Relation of progression of coronary artery atherosclerosis to risk of cardiovascular events (from the Monitored Atherosclerosis Regression Study)

Abstract

We investigated whether change in coronary artery atherosclerosis as measured by quantitative coronary angiography is related to cardiovascular event risk. Although many studies have demonstrated the effectiveness of statins in decreasing atherosclerotic progression and cardiovascular event risk, a relation between coronary atherosclerotic progression and event risk has not been documented in clinical trials that have evaluated statin therapy. The Monitored Atherosclerosis Regression Study (MARS) was a randomized, double-blind, placebo-controlled trial designed to test whether lovastatin would decrease coronary atherosclerotic progression as measured by quantitative coronary angiography. We followed 173 subjects in the MARS who had minimum luminal diameter and percent diameter stenosis measured at the beginning and end of a 2-year intervention. Postintervention follow-up events over a mean period of 9.4 years were reported by subjects and verified by medical records. Two-year percent stenosis and minimum luminal diameter changes were tested in relation to clinical event risk in multivariate Cox's regression models. Events ascertained were (1) coronary death and myocardial infarction, (2) coronary death, myocardial infarction, coronary artery bypass grafting, and percutaneous transluminal coronary angioplasty, and (3) any cardiovascular event. Increased percent stenosis was associated with significantly increased hazard ratios (HRs) in all event categories (category 1 HR 1.55 per SD percent stenosis, p <0.01; category 2 HR 1.58, p <0.01; category 3 HR 1.47, p = 0.01). Conversely, event risks were decreased for subjects who had increased minimum luminal diameter (category 1 HR 0.79, p = 0.04) and were not associated with category 2 (HR 0.79, p = 0.12) or category 3 (HR 0.81, p = 0.17). These results indicate that quantitative coronary angiographic changes are associated with cardiovascular events and support the long-term benefit of early intervention to decrease atherosclerosis.