What is the management of Acute Coronary Syndrome (ACS)?

Management of Acute Coronary Syndrome (ACS)

The management of Acute Coronary Syndrome requires immediate risk stratification followed by a time-sensitive invasive strategy based on risk category, dual antiplatelet therapy, anticoagulation, and secondary prevention measures to reduce mortality and morbidity.

Initial Diagnosis and Risk Stratification

• Obtain 12-lead ECG within 10 minutes of first medical contact to classify ACS as either:

  • ST-segment elevation (STEMI) - requires immediate reperfusion therapy
  • Non-ST-segment elevation (NSTEMI/UA) - requires risk stratification 1, 2

• Laboratory assessment should include:

  • High-sensitivity cardiac troponin (0h/1h protocol recommended)
  • Complete blood count (to detect anemia)
  • Renal function tests 1

• Echocardiography to evaluate left ventricular function and rule out other causes 1

Risk-Based Invasive Strategy

Immediate Invasive Strategy (<2 hours)

For patients with any of these very-high-risk criteria:

• Hemodynamic instability or cardiogenic shock
• Recurrent/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/T-wave changes, particularly with intermittent ST elevation 1, 2

Early Invasive Strategy (<24 hours)

For patients with any of these high-risk criteria:

• Rise/fall in cardiac troponin compatible with MI
• Dynamic ST/T-wave changes (symptomatic or silent)
• GRACE score >140 1

Invasive Strategy (<72 hours)

For patients with intermediate-risk criteria:

• Diabetes mellitus
• Renal insufficiency (eGFR <60 mL/min/1.73 m²)
• LVEF <40% or heart failure
• Early post-infarction angina
• Recent PCI or prior CABG
• GRACE score >109 and <140 1

Pharmacological Management

Antiplatelet Therapy

1. Aspirin: 150-300mg loading dose followed by 75-100mg daily maintenance indefinitely 1, 2

2. P2Y12 inhibitor for 12 months (in addition to aspirin) unless contraindicated:

   • Ticagrelor (preferred): 180mg loading dose, then 90mg twice daily for moderate-high risk patients
   • Prasugrel: 60mg loading dose, then 10mg daily for patients proceeding to PCI
   • Clopidogrel: 300-600mg loading dose, then 75mg daily for patients who cannot receive ticagrelor/prasugrel 1, 2, 3

   Important contraindications:

   • Prasugrel: Previous intracranial hemorrhage, previous stroke/TIA, ongoing bleeding, generally not recommended for patients ≥75 years or <60kg 1, 3
   • Ticagrelor: Previous intracranial hemorrhage, ongoing bleeding 1

Anticoagulation

Choose one of the following:

• Unfractionated heparin: 60-70 IU/kg IV bolus, followed by 12-15 IU/kg/h infusion
• Enoxaparin: 1mg/kg subcutaneously twice daily
• Fondaparinux: 2.5mg daily subcutaneously (not for PCI support due to catheter thrombosis risk)
• Bivalirudin: Alternative to UFH in patients undergoing PCI 2

Additional Medications

• Beta-blockers: If tachycardic or hypertensive without signs of heart failure
• Nitrates: For symptom relief
• High-intensity statins: Start as early as possible 1, 2
• ACE inhibitors/ARBs: Particularly for patients with LV dysfunction, heart failure, diabetes, or hypertension 2

Special Considerations

Timing of P2Y12 Inhibitor Administration

• For NSTEMI/UA: After coronary anatomy is established
• For STEMI presenting within 12 hours: At time of diagnosis 3

Bleeding Risk Management

• Consider lower maintenance dose (5mg) of prasugrel in patients <60kg 3
• Avoid prasugrel in patients with unknown coronary anatomy 1
• Discontinue P2Y12 inhibitors at least 5-7 days before CABG if possible 2, 3
• Consider proton pump inhibitors in patients at higher risk of gastrointestinal bleeding 4

Elderly Patients (≥75 years)

• Generally avoid prasugrel due to increased bleeding risk
• Consider prasugrel only in high-risk situations (diabetes or prior MI) 3

Secondary Prevention

• High-intensity statin therapy: Start as early as possible and maintain long-term 1
• Risk factor modification: Smoking cessation, blood pressure control, diabetes management, dietary modification, and regular physical activity 2
• Cardiac rehabilitation: Improves outcomes and reduces mortality 5
• Annual influenza vaccination: Reduces mortality in post-MI patients 5

Follow-up

• Schedule follow-up appointments 1-2 weeks for high-risk patients and 2-6 weeks for lower-risk patients 2
• Monitor for recurrent symptoms, medication adherence, and side effects

By following this evidence-based approach to ACS management, focusing on rapid diagnosis, risk stratification, appropriate invasive strategy timing, and optimal medical therapy, patient outcomes can be significantly improved with reduced mortality and morbidity.