For an emergency department patient with chest pain who is hemodynamically stable, has a normal 12‑lead electrocardiogram and normal cardiac troponins, how should I decide between a coronary artery calcium (CAC) scan (or coronary CT angiography) and a stress test?

Choosing Between CAC/CCTA and Stress Testing in ED Chest Pain Patients

For hemodynamically stable ED patients with chest pain, normal ECG, and normal troponins, coronary CT angiography (CCTA) and stress testing are both acceptable first-line options, but CCTA is preferred when you need to rapidly exclude coronary artery disease in low-to-intermediate risk patients, while stress testing (preferably with imaging) is preferred when assessing for inducible ischemia in patients with suspected but not yet excluded ACS. 1

Decision Algorithm

Step 1: Complete Risk Stratification First

• Calculate a modified HEART score or EDACS score after obtaining serial high-sensitivity troponins at 0 and 1-3 hours 1
• Patients with modified HEART score ≤3 or EDACS <16 with normal/stable troponins are appropriate for either outpatient stress testing or CCTA 1, 2
• Patients with scores above these thresholds require further observation or inpatient evaluation 1

Step 2: Choose CCTA When:

• Low-to-intermediate pre-test probability of CAD with normal or inconclusive troponin and ECG 1
• You need to exclude coronary artery disease entirely (CCTA has >95% negative predictive value) 1
• Patient has no known CAD (CCTA is less useful in patients with prior stents or CABG) 1
• Calcium score is low (severe calcifications limit CCTA interpretation) 1
• Heart rate can be controlled to <65 bpm and patient has no contraindications to contrast 1
• You want to simultaneously rule out pulmonary embolism or aortic dissection (triple rule-out protocol in selected cases) 1, 3

Step 3: Choose Stress Testing (Preferably With Imaging) When:

• Patient has known coronary artery disease and you need to assess for inducible ischemia 1
• Patient remains symptom-free for several hours with normal ECG and normal hs-cTn but ACS is still suspected 1
• You need functional assessment rather than anatomic evaluation 1
• Patient has contraindications to CCTA (severe renal dysfunction, contrast allergy, inability to control heart rate, severe obesity) 1
• Stress echocardiography specifically has superior prognostic value over exercise ECG alone and excellent negative predictive value 1
• Patient cannot exercise: use pharmacological stress imaging (dobutamine echo, nuclear perfusion, or stress CMR) 1

Important Caveats and Pitfalls

CCTA Limitations to Recognize:

• High-sensitivity troponin protocols have reduced CCTA's advantage in shortening ED length of stay—one randomized trial showed CCTA no longer improved patient flow when hs-cTn was standard of care 1
• CCTA increases downstream invasive angiography rates (up to 25% increase in some studies) 1
• Not validated for patients with prior stents or CABG in the acute setting 1
• Requires 24-hour availability which is not universal 1

Stress Testing Considerations:

• Stress imaging (echo, nuclear, CMR) is superior to exercise ECG alone for diagnostic accuracy 1
• Timing matters: stress testing should occur within 72 hours for low-risk patients discharged from ED 1, 2
• Do not stress test patients with ongoing chest pain, dynamic ECG changes, or rising troponins—these patients need urgent invasive evaluation 1, 4

When Neither Test Is Appropriate:

• High-risk features (hemodynamic instability, ongoing ischemia, dynamic ECG changes, significantly elevated troponin) require urgent invasive coronary angiography within 24 hours, not noninvasive testing 1, 4
• Patients with refractory chest pain despite optimal medical therapy should proceed directly to catheterization 5, 4

Practical Implementation

• For same-day discharge: CCTA allows faster rule-out if available and patient is appropriate candidate 1
• For observation unit: Either modality can be used within 24-72 hours based on local availability and expertise 1
• For outpatient follow-up: Stress testing within 72 hours to 2 weeks is standard for low-risk patients 1, 2

Special Population: No Known CAD, Atypical Symptoms, Low Risk

• CCTA is particularly valuable as it can completely exclude CAD and avoid unnecessary downstream functional testing 1
• A normal CCTA allows safe discharge with excellent prognosis (>99% negative predictive value for 30-day events) 1

Special Population: Known CAD or Prior Revascularization

• Stress imaging is preferred to assess for inducible ischemia and guide need for repeat revascularization 1
• CCTA interpretation is limited by stents and calcification in this population 1