Hypothesis Evaluated in these Papers CIMT is Used a Tool for Atherosclerosis-Related Event Prediction and for the Evaluating Atherosclerosis Progression/Regression 400 scientific articles published in peer-reviewed journals during 2003 that included CIMT Hypothesis Evaluated in these Papers Prediction of CVD events Association with prevalent disease Efficacy of pharmaceutical interventions impact of diet and exercise modification Association with traditional and non- traditional risk factors Evidence of genetic determinants of atherosclerosis

Advantages of Carotid IMT (cIMT) Testing Noninvasive, safe, inexpensive, accepted by patients, ethically sound Identifies minor (early) and major (late) ASO Nomograms (age, sex, and race-based) for normal values exist Predicts risk of future MI and STROKE Incremental predictive power Recommended by AHA for patients > 45 for “further clarification of CHD risk” In one population-based study cIMT was the single risk factor best able to predict cardiovascular events, with a level of event prediction nearly as great as all of the other risk factors combined !!! del Sol AL, et al. Stroke 2001, 32:1532

cIMT shown in clinical trials to Identify prevalence of cardiovascular disease (total CVD, angina, MI, Stroke, TIA, and PAD) Predict future risk of coronary heart disease and stroke (i.e., predicts incidence!) In these (and other prospective studies), CIMT remains a statistically significant predictor even after adjustment for know cardiovascular risk factors ARIC Study, Burke GL, et al. Stroke 1995;26:286 Chambless EL, et al. Am J Epidemiol 2000;151:487 ARIC, Chambless LE, et al. Am J Epidemiol 1997;146:1483

The FDA-Accepted Means to evaluate Progression of ASO Quantitative angiograms cIMT

How Can CIMT be Used in Clinical Trials As means of predicting the rate of progression/regression of atherosclerosis in response to using/withholding an intervention Regression Progression CIMT

Principles of Image Acquisition 3 segments can be evaluated: - CCA Bulb ICA Focus on the WALL - not the lumen - Gated measurement (3 ECG leads in place throughout the study) Properly insonate the artery May need to use several angles

Technical Considerations High frequency transducer VCR or Digital storage High frame rate High dynamic range One focal zone at the level of interest ECG on TGC slope numbers if possible displayed

Segment: R CCA Angle of insonation: 135

Image Acquisition Doppler of the CCA, ECA, and ICA Transverse scan to look at intima 135 degree approach for the right 225 degree approach for the left AP diameter of the distal CCA Find the Y bifurcation Best practice for identifying the flow divider

Identify CCA

Identify ECA

Identify ICA

Flow Divider CCA ICA Bulb