I am a physician researcher in the area of cardiovascular medicine with specialty interests in cardiomyopathy, heart failure and exercise. My background includes clinical training in internal medicine and cardiology through the Royal Australian College of Physicians. I have completed a one year advance cardiac imaging fellowship in echocardiography and exercise testing. My current research projects are aimed at defining inflammasome pathways with exercise and optimizing the use of demographic data to predict exercise performance in healthy individuals and those with heart failure.
Instructor, Medicine - Cardiovascular Medicine
Honors & Awards
Young Investigator Award, American College of Chest Physicians/Asian Pacific Society of Respirology (2009)
Boards, Advisory Committees, Professional Organizations
International Associate, American College of Cardiology (2017 - Present)
Member, American Society of Echocardiography (2015 - Present)
Member, American Heart Association (2015 - Present)
Fellow, Royal Australian College of Physicians (2007 - Present)
Community and International Work
Young Athletes Academy (YAA), Health Screening
Opportunities for Student Involvement
IPOP Personalised Exercise Study, Stanford University/Stanford Cardiovascular Institue (January 1, 2016)
Cardiovascular Phenotyping with Exercise
Palo Alto, California
Novel Prediction Models for Patient-Centered Clinical Outcomes After Transcatheter Aortic Valve Replacement for Aortic Stenosis, Stanford University (10/1/2015)
The purpose of this study is to provide more information to guide treatment decision for patients with aortic stenosis being escalated for TAVR.
Palo Alto, California
Project Baseline (Verily), Stanford University (6/27/2017)
This study is led by Verily, Duke University School of Medicine, Stanford Medicine, and Google
Applying current normative data to prognosis in heart failure: The Fitness Registry and the Importance of Exercise National Database (FRIEND)
INTERNATIONAL JOURNAL OF CARDIOLOGY
2018; 263: 75–79
Percent of predicted peak VO2 (ppVO2) is considered a standard measure for establishing disease severity, however, there are known limitations to traditional normative values. This study sought to compare ppVO2 from the newly derived "Fitness Registry and the Importance of Exercise: a National Database" (FRIEND) registry equation to conventional prediction equations in a clinical cohort of patients undergoing cardiopulmonary exercise testing (CPX).We selected 1094 patients referred for evaluation of heart failure (HF) symptoms who underwent CPX. ppVO2 was calculated using the FRIEND, Wasserman/Hansen and Jones equations. Participants were followed for a median of 4.5 years [Interquartile range 3.5-6.0] for the composite endpoint of death, advanced HF therapy, or acute decompensated HF requiring hospital admission. Mean age was 48 ± 15 years and 62% were female. The FRIEND registry equation predicted the lowest ppVO2 (measured/predicted; 71 ± 31%), compared to the Wasserman/Hansen (74 ± 29%) and Jones equations (83 ± 33%) (p < 0.001). All expressions of peak VO2 were significant as univariate predictors of outcome with no significant differences between equations on pairwise analysis of receiver operating characteristic curves. When compared at a similar threshold of ppVO2 the event rate was significantly lower in the FRIEND registry equation versus the currently used Wasserman and Jones equations.The use of the newly derived FRIEND registry equation predicts HF outcomes; however, it appears to predict a higher predicted VO2; the clinical implication being a lower threshold of percent predicted peak VO2 should be considered when risk stratifying patients with HF.
View details for DOI 10.1016/j.ijcard.2018.02.102
View details for Web of Science ID 000432918000017
View details for PubMedID 29525067
- Heart Rate Variability: An Old Metric with New Meaning in the Era of using nnHealth Technologies for Health and Exercise Training Guidance. Part One: Physiology and Methods ARRHYTHMIA & ELECTROPHYSIOLOGY REVIEW 2018; 7 (3): 193–98
Value of Circulating Cytokine Profiling During Submaximal Exercise Testing in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.
2018; 8 (1): 2779
Myalgic Encephalomyelitis or Chronic Fatigue Syndrome (ME/CFS) is a heterogeneous syndrome in which patients often experience severe fatigue and malaise following exertion. Immune and cardiovascular dysfunction have been postulated to play a role in the pathophysiology. We therefore, examined whether cytokine profiling or cardiovascular testing following exercise would differentiate patients with ME/CFS. Twenty-four ME/CFS patients were matched to 24 sedentary controls and underwent cardiovascular and circulating immune profiling. Cardiovascular analysis included echocardiography, cardiopulmonary exercise and endothelial function testing. Cytokine and growth factor profiles were analyzed using a 51-plex Luminex bead kit at baseline and 18 hours following exercise. Cardiac structure and exercise capacity were similar between groups. Sparse partial least square discriminant analyses of cytokine profiles 18 hours post exercise offered the most reliable discrimination between ME/CFS and controls (κ = 0.62(0.34,0.84)). The most discriminatory cytokines post exercise were CD40L, platelet activator inhibitor, interleukin 1-β, interferon-α and CXCL1. In conclusion, cytokine profiling following exercise may help differentiate patients with ME/CFS from sedentary controls.
View details for DOI 10.1038/s41598-018-20941-w
View details for PubMedID 29426834
View details for PubMedCentralID PMC5807550
Value of Strain Imaging and Maximal Oxygen Consumption in Patients with Hypertrophic Cardiomyopathy
American Journal of Cardiology
View details for DOI 10.1016/j.amjcard.2017.06.070
Incremental value of right heart metrics and exercise performance to well-validated risk scores in dilated cardiomyopathy
European Heart Journal - Cardiovascular Imaging
View details for DOI 10.1093/ehjci/jex187
INDEPENDENT PROGNOSTIC VALUES OF CLINICAL RISK SCORES, RIGHT VENTRICULAR SYSTOLIC PRESSURE, AND N-TERMINAL PRO-B-TYPE PEPTIDE IN HEART FAILURE WITH PRESERVED EJECTION FRACTION: INSIGHTS FROM SUPERVISED AND UNSUPERVISED MODELS
ELSEVIER SCIENCE INC. 2019: 718
View details for Web of Science ID 000460565900718
RESTING BLOOD PRESSURE IN 2881 ATHLETES AGED 9-35 YEARS OF AGE AND THE RELATION TO SEX, AGE, BODY SIZE, AND AFRO-AMERICAN DESCENT
ELSEVIER SCIENCE INC. 2019: 447
View details for Web of Science ID 000460565900447
COMPARISON OF UNITED STATES AND EUROPEAN CRITERIA FOR HYPERTENSION IN A LARGE COHORT OF COMPETITIVE ATHLETES EXAMINED AS PART OF PRE-PARTICIPATION EVALUATION
ELSEVIER SCIENCE INC. 2019: 446
View details for Web of Science ID 000460565900446
The Incremental Value of Right Ventricular Size and Strain in the Risk Assessment of Right Heart Failure Post - Left Ventricular Assist Device Implantation.
Journal of cardiac failure
2018; 24 (12): 823–32
BACKGROUND: Right heart failure (RHF) after left ventricular assist device (LVAD) implantation is associated with high morbidity and mortality. Existing risk scores include semiquantitative evaluation of right ventricular (RV) dysfunction. This study aimed to determine whether quantitative evaluation of both RV size and function improve risk stratification for RHF after LVAD implantation beyond validated scores.METHODS AND RESULTS: From 2009 to 2015, 158 patients who underwent implantation of continuous-flow devices who had complete echocardiographic and hemodynamic data were included. Quantitative RV parameters included RV end-diastolic (RVEDAI) and end-systolic area index, RV free-wall longitudinal strain (RVLS), fractional area change, tricuspid annular plane systolic excursion, and right atrial area and pressure. Independent correlates of early RHF (<30 days) were determined with the use of logistic regression analysis. Mean age was 56 ± 13 years, with 79% male; 49% had INTERMACS profiles ≤2. RHF occurred in 60 patients (38%), with 20 (13%) requiring right ventricular assist device. On multivariate analysis, INTERMACS profiles (adjusted odds ratio 2.38 [95% confidence interval [CI] 1.47-3.85]), RVEDAI (1.61 [1.08-2.32]), and RVLS (2.72 [1.65-4.51]) were independent correlates of RHF (all P < .05). Both RVLS and RVEDAI were incremental to validated risk scores (including the EUROMACS score) for early RHF after LVAD (all P < .01).CONCLUSIONS: RV end-diastolic and strain are complementary prognostic markers of RHF after LVAD implantation.
View details for DOI 10.1016/j.cardfail.2018.10.012
View details for PubMedID 30539717
Heart Rate Variability: An Old Metric with New Meaning in the Era of Using mHealth technologies for Health and Exercise Training Guidance. Part Two: Prognosis and Training.
Arrhythmia & electrophysiology review
2018; 7 (4): 247–55
It has been demonstrated that heart rate variability (HRV) is predictive of all-cause and cardiovascular mortality using clinical ECG recordings. This is true for rest, exercise and ambulatory HRV clinical ECG device recordings in prospective cohorts. Recently, there has been a rapid increase in the use of mobile health technologies (mHealth) and commercial wearable fitness devices. Most of these devices use ECG or photo-based plethysmography and both are validated for providing accurate heart rate measurements. This offers the opportunity to make risk information from HRV more widely available. The physiology of HRV and the available technology by which it can be assessed has been summarised in Part 1 of this review. In Part 2 the association between HRV and risk stratification is addressed by reviewing the current evidence from data acquired by resting ECG, exercise ECG and medical ambulatory devices. This is followed by a discussion of the use of HRV to guide the training of athletes and as a part of fitness programmes.
View details for DOI 10.15420/aer.2018.30.2
View details for PubMedID 30588312
Cytokines profile of reverse cardiac remodeling following transcatheter aortic valve replacement.
International journal of cardiology
2018; 270: 83–88
OBJECTIVE: Previous studies have suggested that cytokines and growth factors may predict ventricular recovery following aortic valve replacement (AVR). The primary objective of this study was to identify cytokines that predict ventricular recovery following transcatheter AVR (TAVR).METHODS: We prospectively enrolled 121 consecutive patients who underwent TAVR. Standard echocardiographic assessment at baseline, 1-month and 1-year after TAVR included left ventricular (LV) mass index (LVMI) and global longitudinal strain (GLS). Blood samples were obtained at the time of the procedure to measure cytokines using a 63-plex Luminex platform. Partial least squares-discriminant analysis was performed to identify cytokines associated with ventricular remodeling and function at baseline as well as 1 year after TAVR.RESULTS: The mean age was 84 ± 9 years, with a majority of male subjects (59%), a mean LVMI of 120.4 ± 45.1 g/m2 and LVGLS of -13.0 ± 3.2%. On average, LV mass decreased by 8.1% and GLS improved by 20.3% at 1 year following TAVR. Among cytokines assayed, elevated hepatocyte growth factor (HGF) emerged as a common factor significantly associated with worse baseline LVMI and GLS as well as reduced ventricular recovery (p < 0.005). Other factors associated with ventricular recovery included a select group of vascular growth factors, inflammatory mediators and tumor necrosis factors, including VEGF-D, ICAM-1, TNFbeta, and IL1beta.CONCLUSION: We identified a network of cytokines, including HGF, that are significantly correlated with baseline LVMI and GLS, and ventricular recovery following TAVR.
View details for DOI 10.1016/j.ijcard.2018.05.020
View details for PubMedID 30219541
Forgotten No More: A Focused Update on the Right Ventricle in CardiovascularDisease.
JACC. Heart failure
In the last decade, there has been renewed interest in the study of the right ventricle. It is now well established that right ventricular function is a strong predictor of mortality, not only in heart failure but also in pulmonary hypertension, congenital heart disease, and cardiothoracic surgery. The right ventricle is part of a cardiopulmonary unit with connections to the pulmonary circulation, venous return, atria, and left ventricle. In this context, ventriculoarterial coupling, interventricular interactions, and pericardial constraint become important to understand right ventricular adaptation to injury or abnormal loading conditions. This state-of-the-art review summarizes major advances that occurred in the field of right ventricular research over the last decade. The first section focuses on right ventricular physiology and pulmonary circulation. The second section discusses the emerging data on right ventricular phenotyping, highlighting the importance of myocardial deformation (strain) imaging and assessment of end-systolic dimensions. The third section reviews recent clinical trials involving patients at risk for or with established right ventricular failure, focusing on beta blockade, phosphodiesterase inhibition, and mechanical support of the failing right heart. The final section presents a perspective on active areas of research that are most likely to translate in clinical practice in the next decade.
View details for DOI 10.1016/j.jchf.2018.05.022
View details for PubMedID 30316939
Right ventricular load adaptability metrics in patients undergoing left ventricular assist device implantation.
The Journal of thoracic and cardiovascular surgery
OBJECTIVE: Several right load adaptability metrics have been proposed as predictors of right heart failure (RHF) following left ventricular assist device implantation. This study sought to validate and compare the prognostic value of these indices.METHODS: This retrospective study included 194 patients undergoing continuous-flow left ventricular assist device implantation. The primary end point was unplanned right atrial assist device (RVAD) need within 30days after left ventricular assist device implantation; the secondary end points included clinical RHF syndrome without RVAD need and the composite of RHF or RVAD need. Load adaptability indices or interventricular ratios were divided into surrogates of ventriculoarterial coupling (RV area change:end-systolic area), indices reflecting adaptation proportionality (Dandel's index=tricuspid regurgitation velocity-time integral normalized for average RV radius in diastole or systole), and simple ratios (eg, pulse pressure:right atrial pressure or right arterial pressure:pulmonary arterial wedge pressure).RESULTS: Mean age was 55±13years with 77% of men. RHF occurred in 75 patients with 30 patients requiring RVAD implantation. Among right heart metrics, right arterial pressure (normalized odd ratio, 1.62; 95% confidence interval, 1.15-2.38), right arterial pressure:pulmonary arterial wedge pressure (normalized odds ratio, 1.59; 95% confidence interval, 1.08-2.32) and pulse pressure:right arterial pressure<2.0 (normalized odds ratio, 2.56; 95% confidence interval, 1.16-5.56) were associated with RVAD need (all P values<.02). These 3 metrics significantly added incremental prognostic value to the Interagency Registry for Mechanically Assisted Circulatory Support classification score in a similar range, whereas only RAP was incremental to the Michigan score. Correlates of RHF not requiring RVAD included RV end-systolic area index and the Dandel indices, which provided similar incremental value to the Interagency Registry for Mechanically Assisted Circulatory Support, Michigan, and European Registry for Patients with Mechanical Circulatory Support scores.CONCLUSIONS: Although associated with outcome, right load adaptability indices do not appear to provide strong incremental value when compared with simple metrics.
View details for DOI 10.1016/j.jtcvs.2018.08.095
View details for PubMedID 30482529
Time based versus strain based myocardial performance indices in hypertrophic cardiomyopathy, the merging role of left atrial strain.
European heart journal cardiovascular Imaging
Aims: The myocardial performance index (MPI) is a time-based index of global myocardial performance. In this study, we sought to compare the prognostic value of the MPI with other strain and remodelling indices in hypertrophic cardiomyopathy (HCM).Methods and results: We enrolled 126 patients with HCM and 50 age- and sex-matched controls. Along with traditional echocardiographic assessment, MPI, left ventricular global longitudinal strain (LVGLS), E/e' ratio, and total left atrial (LA) global strain (LAS) were also measured. Time-based MPI was calculated from flow or tissue-based pulse wave Doppler (PWD and TDI) as the (isovolumic-relaxation and contraction time)/systolic-time. We used hierarchical clustering and network analysis to better visualize the relationship between parameters. The primary endpoint was the composite of all-cause death, heart transplantation, left ventricular assist device implantation, and clinical worsening. Left ventricular outflow tract (LVOT) obstruction was present in 56% of patients. Compared with controls, patients with HCM had worse LVGLS (-14.0±3.4% vs. -19.6±1.5%), higher E/e' (12.9±7.2 vs. 6.1±1.5), LA volume index (LAVI) (36.4±13.8ml/m2 vs. 25.6±6.7ml/m2), and MPI (0.55±0.17 vs. 0.40±0.11 for PWD and 0.59±0.22 vs. 0.46±0.09 for TDI) (all P<0.001). During a median follow-up of 55months, 47 endpoints occurred. PWD or TDI-based MPI was not associated with outcome, while LAVI, LAS, LVGLS, and E/e' were (all P<0.01). On multivariable analysis, LVOT obstruction (P<0.001), LAS (P<0.001), and E/e' (P=0.02) were retained as independent associates. They were in different clusters suggesting complemental relationship between them.Conclusion: Time-based index is less predictive of outcome than strain or tissue Doppler indices. LAS may be a promising prognostic marker in HCM.
View details for DOI 10.1093/ehjci/jey097
View details for PubMedID 30060097
Applying Cardiopulmonary Exercise Testing to the Evaluation of Left Ventricular Function for Patients Ventricular Assist Device Therapy
American College of Sports Medicine
View details for DOI 10.1249/01.mss.0000518376.31161.d1
The Use of Peak Oxygen Uptake Prediction Equations for Prognosis in Patients with Cardiomyopathy
American College of Sports Medicine
View details for DOI 10.1249/01.mss.0000518565.03148.13
Optimizing right ventricular focused four-chamber views using three-dimensional imaging, a comparative magnetic resonance based study.
The international journal of cardiovascular imaging
Obtaining focused right ventricular (RV) apical view remains challenging using conventional two-dimensional (2D) echocardiography. This study main objective was to determine whether measurements from RV focused views derived from three-dimensional (3D) echocardiography (3D-RV-focused) are closely related to measurements from magnetic resonance (CMR). A first cohort of 47 patients underwent 3D echocardiography and CMR imaging within 2h of each other. A second cohort of 25 patients had repeat 3D echocardiography to determine the test-retest characteristics; and evaluate the bias associated with unfocused RV views. Tomographic views were extracted from the 3D dataset: RV focused views were obtained using the maximal RV diameter in the transverse plane, and unfocused views from a smaller transverse diameter enabling visualization of the tricuspid valve opening. Measures derived using the 3D-RV-focused view were strongly associated with CMR measurements. Among functional metrics, the strongest association was between RV fractional area change (RVFAC) and ejection fraction (RVEF) (r=0.92) while tricuspid annular plane systolic excursion moderately correlated with RVEF (r=0.47), all p<0.001. Among RV size measures, the strongest association was found between RV end-systolic area (RVESA) and volume (r=0.87, p<0.001). RV unfocused views led on average to 10% underestimation of RVESA. The 3D-RV-focused method had acceptable test-retest characteristics with a coefficient of variation of 10% for RVESA and 11% for RVFAC. Deriving standardized RV focused views using 3D echocardiography strongly relates to CMR-derived measures and may improve reproducibility in RV 2D measurements.
View details for DOI 10.1007/s10554-018-1356-7
View details for PubMedID 29654480
- PREDICTING MORTALITY WITH AORTOMITRAL CALCIFICATIONS IN 317 TAVR PATIENTS ELSEVIER SCIENCE INC. 2018: 1591
- RIGHT HEART MALADAPTIVE PHENOTYPES AND PREDICTION OF RIGHT HEART FAILURE FOLLOWING CONTINUOUS-FLOW LEFT VENTRICULAR ASSIST DEVICE IMPLANTATION ELSEVIER SCIENCE INC. 2018: 652
- RIGHT VENTRICULAR LOAD ADAPTABILITY IN PATIENTS UNDERGOING CONTINUOUS-FLOW LEFT VENTRICULAR ASSIST DEVICE IMPLANTATION ELSEVIER SCIENCE INC. 2018: 1624
- INTEGRATING CORRELATION BASED NETWORKS INTO RISK PROGNOSTICATION OF CARDIOMYOPATHY ELSEVIER SCIENCE INC. 2018: 837
IMMUNE PROFILE OF HEALTHY CARDIOVASCULAR AGING: INSIGHTS FROM A POPULATION-BASED STUDY AND NETWORK MODELING
ELSEVIER SCIENCE INC. 2018: 1657
View details for Web of Science ID 000429659703307
- THE PROGNOSTIC VALUE OF COMPUTED TOMOGRAPHY FRAILTY MEASURES FOR PROLONGED HOSPITAL STAY AFTER TAVR IN 429 PATIENTS ELSEVIER SCIENCE INC. 2018: 1414
- THE COMPLEMENTARY VALUE OF THE GET WITH THE GUIDELINES: HEART FAILURE RISK SCORE AND LABORATORY MARKERS AT DISCHARGE IN PREDICTING MORTALITY IN PATIENTS HOSPITALIZED WITH HEART FAILURE WITH PRESERVED EJECTION FRACTION ELSEVIER SCIENCE INC. 2018: 839
Exercise testing in heart failure: a contemporary discussion in an era of novel diagnostic techniques and biomarkers.
Current opinion in cardiology
2018; 33 (2): 217–24
The purpose of this review is to highlight recent advances in the field of exercise testing for patients with heart failure.The importance of assessment of cardiorespiratory fitness (CRF) and exercise testing in heart failure is highlighted in the consensus recommendation of the American Heart Association. Contemporary studies have validated the independent and incremental strength of CRF metrics in patients with heart failure and coronary artery disease. The use of respiratory gas analysis and imaging or hemodynamics during physical exercise is feasible and results in high prognostic utility across the continuum of heart failure. Understanding how CRF metrics complement existing and novel biomarkers and risk scores is an emerging subject of scientific inquiry.In the current era of personalized medicine, integrating CRF, imaging and circulating biomarkers will allow us to further develop individualized strategies for improving outcome in patients with heart failure.
View details for DOI 10.1097/HCO.0000000000000490
View details for PubMedID 29227300
Athletic Remodeling in Female College Athletes, the "Morganroth Hypothesis" Revisited.
Clinical journal of sport medicine : official journal of the Canadian Academy of Sport Medicine
There is limited data regarding ventricular remodeling in college female athletes, especially when appropriate scaling of cardiac dimensions to lean body mass (LBM) is considered. Moreover, it is not well established whether cardiac remodeling in female athletes is a balanced process with proportional increase in left ventricular (LV) mass and volume or the right and LV size.During the preparticipation competitive screening, 72 female college athletes volunteered to undergo dual energy x-ray absorptiometry scan for quantification of LBM and comprehensive 2D echocardiography including assessment of longitudinal myocardial strain. The athletes were divided in 2 groups according to the intensity of the dynamic and static components of their sport categories, ie, a higher intensity dynamic and resistive group (n = 37 participating in rowing, water polo and lacrosse) and a lower intensity group (n = 35, participating in short distance running, sailing, synchronized swimming, and softball). In addition, we recruited a group of 31 age-matched nonathlete controls.The mean age of the study population was 18.7 ± 1.0 years. When scaled to body surface area, the higher intensity group had 17.1 ± 3.6% (P < 0.001) greater LV mass when compared with the lower intensity group and 21.7 ± 4.0% (P < 0.001) greater LV mass than the control group. The differences persisted after scaling to LBM with 14.2 ± 3.2% (P < 0.001) greater LV mass in the higher intensity group. By contrast, there was no difference in any of the relative remodeling indices including the LV mass to volume ratio, right to LV area ratio, or left atrial to LV volume ratio (P > 0.50 for all). In addition, no significant difference was noted among the 3 groups in LV ejection fraction (P = 0.22), LV global longitudinal strain (P = 0.55), LV systolic strain rate (P = 0.62), or right ventricular global longitudinal strain (P = 0.61).Female collegiate athletes participating in higher intensity dynamic and resistive sports have higher indexed LV mass even when scaled to LBM. The remodeling process does however appear to be a balanced process not only at the intraventricular level but also at the interventricular and atrioventricular levels.
View details for DOI 10.1097/JSM.0000000000000501
View details for PubMedID 29369833
- Complementary Role of Exercise Performance and Right Heart Metrics to the Validated MAGGIC score: Insights From a Network Analysis American Heart Association Scientific Sessions and Resuscitation Science Symposium
Combining echocardiography with cardiopulmonary exercise stress testing to evaluate recovery of systolic function in patients with left ventricular assist devices
Heart Failure 2017 and the 4th World Congress on Acute Heart Failure
View details for DOI 10.1002/ejhf.833
Addressing Reference Echocardiographic Parameters in Athletic Screening: A College Football-Based Study focusing on the implications of race and correction for body composition
View details for DOI 10.1016/S0735-1097(17)34842-8
The Inflammasome Pathway is Associated with Adverse Ventricular Remodeling Following Transcatheter Aortic Value Replacement
American College of Cardiology Scientific Sessions
View details for DOI 10.1016/S0735-1097(17)34429-7
Integrating Myocardial Strain and Exercise Performance into Prognostication of Hypertrophic Cardiomyopathy
American College of Cardiology Scientific Sessions
View details for DOI 10.1016/S0735-1097(17)34222-5
Identifying the Optimal Echocardiographic Variables to Predict Outcome Through Correlation Mapping in Patients with Dilated Cardiomyopathy
View details for DOI 10.1016/S0735-1097(17)34924-0
- Baseline growth differentiation factor 15 (GDF15) is an independent predictor of reverse left atrial remodeling and mortality at 1-year following Transcatheter Aortic Valve Replacement Twenty-Eighth Annual Symposium Transcatheter Cardiovascular Therapeutics
- Clinical Predictors of Short and Long Term Mortality in Patients With Heart Failure Preserved Ejection Fraction American Heart Association Scientific Sessions and Resuscitation Science Symposium
- Left Ventricular Response to Exercise in Dilated Cardiomyopathy and the Potential for Reclassification of Heart Failure Severity American Society of Echocardiography Scientific Sessions
Dynamic changes in aortic impedance after transcatheter aortic valve replacement and its impact on exploratory outcome.
international journal of cardiovascular imaging
Valvulo-arterial impedance (Zva) has been shown to predict worse outcome in medically managed aortic stenosis (AS) patients. We aimed to investigate the association between Zva and left ventricular (LV) adaptation and to explore the predictive value of Zva for cardiac functional recovery and outcome after transcatheter aortic valve replacement (TAVR). We prospectively enrolled 128 patients with AS who underwent TAVR. Zva was calculated as: (systolic blood pressure + mean transaortic gradient)/stroke volume index). Echocardiographic assessment occurred at baseline, 1-month and 1-year after TAVR. The primary endpoints were to investigate associations between Zva and global longitudinal strain (GLS) at baseline as well as GLS change after TAVR. The secondary was to compare all-cause mortality after TAVR between patients with pre-defined Zva (=5 mmHg m(2)/ml), stroke volume index (=35 ml/m(2)), and GLS (=-15%) cutoffs. The mean GLS was reduced (-13.0 ± 3.2%). The mean Zva was 5.2 ± 1.6 mmHg*m(2)/ml with 55% of values ≥5.0 mmHg*m(2)/ml, considered to be abnormally high. Higher Zva correlated with worse GLS (r = -0.33, p < 0.001). After TAVR, Zva decreased significantly (5.1 ± 1.6 vs. 4.5 ± 1.6 mmHg*m(2)/ml, p = 0.001). A reduction of Zva at 1-month was associated with GLS improvement at 1-month (r = -0.31, p = 0.001) and at 1-year (r = -0.36 and p = 0.001). By Kaplan-Meier analysis, patients with higher Zva at baseline had higher mortality (Log-rank p = 0.046), while stroke volume index and GLS did not differentiate outcome (Log-rank p = 0.09 and 0.25, respectively). As a conclusion, Zva is correlated with GLS in AS as well as GLS improvement after TAVR. Furthermore, a high baseline Zva may have an additional impact to traditional parameters on predicting worse mortality after TAVR.
View details for DOI 10.1007/s10554-017-1155-6
View details for PubMedID 28516313
Contractile reserve and cardiopulmonary exercise parameters in patients with dilated cardiomyopathy, the two dimensions of exercise testing.
Echocardiography (Mount Kisco, N.Y.)
Left ventricular (LV) contractile reserve assessed using imaging and cardiopulmonary exercise testing (CPX) has been shown to predict outcome in patients with dilated cardiomyopathy (DCM). Few clinical studies have, however, analyzed the relationship between them.A cohort of 75 ambulatory patients with DCM underwent stress treadmill echocardiography with CPX. LV contractile reserve was calculated as absolute change (ΔLVEF=LVEFpeak -LVEFrest ) and percent change (%LVEF=[(LVEFpeak -LVEFrest )/LVEFpeak) ]×100) in LVEF, circumferential and longitudinal strain (LS). Exercise capacity was measured as peak oxygen uptake (peak VO2 ) and ventilatory efficiency as the slope of minute ventilation to CO2 production (VE/VCO2 slope). Values of contractile reserve were compared to matched controls. We also explored which metric of ventricular response (absolute or percent change) was less dependent on baseline LV function.Patients with DCM had a mean age, rest and peak LVEF of 44±10 years, 42±10% and 50±12%, respectively. Among parameters of contractile reserve, peak cardiac output was the strongest parameter associated with peak VO2 (r=.63, P<.001). Along with age, sex, and BMI, it explained more than 70% of the variance in peak VO2 . In contrast, LVEF and LS were only weakly related to peak VO2 . With regard to ventilatory efficiency, the strongest parameter that emerged was right atrial volume index (r=.36, P<.001). Percent change in LVEF was more independent of baseline function than absolute change.Echocardiographic contractile reserve and CPX provide complementary information. Percent change in contractile reserve was most independent of baseline function, therefore may be preferred when analyzing the ventricular response to exercise.
View details for DOI 10.1111/echo.13623
View details for PubMedID 28681553
GDF-15 (Growth Differentiation Factor 15) Is Associated With Lack of Ventricular Recovery and Mortality After Transcatheter Aortic Valve Replacement.
Circulation. Cardiovascular interventions
2017; 10 (12)
Recent data suggest that circulating biomarkers may predict outcome in patients undergoing transcatheter aortic valve replacement (TAVR). We examined the association between inflammatory, myocardial, and renal biomarkers and their role in ventricular recovery and outcome after TAVR.A total of 112 subjects undergoing TAVR were included in the prospective registry. Plasma levels of B-type natriuretic peptide, hs-TnI (high-sensitivity troponin I), CRP (C-reactive protein), GDF-15 (growth differentiation factor 15), GAL-3 (galectin-3), and Cys-C (cystatin-C) were assessed before TAVR and in 100 sex-matched healthy controls. Among echocardiographic parameters, we measured global longitudinal strain, indexed left ventricular mass, and indexed left atrial volume. The TAVR group included 59% male, with an average age of 84 years, and 1-year mortality of 18%. Among biomarkers, we found GDF-15 and CRP to be strongly associated with all-cause mortality (P<0.001). Inclusion of GDF-15 and CRP to the Society of Thoracic Surgeons score significantly improved C index (0.65-0.79; P<0.05) and provided a category-free net reclassification improvement of 106% at 2 years (P=0.01). Among survivors, functional recovery in global longitudinal strain (>15% improvement) and indexed left ventricular mass (>20% decrease) at 1 year occurred in 48% and 22%, respectively. On multivariate logistic regression, lower baseline GDF-15 was associated with improved global longitudinal strain at 1 year (hazard ratio=0.29; P<0.001). Furthermore, improvement in global longitudinal strain at 1 month correlated with lower overall mortality (hazard ratio=0.45; P=0.03).Elevated GDF-15 correlates with lack of reverse remodeling and increased mortality after TAVR and improves risk prediction of mortality when added to the Society of Thoracic Surgeons score.
View details for DOI 10.1161/CIRCINTERVENTIONS.117.005594
View details for PubMedID 29222133
- Normative Values for Cardiorespiratory Fitness: 45 Years after Bruce Journal of Clinical Exercise Physiology 2017; 3 (6): 59-60
Moving Beyond Linear Formulas for Left Ventricular Mass in Aortic Valve Replacement
View details for DOI 10.1080/24748706.2017.1377364
Incremental Value of Deformation Imaging and Hemodynamics Following Heart Transplantation: Insights From Graft Function Profiling.
JACC. Heart failure
2017; 5 (12): 930–39
This study investigated to define graft dysfunction and to determine its incremental association with long-term outcome after heart transplantation (HT).Although graft failure is an established cause of late mortality after HT, few studies have analyzed the prognostic value of graft dysfunction at 1- and 5-year follow-up of HT.Patients who underwent HT and completed their first annual evaluation with right heart catheterization and echocardiography at Stanford University between January 1999 and December 2011 were included in the study. Hierarchical clustering was used to identify modules to capture independent features of graft dysfunction at 1 year. The primary endpoint for analysis consisted of the composite of cardiovascular mortality, re-transplantation, or heart failure hospitalization within 5 years of HT. The study further explored whether changes in graft dysfunction between 1 and 5 years were associated with 10-year all-cause mortality.A total of 215 HT recipients were included in the study. Using hierarchical clustering, 3 functional modules were identified; among them, left ventricular global longitudinal strain (LVGLS), stroke volume index, and right atrial pressure (RAP) or pulmonary capillary wedge pressure (PCWP) captured key features of graft function. Graft dysfunction based on pre defined LVGLS in absolute value <14%, stroke volume index <35 ml/m2, RAP >10 mm Hg, or PCWP >15 mm Hg were present in 41%, 36%, and 27%, respectively. The primary endpoint at 5 years occurred in 52 patients (24%), whereas 10-year all-cause mortality occurred in 30 (27%) of 110 patients alive at 5 years. On multivariate analysis, RAP (standardized hazard ratio: 1.63), LVGLS (standardized hazard ratio: 1.39), and a history of hemodynamically compromising rejection within 1 year (hazard ratio: 2.18) were independent predictors of 5-year outcome. RAP at 5 years, as well as change in RAP from 1 to 5 years, was predictive of 10-year all-cause mortality.RAP and LVGLS at the first annual evaluation provide complementary prognostic information in predicting 5-year outcome after HT.
View details for DOI 10.1016/j.jchf.2017.10.011
View details for PubMedID 29191301
Challenging the complementarity of different metrics of left atrial function: insight from a cardiomyopathy-based study.
European heart journal cardiovascular Imaging
Left ventricular (LV) strain provides incremental values to LV ejection fraction (LVEF) in predicting outcome. We sought to investigate if similar relationship is observed between left atrial (LA) emptying fraction and LA strain.In this study, we selected 50 healthy subjects, 50 patients with dilated, 50 hypertrophic, and 50 infiltrative (light-chain (AL) amyloidosis) cardiomyopathy (CMP). Echocardiographic measures included LVEF and LA emptying fraction as well as LV and LA longitudinal strain (LVLS and LALS). After regression analysis, comparison of least square means of LA strain among aetiologies was performed. Intraclass correlation coefficient (ICC) and coefficient of variation (COV) were used in the assessment of variability and reproducibility of LV and LA metrics. The mean LVLS and all LA metrics were impaired in patients with all CMP compared with healthy subjects. In contrast to the moderate relationship between LVEF and LVLS (r = -0.51, P < 0.001), there was a strong linear relationship between LA emptying fraction and LA strain (r = 0.87, P < 0.001). In multiple regression analysis, total LA strain was associated with LVLS (β = -0.48, P < 0.001), lateral E/e' (β = -0.24, P < 0.001), age (β = -0.21, P < 0.001), and heart rate (β = -0.14, P = 0.02). The least square mean of LA strain adjusted for the parameters was not different among aetiologies (ANOVA P = 0.82). The ICC (>0.77) and COV (<13) were acceptable.In contrast to LV measures, there is a strong linear relationship between volumetric and longitudinal deformation indices of left atrium irrespective of CMP aetiology. Either LA emptying fraction or LA strain could be used as an important parameter in predictive models.
View details for PubMedID 27638850
Asystole Following Complex Partial Seizures
HEART LUNG AND CIRCULATION
2013; 22 (2): 146-148
A case is presented of a patient with a long history of epilepsy who presents with recurrent seizures and develops a period of asystole. The case highlights the need to consider the potential arrhythmic complications of seizures and the clinical characteristics that may be present in those with epilepsy that may warrant evaluation for arrhythmias.
View details for DOI 10.1016/j.hlc.2012.06.004
View details for Web of Science ID 000315370600011
View details for PubMedID 22877730
- An Update in Lung Transplantation Minerva Pneumologica 2010; 1 (49)