Management of Acute Coronary Syndrome (ACS)
The management of Acute Coronary Syndrome requires rapid diagnosis, risk stratification, and implementation of an appropriate invasive strategy based on risk level, along with optimal antiplatelet and anticoagulant therapy to reduce mortality and morbidity. 1, 2
Initial Assessment and Diagnosis
- Obtain a 12-lead ECG within 10 minutes of presentation to differentiate between ST-segment elevation myocardial infarction (STEMI) and non-ST-segment elevation ACS (NSTE-ACS) 2
- Collect blood samples for high-sensitivity cardiac troponin measurement at presentation (0h) and after 1-3 hours to rapidly rule-in or rule-out myocardial infarction 1, 2
- Perform echocardiography to evaluate regional and global left ventricular function and rule out differential diagnoses 1
- Monitor cardiac rhythm continuously for detection of arrhythmias 2
- Assess vital signs with particular attention to hemodynamic stability and signs of heart failure 2
Risk Stratification and Invasive Strategy
Risk stratification is crucial for determining the timing of invasive management:
Immediate invasive strategy (<2h) for patients with 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 (<24h) for patients with 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
Invasive strategy (<72h) for patients with 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
Pharmacological Management
Antiplatelet Therapy
- Administer aspirin 150-300mg loading dose immediately to all patients without contraindications 2
- Add a P2Y12 inhibitor for 12 months unless contraindicated due to excessive bleeding risk 1:
- Ticagrelor (180 mg loading dose, 90 mg twice daily) is recommended for all patients at moderate to high risk of ischemic events, regardless of initial treatment strategy 1, 3
- Prasugrel (60 mg loading dose, 10 mg daily dose) is recommended for patients proceeding to PCI without contraindications (avoid in patients with history of stroke/TIA, age ≥75 years, or weight <60 kg) 1, 4
- Clopidogrel (300-600 mg loading dose, 75 mg daily dose) is recommended for patients who cannot receive ticagrelor or prasugrel or who require oral anticoagulation 1, 3
Anticoagulation
- Administer parenteral anticoagulation with low molecular weight heparin (LMWH) or unfractionated heparin 2, 5
- Continue anticoagulation until revascularization is performed or hospital discharge 2
Other Medical Therapy
- Administer sublingual or intravenous nitrates for ongoing chest pain 2
- Initiate 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
- Start high-intensity statin therapy as early as possible and maintain it long term 1
Special Considerations
- In patients with NSTE-ACS requiring oral anticoagulation, carefully balance the risk of bleeding against the risk of recurrent ischemic events 3, 5
- For patients weighing <60 kg on prasugrel, consider lowering the maintenance dose to 5 mg due to increased bleeding risk 4
- Consider GP IIb/IIIa inhibitors for high-risk patients with elevated troponins undergoing PCI 1
Common Pitfalls to Avoid
- Delaying ECG beyond 10 minutes of presentation can lead to missed diagnosis and delayed treatment 2, 6
- Administering prasugrel to patients with unknown coronary anatomy or those with history of stroke/TIA 1, 4
- Waiting for troponin results before initiating antiplatelet therapy in high-risk patients 2
- Failing to recognize atypical presentations of ACS, particularly in women, elderly, and diabetic patients 2, 6