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Acute Coronary Syndromes (Non–ST-Segment Elevation - Adult)

Critical Issues in the Evaluation and Management of Adult Patients with Non–ST-Segment Elevation Acute Coronary Syndromes (September 2006)

Complete Clinical Policy on Non–ST-Segment Elevation Acute Coronary Syndromes (PDF)

Scope of Application. This guideline is intended for physicians working in hospital-based emergency departments (EDs) or chest pain evaluation units.

Inclusion Criteria. This guideline is intended for adult patients presenting to the ED with suspected non–ST-segment elevation acute coronary syndromes.

Exclusion Criteria. This guideline is not intended for pediatric patients, patients in cardiogenic shock, or patients with injury on the initial 12-lead electrocardiogram (ECG).

Critical Questions

1.  Are serial ECGs useful during the ED evaluation of patients with suspected acute coronary syndromes?

  • Level A recommendations. None specified.


  • Level B recommendations. Perform repeat ECG or automated serial ECGs during the ED evaluation of patients in whom the initial ECG is nondiagnostic for injury and who have symptoms consistent with ongoing or recurrent ischemia. No recommendations can be made in regards to the exact timing of repeat ECGs. Studies suggest that 30 to 60 minutes after baseline may be a reasonable time interval for repeat ECG.


  • Level C recommendations. None specified.


2.  Is there a preferred regimen of serum marker testing in the ED for the exclusion of non–ST-segment elevation acute myocardial infarction (AMI)?

Inclusion Criteria. Patients with symptoms suggestive of acute coronary syndromes presenting less than or equal to 12 hours of symptom onset.

  • Level A recommendations. Do not utilize cardiac serum marker tests to exclude non-AMI acute coronary syndromes (ie, unstable angina).


  • Level B recommendations. Utilize any of the following cardiac serum marker tests to exclude non–ST-segment elevation AMI as defined by the World Health Organization (WHO) or modified WHO criteria (Figure 1 - see policy):*


    1. A single negative CK-MB mass, Troponin I, or Troponin T measured 8 to 12 hours after symptom onset.

    2. A negative myoglobin in conjunction with a negative CK-MB mass, or negative Troponin§ when measured at baseline and 90 minutes in patients presenting less than 8 hours after symptom onset.

    3. A negative 2-hour delta|| CK-MB mass in conjunction with a negative 2-hour delta|| Troponin§ in patients presenting less than 8 hours after symptom onset.

    *There is insufficient evidence at this time to make any recommendations in regards to utilization of cardiac serum markers to exclude non–ST-segment elevation AMI using current Joint European Society of Cardiology / American College of Cardiology criteria for AMI (Figure 2 - see policy).
    The exact timing of serum marker measurement as it relates to time of symptom onset should take into account the sensitivity, precision, and institutional norms of the assay being utilized, as well as the release kinetics of the marker being measured.
    If time of symptom onset is unknown, unreliable, or more consistent with preinfarctional angina, then time of symptom onset should be referenced to the time of ED presentation.
    §Only Troponin I has been investigated in the serial 90 minute multimarker protocol and the 2-hour delta protocol.
    || The appropriate delta values for exclusion of AMI should take into account the sensitivity and precision of the assay utilized and confirmed by in-house studies. It is also important that delta serum marker levels are measured on the same instrument due to subtle variations in calibration among individual instruments of the same model.

  • Level C recommendations. None specified.


3.  What are the indications for ED administration of glycoprotein IIb/IIIa inhibitors in patients with non–ST-segment elevation acute coronary syndromes?

Exclusion Criteria: Contraindications for a glycoprotein inhibitor (bleeding disorder, renal insufficiency, etc).

  • Level A recommendations. None specified.


  • Level B recommendations. Consider administration of glycoprotein IIb/IIIa inhibitors (abciximab, tirofiban, or eptifibatide) prior to percutaneous coronary intervention to patients with positive troponin or ischemic ST-segment depression in whom an early interventional strategy is anticipated.* Studies suggest that benefit is greatest in patients in whom treatment was initiated within 6 hours of symptom onset and in patients in whom there will be a delay in percutaneous coronary intervention.


  • Level C recommendations. Consider administration of glycoprotein IIb/IIIa inhibitors (tirofiban, or eptifibatide) to patients with positive troponin or ischemic ST-segment depression in whom a non-interventional strategy is planned.*


    *There is insufficient information at this time to make any recommendations in regards to the exact location or timing for initiation of glycoprotein IIb/IIIa inhibitor therapy (ie, ED versus inhospital).

4.  What are the indications for ED administration of clopidogrel in patients with non–ST-segment elevation acute coronary syndromes?

Exclusion Criteria: Aspirin allergy; contraindications for clopidogrel therapy (eg, bleeding disorder, other).

  • Level A recommendations. None specified.


  • Level B recommendations. Administer a loading dose of clopidogrel in patients with elevated troponin or ischemic ST-segment depression*:


    1. In whom a non-interventional approach is planned

    2. Prior to percutaneous coronary intervention in patients in whom an interventional approach is planned and who are not at significant risk for urgent coronary artery bypass graft. 

    *There is insufficient information at this time to make any recommendations in regard to the exact location or timing for administration of the initial clopidogrel loading dose (ie, ED versus inhospital administration). Studies in elective percutaneous coronary intervention suggest benefit is greatest if clopidogrel is administered at least 6 hours prior to percutaneous coronary intervention.  

  • Level C recommendations. None specified. 

Purpose of ACEP's Clinical Policies

Clinical Findings and Strength of Recommendations