Upon completing my undergraduate degree in chemistry, MS in biology, and medical degree all from Indiana University, and I spent 6 years in pursing my pediatric residency and pediatric cardiology fellowship at Washington University in St. Louis. I then completed a fellowship in pediatric intensive care here at Stanford University. Currently, I am a Clinical Assistant Professor and pediatric cardiac intensivist at Stanford. My research focus is on outcomes in cardiac disease, primarily focusing on immune signatures and perturbations in various stages of heart failure and after surgical trauma.
- Pediatric Cardiology
Board Certification: American Board of Pediatrics, Pediatric Critical Care Medicine (2018)
Fellowship: Stanford University Pediatric Critical Care Fellowship (2018) CA
Residency: St Louis Children's Hospital Washington University Pediatric Residency (2013) MO
Board Certification, Pediatric Critical Care, American Board of Pediatrics (2018)
Board Certification: American Board of Pediatrics, Pediatric Cardiology (2016)
Fellowship: Washington University Pediatric Cardiology Fellowship (2016) MO
Board Certification: American Board of Pediatrics, Pediatrics (2015)
Medical Education: Indiana University School of Medicine (2010) IN
Current Research and Scholarly Interests
My current academic focus is in end stage heart failure. Working with mentors Daniel Bernstein and Greg Hammer, and we will be using CyTOF (mass cytometry) to profile the immune system in heart failure and ventricular assist device therapy. We are funded internally by the Jackson Vaughan Research Fund and the NIH Cooperative Centers for Translational Research in Human Immunology (CCHI) Pilot Project Grant. We have recently been awarded as the first recipient of the Pediatric Cardiomyopathy Early Career Research Grant sponsored by the American Academy of Pediatrics and the Children’s Cardiomyopathy Foundation for this work.
Maturational patterns of left ventricular rotational mechanics in pre-term infants through 1 year of age.
Cardiology in the young
BACKGROUND: Pre-mature birth impacts left ventricular development, predisposing this population to long-term cardiovascular risk. The aims of this study were to investigate maturational changes in rotational properties from the neonatal period through 1 year of age and to discern the impact of cardiopulmonary complications of pre-maturity on these measures.METHODS: Pre-term infants (<29 weeks at birth, n = 117) were prospectively enrolled and followed to 1-year corrected age. Left ventricular basal and apical rotation, twist, and torsion were measured by two-dimensional speckle-tracking echocardiography and analysed at 32 and 36 weeks post-menstrual age and 1-year corrected age. A mixed random effects model with repeated measures analysis was used to compare rotational mechanics over time. Torsion was compared in infants with and without complications of cardiopulmonary diseases of pre-maturity, specifically bronchopulmonary dysplasia, pulmonary hypertension, and patent ductus arteriosus.RESULTS: Torsion decreased from 32 weeks post-menstrual age to 1-year corrected age in all pre-term infants (p < 0.001). The decline from 32 to 36 weeks post-menstrual age was more pronounced in infants with cardiopulmonary complications, but was similar to healthy pre-term infants from 36 weeks post-menstrual age to 1-year corrected age. The decline was due to directional and magnitude changes in apical rotation over time (p < 0.05).CONCLUSION: This study tracks maturational patterns of rotational mechanics in pre-term infants and reveals torsion declines from the neonatal period through 1 year. Cardiopulmonary diseases of pre-maturity may negatively impact rotational mechanics during the neonatal period, but the myocardium recovers by 1-year corrected age.
View details for DOI 10.1017/S1047951120001912
View details for PubMedID 32665043
Cardiac Dysfunction Identified by Strain Echocardiography Is Associated With Illness Severity in Pediatric Sepsis.
Pediatric critical care medicine : a journal of the Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies
Sepsis-induced myocardial dysfunction has been associated with illness severity and mortality in pediatrics. Although early sepsis-induced myocardial dysfunction diagnosis could aid in hemodynamic management, current echocardiographic metrics for assessing biventricular function are limited in detecting early impairment. Strain echocardiography is a validated quantitative measure that can detect subtle perturbations in left ventricular and right ventricular function. This investigation evaluates the utility of strain echocardiography in pediatric sepsis and compares with to conventional methods.Retrospective, observational study comparing left ventricular and right ventricular strain. Strain was compared with ejection fraction and fractional shortening and established sepsis severity of illness markers.Tertiary care medical-surgical PICU from July 2013 to January 2018.Seventy-nine septic children and 28 healthy controls.None.Compared with healthy controls, patients with severe sepsis demonstrated abnormal left ventricular strain (left ventricular longitudinal strain: -13.0% ± 0.72; p = 0.04 and left ventricular circumferential strain: -16.5% ± 0.99; p = 0.046) and right ventricular (right ventricular longitudinal strain = -14.3% ± 6.3; p < 0.01) despite normal fractional shortening (36.0% ± 1.6 vs 38.1% ± 1.1; p = 0.5129) and ejection fraction (60.7% ± 2.2 vs 65.3% ± 1.5; p = 0.33). There was significant association between depressed left ventricular longitudinal strain and increased Vasotrope-Inotrope Score (r = 0.52; p = 0.034). Worsening left ventricular circumferential strain was correlated with higher lactate (r = 0.31; p = 0.03) and higher Pediatric Risk of Mortality-III score (r = 0.39; p < 0.01). Depressed right ventricular longitudinal strain was associated with elevated pediatric multiple organ dysfunction score (r = 0.44; p < 0.01) CONCLUSIONS:: Compared with healthy children, pediatric septic patients demonstrated abnormal left ventricular and right ventricular strain concerning for early signs of cardiac dysfunction. This was despite having normal ejection fraction and fractional shortening. Abnormal strain was associated with abnormal severity of illness markers. Strain echocardiography may have utility as an early indicator of sepsis-induced myocardial dysfunction in pediatric sepsis.
View details for DOI 10.1097/PCC.0000000000002247
View details for PubMedID 32084099
Two-Dimensional Strain is more Precise than Conventional Measures of Left Ventricular Systolic Function in Pediatric Patients.
Ejection fraction (EF) and fractional shortening (FS) are standard methods of quantifying left ventricular (LV) systolic function. 2D global longitudinal strain (2D GLS) is a well-established, but underutilized method for LV function quantification. The aim of this study was to assess precision of GLS compared to EF & FS in pediatrics. Echocardiograms were prospectively analyzed by 2 blinded observers. FS, EF, and GLS were calculated following standard methods. Bland-Altman was applied to assess agreement. Intraclass correlation coefficient (ICC) was used to measure reliability. Coefficient of variation was used to demonstrate relative variability between methods. 103 pediatric echos were evaluated for inter-observer reproducibility, and 15 patients for intra-observer reproducibility. GLS had higher inter-observer agreement and reliability (bias 7%, 95% LOA -3.4 to +3.5, ICC 0.86 CI 0.80-0.90) compared to EF (bias 27%, 95% LOA -18.9 to +19.5; ICC 0.25 CI 0.07-0.43) and FS (bias 12%, 95% LOA -11.9 to +12.2; ICC 0.53 CI 0.38-0.66). GLS also had higher intra-observer agreement (bias 4%, 95% LOA -3.6 to+3.7; ICC 0.87 CI 0.66-0.96) compared to EF (bias 11%, 95% LOA -14.9 to+15.1; ICC 0.26 CI - 0.28-0.67) and FS (bias 12%, 95% LOA -12.2 to+12.5; ICC 0.38 CI -0.15-0.74). GLS is a more precise method for quantifying LV function in pediatrics, with lower variability compared to EF and FS. GLS provides a more reliable evaluation of LV systolic function and should be utilized more widely in pediatrics.
View details for DOI 10.1007/s00246-019-02243-8
View details for PubMedID 31707490
Persistence of right ventricular dysfunction and altered morphometry in asymptomatic preterm Infants through one year of age: Cardiac phenotype of prematurity.
Cardiology in the young
INTRODUCTION: Prematurity impacts myocardial development and may determine long-term outcomes. The objective of this study was to test the hypothesis that preterm neonates develop right ventricle dysfunction and adaptive remodelling by 32 weeks post-menstrual age that persists through 1 year corrected age.MATERIALS AND METHODS: A subset of 80 preterm infants (born <29 weeks) was selected retrospectively from a prospectively enrolled cohort and measures of right ventricle systolic function and morphology by two-dimensional echocardiography were assessed at 32 weeks post-menstrual age and at 1 year of corrected age. Comparisons were made to 50 term infants at 1 month and 1 year of age. Sub-analyses were performed in preterm-born infants with bronchopulmonary dysplasia and/or pulmonary hypertension.RESULT: In both term and preterm infants, right ventricle function and morphology increased over the first year (p < 0.01). The magnitudes of right ventricle function measures were lower in preterm-born infants at each time period (p < 0.01 for all) and right ventricle morphology indices were wider in all preterm infants by 1 year corrected age, irrespective of lung disease. Measures of a) right ventricle function were further decreased and b) morphology increased through 1 year in preterm infants with bronchopulmonary dysplasia and/or pulmonary hypertension (p < 0.01).CONCLUSION: Preterm infants exhibit abnormal right ventricle performance with remodelling at 32 weeks post-menstrual age that persists through 1 year corrected age, suggesting a less developed intrinsic myocardial function response following preterm birth. The development of bronchopulmonary dysplasia and pulmonary hypertension leave a further negative impact on right ventricle mechanics over the first year of age.
View details for DOI 10.1017/S1047951119001161
View details for PubMedID 31287038
Echocardiographic Assessment of Right Ventricular Afterload in Preterm Infants: Maturational Patterns of Pulmonary Artery Acceleration Time Over the First Year of Age and Implications for Pulmonary Hypertension.
Journal of the American Society of Echocardiography : official publication of the American Society of Echocardiography
2019; 32 (7): 884
BACKGROUND: Assessment of pulmonary hemodynamics is critical in the diagnosis and management of cardiopulmonary disease of premature infants, but reliable noninvasive indices of pulmonary hemodynamics in preterm infants are lacking. Because pulmonary artery acceleration time (PAAT) is a validated noninvasive method to assess right ventricular (RV) afterload in infants and children, the aim of this study was to investigate the maturational changes of PAAT measures in preterm infants over the first year of age and to discern the impact of typical cardiopulmonary abnormalities on these measures.METHODS: In a prospective multicenter study of 239 preterm infants (<29weeks at birth), PAAT was assessed at days 1, 2, and 5 to 7, at 32 and 36weeks' postmenstrual age, and at 1-year corrected age. To account for heart rate variability, PAAT was adjusted for RV ejection time. Premature infants who developed bronchopulmonary dysplasia or had echocardiographic findings of pulmonary hypertension were analyzed separately. Intra- and interobserver reproducibility analysis was performed.RESULTS: PAAT was feasible in 95% of the image acquisitions, and there was high intra- and interobserver agreement (intraclass correlation coefficients>0.9 and coefficients of variation<6%). In uncomplicated preterm infants (n=103 [48%]) PAAT and PAAT adjusted for RV ejection time increased longitudinally from birth to 1-year corrected age (P<.001) and were linearly associated with gestational age at birth (r=0.81 and r=0.82, P<.001) and increasing postnatal weight and postnatal age (r>0.81, P<.001). PAAT measures were significantly reduced (P<.001) in infants with bronchopulmonary dysplasia and/or pulmonary hypertension (n=119 [51%]) beyond 1week of age.CONCLUSIONS: PAAT measures increase in preterm infants from birth to 1-year corrected age, reflective of the physiologic postnatal drop in RV afterload. Bronchopulmonary dysplasia and pulmonary hypertension have a negative impact on PAAT measures. By demonstrating excellent reliability and establishing reference patterns of PAAT in preterm infants, this study suggests that PAAT and PAAT adjusted for RV ejection time can be used as complementary parameters to assess physiologic and pathologic changes in pulmonary hemodynamics in neonates.
View details for DOI 10.1016/j.echo.2019.03.015
View details for PubMedID 31272593
The Journal of pediatrics
View details for PubMedID 30195560
Evidence of Echocardiographic Markers of Pulmonary Vascular Disease in Asymptomatic Infants Born Preterm at One Year of Age
JOURNAL OF PEDIATRICS
2018; 197: 48-+
To test the hypothesis that echocardiographic markers of pulmonary vascular disease (PVD) exist in asymptomatic infants born preterm at 1-year corrected age.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%).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.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.
View details for PubMedID 29625733
View details for PubMedCentralID PMC5970955
- EVALUATION OF STRAIN ECHOCARDIOGRAPHY IN PEDIATRIC SEPSIS LIPPINCOTT WILLIAMS & WILKINS. 2018: 742
- Pediatric and adult dilated cardiomyopathy represent distinct pathological entities JCI INSIGHT 2017; 2 (14)
Pediatric and adult dilated cardiomyopathy represent distinct pathological entities.
2017; 2 (14)
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.
View details for DOI 10.1172/jci.insight.94382
View details for PubMedID 28724792
View details for PubMedCentralID PMC5518561
Maturational Patterns of Systolic Ventricular Deformation Mechanics by Two-Dimensional Speckle-Tracking Echocardiography in Preterm Infants over the First Year of Age
JOURNAL OF THE AMERICAN SOCIETY OF ECHOCARDIOGRAPHY
2017; 30 (7): 685–U249
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.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.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.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.
View details for PubMedID 28433214
Pulmonary Artery Acceleration Time Provides a Reliable Estimate of Invasive Pulmonary Hemodynamics in Children
JOURNAL OF THE AMERICAN SOCIETY OF ECHOCARDIOGRAPHY
2016; 29 (11): 1056-+
Pulmonary artery acceleration time (PAAT) is a noninvasive method to assess pulmonary hemodynamics, but it lacks validity in children. The aim of this study was to evaluate the accuracy of Doppler echocardiography-derived PAAT in predicting right heart catheterization (RHC)-derived pulmonary artery pressure (PAP), pulmonary vascular resistance (PVR), and compliance in children.Prospectively acquired and retrospectively measured Doppler echocardiography-derived PAAT and RHC-derived systolic PAP, mean PAP (mPAP), indexed PVR (PVRi), and compliance were compared using regression analysis in a derivation cohort of 75 children (median age, 5.3 years; interquartile range, 1.3-12.6 years) with wide ranges of pulmonary hemodynamics. To account for heart rate variability, PAAT was adjusted for right ventricular ejection time and corrected by the RR interval. Regression equations incorporating PAAT and PAAT/right ventricular ejection time from the derivation cohort were then evaluated for the accuracy of their predictive values for invasive pulmonary hemodynamics in a validation cohort of 50 age- and weight-matched children with elevated PAP and PVR.There were significant inverse correlations between PAAT and RHC-derived mPAP (r = -0.82) and PVRi (r = -0.78) and a direct correlation (r = 0.78) between PAAT and pulmonary compliance in the derivation cohort. For detection of pulmonary hypertension (PRVi > 3 Wood units · m2 and mPAP > 25 mm Hg), PAAT < 90 msec and PAAT/right ventricular ejection time < 0.31 resulted in sensitivity of 97% and specificity of 95%. In the derivation cohort, the regression equations relating PAAT with mPAP and PVRi were mPAP = 48 - 0.28 × PAAT and PVRi = 9 - 0.07 × PAAT. These PAAT-integrated equations predicted RHC-measured pulmonary hemodynamics in the validation cohort with good correlations (r = 0.88 and r = 0.83, respectively), small biases (<10%), and minimal coefficients of variation (<8%).PAAT inversely correlates with RHC-measured pulmonary hemodynamics and directly correlates with pulmonary arterial compliance in children. The study established PAAT-based regression equations in children to accurately predict RHC-derived PAP and PVR.
View details for PubMedID 27641101
- MATURATIONAL PATTERNS OF VENTRICULAR SEPTAL DEFORMATION IN PRETERM AND TERM INFANTS IN THE FIRST MONTH OF LIFE ELSEVIER SCIENCE INC. 2016: 1789
- LONGITUDINAL MATURATIONAL CHANGES IN PULMONARY HEMODYNAMICS IN PREMATURE INFANTS ASSESSED BY PULMONARY ARTERY ACCELERATION TIME: REFERENCE AND PREDICTIVE VALUES ELSEVIER SCIENCE INC. 2016: 1790
- SHAPE OF THE RIGHT VENTRICULAR OUTFLOW TRACT DOPPLER ENVELOPE IS A SENSITIVE PREDICTOR OF ALTERED PULMONARY HEMODYNAMICS IN PEDIATRIC PATIENTS ELSEVIER SCIENCE INC. 2016: 1791
- 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 ELSEVIER SCIENCE INC. 2016: 1788
Reference Ranges of Left Ventricular Strain Measures by Two-Dimensional Speckle-Tracking Echocardiography in Children: A Systematic Review and Meta-Analysis
JOURNAL OF THE AMERICAN SOCIETY OF ECHOCARDIOGRAPHY
2016; 29 (3): 209-+
Establishment of the range of reference values and associated variations of two-dimensional speckle-tracking echocardiography (2DSTE)-derived left ventricular (LV) strain is a prerequisite for its routine clinical adoption in pediatrics. The aims of this study were to perform a meta-analysis of normal ranges of LV global longitudinal strain (GLS), global circumferential strain (GCS), and global radial strain (GRS) measurements derived by 2DSTE in children and to identify confounding factors that may contribute to variance in reported measures.A systematic review was launched in MEDLINE, Embase, Scopus, the Cumulative Index to Nursing and Allied Health Literature, and the Cochrane Library. Search hedges were created to cover the concepts of pediatrics, STE, and left-heart ventricle. Two investigators independently identified and included studies if they reported 2DSTE-derived LV GLS, GCS, or GRS. The weighted mean was estimated by using random effects models with 95% CIs, heterogeneity was assessed using the Cochran Q statistic and the inconsistency index (I(2)), and publication bias was evaluated using the Egger test. Effects of demographic (age), clinical, and vendor variables were assessed in a metaregression.The search identified 2,325 children from 43 data sets. The reported normal mean values of GLS among the studies varied from -16.7% to -23.6% (mean, -20.2%; 95% CI, -19.5% to -20.8%), GCS varied from -12.9% to -31.4% (mean, -22.3%; 95% CI, -19.9% to -24.6%), and GRS varied from 33.9% to 54.5% (mean, 45.2%; 95% CI, 38.3% to 51.7%). Twenty-six studies reported longitudinal strain only from the apical four-chamber view, with a mean of -20.4% (95% CI, -19.8% to -21.7%). Twenty-three studies reported circumferential strain (mean, -20.3%; 95% CI, -19.4% to -21.2%) and radial strain (mean, 46.7%; 95% CI, 42.3% to 51.1%) from the short-axis view at the midventricular level. A significant apex-to-base segmental longitudinal strain gradient (P < .01) was observed in the LV free wall. There was significant between-study heterogeneity and inconsistency (I(2) > 94% and P < .001 for each strain measure), which was not explained by age, gender, body surface area, blood pressure, heart rate, frame rate, frame rate/heart rate ratio, tissue-tracking methodology, location of reported strain value along the strain curve, ultrasound equipment, or software. The metaregression showed that these effects were not significant determinants of variations among normal ranges of strain values. There was no evidence of publication bias (P = .40).This study defines reference values of 2DSTE-derived LV strain in children on the basis of a meta-analysis. In healthy children, mean LV GLS was -20.2% (95% CI, -19.5% to -20.8%), mean GCS was -22.3% (95% CI, -19.9% to -24.6%), and mean GRS was 45.2% (95% CI, 38.3% to 51.7%). LV segmental longitudinal strain has a stable apex-to-base gradient that is preserved throughout maturation. Although variations among different reference ranges in this meta-analysis were not dependent on differences in demographic, clinical, or vendor parameters, age- and vendor-specific referenced ranges were established as well.
View details for PubMedID 26747685