Vulnerable plaque features on coronary CT angiography as markers of inducible regional myocardial hypoperfusion from severe coronary artery stenoses
Introduction
Presence of severe coronary artery stenosis (≥70% diameter) is often used as a surrogate for myocardial blood flow compromise, based on hemodynamic studies demonstrating that severe coronary artery stenosis leads to stress-induced myocardial hypoperfusion [1], [2]. Yet, a substantial proportion of severe coronary artery stenoses do not produce significant hypoperfusion on myocardial perfusion imaging (MPI) [3], [4]. In the nuclear sub-study of the COURAGE (Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation) trial, 40% of patients with ≥70% diameter stenosis on invasive coronary angiography exhibited none or mild myocardial hypoperfusion on single-photon emission computed tomographic MPI (SPECT-MPI) [4].
Processes that can increase myocardial hypoperfusion, including arterial wall injury and endothelial dysfunction, have been associated with specific changes in coronary plaque appearance, such as development of intra-plaque lipid core and positive vessel remodeling [5]. Non-invasive detection of lipid core (appearing as “low-attenuation” plaque, LAP), outward or “positive” vessel remodeling (PR), and spotty calcification (SC) on coronary computed tomographic angiography (CCTA) has been linked to the risk of acute coronary syndrome, denoting these findings as markers of plaque vulnerability [6]. However, whether these 3 features have impact on myocardial perfusion has not been evaluated. We conducted an exploratory study to test the hypothesis that severe coronary artery stenoses caused by plaques exhibiting LAP, PR, and/or SC result in greater myocardial hypoperfusion than similar stenoses caused by plaques that do not exhibit these features.
Section snippets
Patient population
From April 2006 through March 2011, we identified 49 consecutive patients who met all of the following criteria: no prior myocardial infarction or coronary artery revascularization, underwent both CCTA and SPECT-MPI or positron-emission tomography (PET)-MPI within a 6-month period at our center, CCTA showed severe single-vessel coronary artery stenosis from a discrete, predominantly non-calcified atherosclerotic plaque (<50% calcified component by visual estimation of whole plaque volume)
Results
Of the 49 patients studied, 34 were men (69%), and median age was 66 years. Ten patients had RevTPDART = 0%, and 34 had RevTPDART ≥ 1%, including 20 with RevTPDART ≥ 3% (range 3.2–11.4%). Locations of the severely stenotic plaques in these 20 patients were: 10 proximal and 3 mid LAD, 1 proximal and 2 mid LCX, and 3 proximal and 1 mid RCA. Reference luminal diameter on CCTA ranged between 2 and 5.5 mm with a median of 3.25 mm. Comparisons of demographic and coronary artery plaque anatomic
Discussion
In this study we demonstrated a novel relationship between coronary artery plaque morphology and myocardial hypoperfusion. In severely stenotic plaques, noninvasive detection of LAP and PR – 2 vulnerable plaque features linked to risk of acute coronary syndrome – was highly associated with increased myocardial hypoperfusion by quantitative MPI. Severe stenoses from plaques without LAP and PR produced low amounts of myocardial hypoperfusion. Importantly, these strong relationships were found
Conclusions
In this exploratory study, severe coronary arterial stenoses on CCTA from plaques exhibiting low-attenuation plaque and positive remodeling were strongly related to greater inducible myocardial hypoperfusion. These findings were independent of stenosis severity and indicate that plaque content and morphology may be useful in assessing the hemodynamic significance of severe stenoses.
Funding
Fellowship grant, American Physician-Fellowship for Medicine in Israel (Dr. Shmilovich); National Heart, Lung, and Blood Institute (Dr. Cheng, 1K23HL107458-01); American Heart Association Grant-in-Aid (Dr. Dey, 09GRNT2330000); The Lincy and Glazer Foundations (Beverly Hills, California, USA). Funding sources had no role in research conduct or preparation of the manuscript.
Disclosures
Drs. Berman, Germano, and Slomka receive QPS software royalties (Cedars-Sinai Medical Center, Los Angeles, CA, USA).
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2022, Journal of Cardiovascular Computed TomographyCitation Excerpt :Achenbach et al. reported that remodeling indices measured by CCTA correlated closely to IVUS (r2 = 0.82).25 Of the four HRP features, spotty calcification (SC) of <3 mm is likely the least useful sign because CCTA spatial resolution is too limited to depict the small calcifications seen histologically; the SC on CT may, in fact, represent histologic macro-calcifications.3,21,36,37 Vulnerable plaque (low attenuation plaque, positive remodeling, spotty calcification, or the napkin ring sign) have also been incorporated into the SCCT Coronary Artery Disease – Reporting and Data System (CAD-RADS).24
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2021, European Journal of RadiologyCitation Excerpt :Increased coronary stenosis degree usually causes the compromise of flow [9]. The quantitative and qualitative lesion features, involving the location, length, plaque burden, low-attenuation plaque, and spotty calcification, have been also demonstrated associated with ischemia and independent of the luminal stenosis degree [10–16]. Previous studies have confirmed the added value of combining plaque characteristics with CCTA for stenosis in the discrimination of ischemia [13,17,18].
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These authors contributed equally.