Morphological characteristics of optical coherence tomography defined plaque fissure in patients with acute coronary syndrome.

We assessed the plaque disruption in 245 consecutive patients with acute coronary syndrome undergoing percutaneous coronary intervention. The plaque fissure was diagnosed with optical coherence tomography, and intravascular ultrasound was used to determine arterial remodeling. Of them, 26 fissures were found in this study. The definite fissure was seen in 17 (65.4%) and probable fissure was seen in 9 (34.6%) patients. In 18 (69.2%), plaque fissure component was lipidic or thin-capped fibroatheroma. Eighteen (69.2%) of fissured plaque were seen within 30 mm of coronary ostium. Combined plaque fissure with plaque rupture/erosion was seen in 21 (80.8%) cases. The isolated fissure was seen in 5 (19.2%). Compared to the maximal necrotic core site of the ruptured plaque, the fissure site showed a smaller %necrotic core (p = 0.012), however, greater in fissure site than minimal lumen area site (24.93 ± 11.50% vs 15.34 ± 10.40%, p < 0.0001). The remodeling index was higher at fissure site as compared to minimal lumen area site (1.02 ± 0.22 vs 0.94 ± 0.27; p = 0.047), but similar to the rupture plaque (p = 0.31). The frequency of positive remodeling was 34.6% (9/26) at the plaque fissure. Although the plaque fissure can be interchangeable with the rupture in acute coronary syndrome, the limited extension to the small lipid core might and less positive remodeling provoke a fissuring of the plaque. Further study is necessary to assess the plaque fissure.