The typical clinical end points for studies in cardiovascular disease have been defined by their manifestations in adults but these end points rarely occur in pediatric patients. Thus clinical researchers have traditionally used end points known to be linked to manifestations of cardiovascular disease in adults to serve as measures to assess the effectiveness of treatments in children. However, in pediatric trials, it is difficult to identify, and validate these end points to ensure that observed outcomes have clinical significance. In testing drugs in children, as in adults, the goal is not necessarily to demonstrate that an agent lowers blood pressure, lowers blood lipid levels, prevents blood clot formation, or improves ventricular function. Rather, the goal is to determine whether the drug being studied improves the likelihood that patients who receive it will live longer, live better, and avoid illness.