What is the treatment for Acute Coronary Syndrome (ACS)?

Treatment of Acute Coronary Syndrome (ACS)

All patients with suspected ACS should receive immediate aspirin (150-300 mg loading dose, then 75-100 mg daily) and dual antiplatelet therapy with a P2Y12 inhibitor for at least 12 months, combined with parenteral anticoagulation and risk-stratified invasive management based on presentation type (STEMI vs NSTE-ACS) and timing. 1, 2

Immediate Medical Management

Antiplatelet Therapy

• Aspirin should be administered immediately to all patients with suspected ACS at a loading dose of 150-300 mg, followed by 75-100 mg daily maintenance 1, 2
• Add a P2Y12 inhibitor for dual antiplatelet therapy (DAPT) for 12 months unless contraindicated by high bleeding risk 1, 2
• Ticagrelor (180 mg loading, 90 mg twice daily) is the preferred P2Y12 inhibitor for moderate to high-risk patients, including those with elevated troponins 1
• Prasugrel (60 mg loading, 10 mg daily) is preferred over clopidogrel in patients undergoing PCI, but is contraindicated in patients with prior stroke/TIA and generally not recommended in patients ≥75 years due to increased bleeding risk 1, 3
• Clopidogrel (300-600 mg loading, 75 mg daily) is an alternative when ticagrelor or prasugrel are contraindicated 1, 4

Anticoagulation

• Parenteral anticoagulation is mandatory for all ACS patients with options including unfractionated heparin (UFH), low-molecular-weight heparin (LMWH), fondaparinux, or bivalirudin 2, 5, 4
• Enoxaparin may be considered as an alternative to UFH in prehospital settings for STEMI patients being transferred for primary PCI 1

Symptom Management

• Nitroglycerin (sublingual then IV) should be given for relief of ischemia and chest pain 2
• Morphine is indicated for persistent severe chest pain or acute pulmonary congestion 2
• Beta-blockers should be administered for symptom control and to reduce myocardial oxygen demand, particularly in patients with preserved left ventricular function 2, 6
• Supplementary oxygen should be withheld in normoxic patients (Class IIb recommendation) 1

Risk Stratification and Invasive Strategy Timing

STEMI Management

• Primary PCI within 120 minutes of first medical contact is the goal for all STEMI patients 1, 7
• If PCI cannot be achieved within 120 minutes, fibrinolytic therapy should be administered (alteplase, reteplase, or tenecteplase at full dose for patients <75 years; half dose for ≥75 years), followed by transfer for PCI within 24 hours 1, 7
• For STEMI presenting within 2 hours of symptom onset, immediate fibrinolysis may be considered if expected delay to PCI exceeds 60 minutes 1
• Prehospital fibrinolysis is reasonable when transport times exceed 30 minutes and in-hospital fibrinolysis is the alternative 1
• Combined fibrinolytic therapy followed by immediate PCI is not recommended (Class III: Harm) 1

NSTE-ACS Management

The timing of invasive strategy depends on risk stratification 1, 2:

Immediate invasive strategy (<2 hours) for very high-risk patients with: 1, 2

• Hemodynamic instability or cardiogenic shock
• Recurrent or refractory chest pain despite medical treatment
• Life-threatening arrhythmias or cardiac arrest
• Mechanical complications of MI
• Acute heart failure with refractory angina or ST deviation

Early invasive strategy (<24 hours) for high-risk patients with: 1, 2

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

Invasive strategy (<72 hours) for intermediate-risk patients with: 1, 2

• 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 score 109-140

Revascularization Strategy

• Complete revascularization is recommended in patients with STEMI or NSTE-ACS 1
• Radial approach is preferred over femoral approach to reduce bleeding, vascular complications, and death 1
• Intracoronary imaging should guide PCI in patients with complex coronary lesions 1
• For STEMI with multivessel disease, PCI of nonculprit lesions can be performed in a single procedure or staged, with preference toward single-procedure multivessel PCI 1
• In cardiogenic shock, emergency revascularization of the culprit vessel is indicated, but routine PCI of non-infarct-related arteries at the same time is not recommended 1

Special Considerations

Bleeding Risk Management

• Proton pump inhibitors are recommended for patients at risk of gastrointestinal bleeding 1, 6, 4
• In patients weighing <60 kg, consider reducing prasugrel maintenance dose to 5 mg daily due to increased bleeding risk 3
• DAPT de-escalation to ticagrelor monotherapy ≥1 month after PCI is recommended in patients who have tolerated DAPT with ticagrelor 1, 5
• In patients requiring long-term anticoagulation, discontinue aspirin 1-4 weeks after PCI and continue P2Y12 inhibitor (preferably clopidogrel) 1

CABG Considerations

• Discontinue prasugrel at least 7 days prior to CABG when possible 3
• Do not start prasugrel in patients likely to undergo urgent CABG 3

Cardiogenic Shock

• Microaxial flow pump use is reasonable in selected patients with cardiogenic shock related to acute MI to reduce death, though bleeding, limb ischemia, and renal failure risks are higher 1

Long-Term Secondary Prevention

Pharmacotherapy

• High-intensity statin therapy should be initiated as early as possible (within 1-4 days) and continued long-term, targeting LDL-C reduction ≥50% and LDL-C <1.4 mmol/L (<55 mg/dL) 1, 2, 6
• ACE inhibitors are recommended for patients with LVEF ≤40%, heart failure, hypertension, or diabetes 1, 2, 6
• Angiotensin receptor blockers (ARBs) are alternatives for ACE inhibitor-intolerant patients 1, 2
• Beta-blockers are recommended in patients with reduced LVEF (≤40%) or heart failure 1, 2, 6
• Mineralocorticoid receptor antagonists (preferably eplerenone) are recommended for patients with LVEF ≤35% and either heart failure or diabetes 2

Lifestyle Modifications

• Smoking cessation is highly effective to reduce morbidity and mortality 1, 8
• Regular aerobic exercise training three or more times weekly for 30 minutes per session is recommended 1
• Cardiac rehabilitation program enrollment should be offered to all ACS patients 1, 2, 6

Common Pitfalls

• Avoid premature discontinuation of DAPT, particularly in the first few weeks after ACS, as this increases risk of subsequent cardiovascular events 3
• Do not administer prasugrel to patients with prior stroke/TIA (absolute contraindication) 3
• Monitor for thrombotic thrombocytopenic purpura (TTP) in patients on prasugrel, which can occur after brief exposure (<2 weeks) and requires urgent plasmapheresis 3
• Avoid routine supplementary oxygen in normoxic patients, as its usefulness has not been established 1
• Do not combine immediate fibrinolysis with immediate PCI in STEMI patients, as this increases harm without benefit 1