What are the management guidelines for ST-Elevation Myocardial Infarction (STEMI)?

Management Guidelines for ST-Elevation Myocardial Infarction (STEMI)

Primary percutaneous coronary intervention (PCI) is the preferred reperfusion strategy for all STEMI patients presenting within 12 hours of symptom onset, and should be performed as rapidly as possible with a target door-to-balloon time of less than 90 minutes. 1, 2

Initial Assessment and Management

Immediate Interventions

• Administer aspirin 162-325 mg (chewable or non-enteric coated) immediately upon STEMI diagnosis 1, 2
• Administer a P2Y12 inhibitor loading dose as early as possible:
  • Clopidogrel 600 mg, OR
  • Prasugrel 60 mg (contraindicated in patients with history of stroke/TIA or weight <60 kg), OR
  • Ticagrelor 180 mg 1, 2, 3
• Initiate anticoagulation therapy:
  • Unfractionated heparin: 70-100 U/kg IV bolus if no planned GP IIb/IIIa inhibitor; 50-70 U/kg if planned GP IIb/IIIa inhibitor 2
  • Bivalirudin may be preferred in patients at high risk of bleeding 1, 2
• Administer supplemental oxygen if oxygen saturation <90% 1

Reperfusion Strategy Decision

1. Primary PCI (Class I, Level A) for:

   • Patients presenting within 12 hours of symptom onset 1
   • Patients with contraindications to fibrinolytic therapy regardless of time delay 1
   • Patients with cardiogenic shock or acute severe heart failure regardless of time delay 1

2. Fibrinolytic therapy if:

   • Primary PCI cannot be performed within 120 minutes of first medical contact 2
   • Patient presents within 12 hours of symptom onset 1

3. PCI after 12 hours is reasonable if:

   • Clinical and/or ECG evidence of ongoing ischemia between 12-24 hours after symptom onset (Class IIa, Level B) 1

Procedural Considerations for Primary PCI

Stent Selection

• Placement of a stent (bare-metal or drug-eluting) is recommended (Class I, Level A) 1
• Use bare-metal stents in patients with:
  • High bleeding risk
  • Inability to comply with 1 year of dual antiplatelet therapy
  • Anticipated invasive or surgical procedures within the next year 1
• Avoid drug-eluting stents in patients unable to tolerate or comply with prolonged DAPT (Class III: Harm) 1

Procedural Cautions

• Do not perform PCI of a non-infarct artery during primary PCI in hemodynamically stable patients (Class III: Harm) 1
• Do not use fondaparinux as the sole anticoagulant for primary PCI due to risk of catheter thrombosis (Class III: Harm) 1, 2

Post-PCI Antithrombotic Therapy

Antiplatelet Therapy

• Continue aspirin 81 mg daily indefinitely 1, 2
• Continue P2Y12 inhibitor for 1 year after stent placement:
  • Clopidogrel 75 mg daily, OR
  • Prasugrel 10 mg daily (5 mg if weight <60 kg), OR
  • Ticagrelor 90 mg twice daily 1, 2, 3

Anticoagulation

• Continue anticoagulation for a minimum of 48 hours and preferably for the duration of hospitalization (up to 8 days) 2

Management of Complications

Cardiogenic Shock

• Perform immediate angiography and PCI when indicated 1
• Initiate intra-aortic balloon counterpulsation if shock is not quickly reversed with pharmacological therapy 1
• Consider early revascularization (PCI or CABG) for patients <75 years with shock developing within 36 hours of MI 1
• Use intra-arterial monitoring 1
• Consider pulmonary artery catheter monitoring 1

Pulmonary Congestion

• Administer oxygen to maintain saturation >90% 1
• Give morphine sulfate 1
• Initiate ACE inhibitors within 24 hours (start with low dose, e.g., captopril 1-6.25 mg) unless systolic BP <100 mmHg 1
• Consider intra-aortic balloon pump for refractory pulmonary congestion 1

Post-Cardiac Arrest

• Initiate therapeutic hypothermia as soon as possible in comatose patients with STEMI and out-of-hospital cardiac arrest 1, 2
• Perform immediate angiography and PCI when indicated 1

Secondary Prevention

Pharmacological Therapy

• Initiate high-intensity statin therapy as early as possible 2
• Start beta-blockers within a few days if no contraindications 1
• Initiate ACE inhibitors within 24 hours for patients with:
  • Anterior infarction
  • Pulmonary congestion
  • LVEF <40% 1, 2
• Consider aldosterone blockade for patients with LVEF ≤40% and heart failure or diabetes 2
• Treat hypertension to target <140/90 mmHg (<130/80 mmHg for patients with diabetes or chronic kidney disease) 1
• Initiate hypoglycemic therapy to achieve HbA1c <7% in diabetic patients 1

Anticoagulation for Specific Indications

• Warfarin (INR 2.0-3.0) for patients with:
  • Persistent or paroxysmal atrial fibrillation
  • LV thrombus (for at least 3 months)
  • LV dysfunction with extensive regional wall-motion abnormalities 1

Lifestyle Modifications

• Encourage regular exercise (minimum 30 minutes daily or at least 3-4 times per week) 1
• Implement cardiac rehabilitation programs 1, 2
• Promote smoking cessation with appropriate support 2

Follow-up Assessment

• Perform echocardiography during hospitalization to assess:
  • Left and right ventricular function
  • Mechanical complications
  • Left ventricular thrombus 2

Common Pitfalls to Avoid

• Delaying primary PCI beyond recommended timeframes
• Using prasugrel in patients with history of stroke/TIA or weight <60 kg 3
• Discontinuing dual antiplatelet therapy prematurely, especially in the first few weeks after acute coronary syndrome 3
• Administering beta-blockers or calcium channel blockers to patients with frank cardiac failure 1
• Using short-acting dihydropyridine calcium channel blockers for hypertension 1