Potential for treating vulnerable plaque

Each year in the United States, myocardial infarction (MI) is an underlying or contributing cause of death for 653,000 people; and an additional 767,000 are listed as being hospital discharged following MI. Many of these events occur suddenly in patients previously free of coronary artery disease (CAD), with almost as many events occurring in those with known CAD already receiving optimal current therapy, including percutaneous coronary interventions (PCIs) and aggressive medical therapy with statins and antiplatelet agents. The majority of these infarctions result from the rupture of high-risk vulnerable plaques that in most cases did not cause flow limitations before the acute event. Consequently, it is imperative that new methods be developed to identify patients at high risk of developing acute events (vulnerable patients) and the lesions at imminent risk of inducing events (vulnerable plaques). A recent Journal of the American College of Cardiology supplement featured widely acclaimed investigators reviewing new opportunities for the identification of vulnerable plaques. In a prologue, Narula and Willerson noted that pathological studies have demonstrated that lesions likely to be vulnerable to rupture share certain characteristics: Usually, they are not multiple, occur in the proximal and middle part of major arteries, and are fairly sizable. The sites of vulnerability are not necessarily confined to plaque shoulders. Also, such lesions may only display minimal encroachment on the lumen because of positive remodeling, and often occur in proximal or middle parts of coronary arteries. Relative proximity of these sizable lesions renders them amenable to imaging modalities (Slide 1). In the future, risk assessment may involve noninvasive imaging by computed tomography (CT) or magnetic resonance imaging (MRI). Invasive techniques could involve intravascular ultrasound (IVUS), optical coherence, or intravascular MRI; the technology could include near-infrared or thermographic measurements, although optical coherence tomography may be required for evaluation of fibrous cap thickness.