What is the initial management for a patient presenting with Acute Coronary Syndrome (ACS)?

Initial Management of Acute Coronary Syndrome (ACS)

All patients presenting with suspected ACS require immediate ECG within 10 minutes, aspirin 150-300mg loading dose, continuous cardiac monitoring, high-sensitivity troponin measurement at 0 and 1-3 hours, and dual antiplatelet therapy with a P2Y12 inhibitor once diagnosis is confirmed. 1, 2

Immediate Assessment (First 10 Minutes)

• Obtain 12-lead ECG within 10 minutes of presentation to differentiate STEMI from non-ST-elevation ACS (NSTE-ACS), as this determines the urgency of invasive management 1, 2, 3
• Administer aspirin 150-300mg loading dose immediately to all patients unless contraindicated—do not wait for troponin results in high-risk patients 1, 2, 4
• Initiate continuous cardiac rhythm monitoring to detect life-threatening arrhythmias 1, 2
• Assess vital signs including systolic blood pressure, heart rate, oxygen saturation, and evaluate for signs of hemodynamic instability, cardiogenic shock, or acute heart failure 1, 2

Diagnostic Workup

• Collect blood samples for high-sensitivity cardiac troponin at presentation (0h) and after 1-3 hours using validated rapid rule-in/rule-out algorithms 1, 4
• Perform echocardiography to evaluate left ventricular function, assess for regional wall motion abnormalities, and exclude mechanical complications or alternative diagnoses 1, 4
• Calculate GRACE score for risk stratification to determine timing of invasive strategy 4

Immediate Pharmacological Management

Antiplatelet Therapy

• Continue aspirin 75-100mg daily after the loading dose 4
• Add a P2Y12 inhibitor for dual antiplatelet therapy (DAPT) for 12 months unless contraindicated 1, 2, 4:
  • Ticagrelor is preferred: 180mg loading dose, then 90mg twice daily 4
  • Prasugrel alternative: 60mg loading dose, then 10mg daily (reduce to 5mg daily if weight <60kg) 4, 5
  • Important timing consideration: In NSTE-ACS patients undergoing angiography within 24 hours, consider delaying P2Y12 inhibitor loading until coronary anatomy is known to avoid increased bleeding risk if urgent CABG is needed 5

Anticoagulation

• Initiate parenteral anticoagulation immediately with one of the following 1, 2, 4:
  • Fondaparinux 2.5mg subcutaneously once daily (preferred for medically managed patients) 4
  • Enoxaparin 1mg/kg subcutaneously every 12 hours (alternative) 4
  • Unfractionated heparin (60 IU/kg bolus, then 12 IU/kg/hour infusion for patients proceeding directly to PCI) 4
• Continue anticoagulation until revascularization or hospital discharge 1

Additional Medical Therapy

• Initiate high-intensity statin therapy immediately (atorvastatin 80mg daily) regardless of baseline cholesterol levels, with target LDL-C <70 mg/dL 1, 2, 4
• Administer sublingual or intravenous nitrates for ongoing chest pain 1
• Initiate beta-blockers in the absence of contraindications (hypotension, bradycardia, acute heart failure) 1
• Consider calcium channel blockers only for patients with contraindications to beta-blockers 1

Risk-Stratified Invasive Strategy Timing

Very High-Risk: Immediate Angiography (<2 hours) 1, 2, 4

• Hemodynamic instability or cardiogenic shock
• Recurrent or ongoing chest pain refractory to medical therapy
• Life-threatening arrhythmias
• Mechanical complications of MI
• Acute heart failure

High-Risk: Early Angiography (<24 hours) 1, 2, 4

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

Intermediate-Risk: Invasive Strategy (<72 hours) 1, 4

• Diabetes mellitus
• Renal insufficiency
• Left ventricular ejection fraction <40%
• Congestive heart failure

Revascularization Approach

• Use radial access as the standard approach for coronary angiography 2
• Drug-eluting stents are recommended over bare-metal stents for any PCI 2
• Base revascularization strategy on clinical status, comorbidities, and SYNTAX score 2

Long-Term Secondary Prevention (Post-Discharge)

• Continue DAPT for 12 months, then transition to aspirin monotherapy indefinitely 2, 4
• Continue beta-blockers, especially if LVEF ≤40% 2
• Initiate ACE inhibitors or ARBs for LVEF ≤40%, heart failure, hypertension, or diabetes 2

Critical Pitfalls to Avoid

• Delaying ECG beyond 10 minutes leads to missed diagnosis and delayed treatment—this is the single most important time-sensitive intervention 1
• Waiting for troponin results before initiating antiplatelet therapy in high-risk patients causes treatment delays and worse outcomes 1
• Administering P2Y12 inhibitor loading dose before coronary anatomy is known in NSTE-ACS patients increases bleeding risk if urgent CABG is required, with no clear benefit demonstrated 5
• Failing to recognize atypical presentations particularly in women, elderly, and diabetic patients who may present with dyspnea, nausea, or fatigue rather than chest pain 1
• Discontinuing antiplatelet therapy prematurely in the first few weeks after ACS substantially increases risk of subsequent cardiovascular events 5
• Using prasugrel in patients ≥75 years or with prior stroke/TIA—prasugrel is contraindicated in patients with prior stroke/TIA and generally not recommended in those ≥75 years due to increased fatal and intracranial bleeding risk 5