Coronary atherosclerotic disease burden: an emerging endpoint in progression/regression studies using intravascular ultrasound.

Coronary artery disease (CAD) represents the major cause of mortality in North America and Western Europe. Most acute coronary events, including myocardial infarction (MI) and sudden cardiac death, are initiated by the sudden rupture of mildly stenotic but vulnerable lesions and subsequent thrombosis. Recent results demonstrate a high prevalence of such plaques many years before clinical events occur. Because the event rate in asymptomatic patients, which would be candidate for primary prevention, is relatively low, pharmacological studies with the endpoint of MI and death require large study populations and long follow-up. Alternatively, the direct observation of coronary plaque burden and morphology with in vivo imaging modalities has been proposed as an endpoint in serial studies. This review will summarize the rational of this approach and describe the use of intravascular ultrasound (IVUS) for such studies.