Use of vascular ultrasound in clinical trials to evaluate new cardiovascular therapies.

Though progress has been made in the fight against cardiovascular disease (CVD), the increasing global prevalence of cardiovascular (CV) risk factors ensures that CVD rates remain high. In order to reduce CVD incidence, a huge effort has been made to uncover additional targets for therapy and novel methods of identifying patients at risk. A low level of high-density-lipoprotein (HDL) cholesterol is recognized as an important independent risk factor for occurrence of a CV event, and new therapies capable of producing effective, clinically relevant increases in this key lipoprotein particle are in development. These therapies will most likely be assessed in comparison with proven CV-risk-reducing therapies such as statin treatment, rather than against a placebo comparator. Inevitably, therefore, clinical end-point trials will increase in both complexity and longevity. Potential efficacy data on new therapies may be revealed sooner by trials using surrogate end points, biomarkers of disease progression known to correlate with clinical events. For novel CV therapies, ultrasound-measured changes in atherosclerosis, such as the change in atheroma burden or plaque volume measured by intravascular ultrasound (IVUS), or ultrasound-measured increase in carotid intima-media thickness (CIMT), may represent useful biomarkers. Both IVUS and CIMT are being widely deployed in trials of new and existing CV therapies to assess their impact on slowing the progression of atherosclerosis, and their use in this regard is the subject of this review.