Relationship Between Cardiovascular Risk as Predicted by Established Risk Scores Versus Plaque Progression as Measured by Serial Intravascular Ultrasound in Left Main Coronary Arteries

Abstract

Background— Intravascular ultrasound (IVUS) is increasingly used as an end point in studies aimed at reducing progression or inducing regression of coronary artery disease. However, data linking serial changes by IVUS with clinical outcomes are scarce. Methods and Results— In the absence of a validated risk score for secondary prevention, we compared 3 established risk scores for primary prevention—PROCAM, SCORE, and Framingham—with plaque progression and lumen reduction as assessed with serial IVUS (follow-up, 18±9 months) in atherosclerotic left main coronary arteries of 56 patients with established atherosclerosis. For all 3 algorithms, patients at highest estimated risk of events showed greater plaque progression than patients at lowest risk ( P <0.05 to <0.01). There were positive linear relationships between the risk of clinical events and plaque progression ( r =0.41 to 0.60; P <0.002 to <0.0001). This translated into a greater decrease in lumen dimensions with increasing risk ( P <0.05, PROCAM and SCORE). Risk prediction using the PROCAM algorithm showed the strongest relation with serial IVUS. During follow-up, 18 patients suffered from adverse cardiovascular events; these patients had an annual plaque progression that was significantly greater than other patients (25.2±19.4% versus 5.9±15.6%, P <0.001). Conclusions— There was a positive linear relationship between the estimated risk of clinical events derived from all 3 established risk-score algorithms and the extent of plaque progression measured by serial IVUS. This translated into stenosis progression (reduction in lumen dimensions) with increasing clinical risk.