What is the initial management of acute coronary syndrome?

Initial Management of Acute Coronary Syndrome

Obtain a 12-lead ECG within 10 minutes of presentation and immediately administer aspirin 150-300 mg (or 250-500 mg per older protocols) along with parenteral anticoagulation while initiating continuous cardiac monitoring. 1, 2

Immediate Assessment (0-10 Minutes)

ECG and Vital Signs:

• Acquire and interpret a 12-lead ECG by a trained clinician within 10 minutes to differentiate STEMI from NSTE-ACS 1, 2
• Start continuous multi-lead ECG monitoring for arrhythmias and dynamic ST-segment changes 1, 2
• Assess hemodynamic stability: blood pressure, heart rate, presence of pulmonary rales (Killip classification), and signs of cardiogenic shock 1, 2

Initial Blood Work:

• Draw high-sensitivity cardiac troponin (hs-cTn) immediately at presentation (time zero) 1, 2
• Obtain hemoglobin/hematocrit to detect anemia, serum creatinine for renal function, platelet count, and blood glucose 1, 3
• Results should be available within 60 minutes 1

Immediate Pharmacological Treatment

Antiplatelet Therapy:

• Administer aspirin 150-300 mg loading dose orally (or 250-500 mg per older protocols) immediately to all patients without contraindications 1, 2
• Aspirin should continue at 75-325 mg daily 2, 4

Anticoagulation:

• Initiate parenteral anticoagulation with either low molecular weight heparin (LMWH) or unfractionated heparin immediately 1, 2, 3
• Continue anticoagulation until revascularization or hospital discharge 2

Anti-Ischemic Therapy:

• Give sublingual or intravenous nitrates for persistent or recurrent chest pain 1, 2, 3
• Initiate beta-blockers unless contraindicated by hypotension, bradycardia, or acute heart failure 1, 2, 3
• Consider calcium channel blockers only if beta-blockers are contraindicated or not tolerated 1, 2

Risk Stratification and P2Y12 Inhibitor Selection (Within First Hours)

Repeat Troponin Measurement:

• Repeat hs-cTn at 1-2 hours after initial sample for rapid rule-in/rule-out protocols 1, 2
• If using conventional troponin assays, repeat at 3-6 hours 1

P2Y12 Inhibitor Administration:

The timing and choice of P2Y12 inhibitor depends on your invasive strategy and patient characteristics:

For patients proceeding to early invasive strategy (<24 hours):

• Ticagrelor (180 mg loading dose, then 90 mg twice daily) is preferred for all moderate-to-high risk patients, including those with elevated troponin, regardless of whether they received prior clopidogrel 1, 2
• Prasugrel (60 mg loading dose, then 10 mg daily) is recommended for patients proceeding to PCI, but only after coronary anatomy is known in UA/NSTEMI patients 1, 4
• Prasugrel is contraindicated in patients with prior stroke/TIA and generally not recommended in patients ≥75 years old or <60 kg body weight 4
• For patients <60 kg, if prasugrel is used, reduce maintenance dose to 5 mg daily 4

For patients managed conservatively:

• Administer ticagrelor (preferred) or clopidogrel (300-600 mg loading dose, then 75 mg daily) once NSTEMI diagnosis is established 1

Critical Caveat: In NSTEMI patients, do not administer prasugrel until coronary anatomy is established at catheterization, as urgent CABG carries substantial bleeding risk 4. The FDA label specifically notes no clear benefit was observed when prasugrel was given prior to diagnostic angiography compared to at time of PCI, but bleeding risk increased with early administration 4.

Invasive Strategy Timing

Immediate invasive strategy (<2 hours) for very high-risk patients with: 1, 2

• Hemodynamic instability or cardiogenic shock
• Recurrent or refractory chest pain despite medical treatment
• Life-threatening arrhythmias or cardiac arrest
• Mechanical complications of MI
• Acute heart failure with refractory angina or ST-segment deviation

Early invasive strategy (<24 hours) for high-risk patients with: 1, 2

• Rise or fall in cardiac troponin compatible with MI
• Dynamic ST- or T-wave changes (symptomatic or silent)
• GRACE score >140

Invasive strategy (<72 hours) for intermediate-risk patients with: 1, 2

• Diabetes mellitus
• Renal insufficiency (eGFR <60 mL/min/1.73 m²)
• LVEF <40% or congestive heart failure
• GRACE risk score 109-140
• Early post-infarction angina, recent PCI, or prior CABG

GP IIb/IIIa Inhibitors

For very high-risk patients proceeding to angiography:

• Initiate GP IIb/IIIa receptor blocker while preparing for catheterization 1
• Continue for 12 hours (abciximab) or 24 hours (tirofiban, eptifibatide) after PCI if performed 1

Additional Immediate Measures

Echocardiography:

• Perform urgent echocardiography for patients with cardiogenic shock, hemodynamic instability, or suspected mechanical complications 1, 2
• Use to evaluate regional wall motion abnormalities and rule out differential diagnoses 1

High-Intensity Statin:

• Initiate high-intensity statin therapy as early as possible during admission 2

Common Pitfalls to Avoid

• Never delay ECG beyond 10 minutes of presentation—this leads to missed diagnosis and delayed reperfusion 2, 3
• Do not wait for troponin results before initiating aspirin and anticoagulation in high-risk patients 2, 3
• Do not give prasugrel before knowing coronary anatomy in NSTE-ACS patients due to bleeding risk if urgent CABG is needed 4
• Do not miss atypical presentations in women, elderly patients, and those with diabetes who may present without classic chest pain 2
• Discontinue prasugrel at least 7 days prior to any surgery when possible 4
• Do not delay transfer for troponin testing in office settings—send patient to ED immediately 3