What is the current management approach for a patient with acute coronary syndrome (ACS) in the emergency room (ER)?

Emergency Department Management of Acute Coronary Syndrome

All patients with suspected ACS require immediate physician assessment with a 12-lead ECG obtained within 10 minutes of first medical contact, followed by risk stratification to determine whether early invasive (angiography within 24 hours) or conservative management is appropriate. 1

Immediate Actions Upon Arrival

ECG and Initial Assessment

• Obtain 12-lead ECG within 10 minutes to differentiate STEMI from NSTE-ACS (unstable angina/NSTEMI) 2, 1
• Document chest pain characteristics: quality, duration, radiation, and associated symptoms including dyspnea, diaphoresis, nausea, and lightheadedness 1
• Assess hemodynamic stability, signs of heart failure (S3 gallop, pulmonary rales, new mitral regurgitation), and peripheral perfusion 1
• Draw high-sensitivity troponin on arrival and repeat at 3-6 hours; any elevation indicates high-risk pathway 1, 3

Oxygen Administration

• Do NOT routinely administer high-flow oxygen 2
• Guide oxygen therapy by arterial oxygen saturation only; use supplemental oxygen if SpO2 <90% 2

Antiplatelet Therapy (Start Immediately)

Aspirin

• Loading dose: 150-325 mg non-enteric formulation, chewed 1, 3
• Maintenance: 75-100 mg daily indefinitely 4, 1, 3
• If aspirin contraindicated, give clopidogrel alone 2

P2Y12 Inhibitor Selection

Ticagrelor is the preferred first-line P2Y12 inhibitor for NSTE-ACS 4, 3:

• Loading dose: 180 mg
• Maintenance: 90 mg twice daily for 12 months 4, 3
• Superior to clopidogrel in moderate-to-high risk patients with elevated troponin 3

Prasugrel as alternative 4:

• Loading dose: 60 mg
• Maintenance: 10 mg daily (reduce to 5 mg if age ≥75 years or weight <60 kg) 4

Clopidogrel if ticagrelor/prasugrel unavailable or contraindicated 5:

• Loading dose: 300 mg
• Maintenance: 75 mg daily 5

Anticoagulation (Start Immediately)

Choose ONE of the following based on clinical scenario 4, 3:

Fondaparinux (Preferred for Conservative Management)

• 2.5 mg subcutaneously once daily 4, 3
• Best efficacy-safety profile for medical management 4
• Caveat: Requires addition of UFH or bivalirudin during PCI 3

Enoxaparin (Preferred if Early Invasive Strategy Planned)

• 1 mg/kg subcutaneously every 12 hours 4, 3
• Adjust for renal impairment 4
• At least as effective as UFH with easier administration 4

Unfractionated Heparin

• Weight-adjusted IV bolus followed by continuous infusion (aPTT target 1.5-2.5 times control) 4
• Use if LMWH or fondaparinux unavailable, or if CABG planned within 24 hours 2

Risk Stratification and Invasive Strategy Decision

High-Risk Criteria (Requires Early Invasive Strategy)

Proceed to angiography within 24 hours if ANY of the following 2, 1, 3:

• New or presumed new ST-segment depression 2
• Elevated troponin I or T 2, 3
• GRACE risk score >140 1, 3
• Recurrent angina/ischemia at rest or with minimal activity despite medical therapy 2
• Heart failure signs (S3 gallop, pulmonary edema, worsening rales, new/worsening mitral regurgitation) 2
• Hemodynamic instability 2
• Sustained ventricular tachycardia 2
• PCI within last 6 months 2
• Previous CABG 2

Immediate angiography (<2 hours) if 2, 3:

• Cardiogenic shock 2, 3
• Hemodynamic instability 3

Low-Risk Criteria (Conservative Strategy Acceptable)

GRACE score <109 AND no high-risk features 4:

• Admit for serial ECGs and troponins 2
• Continue dual antiplatelet therapy and anticoagulation 4
• Perform stress testing; proceed to angiography only if significant reversible ischemia demonstrated 4

Additional Medical Therapy

Beta-Blockers

• Initiate early if ongoing ischemic symptoms without contraindications (heart failure, hypotension, bradycardia, heart block) 4

Nitrates

• Use for ongoing chest pain, uncontrolled hypertension, or heart failure signs 4
• Sublingual nitroglycerin 0.4 mg every 5 minutes up to 3 doses, then IV infusion if needed 2

High-Intensity Statin

• Start immediately regardless of baseline cholesterol 4, 3
• Provides plaque stabilization and anti-inflammatory effects beyond LDL lowering 3
• Atorvastatin 80 mg or rosuvastatin 40 mg daily 3

Glycoprotein IIb/IIIa Inhibitors

Do NOT routinely give upstream GP IIb/IIIa inhibitors 3:

• Increase bleeding without ischemic benefit 3
• Consider eptifibatide or tirofiban only in high-risk conservative strategy patients with continuing ischemia or elevated troponin 2
• Never use abciximab unless PCI is planned 2

Special Populations

Cardiogenic Shock

• Emergency coronary angiography indicated 2
• Emergency PCI of culprit lesion only; do NOT routinely revascularize non-culprit lesions immediately 2
• Emergency CABG if anatomy not amenable to PCI 2
• Emergency echocardiography to assess LV function, valvular disease, and mechanical complications 2

Renal Impairment

• Adjust anticoagulant and antiplatelet doses according to creatinine clearance 4, 1
• Use low- or iso-osmolar contrast if angiography performed 4

Elderly (≥75 years)

• Apply same diagnostic and therapeutic strategies 4, 1
• Reduce prasugrel to 5 mg daily if used 4
• Adjust antithrombotic dosing based on renal function and bleeding risk 4, 1

Atrial Fibrillation Requiring Oral Anticoagulation

• Triple therapy (aspirin + clopidogrel + OAC) for acute phase only (up to 1 week) 4
• Transition to dual therapy (OAC + clopidogrel) after acute phase 4

Common Pitfalls to Avoid

• Do not delay ECG: Must be obtained within 10 minutes, not after "complete history and physical" 1
• Do not give routine oxygen: Only if hypoxic (SpO2 <90%) 2
• Do not use enoxaparin if CABG planned within 24 hours: Switch to UFH 2
• Do not give abciximab in ED: Only at time of PCI 2, 3
• Do not perform immediate multivessel PCI in cardiogenic shock: Culprit lesion only 2
• Do not withhold invasive strategy in elderly: Same benefit as younger patients 4, 1

Monitoring and Disposition

• Serial ECGs and troponins for any patient with initially negative biomarkers or nondiagnostic ECG 2
• Patients can evolve from low to high risk; reassess frequently 2
• High-risk patients require intensive monitoring and cardiology consultation for angiography timing 4, 1
• Low-risk patients with negative serial troponins and stress testing can be discharged with cardiology follow-up 2