The Nonculprit Coronary Lesion as Seen by Coronary CT Angiography: What Should We Be Looking For?

Abstract

439 atherosclerotic disease from positive vessel remodeling (without luminal narrowing) to severe luminal stenosis and occlusion. However, critical events (like hemodynamically significant luminal narrowing causing AMI) are mostly due to changes in the culprit and nonculprit lesions, with plaque erosions and ruptures and subsequent clot formation, causing vessel occlusion. This explains the great interest in the concepts of the vulnerable plaque, vulnerable blood, and vulnerable patient from the perspective of both detection [4, 5] and treatment [6]. It is therefore important to monitor the severity of isolated lesions, all areas of plaque formation in coronary vessels even if there is no significant luminal narrowing, as well as total plaque burden and plaque stability. The use of coronary calcium scoring, which reflects the calcific plaque burden, is relatively well established in stratifying cardiac risk. Coronary CT angiography (CCTA) allows us to go beyond plaque burden quantification by adding characterization of the plaque as noncalcific, calcific, and mixed, with implications for plaque stability. Early disease with positive vessel remodeling and lower CT attenuation plaque also has negative implications as to plaque stability [7]. Varnava et al. [8] showed that coronary artery plaques with positive remodeling have a higher lipid content and macrophage count, both markers of plaque vulnerability. Their results may explain why plaque rupture is often apparent at sites with only modest luminal stenoses (but marked positive remodeling). Is it important to detect early coronary disease? And if it is important, how early can we actually detect and characterize it and will we be able to track changes? Early coronary disease detection may not be a bad thing, assuming there is no excessive associated harm or cost due to unproven premature therapy or interventions. Until the advent of CCTA we had no easy approach to coronary plaque detection The Nonculprit Coronary Lesion as Seen by Coronary CT Angiography: What Should We Be Looking For?