How is the risk of chest pain determined?

Risk Determination for Chest Pain

Risk stratification for chest pain is determined through a structured clinical assessment combining patient history, ECG findings, cardiac biomarkers (particularly high-sensitivity troponin), and validated risk scores—with patients categorized as low-risk (<1% 30-day MACE), intermediate-risk, or high-risk based on these integrated findings. 1

Clinical Assessment Components

History and Symptom Evaluation

The initial risk assessment begins with characterizing the chest pain itself 1:

• Anginal features that increase risk: Retrosternal discomfort described as pressure, heaviness, tightness, or squeezing; pain that gradually builds over minutes; pain precipitated by exertion or emotional stress; radiation to shoulders, arms, neck, jaw, or back 1
• Features that decrease risk: Sharp, stabbing pain; pleuritic or positional pain; pain reproducible by palpation; fleeting pain lasting only seconds; pain localized to a very small area 1, 2
• Accompanying symptoms: Sweating, nausea, vomiting, shortness of breath, and fatigue should all be considered anginal equivalents and increase risk 1

Important caveat: Women may present with accompanying symptoms (nausea, fatigue, jaw/neck/back pain, palpitations) more frequently than men, though chest pain remains the predominant symptom in both sexes with ACS 1. Traditional risk assessment tools often underestimate risk in women and misclassify them as having nonischemic chest pain 1.

Cardiovascular Risk Factors

Multiple methods exist for pretest probability assessment, though they can yield variable results 1:

• Key risk factors to assess: Age, sex, diabetes mellitus, hypertension, hyperlipidemia, smoking, family history of premature CAD, prior cardiovascular disease, peripheral arterial disease 1
• Highest-yield historical findings: Prior abnormal stress test (specificity 96%, LR 3.1), peripheral arterial disease (specificity 97%, LR 2.7), pain radiation to both arms (specificity 96%, LR 2.6) 3

Common pitfall: The Diamond and Forrester method overestimates the prevalence of obstructive CAD; coronary calcium scoring performs better for stable CAD risk stratification than traditional methods 1.

Objective Testing

ECG Findings

A 12-lead ECG should be obtained within 10 minutes of arrival 1, 4:

• High-risk findings: ST-segment elevation (STEMI), ST-segment depression (specificity 95%, LR 5.3), any evidence of ischemia (specificity 91%, LR 3.6) 4, 3
• Lower-risk findings: Normal, nonischemic, or unchanged ECG from previous 1

Cardiac Biomarkers

High-sensitivity cardiac troponins are the preferred standard 1:

• Timing for serial measurements: 1-3 hours after initial sample for high-sensitivity troponin; 3-6 hours for conventional troponin 1
• Single measurement strategy: For patients with symptoms present ≥3 hours before arrival, a single hs-cTn below the limit of detection can exclude myocardial injury 1
• Blood sampling protocol: Draw samples for troponin T or I and CK-MB mass on admission and at 10-12 hours after symptom onset 1, 4

Risk Stratification Categories

Low-Risk Patients (<1% 30-day MACE)

Patients can be designated low-risk using any of these validated approaches 1:

• HEART Pathway: HEART score ≤3 with initial and serial troponin <99th percentile 1
• TIMI score: Score 0 (or 0-1 in modified ADAPT) with negative serial troponins 1
• EDACS: Score ≤16 with negative serial troponins 1
• hs-cTn based: Time-0 hs-cTn below limit of detection (if symptoms ≥3 hours), or time-0 and 1-2 hour delta both below assay "low" thresholds 1

Management: Low-risk patients can be discharged without admission or urgent cardiac testing 1. Routine admission or cardiac testing is not supported by evidence for this group 1.

Intermediate-Risk Patients

These patients have 1-10% risk of 30-day MACE and benefit most from cardiac imaging and testing 1:

• Initial assessment: Transthoracic echocardiography is recommended as a rapid bedside test to evaluate ventricular function, wall motion abnormalities, and pericardial effusion 1
• Management setting: Observation unit management is reasonable to shorten length of stay and lower costs compared to inpatient admission 1

High-Risk Patients

High-risk features requiring immediate intervention 1, 4:

• Ongoing chest pain with ischemic ECG changes
• Elevated troponin levels
• Hemodynamic instability (systolic BP <100 or >200 mmHg, heart rate <40 or >100/min)
• Left ventricular failure
• Major arrhythmias
• Recurrent ischemia
• Diabetes mellitus with ACS

Validated Risk Scores

HEART Score (Most Effective for ED Use)

The HEART score demonstrated superior performance with LR 13 (95% CI 7.0-24) for high-risk range (7-10) and LR 0.20 (95% CI 0.13-0.30) for low-risk range (0-3) 3, 5:

• History: 0-2 points based on suspicion for ACS
• ECG: 0-2 points based on findings
• Age: 0-2 points
• Risk factors: 0-2 points (≥3 factors or history of atherosclerotic disease)
• Troponin: 0-2 points based on elevation

TIMI Score

High-risk range (5-7) has LR 6.8 (95% CI 5.2-8.9); low-risk range (0-1) has LR 0.31 (95% CI 0.23-0.43) 3, 6.

Critical point: Clinical decision pathways incorporating these scores should be used routinely in emergency department and outpatient settings 1. The HEART score is particularly effective for identifying both patients safe for discharge and those requiring further care 5.

Special Populations

Older Patients (>75 years)

ACS should be strongly considered in this age group, as they may present with atypical symptoms including confusion, presyncope, syncope, or vague abdominal symptoms 1.

Patients with Diabetes

This population has higher prevalence of angina with potentially lower functional capacity and may have lower incidence of obstructive CAD despite symptoms 1.