Abstract 17258: Incremental Value of Coronary CT Angiography over Calcium Score in Predicting Intermediate-Term Outcomes and Resource Utilization
Background: Prognostic utility of coronary artery calcium (CAC) is well-established. The incremental value of CAD severity assessed by coronary CT angiography (CCTA) over CAC is not well known.
Methods: This retrospective analysis included patients who underwent CAC + CCTA at our institution and had complete 2-year follow-up. The study group was divided into four: CAC ≤400 + stenosis ≤50% (Group I), CAC ≤400 + stenosis >50% (Group II), CAC >400 + stenosis ≤50% (Group III) and CAC >400 + stenosis >50% (Group IV). Baseline demographics and 2-year follow-up data were compared among the groups for downstream major adverse cardiac events (MACE) (death, acute coronary syndromes and revascularization) and total resource utilization (CAD-related hospitalizations and emergency department (ED) evaluations, stress testing, invasive coronary angiography (ICA) and surgical or percutaneous revascularization).
Results: The study group included 1496 patients (mean age 56 ± 12 years, 54% males) who underwent CAC and CCTA. Distribution among the four groups were: Group I = 1092 (73%), Group II = 236 (15.7%), Group III = 102 (6.8%) and Group IV = 66 (4.4%). Patients in Groups II and IV (stenosis >50%) were more frequently male, older, diabetic, hypertensive and dyslipidemic (all p<0.0001). At 2 years, patients in Groups II and IV had higher rates of MACE as well as resource utilization (p<0.0001). On stepwise multivariable analysis of Framingham Risk Score, additional risk factors (peripheral, cerebrovascular and chronic obstructive lung disease), symptoms, CAC and CCTA findings, stenosis >50% on CCTA alone was the strongest predictor of MACE and resource utilization, with significant incremental value over the combined effect of all clinical variables and CAC (Figure).
Conclusions: CAD severity assessed by CCTA provides significant and incremental value over clinical risk scoring and CAC for predicting MACE and resource utilization at intermediate-term follow-up.
- © 2011 by American Heart Association, Inc.