Coronary Atherosclerotic Plaque Activity and Future Coronary Events

Importance: Recurrent coronary events in patients with recent myocardial infarction remain a major clinical problem. Non-invasive measures of coronary atherosclerotic disease activity have the potential to identify those at greatest risk.
Objective: To determine whether non-invasive assessment of coronary atherosclerotic plaque activity could be associated with recurrent coronary events.
Design: Prospective observational longitudinal cohort study recruiting participants between September 2015 and February 2020 with a minimum 2 years follow up.
Setting: International multicenter study.
Participants: Patients with multivessel coronary artery disease and recent myocardial infarction were eligible for inclusion. From 2,684 patients screened, 995 were eligible, 712 attended for imaging, and 704 had completed an interpretable scan and comprised the study population.
Intervention: Coronary 18F-sodium fluoride positron emission tomography and coronary computed tomography angiography.
Main Outcomes and Measures: Total coronary atherosclerotic plaque activity was assessed by 18F-sodium fluoride uptake. The primary endpoint was cardiac death or non-fatal myocardial infarction but was expanded during study conduct to include unscheduled coronary revascularization due to lower than anticipated primary event rates.
Results: Participants were middle-aged (63.8±8.2 years) and predominantly male (85%). Total coronary atherosclerotic plaque activity was identified in 421 (60%) participants. After a median of 4 years follow-up, 141 participants experienced the primary endpoint: 9 had cardiac death, 49 non-fatal myocardial infarction and 83 unscheduled coronary revascularizations. Increased coronary plaque activity had no demonstrable association with the primary endpoint (hazard ratio (HR) 1.25 [95% confidence interval (CI) 0.89 to 1.76], P=0.20) or unscheduled revascularization (HR 0.98 [95% CI 0.64 to 1.49], P=0.91) but was associated with the secondary endpoints of cardiac death or non-fatal myocardial infarction (47 versus 19; HR 1.82 [95% CI 1.07 to 3.10], P=0.03) and all-cause mortality (30 versus 9; HR 2.43 [95% CI 1.15 to 5.12], P=0.02). These associations were similar after adjustment for differences in baseline clinical, coronary angiographic, and GRACE score characteristics (HR 1.76 [95% CI 1.00 to 3.10] (P=0.05) and HR 2.01 [95% CI 0.90 to 4.49], (P=0.09) respectively).
Conclusions and Relevance: In patients with recent myocardial infarction, coronary atherosclerotic plaque activity was not associated with the primary composite endpoint. The findings suggesting risk of cardiovascular death or myocardial infarction in patients with elevated plaque activity warrants further research to explore its incremental prognostic implications.