BACKGROUND - Vascular inflammation plays a key role in plaque rupture, while the role of inflammation in plaque erosion remains less well defined. Peri-coronary adipose tissue (PCAT) attenuation determined by computed tomography has emerged as a marker specific for coronary artery inflammation.

OBJECTIVES - To compare the level of coronary inflammation between plaque rupture and plaque erosion using PCAT attenuation.

METHODS - Patients with non-ST-segment elevation acute coronary syndromes who underwent pre-intervention coronary computed tomography angiography and optical coherence tomography culprit lesion imaging were enrolled. PCAT attenuation was measured around the culprit lesion and in the proximal 40mm of all coronary arteries.

RESULTS - Out of 198 patients, plaque rupture was the underlying mechanism in 107 patients (54.0%) and plaque erosion in 91 (46.0%) patients. Plaque rupture had higher PCAT attenuation than plaque erosion both at the culprit plaque level (-65.8 ± 7.5 vs. -69.5 ± 11.4 Hounsfield unit [HU], p = 0.010) and at the culprit vessel level (-67.1 ± 7.1 vs. -69.6 ± 8.2 HU, p = 0.024). The mean PCAT attenuation of all 3 coronary arteries was also significantly higher in patients with plaque rupture than in plaque erosion indicating a higher level of inflammation (-67.9 ± 5.7 vs. -69.9 ± 6.8 HU, p = 0.030). In multivariable analysis, plaque rupture was significantly associated with high PCAT attenuation.

CONCLUSIONS - PCAT attenuation in culprit plaque, culprit vessel, and all 3 coronary arteries was higher in plaque rupture than in plaque erosion. The results suggest pan-coronary inflammation plays a more significant role in plaque rupture than in plaque erosion.