Abstract Body (Do not enter title and authors here): Background: While the burden and morphological features of coronary atherosclerosis are both important drivers of major adverse cardiovascular events (MACE), there remains uncertainty about which plaque type is more likely to predispose to MACE i.e. noncalcified plaque (NCP) or calcified plaque (CP).
Research question: Does NCP:CP ratio or NCP volume influence MACE in patients from the CONFIRM2 registry, an international, observational cohort study?
Methods: Symptomatic patients without prior MI/revascularization referred to coronary CTA for clinical indications were included. CP and NCP volumes were determined using artificial intelligence-facilitated coronary CT (AI-QCT). The primary endpoint (MACE) was a composite of all-cause death, myocardial infarction, stroke, heart failure, late revascularization, and hospitalization for unstable angina.
Results: Of the 3,551 patients (median age 59 years; 49.5% women), data were available for 3,301. A total of 250 patients with no identifiable plaque were excluded from the analysis. MACE occurred in 4.7% of patients (median f/u 51 months). Hypertension, hyperlipidemia, and smoking were present in 54.3%, 48.1%, and 14%. Statin use in 67.3%, CACS = 0 in 41.7%. 91% had NCP <250 mm³, 8.4% 250-750 mm³ and 0.7% >750 mm³. MACE rates for tertiles of NCP:CP ratio were statistically significant (Panel A; p=0.0003): 1^st tertile (Mean NCP:CP ratio of 46%; n=1100 patients; median NCP volume = 85.6 mm³; MACE rate of 5.6%); 2^nd tertile (NCP:CP 81%; n=1101; NCPvol. = 67.6 mm³; 6.6%); 3^rd tertile (NCP:CP 99%; n=1100; NCPvol. = 22.3 mm³; 2.9%). However, in a multivariable Cox proportional hazards model adjusted for sex and age, when adjusting also for NCP volume, the NCP:CP tertile ratio did not remain a significant predictor of MACE, p=0.115 (Model#3, Panel B). Only 9 patients had predominant CP (NCP:CP ratio<10%) while the majority had predominant NCP.
Conclusions: The main driver of incident MACE was the noncalcified plaque volume (NCP) rather than the NCP:CP ratio. More data with a larger cohort of patients with relatively more CP is needed to evaluate the role of individual features of partially calcified plaques such as spotty calcification to assess if they are better predictors of MACE or whether NCP volume alone is sufficient.