Predictive value of change in percent calcified plaque burden based on serial coronary computed tomographic angiography for cardiovascular events.

Background: Plaque progression is an independent risk factor for major adverse cardiovascular events (MACE), and change in the total plaque burden (PB) is a common indicator of plaque progression. However, the type of component (calcification or non-calcification) and the magnitude of changes cannot be determined. We aimed to analyze the capability of the percent calcified PB (PCPB) in reflecting the total and its noncalcified and calcified component PB change, and the predictive value of PCPB for MACE.

Methods: Patients who received two or more coronary computed tomographic angiography (CCTA) examinations were included and were divided into MACE and non-MACE groups. The volumes of total plaque, subcomponents and vessel were measured in the serial CCTA. The segmental stenosis score (SSS), high-risk plaque (HRP), total and subcomponent PB, and their annual changes (△PB/year) were calculated. PCPB was calculated as (calcified PB/total PB) × 100%.

Results: Totally 116 patients were enrolled in this study, including 26 (22.4%) patients with MACE. The △PCPB/year showed negative correlation with △total PB/year (r=-0.353, P<0.001), ∆noncalcified PB/year (r=-0.591, P<0.001), while positively correlated with △calcified PB/year (r=0.400, P<0.001). If the △PCPB/year covariate was not added, the baseline HRP, Framingham risk score (FRS), and △total PB/year were independent predictors of MACE. Otherwise, the HRP, FRS, and △PCPB/year became independent risk factors of MACE. The area under the curve (AUC) of HRP + FRS + △PCPB/year was higher than that of HRP + FRS + △total PB/year (AUC: 0.894 0.820, P=0.016).

Conclusions: The △PCPB/year index simultaneously reflects changes of the total and its internal compositions PB. Moreover, our study shows the potential of △PCPB/year to predict MACE independently from the annual change of total PB.