Repeat Coronary CT Angiography in Patients with a Prior Scan Excluding Significant Stenosis
Background—ACCF/SCCT/ACR/AHA/ASE/ASNC/NASCI/SCAI/SCMR 2010 Appropriate Use Criteria for cardiac CT (AUC2010) does not incorporate prior Coronary CT Angiography (CCTA) results in the appropriateness of a CCTA examination. The purpose of this study is to explore the criteria for forgoing repeat CCTA among patients with clinical scenarios suggesting CCTA as "appropriate" after prior CCTA excluding coronary artery disease (CAD).
Methods and Results—Among patients from a single center (02/2006-04/2013) who underwent "appropriate" CCTA based on AUC2010, consecutive 555 CCTAs which had a prior CCTA excluding significant stenosis (>50% stenosis in diameter) were selected. The median time difference between the studies was 34.2 (Q1-to-Q3: 22.9-50.1) months. Significant stenosis was detected at the time of repeat scan (by CCTA or subsequent catheter angiography) in 13.3% (74/555). A multivariable logistic model (c-statistic=0.74, bootstrapped over-fitting bias=0.8%) identified three predictors of significant stenosis: time difference between the studies >3 years (adjusted odds ratio (OR)=2.1, 95% confidence interval (CI):1.2-3.5), diabetes (OR=2.4, 95%CI:1.4-4.3), and 26-50% stenosis on the initial CCTA (OR=5.6, 95%CI:3.2-9.6). When these three factors were all absent (corresponding to 31.9% of the population), the probability of significant stenosis was 4.5% (95%CI: 2.7-7.4%), while 17.1% of patients had significant stenosis among those with at least one positive variable. When coronary arteries were completely normal at the initial scan, the prevalence of significant stenosis was only 1.8% irrespective of other factors and no patient underwent revascularization.
Conclusions—Non-diabetic patients with a prior CCTA within 3 years showing no or ≤25% stenosis had a <5% prevalence of significant stenosis. The value of repeat CCTA in this group is likely very small, especially when the prior CCTA demonstrated normal coronaries, even if the clinical scenario considered a CCTA appropriate.
- Received December 11, 2013.
- Accepted July 7, 2014.