Number of inflamed coronary vessels in prediction of cardiac death and MACE among patients undergoing routine CCTA: the Oxford Risk Factors And Non-Invasive Imaging (ORFAN) Study

Abstract Background Coronary inflammation can be assessed by the changes in perivascular adipose tissue on routine coronary CT angiograms (CCTA). Fat attenuation index score (FAI Score) quantifies the degree of inflammation in each epicardial coronary artery, and adjusts for age, sex, scan technical parameters, biological and anatomical factors. Coronary inflammation assessment in a single coronary artery was previously shown to be predictive of cardiac events in the CRISP-CT study. However, the impact of inflammation in multiple coronary arteries on clinical outcome remains unclear. Purpose To evaluate the prognostic value of the number of inflamed coronary arteries with high inflammation in the risk of cardiac death, and major adverse cardiac events (MACE). Methods In a nested cohort within the Oxford Risk Factors And Non-invasive imaging (ORFAN) study, consecutive patients (n=3,393) who underwent routine clinical CCTA were followed up over a median(IQR) 7.7(6.4-9.1) years for cardiac mortality, and MACE (including myocardial infarction, new onset heart failure, cardiac mortality). FAI Score was calculated for each of the 3 epicardial coronary arteries. Results The number of inflamed arteries (FAI Score >75th centile) showed an additive impact on cardiac mortality compared with no inflamed arteries (all vessels FAI Score <25th centile), with hazard ratio 29.8 (95% CI 13.9-63.9, p<0.001) for 3 inflamed arteries, HR 20.4 (95% CI 9.4-44.7, p<0.001) for 2 inflamed arteries, and HR 13.0 (95% CI 5.9-28.8, p<0.001) for 1 inflamed artery. (Panel A) Similarly, patients with multiple inflamed arteries showed progressively higher risk for MACE (HR 7.2, 8.3 and 12.6 for 1-, 2- and 3-inflamed arteries respectively compared to patients with no inflamed artery). (Panel B) Patients with no inflamed arteries showed very low event rates for cardiac mortality and MACE. In patients with no obstructive CAD (n=2,651), similar trends were observed whereby patients with 3-inflamed arteries showed highest risk for cardiac mortality (Panel C) and MACE (Panel D), with intermediate risk for those with 1 or 2 inflamed arteries. Conclusion The number of coronary arteries with high inflammation, measured by FAI Score from routine CCTA, is associated with adverse cardiovascular events and cardiac mortality in an additive dose-response manner.