Initial Treatment for Acute Coronary Syndrome
The initial treatment for acute coronary syndrome should include immediate administration of aspirin (150-300mg loading dose), initiation of a P2Y12 inhibitor (preferably ticagrelor or prasugrel), parenteral anticoagulation, and risk stratification to determine timing of invasive management. 1, 2
Immediate Assessment and Management
- Obtain a 12-lead ECG within 10 minutes of presentation to differentiate between STEMI and NSTE-ACS 2
- Collect blood samples for high-sensitivity cardiac troponin measurement at presentation (0h) and after 1-3 hours for rapid diagnosis 1, 2
- Administer aspirin 150-300mg loading dose immediately to all patients without contraindications 2
- Initiate a P2Y12 inhibitor in addition to aspirin:
- Ticagrelor (180mg loading dose, 90mg twice daily) is recommended for moderate to high-risk patients 1
- Prasugrel (60mg loading dose, 10mg daily) is recommended for patients proceeding to PCI without contraindications 1
- Clopidogrel (300-600mg loading dose, 75mg daily) for patients who cannot receive ticagrelor or prasugrel or who require oral anticoagulation 1, 3
- Administer parenteral anticoagulation with low molecular weight heparin or unfractionated heparin 2
- Provide sublingual or intravenous nitrates for ongoing chest pain 2
- Monitor cardiac rhythm continuously for detection of arrhythmias 2
Risk Stratification for Invasive Management
The timing of invasive management depends on risk assessment:
Immediate Invasive Strategy (<2 hours)
For patients with any of these very high-risk criteria:
- Hemodynamic instability or cardiogenic shock
- Recurrent or ongoing chest pain refractory to medical treatment
- Life-threatening arrhythmias or cardiac arrest
- Mechanical complications of MI
- Acute heart failure with refractory angina or ST deviation
- Recurrent dynamic ST- or T-wave changes, particularly with intermittent ST elevation 1
Early Invasive Strategy (<24 hours)
For patients with any of these high-risk criteria:
- Rise or fall in cardiac troponin compatible with MI
- Dynamic ST- or T-wave changes (symptomatic or silent)
- GRACE score >140 1
Standard Invasive Strategy (<72 hours)
For patients with any of these intermediate-risk criteria:
- Diabetes mellitus
- Renal insufficiency (eGFR <60 mL/min/1.73 m²)
- LVEF <40% or congestive heart failure
- Early post-infarction angina
- Recent PCI or prior CABG
- GRACE risk score >109 and <140 1
Additional Important Treatments
- Perform echocardiography to evaluate regional and global LV function and rule out differential diagnoses 1
- Initiate high-intensity statin therapy as early as possible 1
- Consider beta-blockers in the absence of contraindications (hypotension, bradycardia, acute heart failure) 2
- Consider calcium channel blockers for patients with contraindications to beta-blockers 2
Common Pitfalls to Avoid
- Delaying ECG beyond 10 minutes of presentation can lead to missed diagnosis and delayed treatment 2, 4
- Administering prasugrel in patients with unknown coronary anatomy is not recommended 1
- Waiting for troponin results before initiating antiplatelet therapy in high-risk patients can delay critical treatment 2
- Failing to recognize atypical presentations of ACS, particularly in women, elderly, and diabetic patients 2, 4
- Delaying reperfusion therapy in STEMI patients - primary PCI should be performed within 120 minutes when available, or fibrinolytic therapy should be administered if PCI is not accessible within this timeframe 4
Evidence on Efficacy
- Dual antiplatelet therapy with aspirin and clopidogrel has been shown to reduce the composite of cardiovascular death, MI, or stroke by 20% compared to aspirin alone in ACS patients 3
- Early invasive strategy in high-risk NSTE-ACS patients is associated with a reduction in death from 6.5% to 4.9% 4
- Timely reperfusion in STEMI patients with primary PCI within 120 minutes reduces mortality from 9% to 7% 4