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21st World Congress on Heart Disease

 

ROLE OF ECHOCARDIOGRAPHY IN EPIDEMIOLOGIC STUDIES AND CLINICAL TRIALS: AN HISTORICAL PERSPECTIVE



Julius M. Gardin, M.D., Hackensack University Medical Center, Rutgers New Jersey Medical School, NJ, USA

 

Non-invasive transthoracic echocardiography (TTE) for assessment of subclinical and clinical heart disease initially, left ventricular (LV) mass, geometry and function dates from the 1980s. In parallel, TTE successfully demonstrated in hypertensive patients reduced LV mass and improved outcomes with antihypertensive therapy. Transesophageal echocardiography (TEE) has been invaluable in intra-operative/interventional trials. Many important uses of TTE/TEE and contributions from our collaborations are summarized in Tables 1 and 2. Challenges have included poor echocardiography windows, sonographer and reader measurement variability, temporal drift, regression-to-the mean, etc. Promising newer study applications include global image telemetry, strain deformation imaging, hand-held and potentially wearable echocardiography devices.

Table 1 - Important uses of TTE and TEE in Epidemiologic Studies and Clinical Trials

1.  Epidemiology: Characterize cardiac structure and function; identify echo prognostic parameters (e.g., in Framingham, Cornell, Helinski and CHS)

2.  Hypertension: Measure LV mass, systolic and diastolic function and assess treatment effects

3.  Valvular Disease: Assess prevalence, risk factors for development; assess prosthetic valve hemodynamics (for FDA, etc.)

4.  CHD/MI: Assess disease impact on LV remodeling/function; assess drug, catheter-based and surgical interventions; stress echo for ischemic vulnerability, myocardial viability, etc.

5.  Heart Failure: Assess LV systolic and diastolic function, LV remodeling, mitral regurgitation, and treatment effects – including reverse remodeling; assess candidates for CRT, other devices

6.  Toxicity: Assess effects of cancer, chemo/radiation therapy, diabetes, etc.

7.  Other: Diet drug valvulopathy, echo contrast agents, atrial fibrillation,TEE-guided cardioversion, interventional device (PFO and LAA closure, CRT, mitral clip, etc.) and surgical trials

Abbreviations: CHD = coronary heart disease, CHS = Cardiovascular Health Study, CRT = cardiac re-synchronization therapy, echo = echocardiography, FDA = U.S. Food and Drug Administration, LAA = left atrial appendage, LV = left ventricular, MI = myocardial infarction, PFO = patent foramen ovale
Modified after Gottdiener,…Gardin, et al: JASE 17(10):1086, 2004.

  Table 2 – Selected Cohort Studies involving our Collaboration

Study

Population

Echocardiography findings

CHS

Elderly US adults:
Bi-ethnic AA and C cohort

  • Elucidated prevalence of HFpEF, HFrEF, CHD and AV disease
  • Predictive value of LV mass, geometry and systolic function for HF, stroke and overall CVD events

CARDIA

Young US adults:
Bi-ethnic AA and C cohort

  • Elucidated prevalence of MV and AV disease, MVP and HCM.
  • Higher prevalence of LV mass in AA, associated with obesity and higher BP
  • Predictive value of LV systolic function for incident HF 10 years later

HF-ACTION

HFrEF patients
(LVEF < 35%)

  • Association of LV diastolic dysfunction with exercise MVO2

Echo NoRMAL

International cohort collaboration:
Adult populations

  • Elucidated normal TTE values in Euro, SA, and EA populations
  • Demonstrated lower range of stroke volume(s) in SA

DIET DRUGS Phentermine/fenfluramine (phen/fen) and Dexfenfluramine

Multicenter phen/fen
and dexfenfluramine
cessation studies

  • Prevalence of AR= 9 - 14% (mild = 8 - 12%) versus 4% in controls; regression or no change noted 1 year later

Abbreviations: AA = African American, AR = aortic regurgitation, AV = aortic valve, BP = blood pressure, C = Caucasian, CARDIA = Coronary Artery Risk Development in Young Adults, CHD = coronary heart disease, CHS = Cardiovascular Health Study, CIMT = carotid intima-media thickness, EA = East Asian, Echo NoRMAL = Echocardiographic Normal Ranges Meta-analysis of the Left Heart, Euro = European, HF = heart failure, HF-ACTION = Heart Failure ACTION, HFpEF = heart failure with preserved ejection fraction, HFrEF =  heart failure with reduced ejection fraction, SA = South Asian

 

 

 

 

 

 

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