Meghna D. Patel

Maturational Patterns of Systolic Ventricular Deformation Mechanics by Two-Dimensional Speckle-Tracking Echocardiography in Preterm Infants over the First Year of Age

Background: The aim of this study was to determine the maturational changes in systolic ventricular strain mechanics by two‐dimensional speckle‐tracking echocardiography in extremely preterm neonates from birth to 1 year of age and discern the impact of common cardiopulmonary abnormalities on the deformation measures. Methods: In a prospective multicenter study of 239 extremely preterm infants (<29 weeks gestation at birth), left ventricular (LV) global longitudinal strain (GLS) and global longitudinal systolic strain rate (GLSRs), interventricular septal wall (IVS) GLS and GLSRs, right ventricular (RV) free wall longitudinal strain and strain rate, and segmental longitudinal strain in the RV free wall, LV free wall, and IVS were serially measured on days 1, 2, and 5 to 7, at 32 and 36 weeks postmenstrual age, and at 1 year corrected age (CA). Premature infants who developed bronchopulmonary dysplasia or had echocardiographic findings of pulmonary hypertension were analyzed separately. Results: In uncomplicated preterm infants (n = 103 [48%]), LV GLS and GLSRs remained unchanged from days 5 to 7 to 1 year CA (P = .60 and P = .59). RV free wall longitudinal strain, RV free wall longitudinal strain rate, and IVS GLS and GLSRs significantly increased over the same time period (P < .01 for all measures). A significant base‐to‐apex (highest to lowest) segmental longitudinal strain gradient (P < .01) was seen in the RV free wall and a reverse apex‐to‐base gradient (P < .01) in the LV free wall. In infants with bronchopulmonary dysplasia and/or pulmonary hypertension (n = 119 [51%]), RV free wall longitudinal strain and IVS GLS were significantly lower (P < .01), LV GLS and GLSRs were similar (P = .56), and IVS segmental longitudinal strain persisted as an RV‐dominant base‐to‐apex gradient from 32 weeks postmenstrual age to 1 year CA. Conclusions: This study tracks the maturational patterns of global and regional deformation by two‐dimensional speckle‐tracking echocardiography in extremely preterm infants from birth to 1 year CA. The maturational patterns are ventricular specific. Bronchopulmonary dysplasia and pulmonary hypertension leave a negative impact on RV and IVS strain, while LV strain remains stable. HighlightsTwo‐dimensional (2D) speckle‐tracking echocardiography (STE)–derived myocardial strain is a feasible and reproducible imaging modality that can be used to characterize systolic ventricular function in premature infants.This study establishes ventricular‐specific systolic strain maturational patterns by 2D STE in a large cohort of extremely preterm infants from birth through 1 year corrected age.Common cardiopulmonary morbidities, such as bronchopulmonary dysplasia and pulmonary hypertension, appear to leave a negative impact on right ventricular strain, while left ventricular strain remains stable through the first year of age.With the establishment of the range of maturational patterns of strain mechanics and associated variations up to 1 year corrected age, deformation imaging by 2D STE may now be implemented in preterm infants as a means to identify cardiovascular compromise earlier, guide therapeutic intervention, monitor treatment response, and improve overall outcome.

Pediatric and adult dilated cardiomyopathy represent distinct pathological entities

Pediatric dilated cardiomyopathy (DCM) is the most common indication for heart transplantation in children. Despite similar genetic etiologies, medications routinely used in adult heart failure patients do not improve outcomes in the pediatric population. The mechanistic basis for these observations is unknown. We hypothesized that pediatric and adult DCM comprise distinct pathological entities, in that children do not undergo adverse remodeling, the target of adult heart failure therapies. To test this hypothesis, we examined LV specimens obtained from pediatric and adult donor controls and DCM patients. Consistent with the established pathophysiology of adult heart failure, adults with DCM displayed marked cardiomyocyte hypertrophy and myocardial fibrosis compared with donor controls. In contrast, pediatric DCM specimens demonstrated minimal cardiomyocyte hypertrophy and myocardial fibrosis compared with both age-matched controls and adults with DCM. Strikingly, RNA sequencing uncovered divergent gene expression profiles in pediatric and adult patients, including enrichment of transcripts associated with adverse remodeling and innate immune activation in adult DCM specimens. Collectively, these findings reveal that pediatric and adult DCM represent distinct pathological entities, provide a mechanistic basis to explain why children fail to respond to adult heart failure therapies, and suggest the need to develop new approaches for pediatric DCM.

Evidence of Echocardiographic Markers of Pulmonary Vascular Disease in Asymptomatic Infants Born Preterm at One Year of Age

Objective To test the hypothesis that echocardiographic markers of pulmonary vascular disease (PVD) exist in asymptomatic infants born preterm at 1‐year corrected age. Study design We conducted a prospective cohort study of 80 infants born preterm (<29 weeks of gestation) and 100 age‐ and weight‐matched infants born at term and compared broad‐based conventional and quantitative echocardiographic measures of pulmonary hemodynamics at 1‐year corrected age. Pulmonary artery acceleration time (PAAT), a validated index of pulmonary vascular resistance, arterial pressure, and compliance, was used to assess pulmonary hemodynamics. Lower PAAT is indicative of PVD. Subanalyses were performed in infants with bronchopulmonary dysplasia (BPD, n = 48, 59%) and/or late‐onset pulmonary hypertension (n = 12, 15%). Results At 1 year, there were no differences between conventional measures of pulmonary hypertension in the infants born at term and preterm. All infants born preterm had significantly lower values of PAAT than infants born at term (73 ± 8 milliseconds vs 98 ± 5 milliseconds, P < .001). Infants born preterm with BPD had even lower PAAT than those without BPD (69 ± 5 milliseconds vs 79 ± 4 milliseconds, P < .01). The degree of PVD at 1‐year corrected age was inversely related to gestation in all infants born preterm. Data analysis included adjustment for ventricular function and other confounding factors. Conclusions In comparison with infants born at term, infants born preterm exhibit abnormal PAAT at 1‐year corrected age irrespective of neonatal lung disease status, suggesting the existence of PVD beyond infancy. PAAT measurements offer a reliable, noninvasive tool for screening and longitudinal monitoring of pulmonary hemodynamics in infants.

SHAPE OF THE RIGHT VENTRICULAR OUTFLOW TRACT DOPPLER ENVELOPE IS A SENSITIVE PREDICTOR OF ALTERED PULMONARY HEMODYNAMICS IN PEDIATRIC PATIENTS

The shape of the RV outflow tract (RVOT) Doppler velocity envelope (DVE) has been shown to be a sensitive marker of altered pulmonary hemodynamics in adults, but this has not been validated in children. Systolic deceleration or ‘‘notching’’ of the RVOT DVE relates to the pathologic wave

MATURATIONAL CHANGES AND REFERENCE VALUES FOR TRICUSPID ANNULAR PLANE SYSTOLIC EXCURSION (TAPSE) FROM BIRTH TO ONE-YEAR CORRECTED AGE: RIGHT VENTRICULAR SYSTOLIC FUNCTION IN PRETERM NEONATES

Tricuspid annular plane systolic excursion (TAPSE), is a sensitive measure of RV systolic function in premature infants, but lacks maturationally adjusted reference values for clinical application in premature infants. The objectives of this study were to determine the maturational (age- and weight