Abstract 18111: Additive Prognostic Value in Cardiac CT-Angiography by Employing a Semi-Automated Coronary Artery Plaque Quantification Algorithm

Abstract

Objectives Cardiac computed tomographic angiography (CCTA) enables the visualization of coronary plaque characteristics, of which several are predictive for the occurrence of acute coronary syndrome (ACS). Our goal was to investigate whether the use of a Philips semi-automated plaque quantification algorithm provided additional predictive value as compared to conventional CCTA assessment (i.e calcium score and luminal obstruction).

Methods 1,650 patients underwent 64-slice CCTA and were followed-up for ACS. In 25 patients who developed ACS and 101 random controls, coronary artery disease was evaluated using eyeballing, and then independently quantified using semi-automated software (Comprehensive Cardiac, version 4.5.2.40007, Philips). Clinical risk profile was calculated with Framingham risk score (FRS).

Results There were no significant differences in conventional parameters between controls and patients who developed ACS. Plaque quantification analysis showed that compared to controls, ACS patients had higher total plaque volume (148±158 vs. 79±120, p=0.02), more plaques (4.2±2.5 vs. 3.1±2.2, p=0.03), higher total non-calcified plaque volume (39±33 vs. 19±33, p<0.01), higher mean plaque burden (36±11 vs. 27±12, p<0.01), higher mean plaque area (4.9±2.0 vs. 3.9±2.2, p=0.04). Two incremental ROC-models were compared, one incorporating FRS and conventional CCTA assessment, and a model also incorporating quantified plaque characteristics. The AUC for the conventional model was 0.64, compared to 0.82 for the quantification model, p=0.02 (Figure).

Conclusion The semi-automated plaque quantification algorithm identified several parameters predictive for ACS. A model incorporating these parameters provided incremental prognostic value over clinical risk profile and conventional CT parameters. Acknowledgement This research was supported by the Center for Translational Molecular Medicine and the Dutch Heart Foundation (PARISk).