Impact of coronary artery remodeling on misinterpretation of angiographic disease eccentricity: evidence from intravascular ultrasound

This study was designed to examine the impact of coronary artery remodeling, enlargement or shrinkage, on the angiographic disease eccentricity. A total of 82 coronary sites from 73 patients with significant stenosis (>50%) were prospectively analyzed by both quantitative coronary angiography and intravascular ultrasound. By quantitative coronary angiography, the maximal and minimal distances from the center of the stenosis to the outline of the vessel wall were measured, and the eccentricity index was calculated by the formula {(maximal-minimal)/maximal}. By intravascular ultrasound, the maximal and minimal distances from the center of the lumen to the leading edge of the second echogenic zone were measured, and the eccentricity index was calculated by the same formula. For identifying the vessel remodeling, the total vessel area that was determined by tracing the leading edge of the second echogenic zone was measured at the stenotic sites and the adjacent proximal and distal segments. By quantitative coronary angiography, the maximal and minimal distances were 1.76 ± 0.6 and 0.97 ± 0.3 mm, respectively, yielding an eccentricity index of 0.42 ± 0,2. The maximal and minimal distances by intravascular ultrasound were 2.77 ± 0.6 mm and 1.46 ± 0.4 mm, respectively, yielding an eccentricity index of 0.45 ± 0.2 (NS). Although the average eccentricity index was not different between the two methods, there was substantially no correlation between the eccentricity index determined by the two methods (r = 0.38, Y = 0.43x + 0.22). However, this correlation was significantly improved (r = 0.55, Y = 0.73x + 0.12, P< 0.001) when 44 stenotic segments with remodeling were excluded for comparison. These results indicate that coronary artery remodeling could be a major contributing factor to angiographic misinterpretation of disease eccentricity. We suggest that intravascular ultrasound is a powerful method that can accurately determine diseases eccentricity as well as disease severity.