Coronary CT angiography versus standard of care strategies to evaluate patients with potential coronary artery disease; effect on long term clinical outcomes Matthew J. Budoff a, * , Sandy Liu a , David Chow a , Ferdinand Flores a , Brian Hsieh a , Dan Gebow a , Tony DeFrance b, 1 , Naser Ahmadi a a Los Angeles Biomedical Research Institute, Torrance, CA, USA b Stanford Medical Group, Palo Alto, CA, USA article info Article history: Received 10 February 2014 Received in revised form 13 September 2014 Accepted 22 September 2014 Available online 18 October 2014 Keywords: Outcomes Cardiac CT angiography Standard of care Cardiac events Follow up abstract Background: Previous studies have shown that computed tomography coronary angiography (CTA) in patients with suspected coronary artery disease (CAD) predicts short term adverse events. However, there is no current data on whether identifying atherosclerosis on CTA impacts outcomes. We performed a caseecontrol study to assess whether information from CTA can improve outcomes. Methods: 4244 symptomatic patients (mean age 58 ± 9, 62.5% male) without known CAD who underwent CTA (n ¼ 2538) to rule out CAD were matched to 1706 patients who underwent standard of care in an ac- ademic cardiology clinic. Patients were propensity-matched by gender, age, ethnicity, CAD risk factors and follow-up duration. The primary outcome measure was all-cause mortality. Multivariable Cox pro- portional hazards models incorporated age, gender and traditional risk factors for coronary disease as well as pre-test probability of CAD. Results: There were no significant differences in age, gender, con- ventional risk factors between groups (p > 0.05). During a mean follow up of 80 ± 11 months, the overall death rate was 6.3% (270 deaths). Death rate was significantly lower in CTA group (n ¼ 106, 4.2%) as compared to the control group (n ¼ 184, 10.8%, p ¼ 0.001). Event free survival was 95.8% and 89.2% in CTA and standard of care groups, respectively. Risk-adjusted hazard ratio of death were 2.5 (95%CI: 1.6e6.7, p ¼ 0.003) in standard of care cohort as compared to CTA group. Multivariate analysis demonstrated that undergoing coronary CTA resulted in a risk reduction of 32%, p ¼ 0$0001. Conclusions: Improved knowledge of atherosclerosis or increased anti-atherosclerotic therapies among those undergoing CTA may have contributed to improved survival. Our results provide evidence of potential benefit from scanning for atherosclerosis with CTA in symptomatic patients. Large randomized trials are warranted. © 2014 Elsevier Ireland Ltd. All rights reserved. 1. Introduction Coronary computed tomographic angiography (CTA) is a non- invasive angiographic modality that allows for direct visualization of obstructive and non-obstructive coronary artery disease (CAD) [1e4]. While several prior studies have carefully examined the prognostic implications of obstructive and non-obstructive CAD for individuals undergoing coronary CTA, the importance of identifying atherosclerosis on the impact of future adverse events remains unexamined. Coronary CTA is a test that demonstrates high diag- nostic performance for the detection and exclusion of any atherosclerosis and anatomically obstructive CAD [5]. Similarly, coronary CTA can identify subclinical atherosclerosis and coronary artery calcium (CAC) [6]. It is likely that identification of plaque and stenosis impacts therapeutic decisions regarding medical therapy, including cholesterol lowering and anti-platelet therapy, and therefore can improve outcomes. Previous studies have shown that coronary CTA in suspected CAD patients predicts short term adverse events [7e9]. However, there are opposing views on the potential of cardiac imaging to impact cardiovascular (CV) outcomes. Therefore, using a large prospective observational caseecontrol study, we examined whether undergoing coronary CTA imparts an outcome benefit as compared to gender, age, ethnicity, CAD risk factors matched con- trols who did not undergo CTA. In this prospective observational study, we assessed occurrence of all-cause death in a large cohort of * Corresponding author.1124 W Carson Street, Torrance, CA 90502, USA. E-mail address: mbudoff@labiomed.org (M.J. Budoff). 1 Dr. DeFrance is on the Educational Advisory Board for Toshiba Medical Systems. Contents lists available at ScienceDirect Atherosclerosis journal homepage: www.elsevier.com/locate/atherosclerosis http://dx.doi.org/10.1016/j.atherosclerosis.2014.09.038 0021-9150/© 2014 Elsevier Ireland Ltd. All rights reserved. Atherosclerosis 237 (2014) 494e498