Acute Coronary Syndrome Assessment and Management

Patient Evaluation

• The American College of Cardiology recommends immediate evaluation for acute coronary syndrome (ACS) in patients with a history of myocardial infarction and current presentation of chest pain radiating to the leg with nausea 1, 2
• Chest pain radiating to the lower extremity with associated nausea in a patient with prior MI is a critical red flag for ACS 1, 2
• Women and diabetic patients frequently present with atypical symptoms including radiating pain to unusual locations and nausea 1, 2
• Prior MI places a patient at very high risk for recurrent ACS 3
• Multiple cardiovascular risk factors, such as diabetes, hypertension, and hyperlipidemia, increase the risk of ACS 1, 2
• Impaired renal function increases cardiovascular risk 3

Diagnostic Testing

• Obtain 12-lead ECG within 10 minutes of presentation 4, 3, 5
• High-sensitivity troponin T or I should be measured immediately and repeated at 3-6 hours if initial negative 7
• Complete blood count, electrolytes, and renal function should be evaluated 3
• Do not wait for troponin results to initiate treatment if ECG shows STEMI 6, 5

ECG Interpretation

• ST-segment elevation or new left bundle branch block is indicative of STEMI requiring immediate reperfusion 6, 5
• ST-segment depression, T-wave inversion, or pathologic Q waves may indicate possible NSTE-ACS 1, 2
• Compare with prior ECGs if available 3, 6

Management

• Activate catheterization lab for primary PCI within 120 minutes if STEMI is identified on ECG 5
• Continue clopidogrel 75 mg daily and aspirin 75-150 mg daily for antiplatelet therapy 7
• Nitroglycerin sublingual 0.4 mg every 5 minutes up to 3 doses may be used for ongoing chest pain 4, 8
• Morphine 4-8 mg IV may be used if pain is not relieved by nitroglycerin 5
• Oxygen 2-4 L/min should be administered if oxygen saturation is <90% or signs of respiratory distress are present 5

Risk Stratification

• High-risk features, such as prior MI, diabetes, renal impairment, and multiple cardiovascular medications, are present in this patient 2, 3, 7
• If troponin is elevated with ST-segment changes, the patient has NSTEMI requiring invasive strategy within 24-48 hours 7
• If GRACE score >140, the patient is at very high risk requiring early invasive approach 7

Disposition Decision

• Admit to hospital with continuous cardiac monitoring if troponin elevation is detected, ECG shows ischemic changes, or high-risk features are present 7, 1, 2, 3
• Invasive strategy should be considered immediately if the patient is hemodynamically unstable or in cardiogenic shock, or early (24-48 hours) if elevated troponin, dynamic ECG changes, or GRACE score >140 are present 7