Cardiovascular disease remains the leading cause of death worldwide for both men and women, taking the lives of over 17.9 million people each year. Recent studies demonstrate coronary computed tomography angiography (CTA) is an effective first-line diagnostic tool for screening patients suspected of CAD.
In this blog post, we have compiled recent clinical trials summarizing the benefits of coronary CTA in clinical practice, as well as the current recommendations on using coronary CTA for screening patients with suspected CAD.
Evidence Supporting a Coronary CTA-first Strategy
Scottish Computed Tomography of the Heart (SCOT-HEART) Trial
Researchers at the University of Edinburgh in Scotland conducted the Scottish Computed Tomography of the Heart (SCOT-HEART) Trial to assess the effectiveness of coronary CTA in the diagnosis, management, and outcomes of patients with suspected CAD. In the prospective, multicenter trial, patients were randomly assigned to two groups: standard of care alone, or standard of care in addition to calcium score and coronary CTA. The study results demonstrated that coronary CTA can lead to the more appropriate use of invasive angiography and care management changes, supporting evidence that coronary CTA can improve clinical decision-making and patient outcomes 
In a follow-up study of the SCOT-HEART trial published in The New England Journal of Medicine, researchers examined the five-year outcomes of 4,146 patients who presented with stable chest pain. The study results showed that coronary CTA in addition to standard of care was associated with a 41% lower risk of nonfatal myocardial infarction (MI) or death from CAD than standard of care alone 
Prospective Multicenter Imaging Study for Evaluation of Chest Pain (PROMISE)
The Prospective Multicenter Imaging Study for Evaluation of Chest Pain (PROMISE) has demonstrated additional benefits related to the usage of coronary CTA. The initial study findings published in the New England Journal of Medicine in 2015 concluded that an initial strategy of coronary CTA compared to functional testing did not improve clinical outcomes over a median follow-up of 2 years (3). However, secondary analyses of the PROMISE trial have revealed improvements in accuracy, safety, and preventative medication with the usage of coronary CTA.
In the research paper “Prognostic Value of Noninvasive Cardiovascular Testing in Patients With Stable Chest Pain” published in Circulation, researchers concluded that coronary CTA can provide better prognostic information than functional testing in patients who have stable chest pain with a low burden of obstructive CAD, myocardial ischemia, and events .
International Study of Comparative Health Effectiveness with Medical and Invasive Approaches (ISCHEMIA)
The International Study of Comparative Health Effectiveness with Medical and Invasive Approaches (ISCHEMIA) aimed to evaluate routine invasive therapy when compared to optimal medical therapy among patients with stable ischemic heart disease and moderate to severe myocardial ischemia on noninvasive stress testing. Insights from the ISCHEMIA trial published in The New England Journal of Medicine demonstrated that an initial invasive strategy compared with an initial conservative strategy did not reduce the risk of ischemic cardiovascular events or death .
According to the results of the ISCHEMIA trial, an initial conservative strategy was equally as effective as an initial invasive strategy in guiding the treatment of patients with stable coronary disease and moderate or severe ischemia. The NHLBI-funded study aimed to determine the best way to manage patients with stable ischemic heart disease.
Randomized Evaluation of Patients with Stable Angina Comparing Utilization of Noninvasive Examinations (RESCUE) Trial
Consistent with the results from the ISCHEMIA study, the results from the Randomized Evaluation of Patients with Stable Angina Comparing Utilization of Noninvasive Examinations (RESCUE) Trial demonstrates that coronary CTA is an effective alternative to SPECT for evaluating patients with stable angina. The randomized, controlled, multi-center clinical trial compared coronary CTA and SPECT-MPI for assisting in the diagnosis of ischemic heart disease in patients with stable angina. In the trial, there were no differences in outcomes between patients who underwent coronary CTA in comparison with SPECT. The study revealed that coronary CTA was a better predictor of major adverse cardiac events (MACE) and revascularization.
Coronary CTA Guidelines and Recommendations
As evidence builds in support of a coronary CTA-first strategy, cardiovascular associations have released new coronary CTA guidelines recommending the first-line usage of the test when diagnosing CAD in clinical practice.
National Institute For Health and Care Excellence (NICE) Guidance
The United Kingdom has paved the way for the use of coronary CTA in clinical practice for the management of patients with CAD. In November 2016, the National Institute for Health and Care Excellence (NICE) published the “NICE Guidance for Stable Chest Pain Patients to Appropriately Diagnose Patients with Suspected Coronary Artery Disease.” According to guideline CG95, CCTA should be offered if clinical assessment indicates typical or atypical angina or clinical assessment has indicated non-anginal chest pain but 12-lead resting ECG has been done and indicates ST-T changes or Q waves. The guidelines also recommend coronary CTA as the first-line investigation for all patients with angina and no prior CAD.
European Society of Cardiology (ESC) Guidelines
Building on evidence from the SCOT-HEART Trial and the PROMISE Trial, the European Society of Cardiology published updated guidelines on the diagnosis and management of chronic coronary syndromes in September 2019. The updated guidelines state that coronary CTA should be used for diagnosing CAD in symptomatic patients in whom obstructive CAD cannot be excluded by clinical assessment alone.
American College of Cardiology (ACC) Recommendations
The American College of Cardiology (ACC) published new recommendations for the usage of coronary CTA in September 2020 in the Journal of the American College of Cardiology. The report titled, “Current Evidence and Recommendations for Coronary CTA First in Evaluation of Stable CAD,” synthesize evidence from the SCOT-HEART, PROMISE, and ISCHEMIA trials in support of the use of coronary CTA. In the report, the authors state that CCTA should be used as a first-line diagnostic tool in patients with stable chest pain with possible obstructive CAD.
Society of Cardiovascular Computed Tomography (SCCT) 2021 Expert Consensus on CCTA
The Society of Cardiovascular Computed Tomography (SCCT), released a new expert consensus document updating previous recommendations for the use of coronary CTA on February 9. The document titled “SCCT 2021 Expert Consensus Document on Coronary Computed Tomographic Angiography” was published in the Journal of Cardiovascular Computed Tomography.
With evidence growing in support of coronary CTA, the consensus statement includes the following recommendations for coronary CTA in the evaluation of stable CAD:
- Evaluation of Stable CAD: Coronary CTA in Native Vessels
- Evaluation of Stable CAD: Coronary CTA Post-revascularization
- Evaluation of Stable CAD: Coronary CTA with FFR or CTP
- Evaluation of Stable CAD: Coronary CTA in Other Conditions
- Reporting on CTA: Coronary and Non-coronary Information
Improving the Adoption and Utilization of Coronary CTA
As evidence continues to build in support of a coronary CTA-first strategy, we can all help contribute to accelerating progress. To help support the adoption and utilization of coronary CTA, consider taking the following steps:
- Improve education on coronary CTA in clinical practice. Associations including the Society of Cardiovascular Computed Tomography have created resources to help educate providers on coronary CTA. Review the educational materials online and share them with colleagues.
- Help address the challenges of coronary CTA reimbursement. CMS underestimates the costs for coronary CTA which impacts the rate at which it is reimbursed in the United States. Contribute to improving reimbursement for coronary CTA by ensuring standardization in reporting and advocating for improved reimbursement.
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 The SCOT-HEART Investigators. Coronary CT Angiography and 5-Year Risk of Myocardial Infarction. N Engl J Med 2018;379:924-33.
 Douglas PS, Hoffmann U, Patel MR, et al. Outcomes of anatomical versus functional testing for coronary artery disease. N Engl J Med. 2015;372(14):1291-1300. doi:10.1056/NEJMoa1415516
 Hoffmann U, Ferencik M, Udelson JE, Picard MH, Truong QA, Patel MR, Huang M, Pencina M, Mark DB, Heitner JF, Fordyce CB, Pellikka PA, Tardif JC, Budoff M, Nahhas G, Chow B, Kosinski AS, Lee KL, Douglas PS; PROMISE Investigators. Circulation. 2017 Apr 7;135:2320-2332. doi: https://doi.org/10.1161/CIRCULATIONAHA.116.024360
 Maron DJ, Hochman JS, Reynolds HR, Bangalore S, O’brien SM, Boden WE, Chaitman BR, Senior R, Lopez-Sendon J, Alexander KP, Lopes RD, Shaw LJ, et al. Initial Invasive or Conservative Strategy for Stable Coronary Disease. N Engl J Med. 2020 Apr 9; 382:1395-1407. doi:10.1056/NEJMoa1915922