Adel K Younoszai

University of Toronto, Toronto, Ontario, Canada

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Publications (24)100.79 Total impact

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    ABSTRACT: Background: Right ventricular (RV) failure is a key determinant of mortality in children with pulmonary arterial hypertension (PAH). RV stroke work (RVSW) can be estimated as the product of RV systolic pressure and stroke volume. The authors have shown that RVSW predicts adverse outcomes in this population when derived from hemodynamic data; noninvasive assessment of RVSW may be advantageous but has not been assessed. There are few data validating noninvasive versus invasive measurements in children with PAH. The aim of this study was to compare echocardiographically derived RVSW with RVSW determined from hemodynamic data. Methods: This was a retrospective study, including subjects with idiopathic PAH and minor or repaired congenital heart disease. Forty-nine subjects were included, in whom cardiac catheterization and echocardiography were performed within 1 month. Fourteen additional patients were included in a separate cohort, in whom catheterization and echocardiography were performed simultaneously. Catheterization-derived RVSW was calculated as RV systolic pressure × (cardiac output/heart rate). Echocardiographically derived RVSW was calculated as 4 × (peak tricuspid regurgitant jet velocity)(2) × (pulmonary valve area × velocity-time integral). Statistics included the intraclass correlation coefficient and Bland-Altman analysis. Results: Echocardiographically derived RVSW was linearly correlated with invasively derived RVSW (r = 0.74, P < .0001, intraclass correlation coefficient = 0.76). Bland-Altman analysis showed adequate agreement. Echocardiographically derived RV work was related to indexed pulmonary vascular resistance (r = 0.43, P = .002), tricuspid annular plane systolic excursion (r = 0.41, P = .004), and RV wall thickness (r = 0.62, P < .0001). Conclusions: The authors demonstrate that RV work, a potential novel index of RV function, can be estimated noninvasively and is related to pulmonary hemodynamics and other indices of RV performance.
    Full-text · Article · Aug 2015 · Journal of the American Society of Echocardiography: official publication of the American Society of Echocardiography
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    ABSTRACT: Through ventricular interdependence, pulmonary hypertension (PH) induces left ventricular (LV) dysfunction. We hypothesized that LV strain/strain rate, surrogate measures of myocardial contractility, are reduced in pediatric PH and relate to invasive hemodynamics, right ventricular strain, and functional measures of PH. At 2 institutions, echocardiography was prospectively performed in 54 pediatric PH patients during cardiac catheterization, and in 54 matched controls. Patients with PH had reduced LV global longitudinal strain (LS; -18.8 [-17.3 to -20.4]% versus -20.2 [-19.0 to -20.9]%; P=0.0046) predominantly because of reduced basal (-12.9 [-10.8 to -16.3]% versus -17.9 [-14.5 to -20.7]%; P<0.0001) and mid (-17.5 [-15.5 to -19.0]% versus -21.1 [-19.1 to -23.0]%; P<0.0001) septal strain. Basal global circumferential strain was reduced (-18.7 [-15.7 to -22.1]% versus -20.6 [-19.0 to -22.5]%; P=0.0098), as were septal and free-wall segments. Mid circumferential strain was reduced within the free-wall. Strain rates were reduced in similar patterns. Basal septum LS, the combined average LS of basal and mid interventricular septal segments, correlated strongly with degree of PH (r=0.66; P<0.0001), pulmonary vascular resistance (r=0.60; P<0.0001), and right ventricular free-wall LS (r=0.64; P<0.0001). Brain natriuretic peptide levels correlated moderately with septal LS (r=0.48; P=0.0038). PH functional class correlated moderately with LV free-wall LS (r=-0.48; P=0.0051). The septum, shared between ventricles and affected by septal shift, was the most affected LV region in PH. Pediatric PH patients demonstrate reduced LV strain/strain rate, predominantly within the septum, with relationships to invasive hemodynamics, right ventricular strain, and functional PH measures. © 2015 American Heart Association, Inc.
    No preview · Article · Aug 2015 · Circulation Cardiovascular Imaging
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    ABSTRACT: Doppler tissue imaging (DTI) has been used to evaluate myocardial velocity during ventricular filling, a means of characterizing diastolic function. Previous studies in older children have shown age-related increases in early diastolic tissue velocities, but there are limited data in preterm infants. The aim of this study was to prospectively determine maturational changes in diastolic tissue velocities at two points in time: (1) 7 days of age and (2) 36 weeks' postmenstrual age (PMA). It was further determined whether DTI measures were altered in infants who developed bronchopulmonary dysplasia with or without pulmonary hypertension. A total of 277 preterm infants born at <34 weeks' PMA, with birth weights between 500 and 1,250 g, were prospectively enrolled. Echocardiograms were obtained at 7 days of age and repeated at 36 weeks' PMA. Measurements included DTI assessment of early (E') and late (A') annular velocities of the left ventricular free wall, septum and the right ventricular free wall. Statistical analysis included the Wilcoxon rank sum test, simple linear regression, and the χ(2) test. At 7 days of age, there was a statistically significant increase in the E'/A' ratio as a function of gestational age at birth. At 36 weeks' PMA, E'/A' ratio was increased, but there was no association with gestational age. DTI measures were not different between infants who did or did not develop bronchopulmonary dysplasia or pulmonary hypertension at either time point. A gestational age-related increase was found in the early diastolic tissue velocities of preterm infants. At a gestational age equivalent to near term, no difference was observed in diastolic tissue velocities, regardless of gestational age at birth. These findings suggest that maturational changes in diastolic function occur relatively independently of the timing of birth. Copyright © 2015 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.
    Full-text · Article · May 2015 · Journal of the American Society of Echocardiography: official publication of the American Society of Echocardiography
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    ABSTRACT: Predicting later outcome around time of diagnosis of acute dilated cardiomyopathy (DCM) is difficult. We hypothesized that strain and strain rate on initial and follow-up echoes were worse in patients with acute DCM from all causes with poor one-year outcomes. This was a retrospective study including all patients with DCM aged 0-18 years with left ventricle dilation, low ejection fraction, or low fractional shortening on initial echo. Longitudinal and circumferential strain and systolic and diastolic strain rate were measured on echo at presentation, 1-3 weeks after presentation, and at 1 year. Patients were separated into "Stable" (survivors) and "Progressive" (referred for transplant or died) outcome groups, and results were analyzed to determine whether strain or strain rate at each echo was worse in the "Stable" group compared with the "Progressive" group. The patient population included patients with DCM from idiopathic causes, myocarditis, iron deficiency anemia, lupus, chemotherapy, and LV noncompaction. Longitudinal and circumferential strain and systolic strain rate were significantly better in the "Stable" (n = 7) compared with the "Progressive" (n = 8) outcome group on 1- to 3-week echo. Longitudinal strain more negative than -10% had 87% specificity and 100% sensitivity for predicting "stable" outcome (AUC 0.98), while circumferential strain more negative than -8% had 60% specificity and 100% sensitivity (AUC 0.83). Longitudinal and circumferential strain and systolic strain rate measured 1-3 weeks after starting therapy are worse in acute dilated cardiomyopathy patients with poor one-year outcomes. Further studies with less heterogeneity and more study subjects are needed. © 2015, Wiley Periodicals, Inc.
    No preview · Article · Apr 2015 · Echocardiography

  • No preview · Article · Jan 2015
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    ABSTRACT: Sickle cell disease (SCD) is a common inherited hemoglobinopathy. Adults with SCD manifest both systolic and diastolic cardiac dysfunction, though the age of onset of dysfunction has not been defined. Left ventricular (LV) rotational mechanics have not been studied in children with SCD. The aim of this study was to investigate whether cardiac rotational mechanics differed between children with SCD and age-matched controls. Basal and apical LV short-axis images were acquired prospectively in 213 patients with SCD (mean age, 14.1 ± 2.6 years) and 49 controls (mean age, 13.3 ± 2.8 years) from the Muhimbili Sickle Cohort in Dar es Salaam, Tanzania. The magnitude of basal and apical rotation, net twist angle, torsion, and untwist rate were obtained by two-dimensional speckle-tracking. The timing of events was normalized to aortic valve closure. Mean basal rotation was significantly lower in patients with SCD compared with controls (P = .012), although no difference was observed in apical rotation (P = .37). No statistically significant differences in torsion or net twist angle were detected. Rotation rate at the apex (P = .001) and base (P = .0004) were significantly slower in subjects with SCD compared with controls. Mean peak untwisting rate was also significantly slower in patients with SCD (P = .006). No associations were found between hemoglobin concentration and apical rotation, basal rotation, net twist, and torsion. This study demonstrates alterations in LV rotational mechanics in children with SCD, including lower basal rotation, peak differential twist, and untwist rate. These abnormalities denote subclinical changes in LV systolic and diastolic performance in children with SCD. Future work may reveal an association between rotational metrics and long-term patient outcomes. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.
    Full-text · Article · Dec 2014 · Journal of the American Society of Echocardiography: official publication of the American Society of Echocardiography
  • Dale A Burkett · Neil Wilson · Max B Mitchell · Adel K Younoszai
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    ABSTRACT: In hypoplastic left heart syndrome, thrombosis of the native ascending aorta is rare and often fatal; there are no previously reported cases presenting with acute heart block. We review a case of native ascending aorta thrombosis in a 2-year-old boy with hypoplastic left heart syndrome, presenting with acute heart block. This case highlights the benefit of multi-modality imaging in complex cases.
    No preview · Article · Dec 2014 · Cardiology in the Young
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    ABSTRACT: Real time three-dimensional echocardiography (RT3DE) allows for accurate morphological characterization of congenital heart disease and compliments two-dimensional (2D) echocardiography. Accurate evaluation of the mitral valve and supramitral ring prior to surgery aids the surgeon in successful resection of the ring and repair of associated mitral valve abnormalities. We report a case of congenital mitral valve stenosis from a supramitral ring in a young child using real time three-dimensional transesophageal echocardiography.
    Full-text · Article · Dec 2014 · Echocardiography
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    ABSTRACT: Rationale: Pulmonary hypertension (PH) is associated with poor outcomes among preterm infants with bronchopulmonary dysplasia (BPD), but whether early signs of pulmonary vascular disease are associated with the subsequent development of BPD or PH at 36 weeks post menstrual age (PMA) is unknown. Objective: To prospectively evaluate the relationship of early echocardiogram signs of pulmonary vascular disease in preterm infants to the subsequent development of BPD and late PH (at 36 weeks PMA). Methods: Prospectively enrolled preterm infants with birth weights 500 - 1250g underwent echocardiogram evaluations at 7 days of life (early) and 36 weeks PMA (late). Clinical and echocardiographic data were analyzed to identify early risk factors for BPD and late PH. Measurements and Main Results: 277 preterm infants completed echocardiogram and BPD assessments at 36 week PMA. The median gestational age at birth and birth weight of the infants were 27 weeks and 909 g, respectively. Early PH was identified in 42% of infants, and 14% were diagnosed with late PH. Early PH was a risk factor for increased BPD severity (RR, 1.12; 95% CI: 1.03 - 1.23) and late PH (RR, 2.85; 95% CI: 1.28 - 6.33). Infants with late PH had greater duration of oxygen therapy and increased mortality in the first year of life (p <0.05). Conclusions: Early pulmonary vascular disease is associated with the development of BPD and with late PH in preterm infants. Echocardiograms at 7 days of life may be a useful tool to identify infants at high risk for BPD and PH.
    No preview · Article · Nov 2014 · American Journal of Respiratory and Critical Care Medicine
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    ABSTRACT: RV performance is an important determinant of outcomes in children with pulmonary arterial hypertension (PAH). RV stroke work (RVSW), the product of mean pulmonary artery pressure and stroke volume, integrates contractility, afterload and ventricular-vascular coupling. RVSW has not been evaluated in children with PAH. We tested the hypothesis that RVSW would be a predictor of outcomes in children with PAH. Patients in the Children's Hospital Colorado PAH database were evaluated retrospectively, and those with idiopathic PAH and those with minor or repaired congenital heart disease were included. Haemodynamic data were obtained by catheterisation and echocardiography, performed within 3 months. RVSW was calculated: mean pulmonary arterial pressure × stroke volume, and indexed to body surface area. Statistics included Kruskal-Wallis, Wilcoxon rank sum, and Spearman correlation. Fifty patients were included. Median age of the cohort was 9.5 (6.0, 15.7) years, with a median indexed pulmonary vascular resistance (PVRi) of 6.5 (3.7, 11.6) WU m(2). RVSW had a significant association with PVRi (r=0.6, p<0.0001), tricuspid annular systolic plane excursion (r=0.55, p=0.0001), and RV fractional area change (r=-0.4, p=0.005). Grouped by WHO class, there was a significant difference in RVSW (p=0.04). Need for atrial septostomy and death were associated with higher RVSW (p=0.04 and p=0.03, respectively). RVSW can be estimated in children with PAH, and is significantly associated with abnormal WHO class, the need for septostomy, as well as mortality. Indices accounting for RV performance as well as ventricular-vascular coupling may be useful in the prognosis and, hence, management of children with PAH.
    Full-text · Article · Apr 2014 · Heart (British Cardiac Society)
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    Full-text · Article · Jan 2014 · Haematologica
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    ABSTRACT: Pulmonary hypertension (PH) increases right ventricular (RV) pressure, resulting in septal shift and RV dilation. Few echocardiographic measures have been used to evaluate severity and outcomes in children with PH. The aims of this study were to compare the RV to left ventricular (LV) diameter ratio at end-systole (RV/LV ratio) in normal controls and patients with PH, to correlate the RV/LV ratio with invasive hemodynamic measures, and to evaluate its association with outcomes in children with PH. The RV/LV ratio was compared retrospectively between 80 matched normal controls and 84 PH patients without shunts. Of the patients with PH, 49 children underwent 94 echocardiographic studies and cardiac catheterizations within 48 hours (13 patients had simultaneous measurements). The RV/LV ratio was correlated against hemodynamic measures. Kaplan-Meier curves and a Cox proportional-hazards regression model were used to assess relationships between RV/LV ratio and time until an adverse clinical event (initiation of intravenous prostacyclin therapy, atrial septostomy, death, or transplantation). RV/LV ratios were lower in controls compared with patients with PH (mean, 0.51 [95% confidence interval, 0.48-0.54] vs 1.47 [95% confidence interval, 1.25-1.70], P < .01). The RV/LV ratio correlated significantly with mean pulmonary artery pressure, systolic pulmonary artery pressure, systolic pulmonary artery pressure as a percentage of systemic pressure, and pulmonary vascular resistance index (r = 0.65 [P < .01], r = 0.6 [P < .01], r = 0.49 [P < .01], and r = 0.43 [P < .01], respectively). Twenty-two patients with PH with RV/LV ratios > 1 had adverse events within a median of 1.1 years from their earliest echocardiographic studies. Increasing RV/LV ratio was associated with an increasing hazard for a clinical event (hazard ratio, 2.49; 95% confidence interval, 1.92-3.24). The RV/LV end-systolic diameter ratio can easily be obtained noninvasively in the clinical setting and can be used in the management of patients with PH. The RV/LV ratio incorporates both pathologic septal shift and RV dilation in children with PH and correlates with invasive measures of PH. An RV/LV ratio > 1 is associated with adverse clinical events.
    Full-text · Article · Dec 2013 · Journal of the American Society of Echocardiography: official publication of the American Society of Echocardiography
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    ABSTRACT: Anthracycline chemotherapeutic agents carry the well-recognised risk of cardiotoxicity. Previous methods to evaluate cardiac function are useful, but have significant limitations. We sought to determine the left ventricular strain and strain rate of paediatric cancer patients with normal fractional shortening treated with anthracyclines using the latest ultrasound feature-tracking technology. Patients and methods Echocardiograms on cancer patients before anthracycline exposure and following completion of treatment were retrospectively analysed using Velocity Vector Imaging software in the circumferential and longitudinal planes. The same analysis was performed on matched controls. Only patients with a fractional shortening ≥28% were included. In all, 71 patients were identified with an age at diagnosis of 10.5 ± 4.7 years. The time from diagnosis to follow-up was 3.9 ± 4.0 years and the cumulative anthracycline dose was 356 ± 106 mg/m2. Following anthracycline exposure, paediatric cancer patients had a higher heart rate and a lower longitudinal strain, longitudinal diastolic strain rate, circumferential strain, and circumferential systolic and diastolic strain rate when compared with controls. Diastolic strain rate showed the greatest percent difference following anthracycline exposure versus controls. Despite having a normal fractional shortening, children exposed to anthracyclines have subclinical derangement of their left ventricular deformation as measured by decreases in strain and strain rate in both the circumferential and longitudinal axis. In particular, there was a profound decrease in diastolic strain rate following anthracycline exposure compared with controls. Whether the decline of strain or strain rate can predict future risk of developing cardiomyopathy requires further investigation.
    No preview · Article · Sep 2013 · Cardiology in the Young
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    Pei-Ni Jone · Julie Hinzman · David Ivy · Adel Younoszai

    Full-text · Article · Mar 2012 · Journal of the American College of Cardiology
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    ABSTRACT: The transplanted heart experiences numerous hemodynamic changes during and after cardiac transplantation. This study sought to evaluate the left ventricular myocardial mechanics in the pediatric heart transplant population using Velocity Vector Imaging (VVI). This study retrospectively evaluated 28 heart transplant recipients by echocardiography 12 months after transplantation. Echocardiograms from 28 age- and gender-matched subjects were used as a control group. Peak global longitudinal and circumferential left ventricular strain, systolic strain rate, and diastolic strain rate were obtained. Student's t tests were used to assess differences between the two groups (defined as p ≤ 0.05). The peak global left ventricular longitudinal strain was lower in the transplant group (17.21%) than in the control group (22.14%). The transplant and control groups did not differ significantly in terms of their peak global circumferential strain (20.28% vs. 20.79%, respectively). Similar results were observed for longitudinal and circumferential systolic and diastolic strain rates. The transplant patients showed statistically significant reductions in all peak global longitudinal measures compared with those of the control subjects. Circumferential myocardial deformation appears to be preserved in transplant recipients. This could suggest evidence of ischemia given the known myocardial fiber arrangement of longitudinal fibers toward the endocardial surface, which is also more distal in the coronary arterioles.
    No preview · Article · Feb 2012 · Pediatric Cardiology
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    ABSTRACT: Echocardiographic measures of left ventricular (LV) dyssynchrony in pediatric patients with heart failure (HF) have not been adequately evaluated. The aim of this study was to evaluate LV systolic dyssynchrony in pediatric patients with HF and normal children. Among a total of 68 patients, 22 had HF and 46 were normal. Doppler tissue imaging, M-mode echocardiography, and pulsed-wave Doppler echocardiography were performed. Intraventricular dyssynchrony using the maximal difference in time to peak myocardial systolic contraction (Ts), the standard deviation of Ts of 12 LV segments, septal-to-posterior wall motion delay, and interventricular dyssynchrony by measuring aortic and pulmonary pre-ejection delays were obtained. The maximal difference in Ts (patients with HF, 91.27 ± 31.18 msec; controls, 45.93 ± 21.29 msec; P < .001), the standard deviation of Ts (patients with HF, 31.05 ± 10.68 msec; controls, 15.60 ± 7.70 msec; P < .001), septal-to-posterior wall motion delay (patients with HF, 117.14 ± 45.18 msec; controls, 48.69 ± 16.63 msec; P < .001) and interventricular dyssynchrony (patients with HF, 21.60 ± 16.27 msec; controls, 11.56 ± 9.38 msec; P = .03) were significantly prolonged in the HF group. Defining systolic dyssynchrony as a standard deviation of Ts > 31 msec (+2 standard deviations of normal controls) and a maximal difference in Ts > 89 msec in normal controls and 18 patients with HF due to dilated cardiomyopathy was included for analysis of systolic dyssynchrony; it was present in three (6.5%) and two (4.3%) controls and in nine (50%) and 10 (55%) patients with HF due to dilated cardiomyopathy, respectively. Low ejection fraction, elevated LV end-diastolic volume, and elevated LV end-systolic volume had significant correlations with systolic dyssynchrony. QRS duration was not significantly correlated with measures of dyssynchrony. Systolic mechanical dyssynchrony is common in pediatric patients with HF. QRS duration is not a determinant of systolic dyssynchrony in pediatric patients. Echocardiographic measurements of systolic dyssynchrony are feasible in pediatric patients.
    Full-text · Article · Feb 2012 · Journal of the American Society of Echocardiography: official publication of the American Society of Echocardiography

  • No preview · Article · May 2010 · Journal of the American Society of Echocardiography: official publication of the American Society of Echocardiography

  • No preview · Article · Aug 2009 · The Annals of thoracic surgery
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    ABSTRACT: Evaluation of myocardial perfusion is sometimes necessary in children with congenital heart disease or acquired coronary artery abnormalities. Limited information is available regarding the clinical utility of myocardial perfusion imaging in children. PET imaging with rubidium-82 may provide a convenient clinical means of assessing regional circulatory compromise in pediatric patients with small hearts, due to its improved spatial resolution. Clinically indicated cardiac PET studies obtained in 22 pediatric patients were reviewed by two blinded observers and assigned myocardial perfusion scores using a standard 17-segment model. PET results were correlated with coronary angiography, available in 15 cases, to determine the accuracy of PET scanning for evaluating compromise of the myocardial circulation. Reversible defects consistent with myocardial ischemia were present in 6 of 15 (40%) PET cases. The sensitivity and specificity of cardiac PET for the detection of significant coronary artery disease were 100% and 82%, respectively. The positive predictive value of cardiac PET was 67%, while the negative predictive value was 100%. Cardiac PET imaging with rubidium-82 appears promising for the noninvasive assessment of myocardial perfusion in the pediatric population. The findings from this small series suggest that prospective study in a larger patient cohort merits consideration.
    No preview · Article · Aug 2008 · Pediatric Cardiology
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    Adel K Younoszai · David E Saudek · Stephen P Emery · James D Thomas
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    ABSTRACT: There are limited data on the properties of fetal myocardium with only a small number of Doppler tissue imaging-based studies published. We evaluated the feasibility of using velocity vector imaging, a novel technique for analyzing 2-dimensional images offline, to study myocardial mechanics in the normal fetal heart at different of gestational ages. A single 2-dimensional 4-chamber image of the heart was interrogated offline using velocity vector imaging software. Longitudinal velocity, strain, and strain rate were measured in the right ventricular free wall, ventricular septum, and left ventricular free wall. Images from 24 of 27 (89%) were successfully analyzed. The systolic and diastolic longitudinal velocities increased with gestational age in all myocardial segments analyzed (r = 0.56-0.78, P < .05). Systolic strain and strain rate were not found to have significant correlation with gestational age in any of the wall segments. This implies that increasing velocities during normal gestation are the result of somatic growth rather than changes in myocardial contractility.
    Preview · Article · Jun 2008 · Journal of the American Society of Echocardiography: official publication of the American Society of Echocardiography

Publication Stats

479 Citations
100.79 Total Impact Points

Institutions

  • 2015
    • University of Toronto
      Toronto, Ontario, Canada
  • 2009-2015
    • Children's Hospital Colorado
      • • Department of Pediatrics
      • • Department of Cardiothoracic Surgery
      Aurora, Colorado, United States
  • 2007-2014
    • University of Colorado
      Denver, Colorado, United States