Plaque rupture may be associated with more inflammation in the culprit plaque, culprit vessel and all three major coronary arteries vs. plaque erosion, according to a study evaluating pericoronary adipose tissue (PCAT) attenuation, an emerging marker of coronary inflammation. The findings will be presented during AHA 2021 and published in JACC: Cardiovascular Imaging.

Akihiro Nakajima, MD, and colleagues studied patients with non-ST-segment elevation acute coronary syndromes who underwent coronary computed tomography angiography (CCTA) and optical coherence tomography (OCT) of the culprit lesion prior to intervention. In a collaborative effort, all CCTA and OCT images were acquired at Tsuchiura Kyodo General Hospital (Ibaraki, Japan) and submitted to Massachusetts General Hospital (Boston, MA) for analysis. PCAT attenuation determined by CCTA was measured around the culprit lesion and in the proximal 40 mm of all coronary arteries.

Plaque rupture was the underlying mechanism in 107 of 198 patients studied (54.0%), with plaque erosion seen in 91 patients (46.0%). Results showed that patients with plaque rupture had significantly higher PCAT attenuation than those with plaque erosion, both at the culprit plaque level (–65.8 vs. –69.5 Hounsfield unit [HU]; p=0.010) and at the culprit vessel level (–67.1 vs. –69.6 HU; p=0.024). This difference was most pronounced when the left anterior descending (LAD) artery was the culprit vessel.

To evaluate pan-coronary inflammation, mean PCAT attenuation was measured in the proximal 40 mm segment of the LAD, the left circumflex artery and the proximal 10 to 50 mm segment of the right coronary artery. In all three vessels, PCAT attenuation was significantly higher in patients with plaque rupture than in plaque erosion (–67.9 vs. –69.9 HU; p=0.030).

In a multivariable analysis, plaque rupture and male gender were significantly associated with high PCAT attenuation values.

"The current study demonstrated that (1) plaque rupture had a higher level of vascular inflammation measured by PCAT attenuation at the culprit plaque, culprit vessel, and at pan-coronary levels, [and] (2) OCT features of plaque vulnerability (lipid rich plaque and macrophages) were associated with higher PCAT attenuation at the culprit plaque," write the authors. A larger study with longer follow-up is needed to determine the clinical significance of the findings.

"To the best of our knowledge, this is the first study which compared the underlying mechanism of ACS (plaque rupture and plaque erosion) directly with the level of vascular inflammation using PCAT attenuation."

Clinical Topics: Acute Coronary Syndromes, Cardiovascular Care Team, Dyslipidemia, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Atherosclerotic Disease (CAD/PAD), Lipid Metabolism, Interventions and ACS, Interventions and Coronary Artery Disease, Interventions and Imaging, Computed Tomography, Nuclear Imaging

Keywords: AHA Annual Scientific Sessions, American Heart Association, AHA21, Acute Coronary Syndrome, Tomography, Optical Coherence, Computed Tomography Angiography, Hospitals, General, Follow-Up Studies, Plaque, Atherosclerotic, Coronary Artery Disease, Adipose Tissue, Rupture, Spontaneous, Inflammation, Macrophages, Lipids, ACC International

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