Cardiac CT Angiography (CCTA) is a promising imaging technique that detects stenosis of the coronary arteries quickly and accurately. It can also detect other causes of chest pain when patients present to the emergency department (ED). Several studies have shown that patients with normal cardiac CCTA results are at low risk for adverse events (Oostema 2012). The potential benefits of CCTA must balanced with the harms, which include intravenous contrast and radiation exposure, incidental findings and false positives that lead to increased testing as well as potential morbidity and costs. Additionally, CCTA should offer superior outcomes (whether this be patient safety, identifying disease or costs) to standard workups (serial cardiac biomarkers, stress testing etc). This study is a multicenter randomized control trial that assesses medical outcomes and cost/resource utilization for CCTA protocol compared to “stress echo” testing at up to 1 year after ED visit.

Clinical Question

What is the 1-year risk of major adverse cardiac events (MACE) in patients evaluated in the ED with CCTA?


Adults aged greater than 30 who presented at five hospitals with a chief complaint possibly consistent with ACS. The patients were deemed to have a TIMI score of 2 or less but were determined to require further testing after EKG and troponin x 2 were negative.


Coronary CT Angiography


Traditional testing (stress testing, echocardiography)


Primary: MACE (defined as either cardiac death or AMI) rate at one year
Secondary: Repeat ED visits, hospitalizations, cardiac testing, cardiac medication use, overall costs


Non-blinded, multicenter randomized (2:1 CCTA to standard evaluation) control trial


Patients with an elevated creatinine or a positive D-dimer

Primary Results

  • Enrollment Numbers
    • 1,392 enrolled, 1,368 had data available up to one year after visit
    • CCTA Arm: 929
      • 140 patients randomized to CCTA did not have a CCTA performed
      • 910 needed for 90% power
    • Traditional Care Arm: 463
    • 1-year data available on 94% of patients (1285/1368)

23 patients excluded due to renal insufficiency or +D-dimer, 1 withdrew after 30 days

Critical Results

  • Primary Outcome (MACE at 1 year)
    • CCTA: 1.4% (12/870)
      • Death in CCTA negative: 0.16% (1/640) (95% CI: 0.004 – 0.87%)
    • Traditional Care: 1.1% (5/443)
      • Death in Traditional workup negative: 0.0%
    • No statistically significant difference
  • Selected Secondary Outcomes
1 year after ED visit CCTA Traditional Arm
All cause mortality 2/907 (0.2%) 3/461 (0.6%)
Cardiac Death 1/906 (0.1%) 0/460 (0%)
Acute Myocardial Infarction 2/870 (0.2%) 2/443 (0.4%)
Revascularization 4/870 (0.5%) 4/443 (0.9%)
1 year after ED visit CCTA Traditional Arm
ED Visits 305/852 (35.8%) 166/438 (37.9%)
Hospital Admissions 137/843 (16,3%) 74/432 (17.1%)
Cardiologist Office Visits 148/821 (18.0%) 53/423 (12.6%)
CCTA 2/822 (0.2%) 5/422 (1.2%)
Stress Testing without imaging 19/827 (2.3%) 2/424 (0.5%)
Stress Testing with imaging 60/824 (7.3%) 33/422 (7.8%)
Catheterization 24/829 (2.9%) 13/423 (3.1%)
Echocardiogram 49/824 (5.9%) 26/425 (6.1%)


  • Study asked a simple clinically relevant question
  • Followed patients for one year after ED visit
  • Data available for >90% of patients enrolled in study at one year, demonstrating good follow up


  • Study was non-blinded. While it would be difficult to blind patients and ordering physicians, there is no indication whether outcome assessors were blinded
  • Primary outcome information attained by phone follow up (recall bias) and retrospective chart review
  • Unable to detect difference in safety between arms due to low event rate
  • CCTA did not confer benefit to patient in terms of outcomes or decreased resource utilization

Author's Conclusions

“A coronary CT angiography–based strategy for evaluation of patients with low- to intermediate-risk chest pain who present to the ED does not result in increased resource use during 1 year. A negative coronary CT angiography result is associated with a less than 1% major adverse cardiac event rate during the first year after testing”

Our Conclusions

This multicenter randomized control trial demonstrates that low to moderate risk patients with non-ischemic EKGs and negative biomarkers are at a very low risk for MACE at 1 year regardless of whether they have a CCTA or traditional testing done from the ED. CCTA use did not result in lower resource utilization over the subsequent year.

Potential Impact To Current Practice

Based on this data, the idea of replacing traditional testing methods for low risk chest pain with CCTA has not been shown to improve patient outcomes nor reduce medical costs.

Bottom Line

In patients with low-risk chest pain, CCTA has not been shown to provide improved patient outcomes compared to traditional methods such as stress testing and echocardiography. With event rates so low (<1%) in both arms, it is unclear if any adjunctive testing after EKG and serial troponins is needed at all.

Read More


Oostema JA, Wilkinson B. Does cardiac computed tomography angiography identify patients at low risk for cardiovascular events? Ann Emerg Med 2012; 60(4): 465-6. PMID: 22555338