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NIH assessment for the MESA study

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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  1. NIH assessment for the MESA study

  2. What do these two men have in common

  3. Coronary heart disease

  4. Causes of death in the USA • Heart disease is number one • Newsweek, Jan 31 2000 (p. 49)

  5. 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

  6. How to detect coronary heart disease • If the patient has chest pain • Stress testing • Radionuclide imaging • Coronary catheterization • This is for “advanced disease”

  7. How to detect coronary heart disease • If the patient does not have chest pain • This is for early, possibly reversible disease

  8. 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

  9. MESAMulti-Ethnic Study of Atherosclerosis • Ultrasound markers of atherosclerosis • Carotid IMT • Brachial artery reactivity (endothelial function) • Carotid artery distensibility

  10. What is Carotid IMT ? IMT: thickness of the intima to media interfaces seen on high resolution imaging of the arterial wall

  11. 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

  12. 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

  13. Brachial artery reactivity • Brachial artery endothelial function parallels coronary response • Abnormal: less of an increase in diameter during stimulus

  14. 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

  15. 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

  16. 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

  17. 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

  18. 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

  19. MESA: Ultrasound device selection • Brachial artery diameters

  20. MESA: Ultrasound device selection • Carotid IMT far wall

  21. MESA: Ultrasound device selection • Device ranking

  22. MESA: Ultrasound device selection • Device ranking

  23. 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

  24. 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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