PhD Scientific Days 2022

Clinical Medicine I. (Poster discussion will take place in the Aula during the Coffee Break)

The Link Between Coronary Plaque Volume and Myocardial Ischemia as Detected by Dynamic Perfusion CT Imaging

Text of the abstract

Introduction: Cardiac CT is a uniquely suited imaging modality that can simultaneously evaluate plaque morphology and the functional relevance of coronary lesions.

Aims: We aimed to further elucidate the association between quantitative atherosclerotic plaque metrics derived from coronary computed tomography (CCTA) and segmental myocardial ischemia detected by dynamic perfusion CT (DPCT) images.

Method: Patients with >30% stenosis on rest CCTA were enrolled and regadenoson stress CT perfusion imaging was performed. In total, 480 myocardium segments of 30 patients were analyzed in our prospective study. Quantitative coronary plaque assessment included total, non-calcified and calcified plaque volumes (NCPV, CPV), area stenosis and remodeling index (RI) using a dedicated software. High-risk plaque (HRP) was defined based on low-attenuated plaque burden >4% or a remodeling index >1.1. Absolute myocardial blood flow (MBF) was measured using a 16-segment model. Relative MBF (MBFi) for each segment was calculated as the ratio of absolute MBF to reference MBF, latter defined as the 75th percentile of all MBF values of a given patient. Linear and logistic mixed models correcting for intra-patient clustering and clinical factors were used to evaluate the association between total PV, maximal area stenosis, quantitative HRP features and absolute MBF, MBFi or myocardial ischemia using 101 ml/100g/min as cut-off value for MBF.

Results: Median MBF was 111 ml/100g/min, median MBFi was 0.94. Number of ischemic segments were 164/480 (34.2%). Total PV, NCPV and CPV differed significantly between ischemic and non-ischemic myocardial segments, 120.5±119.5 vs 84.6±82.2, p=0.001; 62.3±59.5 vs 51.4±54.9, p=0.045; 58.3±91.8 vs 33.3±50.6, p=0.001; respectively. Area stenosis and quantitative HRP features were not linked to MBF or MBFi (all p>0.05). Total plaque volume increase led to reduced MBF and MBFi after adjusting for risk factors, area stenosis and HRP (per 10 mm3.; ß=-0.035, p<0.01 for MBF and ß=-0.0002, p<0.01 for MBFi). Similarly, using multivariate logistic regression total PV was associated with myocardial ischemia after adjustments: OR=1.01, p=0.033; per 10 mm3.

Conclusion: Total PV was independently associated with myocardial ischemia based on MBF derived from DPCT imaging, while area stenosis and HRP were not.

Funding: EFOP-3.6.3-VEKOP-16-2017-00009