Abstract 11566: Repeat Coronary CT Angiography in Patients With a Prior Negative Scan
Background: ACCF/SCCT/ACR/AHA 2010 Appropriate Use Criteria for cardiac CT (AUC2010) does not consider, or incorporate, prior Coronary CT Angiography (CCTA) results in the appropriateness of a CCTA examination. The purpose of this study is to test the hypothesis that among patients with a prior CCTA excluding obstructive coronary artery disease (CAD), further risk stratification can identify those patients with a low probability of significant stenosis on a repeat CCTA, even if the clinical scenario suggests CCTA as “appropriate”.
Methods: Among patients from a single center who underwent “appropriate” CCTA based on AUC2010 criteria, consecutive 555 CCTAs (02/2006-04/2013) which had a prior CCTA study without evidence of significant coronary stenosis (>50% in the diameter) were selected as the study cohort. A multivariate logistic regression model determined predictors of significant stenosis at the time of the repeat CCTA, with internal validation by a bootstrap method.
Results: The median time difference between the CCTA studies was 34.2 (interquartile range: 22.9-50.1) months. Significant coronary stenosis was detected at the time of repeat CCTA in 13.3% (74/555). The final logistic model (c-statistic=0.75, bootstrapped over-fitting bias=3.4%) including 8 variables showed 3 significant predictors: time difference between the CCTA studies >3 years (adjusted odds ratio (OR)=1.9, 95% confidence interval (CI):1.1-3.4), diabetes (OR=1.3, 95%CI:1.1-1.6), and 1 or more lesion with 26-50% stenosis on the initial CCTA images (OR=5.3, 95%CI:2.9-9.3). When these 3 factors were all absent (corresponding to 31.9% of the population), the probability of significant stenosis was 4.6% (95%CI: 2.0-7.2%); CAD was detected in 17.2% of patients among those with at least one positive variable.
Conclusion: Non-diabetic patients with a history of prior CCTA within 3 years showing no or ≤25% coronary stenosis had a <5% prevalence of CAD. Considering the retrospective nature of the study (i.e., not all patients with “appropriate” indication underwent a repeat CCTA), the actual CAD prevalence is expected to be even lower. The value of repeat CCTA in this subpopulation is most likely very small, even if the clinical scenario considered a CCTA examination appropriate.
- © 2013 by American Heart Association, Inc.