Surrogate endpoints and newer risk markers in atherosclerosis management

Trials with clinical events as the primary endpoint inherently have poor sensitivity to detect therapeutic effects on plaque stabilization and thrombosis because most plaques that rupture do not cause symptoms. Blood tests or imaging modalities that correlate to the burden or activity of atherosclerosis may provide surrogate endpoints to assess therapeutic efficacy in both clinical trials and clinical practice. For surrogate endpoints to be valid in clinical trials, they must be biologically plausible (i.e., related to the disease process) and altered by therapies that decrease the endpoint for which they are used as a substitute. Examples of surrogate endpoints include progression of coronary disease assessed by angiography, intravascular ultrasound, and other imaging techniques. Risk assessment may be refined and therapy better monitored with blood tests that measure novel markers of atherosclerotic disease. Markers that have been shown to be associated with atherosclerosis include C-reactive protein, intercellular adhesion molecule 1, interleukin-6, and fibrinogen.