Management of Acute Coronary Syndrome
Immediate Assessment (Within 10 Minutes)
Obtain a 12-lead ECG within 10 minutes of presentation and measure high-sensitivity cardiac troponin immediately—these two tests form the cornerstone of ACS diagnosis and must not be delayed. 1, 2, 3
ECG interpretation determines your immediate pathway:
Establish IV access, place on continuous cardiac monitoring, and check oxygen saturation 1, 4
Draw blood immediately for: high-sensitivity troponin, complete blood count, basic metabolic panel (including creatinine), glucose, and coagulation studies 1, 4
Immediate Medical Therapy (Start Before Diagnostic Confirmation)
Administer aspirin 162-325 mg immediately (chewed, non-enteric coated) unless the patient has active gastrointestinal bleeding or documented aspirin allergy. 1, 2, 4
Oxygen: Only if oxygen saturation <90% or respiratory distress—routine oxygen in uncomplicated cases lacks evidence of benefit 1, 2
Nitroglycerin: 0.4 mg sublingual every 5 minutes (up to 3 doses) for ongoing chest pain, unless systolic BP <90 mmHg or suspected right ventricular infarction 2
Morphine: Reserved for severe, persistent chest pain unresponsive to nitroglycerin (use cautiously as it may delay antiplatelet absorption) 1
STEMI Management Pathway
For STEMI, achieve primary PCI within 120 minutes of first medical contact—this reduces mortality from 9% to 7%. 5
If PCI cannot be achieved within 120 minutes: Administer fibrinolytic therapy (alteplase, reteplase, or tenecteplase at full dose for patients <75 years; half dose for ≥75 years), then transfer for PCI within 24 hours 5
Do not delay reperfusion for additional diagnostic testing unless it would immediately change management 1
NSTE-ACS Management Pathway
Serial troponin strategy:
- Repeat high-sensitivity troponin at 1-2 hours after initial sample 1, 2
- If using conventional troponin assays, repeat at 3-6 hours 1, 2
- Dynamic changes (rise or fall) with at least one value above the 99th percentile confirms NSTEMI 1, 3
Risk stratification determines timing of invasive strategy:
Immediate invasive strategy (<2 hours): Ongoing refractory chest pain, hemodynamic instability, cardiogenic shock, life-threatening arrhythmias, or mechanical complications 1, 2
Early invasive strategy (within 24-48 hours): Elevated troponin, dynamic ECG changes, GRACE score indicating high risk, diabetes, renal insufficiency, reduced LV function, or prior PCI/CABG 1, 5
Antithrombotic therapy for confirmed NSTE-ACS:
- Dual antiplatelet therapy: Aspirin plus P2Y12 inhibitor (ticagrelor or prasugrel preferred over clopidogrel) 1, 3
- Anticoagulation: Fondaparinux, enoxaparin, bivalirudin, or unfractionated heparin 1, 3
- Beta-blocker: Unless contraindicated (heart failure, bradycardia, hypotension, or severe reactive airway disease) 1, 3
Critical Pitfalls to Avoid
Do not rely on a single troponin measurement—the "troponin-blind" interval exists where initial troponin may be negative despite ongoing MI 2
Women and elderly patients frequently present with atypical symptoms (dyspnea, nausea, fatigue without chest pain)—maintain high suspicion 3, 5
Troponin results should be available within 60 minutes of blood draw to avoid treatment delays 1
Do not withhold beta-blockers reflexively in COPD patients—cardioselective agents are safe in most cases and reduce mortality 4
Long-Term Management (Before Discharge)
Initiate high-intensity statin therapy immediately unless contraindicated 1
ACE inhibitor: For all patients with LVEF ≤40%, heart failure, hypertension, or diabetes (ARB if ACE inhibitor not tolerated) 1
Beta-blocker: Continue in all patients with LVEF ≤40% 1
Mineralocorticoid receptor antagonist (eplerenone): For patients with LVEF ≤35% and either heart failure or diabetes, without significant renal dysfunction or hyperkalemia 1
Lifestyle counseling: Smoking cessation, cardiac rehabilitation enrollment, dietary modification 1
Blood pressure goal: Diastolic <90 mmHg (<85 mmHg in diabetics) 1