What is the approved guideline for chest pain risk stratification and which diagnostic tests should be ordered?

Chest Pain Risk Stratification and Diagnostic Testing Guidelines

The 2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR guideline recommends using clinical decision pathways (CDPs) to categorize patients with chest pain into low-, intermediate-, and high-risk strata to guide disposition and subsequent diagnostic evaluation. 1

Risk Stratification Process

Step 1: Initial Assessment

• Obtain ECG within 10 minutes of arrival
• Measure cardiac troponin levels (initial and serial)
• Assess vital signs and hemodynamic stability
• Evaluate for STEMI or other life-threatening conditions

Step 2: Risk Stratification Using Clinical Decision Pathways

Low-Risk Patients (30-day risk of death or MACE <1%)

• Defined by:
  • HEART score <3 with negative troponins
  • EDACS score <16 with negative troponins
  • TIMI score 0 (or <1 for mADAPT) with negative troponins
  • Initial high-sensitivity troponin below detection limit or "very low" threshold if symptoms present for at least 3 hours 1

Intermediate-Risk Patients

• HEART score 4-6
• TIMI score 2-4
• Abnormal but non-diagnostic ECG changes
• Initial high-sensitivity troponin between "low" and "high" thresholds 1

High-Risk Patients

• Defined by:
  • New ischemic ECG changes
  • Troponin-confirmed acute myocardial injury
  • New-onset left ventricular systolic dysfunction (EF <40%)
  • Newly diagnosed moderate-severe ischemia on stress testing
  • Hemodynamic instability
  • High CDP risk score (HEART score 7-10, TIMI score 5-7) 1

Diagnostic Testing Based on Risk Level

Low-Risk Patients

• Reasonable to discharge home without admission or urgent cardiac testing 1
• Optional testing may include:
  • ECG
  • Coronary artery calcium (CAC) scan

Intermediate-Risk Patients

• Transthoracic echocardiography (TTE) recommended as initial bedside test to:
  • Establish baseline ventricular and valvular function
  • Evaluate for wall motion abnormalities
  • Assess for pericardial effusion 1
• Management in observation unit is reasonable 1
• Further testing options based on clinical scenario:
  • Anatomic testing:
    • Coronary CT angiography (CCTA) - preferred first-line test for most patients
  • Functional testing:
    • Stress echocardiography
    • Stress SPECT/PET myocardial perfusion imaging
    • Stress cardiovascular magnetic resonance (CMR)
    • Exercise ECG (if normal baseline ECG and patient able to exercise) 1

High-Risk Patients

• Invasive coronary angiography (ICA) is recommended 1
• For troponin-positive patients in whom obstructive CAD has been excluded by CCTA or ICA:
  • CMR or echocardiography can establish alternative diagnoses 1

Special Populations

Patients with Prior CABG

• Stress imaging to evaluate for myocardial ischemia or CCTA for graft stenosis/occlusion
• ICA is useful if no ACS or indeterminate/nondiagnostic stress test 1

Patients on Dialysis

• Transfer by EMS to acute care setting for unremitting chest pain during dialysis 1

Patients with Cocaine/Methamphetamine Use

• Consider stimulant use as a cause of symptoms 1

Implementation Considerations

Troponin Testing Protocols

• High-sensitivity troponin: Repeat at 1-3 hours after initial sample
• Conventional troponin: Repeat at 3-6 hours after initial sample 1

Advantages of Clinical Decision Pathways

• Increase ED discharge rates (19-49% depending on protocol)
• Reduce length of stay
• Maintain high sensitivity for detecting acute myocardial injury 1

Pitfalls to Avoid

1. Not using standardized risk stratification tools - Unstructured assessment leads to both under- and over-testing
2. Inappropriate single troponin testing - Single high-sensitivity troponin should only be used for rule-out if symptoms began >3 hours before arrival
3. Ignoring prior test results - Consider "warranty periods" of previous normal cardiac tests
4. Not considering special populations - Dialysis patients, cocaine users, and post-CABG patients require specific approaches
5. Failing to engage patients in decision-making - Shared decision-making is recommended, especially for intermediate-risk patients 1

The HEART score has shown excellent performance in multiple settings, with a negative predictive value of 98.1-99.3% for 30-day MACE when used to identify low-risk patients 2, 3, 4. A modified prehospital version (preHEART) has also shown promise for EMS risk stratification 4.