Coronary artery disease progression in patients without significant stenosis on coronary computed tomographic angiography

Background: Patients who present to the emergency department (ED) with symptoms of potential acute coronary syndrome (ACS) can be safely discharged home after a coronary computed tomographic angiography (CTA) with a negative result. However, the duration of time for which a negative coronary CTA scan result can be used to inform decision making when patients have recurrent symptoms is not known. Objective: We examined patients who received more than 1 coronary CTA for evaluation of ACS to determine whether they had disease progression. Our main outcome was whether any patient had a maximal stenosis cross the threshold from noncritical (<50% maximal stenosis) to potentially critical disease. Methods: We performed a structured comprehensive record search of all coronary CTAs performed from 2005 to 2010 at a tertiary care health system. Low-to-intermediate risk ED patients who received 2 or more coronary CTAs, at least 1 from an ED evaluation for potential ACS, were identified. Patients who were revascularized between scans were excluded. We collected demographic data, clinical course, time between scans, and number of ED visits between scans. Record review was structured and done by trained abstractors. Our main outcome was progression of coronary stenosis between scans, specifically crossing the threshold from noncritical to potentially critical disease. Results: Overall, 32 patients who received repeat imaging were identified (median age, 45 years; interquartile range, 37.5-48; 56% female; 88% black). The median time between studies was 27.3 months (interquartile range, 18.2-33.2). Twenty-two patients did not have stenosis in any vessel on either coronary CTA, 2 studies showed increasing stenosis of less than 20%, and the rest showed improvement due to better imaging quality. No patient initially below the 50% threshold subsequently exceeded it (0%; 95% confidence interval, 0-11.0%). No patient had acute myocardial infarction or revascularization either between scans or within a year after the repeated imaging. Conclusion: Repeated imaging potentially may not be warranted within 2 years of a negative coronary CTA result. The low rate of progression from subcritical to critical disease is consistent with observations in patients who have had prior negative cardiac catheterizations.