Size of emptied plaque cavity following spontaneous rupture is related to coronary dimensions, not to the degree of lumen narrowing. A study with intravascular ultrasound in vivo

Objective-To identify any potential relations between the size of an emptie d plaque cavity and the remodelling pattern, plaque or vessel dimensions, l umen narrowing, and other ultrasonic lesion characteristics. Design-Intravascular ultrasound was used to examine prospectively 51 ruptur ed ulcerated coronary plaques. Cross sectional area measurements comprised lumen, vessel, plaque, and emptied plaque cavity. Lumen narrowing was calcu lated as 1 - (lesion lumen area/reference lumen area) x 100%. A remodelling index was calculated as lesion vessel area/reference vessel area, and plaq ues were divided into those with values > 1.05 (group A) and less than or e qual to 1.05 (group B). Results-Of the total of 51 plaques, 36 (71%) were assigned to group A and 1 5 (29%) to group B. In neither group was there a significant difference in reference dimensions and lumen narrowing. However, lesion vessel (mean (SD) : 22.6 (8.1) mm(2) v 17.5 (4.3) mm(2); p = 0.006) and plaque areas (15.8 (6 .2) mm(2) v 12.8 (3.2) mm(2); p = 0.03) were greater in group A than in gro up B. The cavity inside the plaque was larger in group A than in group B (2 .8 (1.6) mm(2) v 1.8 (0.9) mm(2); p = 0.007) and showed a positive linear r elation with lesion and reference vessel size (r = 0.58 and 0.56, respectiv ely; p < 0.001), but not with lumen narrowing. Conclusions-The size of the emptied cavity inside ruptured plaques is on av erage larger in lesions with adaptive vascular remodelling, and shows a lin ear relation with lesion plaque and vessel size and with the reference dime nsions, but not with the degree of lumen narrowing.