Abstract 15943: In vivo Assessment of Thrombus Formation Without Coronary Plaque Rupture by Optical Coherence Tomography
Backgrounds: Coronary plaque rupture and subsequent thrombus formation is a major cause of acute coronary syndrome (ACS). However, postmortem histopathological studies revealed that more than 30% of thrombus formation occur without plaque rupture and erosion is considered a substrate for thrombosis. We sought to investigate the morphological differences between thrombotic lesions with plaque rupture and those without by optical coherence tomography (OCT).
Methods and Results: A total of 153 culprit lesions from 147 ACS patients who underwent pre-procedural OCT and IVUS were studied. Thrombus was identified by OCT in 114 lesions (74.5%) and these lesions were investigated. OCT analyses included the presence or absence of fibrous cap disruption, thrombus type (red, white, or mixed thrombus), the thrombus location (proximal, mid, or distal to the minimum lumen area site), the thinnest fibrous cap thickness, and lipid quadrants. IVUS analyses included external elastic membrane area (EEM-A) and plaque area (PA) at the minimum lumen area site and remodeling index (RI). Patient characteristics and plaque morphology were compared between lesions with plaque rupture (rupture group) and those without plaque rupture (non-rupture group). Fibrous cap disruption was observed in 51 lesions (rupture group 44.7%). Female gender was more common in non-rupture group than in rupture group (31.7% versus 9.9%, p<0.01). There was no significant difference in age between the two groups (68.0±12.6 versus 67.0±11.6, p=0.512). In OCT analysis, the frequency of lipid quadrants >3 was significantly greater (94.1% versus 68.3%, p<0.01) and the thinnest cap thickness was significantly smaller in rupture group (50±14µm versus 60±21µm, p<0.01). IVUS analysis showed no significant difference in PA (13.91±6.20 versus 13.65±4.62mm2, p=0.25), EEM-A (16.10±6.35 versus 15.62±4.76, P=0.263), and remodeling index (1.14±0.19 versus 1.09±0.19, p=0.338) between the two groups.
Conclusions: Thrombus without cap disruption had similar morphological characteristics to the lesions with plaque erosion described in the pathological studies, suggesting the capability of OCT and IVUS in in vivo evaluation of plaque erosion causing acute thrombosis.
- © 2011 by American Heart Association, Inc.