Abstract 15854: Prognostic Value of Coronary CT Angiography and Coronary Artery Calcium Score Performed Before Revascularization

Introduction: Cardiac events after revascularization are equally attributable to recurrence at site of culprit lesions and development of non-culprit lesions. Because coronary CT angiography (CCTA) performed before revascularization can evaluate all plaque, including non-culprit lesions, and in theory can serve as a predictor of cardiac events after treatment. We evaluated the hypothesis that CCTA and coronary artery calcium score (CACS) performed before revascularization predicts cardiac events after treatment. Methods: Among 2238 consecutive patients without known coronary artery disease who underwent coronary CCTA and CACS, 359 patients underwent revascularization within 30 days after CT; in 337 of 359 (93.9%) follow-up clinical information was available. In addition to known cardiac risk factors, CT findings were evaluated as predictors of cardiac events after revascularization: CACS and the presence of CT-verified high risk plaque (CT-HRP). Improvement of predictive accuracy by including CT findings was evaluated from discrimination (Harrell’s C-statistics) and reclassification (net reclassification indices (NRI)) standpoints. Results: During the follow-up period (median: 673, interquartile range: 47-1529 days), a total of 98 cardiac events occurred. Cox proportional hazard model revealed that age, diabetes, triglyceride, CACS and non-culprit CT-HRP were significant predictors of overall cardiac events. Although not statistically significant, discriminatory power was greater for the model with CACS (C-stat: 63.2%) and the model with both CACS and CT-HRP (65.8%) compared to the model including neither CACS nor CT-HRP (60.7%). Reclassification improved by including CACS into the model when compared to the model without it (NRI=12.7%; category-free NRI=40.7%) and CT-HRP added to CACS further improved the classification (NRI=6.9%; category-free NRI=14.3%). Conclusions: High CACS and the presence of non-culprit CT-HRP performed before revascularization are significant predictors of cardiac events after revascularization.