What is the protocol for ruling out Acute Coronary Syndrome (ACS) in a patient with chest pain requiring admission?

From the Guidelines

The protocol for ruling out Acute Coronary Syndrome (ACS) in a patient with chest pain requiring admission should include a combination of clinical history, symptoms, physical findings, ECG, and biomarkers, with a focus on risk stratification using tools such as the HEART score, as recommended by the 2020 ESC guidelines 1.

Key Components of the Protocol

• A 12-lead ECG should be obtained within 10 minutes of the patient's arrival at an emergency facility, and repeated if the initial ECG is not diagnostic but the patient remains symptomatic 1.
• Serial cardiac troponin I or T levels should be obtained at presentation and 3 to 6 hours after symptom onset to identify patients with ACS 1.
• The HEART score should be calculated to predict the risk of major adverse cardiac events, and to guide further management and disposition 1.
• Patients with a low HEART score (0-3) can be considered for early discharge, while those with a higher score (4-10) should be admitted for further evaluation and treatment 1.

Risk Stratification and Management

• Patients with a high risk of ACS should be admitted to a dedicated chest pain unit or coronary care unit, and should receive immediate medical treatment, including aspirin, additional antiplatelet therapy if indicated, beta-blockers, and statins 1.
• Patients with a low to intermediate risk of ACS can be considered for non-invasive stress testing or imaging, such as stress SPECT MPI or echocardiography, to further evaluate their risk and guide management 1.
• Patients with a non-coronary etiology for their chest pain should have their post-discharge care altered accordingly, and should receive guidance on risk factor modification and discharge medications 1.

Importance of Recent Guidelines

• The 2020 ESC guidelines 1 provide the most recent and highest quality evidence for the management of patients with ACS, and should be followed in clinical practice.
• The use of high-sensitivity troponin testing, as recommended by the 2019 JACC scientific expert panel 1, can help to rapidly rule out MI and identify patients at low risk for cardiac complications.

From the Research

Protocol for Ruling Out Acute Coronary Syndrome (ACS)

The protocol for ruling out ACS in a patient with chest pain requiring admission involves several steps:

• Evaluation begins with an electrocardiogram (ECG) obtained within 10 minutes of presentation 2
• If ST-segment elevation is present, ST-segment elevation MI (STEMI) is diagnosed 2
• If STEMI is not present, troponin levels should be measured using one of several recommended protocols 2
• Troponin levels greater than 99th percentile of the upper reference limit are consistent with ACS 2
• If the ECG finding is normal and results of two troponin tests are negative, risk stratification should be calculated using Thrombosis in Myocardial Infarction (TIMI) or HEART (History, ECG, Age, Risk factors, initial Troponin) score 2
• Based on the score, further evaluation to exclude coronary artery disease (CAD) is completed during hospitalization or after discharge, using exercise treadmill testing, stress echocardiography, myocardial perfusion scintigraphy, or coronary computed tomography angiography 2

Risk Stratification

Risk stratification is crucial in determining the likelihood of ACS:

• The HEART score and TIMI score are useful in diagnosing ACS, with high-risk ranges having likelihood ratios of 13 and 6.8, respectively 3
• The low-risk range HEART score (0-3) and low-risk range TIMI score (0-1) are useful in identifying patients less likely to have ACS, with likelihood ratios of 0.20 and 0.31, respectively 3
• Other risk factors, such as prior abnormal stress test, peripheral arterial disease, and pain radiation to both arms, can also increase the likelihood of ACS 3

Diagnostic Tests

Diagnostic tests, such as electrocardiogram and troponin levels, play a crucial role in diagnosing ACS:

• ST-segment depression and any evidence of ischemia on electrocardiogram are suggestive of ACS 3
• Troponin levels greater than 99th percentile of the upper reference limit are consistent with ACS 2
• Machine learning techniques, such as support vector machine, can also be used to diagnose ACS with high accuracy 4

Management

Management of patients with ACS involves antiplatelet therapy, percutaneous coronary intervention, and glycoprotein IIb/IIIa inhibitors:

• Antiplatelet agents, such as aspirin and clopidogrel, are recommended for patients with high-risk non-ST-elevation ACS 5
• Percutaneous coronary intervention and glycoprotein IIb/IIIa inhibitors are also recommended for high-risk patients 5
• Early invasive strategy is associated with lower mortality over the long term compared with conservative treatment 5