Coronary Computed Tomography Angiographic Predictors of Non-culprit Territory Unrecognized Myocardial Infarction Assessed by Cardiac Magnetic Resonance in Non-ST-elevation Acute Coronary Syndrome

OBJECTIVES: This study sought to assess the predictors of coronary computed tomography angiographic findings for non-infarct-related (non-IR) territory unrecognized myocardial infarction (UMI) in patients with a first episode of non-ST-elevation acute coronary syndrome (NSTE-ACS). BACKGROUND: UMI detected by cardiac magnetic resonance imaging (CMR) is associated with adverse outcomes in patients with both acute coronary syndrome and chronic coronary syndrome. However, the association between the presence of UMI and coronary computed tomography angiographic (CCTA) findings remains unknown. METHODS: We investigated 158 patients with a first clinical episode of NSTE-ACS, who underwent pre-PCI 320-slice CCTA and uncomplicated urgent percutaneous coronary intervention (PCI) within 48 h of admission. In these patients, post-PCI CMR was performed within 30 days from urgent PCI and before non-IR lesion staged PCI. UMI was assessed using late gadolinium enhancement (LGE)-CMR by identifying regions of hyperenhancement with an ischemic distribution pattern in non-IR territories (non-IR UMI). CCTA analysis included qualitative and quantitative assessments of the culprit segment, Agatston score, mean peri-coronary fat attenuation index (FAI), epicardial fat volume (EFV) and epicardial fat attenuation (EFA). RESULTS: Non-IR UMI was detected in 30 vessel territories (9.7%, 30/308 vessels) of 28 patients (17.7%, 28/158 patients). The presence of low-attenuation plaque, spotty calcification, napkin ring sign, and positive remodeling was not significantly different between vessels with and without subtended non-IR UMI. Agatston score >30.0 (OR: 8.39, 95% confidence interval (CI): 2.17 to 32.45, p = 0.002), mean FAI >-64.3 (OR: 3.23, 95% CI: 1.34 to 7.81, p = 0.009), and stenosis severity (OR: 1.04, 95% CI: 1.02 to 1.06, p < 0.001) were independently associated with non-IR UMI. Neither EFV (p = 0.340) nor EFA (p = 0.700) was associated with non-IR UMI. CONCLUSION: The prevalence of non-IR UMI was 17.7 % in patients with first NSTE-ACS presentation. Agatston score, mean FAI, and coronary stenosis severity were independent CCTA predictors of the presence of non-IR UMI. The integrated CCTA assessment may help identify the presence of non-IR UMI before urgent PCI.