Measurement of Atherosclerosis: Development of an Atherosclerosis Severity Index

Treatment of hypertension has succeeded in preventing the complications attributable to pressure, including heart failure and the arteriolar complications such as brain hemorrhage and renal failure. Recent understanding that antihypertensive drugs have effects on lipoproteins and flow disturbances that may be important in atherosclerosis progression, and the recent development of drugs that are more effective in treating hyperlipidemia, have given impetus to the design of studies to test whether interventions are anti-atherosclerotic. Since studies depending on clinical endpoints by necessity consume vast resources, it is desirable to develop methods for measurement of atherosclerosis, in order to make it possible to conduct intervention studies efficiently. Because angiographic methods are costly and associated with risk, and many patients are unable or unwilling to undergo followup angiography at the end of a study, we are developing an atherosclerosis severity index based on clinical and noninvasive ultrasound assessment. This scale can be used as a surrogate outcome in place of, or complementary to angiographic measurement of atherosclerosis, to avoid costly loss of subjects in intervention studies. It has the additional advantage that it is suitable for repeated assessment over time, permitting the power of analyses such as life table analysis which look at time to development of endpoints.