What is the treatment for Non-ST-Elevation Myocardial Infarction (NSTEMI)?

Treatment of Non-ST-Elevation Myocardial Infarction (NSTEMI)

The cornerstone of NSTEMI treatment includes dual antiplatelet therapy with aspirin plus a P2Y12 inhibitor (preferably ticagrelor), anticoagulation, and an early invasive approach for high-risk patients, along with adjunctive medical therapy including statins, beta-blockers, and ACE inhibitors. 1

Initial Management

Antiplatelet Therapy

• Aspirin:

  • Loading dose: 162-325 mg (non-enteric coated, chewed or crushed) immediately 1
  • Maintenance dose: 81 mg daily indefinitely 2

• P2Y12 Inhibitor (choose one):

  • Ticagrelor: 180 mg loading dose followed by 90 mg twice daily (preferred for moderate to high-risk patients) 1
  • Clopidogrel: 300-600 mg loading dose followed by 75 mg daily 3
  • Prasugrel: 60 mg loading dose followed by 10 mg daily (only after coronary anatomy is defined and PCI is planned) 2

Anticoagulation (choose one)

• Unfractionated heparin (UFH): IV bolus and infusion for at least 48 hours or until PCI 2
• Enoxaparin: 1 mg/kg SC every 12 hours (maximum 10,000 IU twice daily) for duration of hospitalization up to 8 days 2
• Fondaparinux: 2.5 mg SC daily (preferred in patients with high bleeding risk) 1
• Bivalirudin: Alternative to heparin, especially in patients with heparin-induced thrombocytopenia 1

Anti-ischemic Therapy

• Nitroglycerin: IV for ongoing chest pain 2
  • Contraindications: SBP <90 mmHg, severe bradycardia (<50 bpm), tachycardia (>100 bpm) without heart failure, right ventricular infarction 2
• Beta-blockers: Begin within a few days if not initiated acutely 2
  • Avoid IV beta-blockers in patients with signs of heart failure, low cardiac output, or risk for cardiogenic shock 2

Risk Stratification and Invasive Strategy

Risk Assessment Tools

• GRACE Risk Score: Predicts in-hospital and long-term outcomes 1
• TIMI Risk Score: Predicts in-hospital and long-term outcomes 1

Timing of Invasive Strategy

1. Immediate invasive strategy (<2 hours):

   • Hemodynamic instability or cardiogenic shock
   • Refractory angina despite medical treatment
   • Life-threatening arrhythmias or cardiac arrest
   • Mechanical complications of MI
   • Acute heart failure with refractory angina 1

2. Early invasive strategy (<24 hours):

   • Elevated cardiac troponin
   • Dynamic ECG changes
   • GRACE score >140 1

3. Invasive strategy within 72 hours:

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

Revascularization Options

• Percutaneous Coronary Intervention (PCI): Preferred for most patients 2

  • Continue aspirin
  • Continue P2Y12 inhibitor
  • Discontinue anticoagulant therapy after uncomplicated PCI 2

• Coronary Artery Bypass Grafting (CABG): Consider for patients with:

  • Left main disease
  • Three-vessel disease
  • Complex coronary anatomy
  • Note: Discontinue P2Y12 inhibitors prior to CABG (clopidogrel: 5 days, ticagrelor: 5 days, prasugrel: 7 days) 1

Secondary Prevention

Pharmacological Therapy

• High-intensity statin therapy: All patients without contraindications 1
• Beta-blockers: Continue indefinitely 2
• ACE inhibitors/ARBs: Especially for patients with LVEF ≤40%, hypertension, diabetes, or chronic kidney disease 1
  • Avoid IV ACE inhibitors within first 24 hours due to hypotension risk 1
• Aldosterone antagonists: For patients with LVEF ≤40% and either heart failure or diabetes 2

Duration of Dual Antiplatelet Therapy (DAPT)

• Medical management (no stent): Aspirin indefinitely plus P2Y12 inhibitor for up to 12 months 2
• PCI with stent: Aspirin indefinitely plus P2Y12 inhibitor for at least 12 months for DES and up to 12 months for BMS 2

Special Considerations

High Bleeding Risk

• Consider shorter duration of DAPT
• Consider fondaparinux as anticoagulant
• Consider proton pump inhibitor for GI protection 1

Diabetes

• More aggressive antiplatelet therapy
• Early invasive strategy preferred 1

Elderly

• Adjust medication doses
• Monitor renal function
• Higher risk of bleeding complications 2

Common Pitfalls to Avoid

1. Delaying antiplatelet therapy: Initiate immediately upon diagnosis
2. Administering NSAIDs: Avoid all NSAIDs except aspirin due to increased risks of mortality and complications 1
3. Administering nitrates to patients with:
   • SBP <90 mmHg
   • Severe bradycardia (<50 bpm)
   • Recent phosphodiesterase inhibitor use (sildenafil within 24h, tadalafil within 48h) 2
4. Using immediate-release calcium channel blockers without beta-blockers 2
5. Missing high-risk NSTEMI patients who may benefit from very early intervention (those with total coronary occlusion represent ~30% of NSTEMI cases) 4

By following this comprehensive approach to NSTEMI management, focusing on rapid diagnosis, risk stratification, and appropriate interventions, patient outcomes can be significantly improved with reductions in mortality and recurrent events.