Selection of Non‑invasive Imaging for Emergency‑Department Chest‑Pain Evaluation

Risk Stratification

A modified HEART score ≤ 3 or an EDACS < 16 together with normal serial high‑sensitivity troponins identifies patients who may safely undergo either outpatient stress testing or coronary CT angiography (CCTA) as the first diagnostic step【1】【2】.
Patients whose scores exceed these thresholds should receive continued observation or inpatient evaluation rather than immediate discharge with non‑invasive testing【1】.

In hemodynamically stable patients with low‑to‑intermediate pre‑test probability of coronary artery disease (CAD), normal ECG and troponins, CCTA is preferred because it can exclude CAD with a > 95 % negative predictive value【3】【4】.
CCTA is most appropriate when rapid rule‑out of CAD is required (e.g., same‑day discharge) and the patient has no known CAD, no prior stents or coronary‑artery bypass grafting, and a low coronary calcium score; heavy calcification or prior devices impair image interpretation【5】【3】.
The test is feasible only when heart rate can be lowered to < 65 bpm and there are no contraindications to iodinated contrast (e.g., severe renal impairment, contrast allergy, extreme obesity)【5】.
In selected cases, a “triple‑rule‑out” CT protocol can simultaneously evaluate for pulmonary embolism or aortic dissection alongside CAD【4】.
Evidence from a randomized trial indicates that, when high‑sensitivity troponin protocols are standard, CCTA no longer shortens emergency‑department length of stay, diminishing its workflow advantage【3】 (Level I evidence).
Observational data show that CCTA use can increase downstream invasive angiography rates by up to 25 % in some settings【3】 (moderate‑quality evidence).

For patients with known CAD (or prior revascularisation) who need assessment of inducible ischemia, stress testing with imaging (stress echocardiography, nuclear perfusion, or stress cardiac MRI) is the preferred strategy【6】【3】.
When a patient remains symptom‑free for several hours, has a normal ECG and normal high‑sensitivity troponin but acute coronary syndrome is still a concern, stress testing provides functional information to rule out ischemia【7】【6】.
Functional (rather than purely anatomic) assessment is indicated when the clinical question focuses on myocardial ischemia rather than plaque burden【3】.
Contraindications to CCTA (severe renal dysfunction, contrast allergy, inability to achieve target heart rate, severe obesity) shift the choice toward stress testing【5】.
Stress echocardiography offers superior prognostic value and an excellent negative predictive value compared with exercise ECG alone【3】【4】 (high‑quality evidence).
Pharmacologic stress imaging (dobutamine echo, nuclear perfusion, or stress CMR) is recommended for patients unable to exercise【7】【8】.

CCTA is not validated for acute assessment in patients with prior stents or coronary‑artery bypass grafts, and image quality may be compromised by heavy calcification【5】.
Availability of 24‑hour CCTA services is limited in many institutions, which may affect feasibility【5】.
Stress imaging modalities are consistently superior to exercise ECG alone for diagnostic accuracy【3】【4】.
Stress testing should be performed within 72 hours of ED discharge for low‑risk patients to ensure timely diagnosis【8】.
Patients with ongoing chest pain, dynamic ECG changes, or rising troponin levels must not undergo stress testing; they require urgent invasive coronary angiography within 24 hours【7】【6】.
High‑risk features (hemodynamic instability, ongoing ischemia, markedly elevated troponin) mandate urgent invasive angiography rather than any non‑invasive test【7】【6】.

When CCTA is available and the patient meets eligibility criteria, same‑day discharge can be achieved more rapidly than with stress testing【3】【4】.
In observation units, either CCTA or stress testing may be employed within 24–72 hours, guided by local resource availability and expertise【1】【8】.
For low‑risk patients discharged from the ED, outpatient stress testing is recommended within 72 hours to 2 weeks to complete the diagnostic pathway【8】.

Patients without known CAD and with atypical symptoms: CCTA is especially valuable because a normal study provides a > 99 % negative predictive value for 30‑day adverse events, supporting safe discharge and excellent short‑term prognosis【3】【4】.
Patients with known CAD or prior revascularisation: Stress imaging is preferred to detect inducible ischemia and to guide decisions about repeat revascularisation; CCTA interpretation is limited by stents and heavy calcification in this group【6】【3】【5】.

The American College of Cardiology recommends using the HEART score to guide disposition decisions for patients with low-risk acute coronary syndrome, with a score ≤3 indicating low risk (<1% 30-day risk of major adverse cardiac events) 9, 10
A modified HEART score ≤3 identifies patients at low risk who are appropriate for discharge with outpatient testing, as supported by the 2022 ACC Expert Consensus 9, 10

Serial negative troponins at 0 and 3-6 hours effectively rule out acute myocardial infarction in patients with nonischemic ECGs, according to the American College of Cardiology 9, 10, 11
Patients with normal troponin levels, nondiagnostic ECG changes, and low HEART scores can be safely discharged with outpatient noninvasive testing, as recommended by the American College of Cardiology 9, 10

The American College of Cardiology recommends noninvasive stress testing (stress echocardiography, stress nuclear imaging, or coronary CT angiography) within 72 hours to 2 weeks after discharge 9, 12
Cardiovascular risk factor optimization, including blood pressure and diabetes management, is essential for patients with low-risk chest pain, as suggested by the American College of Cardiology 13

The American College of Cardiology advises against discharging patients who develop recurrent ischemic chest pain, new ECG abnormalities suggesting ischemia, rising troponin levels on repeat testing, or hemodynamic instability during observation 9, 12