Nih assessment for the mesa study
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How to detect coronary heart disease. If the patient does not have chest pain ... Carotid IMT and future heart attacks and strokes in individuals with no symptoms ...

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NIH assessment for the MESA study

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Nih assessment for the mesa study

NIH assessment for the MESA study


Nih assessment for the mesa study

  • What do these two men have in common


Coronary heart disease

Coronary heart disease


Causes of death in the usa

Causes of death in the USA

  • Heart disease is number one

  • Newsweek, Jan 31 2000 (p. 49)


Where does heart disease come from

Where does heart disease come from ?

  • Epidemiologic studies, e.g. the Framingham Heart Study

    • Linkage between “risk factors” and coronary artery stenosis

    • What is a risk factor ?

      • Elevated blood pressure

      • Elevated cholesterol

      • Cigarette smoke


How to detect coronary heart disease

How to detect coronary heart disease

  • If the patient has chest pain

    • Stress testing

    • Radionuclide imaging

    • Coronary catheterization

  • This is for “advanced disease”


How to detect coronary heart disease1

How to detect coronary heart disease

  • If the patient does not have chest pain

  • This is for early, possibly reversible disease


Mesa multi ethnic study of atherosclerosis

MESAMulti-Ethnic Study of Atherosclerosis

  • NHLBI/NIH funded

  • Multi-center study:6 centers, 6500 participants

  • Risk factors for atherosclerosis

  • Non-invasive markers of atherosclerosis

    • Coronary calcium scoring

  • Progression of calcium scores


Mesa multi ethnic study of atherosclerosis1

MESAMulti-Ethnic Study of Atherosclerosis

  • Ultrasound markers of atherosclerosis

    • Carotid IMT

    • Brachial artery reactivity (endothelial function)

    • Carotid artery distensibility


What is carotid imt

What is Carotid IMT ?

IMT: thickness of the intima to media interfaces seen on high resolution imaging of the arterial wall


Carotid imt and future heart attacks and strokes in individuals with no symptoms

40

30

20

10

0

1

2

3

4

5

Carotid IMT and future heart attacks and strokes in individuals with no symptoms

Top 20% with thick IMTs

Combined IMT

CCA IMT

29

29

28

ICA IMT

5 times the chance of heart attack and stroke

21.2

20.6

19.5

18.1

Incidence Rates (1,000 person-years)

16.1

16

12.8

12.2

10.4

6.2

5.6

4.8

O’Leary, Polak, Kronmal et al.

NEJM 1999

Quintiles of IMT values


Coronary artery physiology

Coronary artery physiology

  • Healthy coronary arteries should dilate when needed

  • Coronary reactivity is abnormal in patients with coronary disease

  • May represent a generalized dysfunction of the arterial system


Brachial artery reactivity

Brachial artery reactivity

  • Brachial artery endothelial function parallels coronary response

  • Abnormal: less of an increase in diameter during stimulus


Mesa ultrasound device selection

MESA: Ultrasound device selection

  • Goal: select an imaging device that will permit precise measurements of:

    • Level of wall thickening in the carotid artery: IMT

    • Changes in arterial diameter over time: brachial artery reactivity


Mesa ultrasound device selection1

MESA: Ultrasound device selection

  • Acuson Aspen, Hewlett-Packard ImagePoint; Siemens Allegra; Toshiba Power Vision 8000; GE Logiq-700; ATL HDI-5000

  • Same sonographer, same subject

  • Operator: application specialist from the respective companies


Mesa ultrasound device selection2

MESA: Ultrasound device selection

  • 2 of the 6 devices disqualified

    • Poor image quality

    • Insufficient frame rates

  • Unanimous decision by 6 representatives of the field centers


Mesa ultrasound device selection3

MESA: Ultrasound device selection

  • Removal of identifying marks

  • Scaling to same magnification

  • Normalized image intensities (0 to 255; minimum to maximum)

  • Scoring as 1 (best) to 4 (worse)

  • Images transmitted by e-mail


Mesa ultrasound device selection4

MESA: Ultrasound device selection

  • Image evaluation performed by:

    • 6 trained readers: perform the measurements

    • 6 representatives from the field centers

  • Scores tallied for

    • Carotid IMT near wall

    • Carotid IMT far wall

    • Brachial artery image clarity


Mesa ultrasound device selection5

MESA: Ultrasound device selection

  • Brachial artery diameters


Mesa ultrasound device selection6

MESA: Ultrasound device selection

  • Carotid IMT far wall


Mesa ultrasound device selection7

MESA: Ultrasound device selection

  • Device ranking


Mesa ultrasound device selection8

MESA: Ultrasound device selection

  • Device ranking


Mesa ultrasound device selection9

MESA: Ultrasound device selection

  • Based on device ranking, the GE Logiq-700 was picked for MESA

  • The study has enrolled more than 2000 of 6500 individuals

  • Preliminary examination of data quality and completeness shows overall good performance for all imaging tasks


Mesa ultrasound examination

MESA: Ultrasound examination

  • Unanswered questions:

    • Are coronary artery calcium scores superior to carotid IMT ?

    • Does endothelial dysfunction predict the development of coronary disease ?


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