Aortic Valve Thrombus, Stroke, and Endovascular Thrombectomy in a Child With APML and Trisomy 21.

APML, a subtype of acute myeloid leukemia, is highly curable, with cure rates over 90%. Despite its therapeutic success, APML poses elevated bleeding risks due to frequent prior disseminated intravascular coagulation. Less commonly recognized but critical is the thrombotic risk. We document a unique pediatric case: a 13-year-old with trisomy 21 diagnosed with APML had an asymptomatic aortic valve thrombus leading to thromboembolic arterial ischemic stroke. Through endovascular thrombectomy, cerebral circulation was re-established, extracting a fibrin thrombus with APML cells. Neurological recovery was swift. This report underscores the importance of vigilance for thrombotic complications in APML, highlighting the potential severity of overlooked risks.

Practice Patterns in the Management of Pressure Restrictive Perimembranous Ventricular Septal Defects: A Multinational Survey.

Indications for the closure of pressure restrictive perimembranous ventricular septal defects (pmVSD) are not well established in the pediatric population. We sought to assess practice variability among pediatric cardiologists in the United States (US), Canada, Australia, and New Zealand. A survey ascertaining practice patterns, including case vignettes with incremental progression of disease severity, was designed and administered through representative professional cardiac organizations and email listservs in the designated countries. Among the 299 respondents, 209 (70.0%) were from the US, 65 (21.7%) were from Canada and 25 (8.3%) were from Australia and New Zealand. Indications for pressure restrictive pmVSD closure included the presence of left ventricular (LV) dilation for 81.6% (244/299) (defined as z-score ≥ 2 for 59.0% (144/244) and ≥ 3 for 40.2% (98/244)) and significant pulmonary-systemic flow ratio (QP:QS) for 71.2% (213/299) [defined as ≥ 1.5:1 for 36.2% (77/213) and ≥ 2 for 62% (132/213)]. US pediatric cardiologists elected to close restrictive pmVSD at lower LV z-score and QP:QS ratio cut-offs (p-value 0.0002 and 0.013, respectively). In a case vignette, 63.6% (173/272) chose to intervene if there was right coronary cusp prolapse with stable mild aortic regurgitation. Of the remaining cardiologists, 93% (92/99) intervened if the aortic regurgitation was progressive (from trivial to mild). Commonly identified indications with variable thresholds for closure of pressure restrictive pmVSDs included the presence or progression of LV dilation, significant volume loading, and aortic valve prolapse with regurgitation. US pediatric cardiologists may have a lower threshold for pmVSD closure.

QTc and QRS Abnormalities are Associated with Outcome in Pediatric Heart Failure.

Adult studies have shown that depolarization and repolarization abnormalities are associated with worsening heart failure; however, this relationship is not well understood in pediatric congenital heart disease. We evaluated the association between QTc and QRS duration to systolic function and outcome in children with heart failure and reduced ejection fraction (HFrEF). We performed a retrospective, single-center, 14-year cohort study of HFrEF children. Clinical records, echocardiograms, and electrocardiograms were reviewed for every clinical encounter. Diagnosis, interventions, outcomes, QRS and QTc duration, and systolic function were collected. Repeated-measure ANOVA evaluated the association between depolarization and repolarization to cardiac function. Cox regression analysis examined the effects of age, time since diagnosis, and measured and change in QTc and QRS duration on time to transplant/death. We enrolled 136 cardiomyopathy (CM) and 47 structural heart disease (SHD) patients. Prolonged QRS (p = 0.0001) and QTc (p = 0.02) were associated with systolic dysfunction. This association was significant in SHD group (QRS p < 0.0001, QTc p = 0.048), but not CM group (QRS p = 0.5, QTc p = 0.3). Progressive lengthening of QTc was significantly associated with transplant or death in the overall cohort (HR 1.02, CI 1.011-1.028), SHD, (HR 1.020, CI 1.001-1.039), and CM (HR 1.017, CI 1.007-1.027). QTc and QRS prolongation are each associated with ventricular dysfunction in pediatric SHD with heart failure. QTc prolongation is an indication for poor outcomes in SHD and CM groups, leading to a higher risk of death or transplantation. Progressive lengthening of QTc over time in children with HFrEF may indicate increased risk in this population.

Echocardiographic Predictors of Ductal Tissue-Related Branch Pulmonary Artery Stenosis in Pulmonary Atresia.

Branch pulmonary artery (PA) stenosis due to ductus arteriosus (DA) tissue (DA-PS) contributes to the morbidity associated with pulmonary atresia (PAtr). We sought to identify preoperative echocardiographic features predictive of DA-PS. Patients consecutively encountered with PAtr and a DA-dependent pulmonary circulation at birth who underwent intervention in our program over a 5-year period were identified and records reviewed. Preoperative echocardiograms were reviewed to identify features that predicted postoperative DA-PS. Seventy patients with PAtr met inclusion criteria and 36 (51%) had DA-PS. At preoperative echocardiography, the proximal diameter of the PA ipsilateral to the DA was smaller in those with versus without DA-PS (Z-score - 4.8 ± 1.7 vs - 1.1 ± 1.7, respectively p < 0.001). PA origins could not be imaged on the same axial plane in 21/36 (58%) with versus 2/34 (6%) without DA-PS. Patients with DA-PS had an obtuse posterior angle of the PA bifurcation compared to those without (128 ± 17° and 87 ± 21°, p < 0.001), and a posterior angle of > 100° best predicted DA-PS with a sensitivity of 97% and specificity of 76%. An abnormal PA relationship and/or an obtuse posterior bifurcation angle had a sensitivity, specificity, positive and negative predictive value for DA-PS of 78%, 94%, 90% and 86%, respectively. Finally, DA insertion was into the ipsilateral PA in 26/36 (72%) of cases with DA-PS. A smaller proximal ipsilateral PA diameter, inability to image the PAs in the same plane, a posterior PA bifurcation angle of > 100°, and insertion of the DA in the ipsilateral PA demonstrated by echo are useful in identifying patients at risk for DA-PS.

Echocardiographic Assessment of Right Ventricular Function in Paediatric Heart Disease: A Practical Clinical Approach.

As the right ventricle (RV) plays an integral role in different paediatric heart diseases, the accurate assessment of RV size and function is essential in the diagnosis, management, and prognostication of congenital and acquired cardiac lesions. Yet, echocardiographic evaluation of the RV is challenging because of its complex and variable morphology, its different physiology compared with the left ventricle, and its capability to adapt to different loading conditions associated with congenital and acquired heart diseases within certain ranges. Reliable echocardiographic detection of RV systolic and diastolic dysfunction remains challenging while important for patient management. This review provides an updated, practical approach to assessing RV function in structurally normal hearts and in children with common congenital heart defects and in those with pulmonary hypertension. We also review the impact of tricuspid valve function on RV functional parameters. There is no single functional RV parameter that uniquely describes RV function; instead a combination of different parameters is recommended in clinical practice. Qualitative and quantitative analysis of RV function will be reviewed including more recent techniques such as speckle tracking and 3D echocardiography.

Étant donné que le ventricule droit (VD) joue un rôle déterminant dans diverses cardiopathies pédiatriques, l'évaluation précise de sa taille et de sa fonction s'avère essentielle pour le diagnostic, la prise en charge et le pronostic des lésions cardiaques congénitales et acquises. Pourtant, il s'avère difficile d'effectuer une évaluation échocardiographique du VD en raison de sa morphologie complexe et variable, des caractéristiques physiologiques qui le distingue du ventricule gauche et de sa capacité à s'adapter dans une certaine mesure à différentes conditions de charge associées aux cardiopathies congénitales et acquises. La détection échocardiographique fiable des dysfonctions systolique et diastolique du VD représente encore un défi, tout en étant importante pour la prise en charge des patients. Le présent article de synthèse propose une approche pratique et actualisée pour l'évaluation de la fonction ventriculaire droite en l'absence d'anomalie structurelle cardiaque, de même qu'en présence d'anomalies cardiaques congénitales courantes ou d'hypertension pulmonaire chez les enfants. Nous examinons également l'effet de la fonction valvulaire tricuspide sur les paramètres de la fonction ventriculaire droite. Aucun paramètre fonctionnel pris isolément ne suffit à décrire la fonction ventriculaire droite; le recours à une combinaison de différents paramètres est plutôt recommandé en pratique clinique. L'analyse qualitative et quantitative de la fonction ventriculaire droite sera abordée, y compris des techniques plus récentes telles que l'échocardiographie de suivi des marqueurs acoustiques (speckle tracking) et l'échocardiographie tridimensionnelle.

Insights from 3D Echocardiography in Hypoplastic Left Heart Syndrome Patients Undergoing TV Repair.

BACKGROUND: Tricuspid regurgitation (TR) in hypoplastic left heart syndrome (HLHS) is associated with morbidity and mortality. TR mechanisms and the impact of tricuspid valve repair (TVR) are unclear. We examined HLHS TR mechanisms, TVR's impact on tricuspid valve (TV), and features of poor TVR durability. METHODS: We retrospectively compared 35 HLHS TVR cases and 35 age/stage-matched HLHS controls who do not undergo TVR. Pre-operative 3-dimensional echocardiography (3DE) assessed overall TV morphology (prolapse, normal, tethered), leaflet morphology, vena contracta area, and TR location. Two-dimensional echocardiography measured TV annulus diameter, RV fractional area change (RVFAC), sphericity, and TR grade at three time points (pre-op, early post-op, and latest follow-up). RESULTS: Pre-op, TVR group, and controls had no difference in age, RV function or shape, or TV dimension. TVR group most commonly had anterior leaflet prolapse followed by septal leaflet prolapse or tethering. TR jet arises centrally (63%) and anterior septally (26%). Posterior annuloplasty (69%), commissuroplasty (37%), and leaflet repair (37%) were surgical techniques commonly performed. At early post-op, TR grade and TV annulus decreased. At latest follow-up, TV annulus remained reduced; however, 50% had significant TR. 25% required TV reoperation. Larger vena contracta at TVR was associated with significant TR. CONCLUSION: HLHS patients undergoing TVR had more anterior leaflet prolapse and central TR. While TVR initially reduces annular size and TR grade, 50% redevelop significant TR despite maintained annular reduction. The association of greater TR severity prior to repair with post-op recurrence raises the consideration for earlier repair of TR in HLHS patients.

Tricuspid Valve Tethering Is Associated with Residual Regurgitation after Valve Repair in Hypoplastic Left Heart Syndrome: A Three-Dimensional Echocardiographic Study.

BACKGROUND: Tricuspid valve regurgitation (TR) is a risk factor for morbidity and mortality in children with hypoplastic left heart syndrome (HLHS). Surgical tricuspid valve (TV) repair is common, but durable repair remains challenging. The aim of this study was to examine mechanisms of TR requiring surgery, features associated with unsuccessful repair, and TV changes after surgical repair. METHODS: Thirty-six patients with HLHS requiring TV repair (TVR) and 36 matched control subjects with HLHS were assessed using two-dimensional and three-dimensional echocardiography. Using three-dimensional echocardiography, TV coordinates from the annulus, leaflet, and ventricle were used to measure annular, leaflet, prolapse, and tethering values and anterior papillary muscle angle. TR grade and ventricular size, function, and shape were assessed using two-dimensional echocardiography. RESULTS: Patients requiring TVR had greater total leaflet prolapse, larger TV annular and leaflet areas, and flatter annuli, with no difference in tethering, coaptation index, or anterior papillary muscle angle. In patients with HLHS, successful TVR at follow-up (58%) was associated with preoperative total leaflet prolapse (especially posterior). Unsuccessful repair was associated with preoperative tethering of the septal leaflet. TVR in patients with HLHS caused a reduction of total annular and leaflet size and reduced prolapse and tethering of the posterior leaflet but did not affect anterior leaflet prolapse or septal leaflet tethering. CONCLUSIONS: Features associated with TVR include a flattened and dilated TV annulus with leaflet prolapse. The additional presence of a tethered septal leaflet before TVR is associated with significant postoperative TR. Current surgical techniques, predominantly posterior annuloplasty and commissuroplasty, adequately address annular size and posterior leaflet pathology, but not septal leaflet tethering. Individualized and innovative surgical techniques are vital to improve surgical repair success.

Tricuspid Regurgitation in Hypoplastic Left Heart Syndrome: Three-Dimensional Echocardiography Provides Additional Information in Describing Jet Location.

BACKGROUND: Twenty-five percent of patients with hypoplastic left heart syndrome (HLHS) require tricuspid valve (TV) repair. The location of tricuspid regurgitation (TR) is important in determining the type of repair performed. Studies using three-dimensional echocardiography (3DE) have reported a high incidence of error on two-dimensional echocardiography (2DE) for the identification of TV leaflets. The aim of this study was to compare assessment of TR on 3DE and 2DE in patients with HLHS (jet location, TR grade, and reproducibility). METHODS: A retrospective, single-center review was performed. Fifty-six patients with HLHS with available two-dimensional and three-dimensional echocardiograms, and mild or greater TR, were included. TR location, grade, vena contracta area, and TV annular diameter were measured on 2DE and 3DE. Reproducibility was assessed by blinded reviewers. RESULTS: Three-dimensional echocardiography identified the primary jet location as central (57%) followed by anteroseptal (36%). There was poor agreement between findings on 3DE and 2DE for jet location (κ = 0.05; 95 CI, -0.08 to 0.19). Interobserver reproducibility for location on 3DE was excellent (κ = 0.8), whereas reproducibility for 2DE was poor (κ = 0.32). The most common jet location pre-Norwood and pre-Glenn was central (70%), whereas pre-Fontan and post-Fontan, jet location was central (45%) and anteroseptal (48%). Vena contracta area on 2DE correlated moderately with vena contracta area on 3DE (r = 0.60, P < .0001). TV annular diameters on 2DE and 3DE for lateral (r = 0.85, P < .0001) and anteroposterior (r = 0.74, P = .001) dimensions were strongly correlated. CONCLUSIONS: In children with HLHS, assessment of TR location on 2DE had poor agreement with assessment on 3DE and was poorly reproducible. In contrast, TR jet location on 3DE was highly reproducible. Pre-Glenn, a central TR jet was the most common, while post-Glenn, central and anteroseptal locations were equal, highlighting the importance of preoperative identification of TR jet location in patients with HLHS.

Right Ventricular Remodeling in Hypoplastic Left Heart Syndrome is Minimally Impacted by Cardiopulmonary Bypass: A Comparison of Norwood vs. Hybrid.

Right ventricular (RV) remodeling in hypoplastic left heart syndrome (HLHS) begins prenatally and continues through staged palliations. However, it is unclear if the most marked observed remodeling post-Norwood is secondary to cardiopulmonary bypass (CPB) exposure or if it is an adaptation intrinsic to the systemic RV. This study aims to determine the impact of CPB on RV remodeling in HLHS. Echocardiograms of HLHS survivors undergoing stage 1 Norwood (n = 26) or Hybrid (n = 20) were analyzed at pre- and post-stage 1, pre- and post-bidirectional cavo-pulmonary anastomosis (BCPA), and pre-Fontan. RV fractional area change (FAC), vector velocity imaging for longitudinal & derived circumferential deformation (global radial shortening (GRS) = peak radial displacement/end-diastolic diameter), and deformation ratio (longitudinal/ circumferential) were assessed. Both groups had similar age, clinical status and functional parameters pre-stage 1. No difference in RV size and sphericity at any stage between groups. RVFAC was normal (> 35%) throughout for both groups. Both Norwood and Hybrid patients had increased GRS (p = 0.0001) post-stage 1 and corresponding unchanged longitudinal strain, resulting in decreased deformation ratio (greater relative RV circumferential contraction), p = 0.0001. Deformation ratio remained decreased in both groups in subsequent stages. Irrespective of timing of the first CPB exposure, both Norwood and Hybrid patients underwent similar RV remodeling, with relative increase in circumferential to longitudinal contraction soon after stage 1 palliation. The observed RV remodeling in HLHS survivors were minimally impacted by CPB.

Tilt-table Echocardiography Unmasks Early Diastolic Dysfunction in Patients With Hemoglobinopathies.

Individuals with hemoglobinopathy (sickle cell anemia and thalassemia major) are at risk for cardiac complications such as heart failure and cardiomyopathy. Diastolic dysfunction is known to precede systolic dysfunction in many cardiac diseases. This study sought to determine whether changes in left atrial (LA) function during manipulation of cardiac preload by tilt-table echocardiography can unmask subclinical diastolic dysfunction in pediatric patients with hemoglobinopathies. Eleven sickle cell anemia, 9 transfusion-dependent thalassemia major, and 10 control subjects underwent tilt-table echocardiogram in the supine (loading) and 30-degree upright (unloading) positions and cardiac magnetic resonance imaging (MRI). Echocardiography assessed LA and left ventricular (LV) strain, strain rate, mitral inflow, and annular velocities. MRI assessed LV function, myocardial T1 and T2* for iron deposition. Both thalassemia major and sickle cell anemia patients had normal LV function and no evidence of cardiac iron deposition on MRI T2* measurements. During cardiac loading, controls appropriately increased LA conduit (P=0.002) and reservoir strain (P=0.002), mitral e' velocity (P<0.0001) and medial e' velocity (P=0.002), while the hemoglobinopathy patients showed no change in these parameters. In pediatric sickle cell anemia and thalassemia, tilt-table echocardiography unmasked a failure to augment LA function in response to loading, suggesting altered myocardial relaxation is present, before evidence of iron overload or systolic dysfunction.

Quantitative Assessment of Left Ventricular Dysfunction in Fetal Ebstein's Anomaly and Tricuspid Valve Dysplasia.

BACKGROUND: Fetal Ebstein's anomaly and tricuspid valve dysplasia (EA/TVD) are associated with high perinatal mortality relative to pulmonary atresia with intact ventricular septum (PAIVS), despite both requiring redistribution of the cardiac output (CO) to the left ventricle (LV). LV dysfunction is suspected to contribute to adverse outcomes in EA/TVD. OBJECTIVE: We sought to examine global and segmental LV function in fetal EA/TVD with comparison to normal controls and PAIVS. We hypothesized that LV dysfunction in EA/TVD is associated with abnormal LV remodeling and interventricular mechanics. METHODS: We retrospectively identified 63 cases of fetal EA/TVD (40 with retrograde ductal flow) and 22 cases of PAIVS encountered from 2004 to 2015 and compared findings to 77 controls of comparable gestational age. We measured the combined CO and global LV function using two-dimensional, Doppler-derived, deformational (six-segmental vector velocity imaging) and dyssynchrony indices (DIs; SD of time to peak), and a novel global DI. RESULTS: EA/TVD fetuses demonstrated abnormal LV global systolic function with reduced ejection fraction, fractional area change, and CO, while in PAIVS we observed a normal ejection fraction, fractional area change, and CO. PAIVS, but not EA/TVD, demonstrated increased LV sphericity, suggestive of remodeling, and associated enhanced radial function in the third trimester. In contrast, while EA/TVD fetuses had normal LV segmental longitudinal strain, there was abnormal radial segmental deformation and LV dyssynchrony with increased SD of time to peak and DI. CONCLUSIONS: Fetal EA/TVD is associated with a lack of spherical remodeling and presence of mechanical dyssynchrony, which likely contribute to reduced CO and ejection fraction. Clinical monitoring of LV function is warranted in fetal EA/TVD. Further studies incorporating quantification of LV function into prediction models for adverse outcomes are required.

Early tricuspid regurgitation in hypoplastic left heart syndrome is not related to right ventricular function or mechanical dyssynchrony

BACKGROUND: Tricuspid regurgitation (TR) is associated with morbidity and mortality in hypoplastic left heart syndrome (HLHS). We have previously demonstrated that TR prior to stage 2 (S2) surgical palliation is related to tricuspid valve (TV) abnormalities, including dilated annulus and increased leaflet prolapse. Right ventricular (RV) dysfunction and mechanical dyssynchrony have been reported as causes for TR. Thus, we hypothesized that TR and abnormal TV parameters are associated with RV dysfunction. Objective: This study explored the relationship between TV and RV function using quantitative three dimensional echocardiography (3DE) measure of TV parameters and speckle tracking echocardiography (STE) of RV deformation, in HLHS with and without TR. METHODS: Forty-four HLHS patients with median age of 4.7 months (IQR 3.9-5.3) were prospectively recruited prior to S2 palliation. TV parameters assessed using 3DE, included vena contracta area (VCA), leaflet area, prolapse volume, tethering volume, annular bending angle and papillary muscle angle. RV systolic function was assessed by fractional area change and STE derived longitudinal and circumferential strain, strain rate and mechanical dyssynchrony index (MDI). The group was divided into those with (group A) and those without (group B) significant TR by qualitative assessment. RV functional parameters were compared between the two groups using Mann-Whitney signed rank test and Spearman correlation of TV leaflet and annulus area, prolapse and tethering volume, bending angle and VCA, to longitudinal and circumferential strain, strain rate and MDI were performed. RESULTS: Fourteen patients (32%) had moderate or greater TR (group A). RV function parameters were not different between group A and group B. There was no correlation between all 3DE TV parameters and STE RV deformation parameters. CONCLUSION: Contrary to our hypothesis, HLHS RV systolic dysfunction and mechanical dyssynchrony do not play a significant role in early TR. This finding suggests the mechanisms of early TR in HLHS are likely to be secondary to valve and leaflet differences. (AU)

Hypoplastic Left Heart Syndrome Is Not a Predictor of Worse Intermediate Mortality Post Fontan.

BACKGROUND: An increasing proportion of those living with single ventricle physiology have hypoplastic left heart syndrome (HLHS). Our objective was to assess the association between HLHS and outcomes post Fontan operation. METHODS: All pediatric patients who underwent a Fontan procedure at the University of Alberta between 1996 and 2016 were included. Follow-up clinical data collected included early and late surgical or catheter reintervention, echocardiography, and long-term transplant-free survival. Characteristics were compared between those with and without HLHS, and the association between outcomes and HLHS were assessed. RESULTS: A total of 320 children (median age 3.3 years, interquartile range 2.8 to 3.9 years; 121 [43.4%] female) underwent a Fontan procedure over the course of the study. Nearly one third of subjects had HLHS (107, 33.4%). Patients with HLHS were more likely to have abnormal ventricular function (19.6% versus 7.0%, p = 0.003) and worse than mild atrioventricular valve (AVV) regurgitation (23.4 versus 9.2%, p = 0.001) preoperatively. HLHS was not predictive of in-hospital Fontan failure (odds ratio 0.82, 95% CI 0.28, 2.39), late reintervention (hazard ratio [HR] 1.08, 95% CI 0.66, 1.76), or transplant-free survival (HR 1.58, 95% CI 0.72, 3.44). Subjects with HLHS were more likely to have more than mild AVV regurgitation (31.6% versus 13.3%, p = 0.028) and abnormal ventricular function (29.8% versus 10.7%, p < 0.0001) at late follow-up. CONCLUSIONS: Patients with HLHS who survive to the Fontan procedure do no worse with the operation than those with other anatomy. Given worse late ventricular function and AVV regurgitation, equivalent survival may not persist throughout a patient's life course.

Strain Rate in Children and Young Piglets Mirrors Changes in Contractility and Demonstrates a Force-Frequency Relationship.

BACKGROUND: In adult humans and pig models, strain rate (SR) correlates strongly with invasive measures of contractility but does not demonstrate a force-frequency relationship, which is a fundamental behavior of myocardial contraction. Given the considerable maturational changes of the myocardium from fetal stages to adulthood, extrapolation of adult findings to the young heart may not be appropriate. We sought to evaluate the SR response of the immature heart to increased heart rate (HR) and inotropic stimulation. METHODS: The study consisted of two parts. In part 1, children without obvious structural or functional cardiac abnormalities were evaluated following successful radiofrequency ablation. Echocardiography was performed at baseline HR and then with atrial pacing and isoprenaline infusion titrated to achieve 130% of baseline HR. Left ventricular (LV) speckle tracking-derived SR and tissue Doppler isovolumic acceleration (IVA, a load-independent marker of contractility) were measured. In part 2, young piglets were submitted to atrial pacing at 200, 230, and 260 bpm. Invasive LV dP/dt was assessed, and speckle tracking-derived SR was measured at all stages. Repeated measures analysis of variance was used for comparison with baseline values. RESULTS: In part 1, the LV SR and IVA (septal and lateral) in 23 children (ages 7.8-17.5 years) increased significantly with pacing and isoprenaline infusion (P < .001). In part 2, SR and invasive dP/dt increased significantly with increasing HR in young piglets (1-17 days; P < .01 and P < .001, respectively). Both LV SR and dP/dt plateaued at highest HRs concurrent with the decrease in LV end-diastolic dimension from baseline (73.0% ± 9.9% of the baseline value at 260 bpm; P < .001). CONCLUSIONS: SR in children is augmented with chronotropic and inotropic stimulation and in young infant piglets with chronotropic stimulation; in both children and piglets it has a force-frequency relationship, a behavior that is consistent with a measure of contractility.

Can Vco2-Based Estimates of Resting Energy Expenditure Replace the Need for Indirect Calorimetry in Critically Ill Children?

BACKGROUND: Optimal energy provision, guided by measured resting energy expenditure (REE), is fundamental in the care of critically ill children. REE should be determined by indirect calorimetry (IC), which has limited availability. Recently, a novel equation was developed for estimating REE derived from carbon dioxide production (Vco2). The aim of this study was to validate the accuracy of this equation in a population of critically ill children following cardiopulmonary bypass (CPB). METHODS: This is an ancillary study to a larger trial of children undergoing CPB. Respiratory mass spectrometry was used measure oxygen consumption (Vo2) and Vco2. REE was then calculated according to the established Weir equation (REEW) and the modified, Vco2-based equation (REECO2). The agreement between the 2 measurements was assessed using Bland-Altman plots and mixed-model regressions accounting for repeated measures. RESULTS: Data from 104 patients, which included 575 paired measurements, were included. The agreement between REEW and REECO2 was biased during the 72-hour observation period post CPB, with a mean percentage error between measurements of 11% (±7%). The most important determinant of the bias with the Vco2-based equation was the respiratory quotient (RQ). The percentage error between REEW and REECO2 dropped to 4.4% (±2.4%) in those with an RQ between 0.8 and 1. The within-subject variability for RQ in this cohort was wide (11%). CONCLUSIONS: IC remains the most accurate method to determine the REE of critically ill patients. Widespread availability of Vco2 data renders Vco2-based approaches to measurement of REE attractive; however, further research is needed to ensure that REE is estimated accurately.

Systemic inflammation increases energy expenditure following pediatric cardiopulmonary bypass.

OBJECTIVES: To examine the association between cardiopulmonary bypass-related systemic inflammation and resting energy expenditure in pediatric subjects following cardiac surgery. DESIGN: Single-center, prospective cohort study. SETTING: Pediatric cardiac critical care unit in Toronto, Canada. PATIENTS: Children with congenital heart disease undergoing cardiopulmonary bypass surgery. INTERVENTIONS: Resting energy expenditure was determined by indirect calorimetry and the modified Weir equation, using VO2 and VCO2 measured by in-line respiratory mass spectrometry. Measurements were taken at baseline and 6-hour intervals from separation from cardiopulmonary bypass for a maximum of 72 hours. Plasma interleukin-6, glucose delivery, feeding status, and cardiac output (calculated by Fick equation) were monitored at each resting energy expenditure measurement. MEASUREMENTS AND MAIN RESULTS: We studied 111 subjects at a median (interquartile range) age of 5.3 months (0.8-10.5 mo), weighing 5.7 kg (3.9-8.1 kg), of whom 88% underwent biventricular repair. Resting energy expenditure decreased from 51 kcal/kg/d to 45 kcal/kg/d during the study period. Resting energy expenditure was positively associated with increased plasma interleukin-6 (estimate variable, 1.76; p = 0.001) and inversely associated with preoperative methylprednisolone use (estimate variable, -6.7; p = 0.003) even after accounting for other predictors. Increase in cardiac output was also associated (estimate variable, 13.7; p < 0.0001) with higher resting energy expenditure. CONCLUSIONS: Resting energy expenditure ranges between 40 and 60 kcal/kg/d and decreases progressively in children following cardiopulmonary bypass surgery. It is directly associated with increased inflammation and higher cardiac output and inversely associated with anti-inflammatory strategies. Further studies are required to predict the appropriate caloric delivery in this cohort.

Physiologic predictors for the need for patch closure in neonatal congenital diaphragmatic hernia.

Technically expedient repair of CDH defects is desirable. With increasing trend toward thoracoscopic repair, herein we examine physiologic predictors for the need for patch closure (PC) versus primary closure. All neonates who underwent surgical repair of CDH defects in a geographically defined region between 1992 and 2002 were included (n = 210). Two groups of patients were compared, primary repair (PR) versus PC. The 25th quartile was used as a cut off point for continuous variables. Univariate and multivariate logistic regression were performed. One hundred and fifty neonates underwent open PR (71.43%) versus 28.57% had PC. On univariate analyses the following variables were significantly associated with the need for PC: prenatal diagnosis, birth weight <2.7 kg, gestational age <37 weeks, APGAR at 5 min <6, immediate postnatal PCO(2) >34, Immediate oxygen saturation <93%, use of Nitric oxide and the need for high frequency oscillation (HFO). On multivariate analyses, only a PCO(2) >34 and the need for HFO were significantly associated with PC. Neonates with an initial PCO(2) >34 or need HFO pre-operatively should be excluded from attempts to repair the CDH thoracoscopically based on their higher potential need for PC with its entailed technical difficulty and increased operative time.

Predicting the need for fundoplication at the time of congenital diaphragmatic hernia repair.

PURPOSE: This study was conducted to examine the preoperative factors predictive of subsequent intervention for gastroesophageal reflux (GER) in children with congenital diaphragmatic hernia (CDH). METHODS: We conducted a retrospective cohort study on children who underwent repair of a CDH between January 1, 1995, and December 31, 2002 with follow-up continuing to September 1, 2005. Excluded in the study were children who died during their first admission, or who underwent fundoplication at the time of CDH repair. Univariate and multivariate logistic regressions were performed to examine preoperative factors predictive of subsequent intervention (fundoplication or gastrojejunal tube placement). RESULTS: Of 86 children, 13 underwent intervention (fundoplication, 10; gastrojejunal tube, 3) for GER. Univariate predictors included the following: right-sided CDH, use of nonconventional ventilation, liver within the chest, and patch closure of the CDH. However, only liver within the chest and patch closure of the CDH were significant predictors in a multiple variable analysis. The positive and negative predictive values of the multivariate model were 69.2% and 87.7%, respectively. CONCLUSIONS: Infants with CDH who have liver within the chest or require patch closure of their hernia are at increased risk for subsequent intervention for GER. These children may represent a subpopulation that would benefit from fundoplication at the time of CDH repair.