Extent and Direction of Arterial Remodeling in Stable Versus Unstable Coronary Syndromes: An Intravascular Ultrasound Study

Abstract

Background —The morphological characteristics of coronary plaques in patients with stable versus unstable coronary syndromes have been described in vivo with intravascular ultrasound, but the relationship between arterial remodeling and clinical presentation is not well known. Methods and Results —We studied 85 patients with unstable and 46 patients with stable coronary syndromes using intravascular ultrasound before coronary intervention. The lesion site and a proximal reference site were analyzed. The remodeling ratio (RR) was defined as the ratio of the external elastic membrane (EEM) area at the lesion to that at the proximal reference site. Positive remodeling was defined as an RR >1.05 and negative remodeling as an RR <0.95. Plaque area (13.9±5.5 versus 11.1±4.8 mm 2 ; P =0.005), EEM area (16.1±6.2 versus 13.0±4.8 mm 2 ; P =0.004), and the RR (1.06±0.2 versus 0.94±0.2; P =0.008) were significantly greater at target lesions in patients with unstable syndromes than in patients with stable syndromes. Positive remodeling was more frequent in unstable than in stable lesions (51.8% versus 19.6%), whereas negative remodeling was more frequent in stable lesions (56.5% versus 31.8%) ( P =0.001). Conclusions —Positive remodeling and larger plaque areas were associated with unstable clinical presentation, whereas negative remodeling was more common in patients with stable clinical presentation. This association between the extent of remodeling and clinical presentation may reflect a greater tendency of plaques with positive remodeling to cause unstable coronary syndromes.