients with single ventricle physiology frequently demonstrate decreased exercise tolerance after the Fontan operation. The objective of this study was to investigate the contribution of diastolic function to exercise function in these patients. Methods: Core-lab echocardiograms and

Echocardiographic Detection of Increased Ventricular Diastolic Stiffness in Pediatric Heart Transplant Recipients: A Pilot Study

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, &bgr;, was calculated. Echocardiographic measures of diastolic function were derived from spectral and tissue Doppler and two‐dimensional speckle‐tracking. Ventricular volumes were measured using three‐dimensional echocardiography. The novel echocardiographic estimates of ventricular stiffness included E:e′/end‐diastolic volume (EDV) and E:early diastolic strain rate/EDV. Results: Of 24 children, 18 were heart transplant recipients. Six control patients had hemodynamically insignificant patent ductus arteriosus or coronary fistula. The mean age was 9.1 ± 5.6 years. Median end‐diastolic pressure was 9 mm Hg (interquartile range, 8–13 mm Hg). Lateral E:e′/EDV (r = 0.59, P < .01), septal E:e′/EDV (r = 0.57, P < .01), and (E:circumferential early diastolic strain rate)/EDV (r = 0.54, P < .01) correlated with &bgr;. Lateral E:e′/EDV displayed a C statistic of 0.93 in detecting patients with abnormal LV stiffness (&bgr; > 0.015 mL−1). A lateral E:e′/EDV of >0.15 mL−1 had 89% sensitivity and 93% specificity in detecting an abnormal &bgr;. Conclusions: Echocardiographic estimates of ventricular stiffness may be accurate compared with the gold standard in pediatric heart transplant recipients. The clinical usefulness of these noninvasive measures in assessing LV stiffness merits further study in children.

Reproducibility of Left Ventricular Dimension Versus Area Versus Volume Measurements in Pediatric Patients With Dilated CardiomyopathyCLINICAL PERSPECTIVE

Background— Multiple echocardiographic methods are used to measure left ventricular size and function. Clinical management is based on individual evaluations and longitudinal trends. The Pediatric Heart Network VVV study (Ventricular Volume Variability) in pediatric patients with dilated cardiomyopathy has reported reproducibility of several of these measures, and how disease state and number of beats impact their reproducibility. In this study, we investigated the impact of observer and sonographer variation on reproducibility of dimension, area, and volume methods to determine the best method for both individual and sequential evaluations. Methods and Results— In 8 centers, echocardiograms were obtained on 169 patients prospectively. During the same visit, 2 different sonographers acquired the same imaging protocol on each patient. Each acquisition was analyzed by 2 different observers; first observer analyzed the first acquisition twice. Intraobserver, interobserver, interacquisition, and interobserver-acquisition (different observers and different acquisition) reproducibility were assessed on measurements of left ventricular end-diastolic dimension, area, and volume. Left ventricular shortening fraction, ejection fraction, mass, and fractional area change were calculated. Percent difference was calculated as (interobservation difference/mean)×100. Interobserver reproducibility for both acquisitions was better for both volume and dimension measurements (P⩽0.002) compared with area measurements, whereas intraobserver, interacquisition (for both observers), and interobserver-acquisition reproducibilities (for both observer-acquisition sets) were best for volume measurements (P⩽0.01). Overall, interobserver-acquisition percent differences were significantly higher than interobserver and interacquisition percent differences (P<0.001). Conclusions— In pediatric patients with dilated cardiomyopathy, compared with dimension and area methods, left ventricular measurements by volume method have the best reproducibility in settings where assessment is not performed by the same personnel. Clinical Trial Registration— URL: https://www.clinicaltrials.gov. Unique identifier: NCT00123071.

SPECKLE-TRACKING ECHOCARDIOGRAPHY IS USEFUL IN PRE-OPERATIVE RISK STRATIFICATION PRIOR TO THE FONTAN PROCEDURE

Single ventricular function is thought to be associated with outcomes after staged surgical palliation. However, challenges exist in reliably quantifying ventricular function in patients with heterogenous ventricular morphologies. Speckle-tracking echocardiography (STE) is a geometry-independent