CT Angiography for Safe Discharge of Patients With Possible Acute Coronary Syndromes - ACRIN PA 4005


The goal of the trial was to evaluate a strategy of cardiac computed tomography (CT) angiography compared with traditional care among low- to intermediate-risk patients with possible acute coronary syndrome (ACS).


Patients with no obstructive disease on cardiac CT angiography will have a low rate (<1%) of future adverse events within 30 days.

Study Design

  • Randomized
  • Parallel

Patient Populations:

  • Patients at least 30 years of age with signs of a possible ACS
  • TIMI risk score 0-2
  • Need for admission or diagnostic testing to evaluate possible ACS

    Number of enrollees: 1,370
    Duration of follow-up: 1 year
    Mean patient age: 49 years
    Percentage female: 51%


  • Ischemic ECG
  • Clear noncardiac etiology for symptoms
  • Coexisting condition that required admission to the hospital
  • Contraindication to cardiac CT angiography
  • Normal catheterization or CT angiography within the previous year
  • Renal insufficiency (post-randomization exclusion)
  • Suspected pulmonary embolism (post-randomization exclusion)

Primary Endpoints:

  • Cardiovascular death or MI at 30 days

Drug/Procedures Used:

Low- to intermediate-risk patients with possible ACS who were anticipated to be admitted or undergo diagnostic testing were randomized to cardiac CT angiography (n = 908) versus traditional care (n = 462).

Principal Findings:

Overall, 1,370 patients were randomized. The mean age was 49 years, 51% were women, 14% had diabetes, 64% had a normal electrocardiogram (ECG), 51% had a TIMI (Thrombolysis in Myocardial Infarction) risk score of 0, 36% had a TIMI risk score of 1, and 13% had a TIMI risk score of ≥2.

Among patients in the cardiac CT angiography group, 84% ultimately had the scan (27% did not undergo the scan due to persistently elevated heart rate), and no obstructive coronary artery disease (CAD) was observed in 83%. Among those with a negative scan, no patient died or had an MI at 30 days.

Among patients in the traditional care group, 58% underwent stress testing with/without imaging, which was normal in 92%. Among the 6% who underwent cardiac CT angiography, no obstructive CAD was observed in 77%.

Discharge from the emergency department (ED): 50% versus 23% (p < 0.001), median length of stay: 18 hours versus 25 hours (p < 0.001), respectively.

- Outcomes at 1 year for cardiac CT angiography vs. traditional care, respectively
- Mortality: 0.2% vs. 1%
- Cardiac death: 0.1% vs. 0
- MI: 1% vs. 1%
- Revascularization: 3% vs. 2%


Among low- to intermediate-risk patients with possible ACS, evaluation by cardiac CT angiography is feasible. Discharge from the ED was high and median length of stay was reduced by cardiac CT angiography. Among patients with a negative scan, there were no adverse events at 30 days. Findings were similar at 1 year. Studies examining the utility of an anatomical approach for assessing CAD (for example, cardiac CT angiography) versus a functional approach for assessing CAD (for example, myocardial perfusion imaging) are needed.


Presented by Dr. Judd Hollander at ACC.13, San Francisco, March 13, 2013.

Litt HI, Gatsonis C, Snyder B, et al. CT angiography for safe discharge of patients with possible acute coronary syndromes. N Engl J Med 2012;Mar 26:[Epub ahead of print].

Presented by Dr. Harold Litt at ACC.12 & ACC-i2 with TCT, Chicago, IL, March 26, 2012.

Clinical Topics: Acute Coronary Syndromes, Noninvasive Imaging, Atherosclerotic Disease (CAD/PAD), Nuclear Imaging

Keywords: Myocardial Perfusion Imaging, Coronary Artery Disease, Myocardial Infarction, Acute Coronary Syndrome, Tomography, Emergency Service, Hospital, Electrocardiography, Heart Rate, Diabetes Mellitus, Length of Stay, Exercise Test

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