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

NSTEMI Treatment Protocol

The optimal management of Non-ST-Elevation Myocardial Infarction (NSTEMI) requires a comprehensive approach including anti-ischemic therapy, antithrombotic therapy, ongoing risk stratification, and appropriate use of invasive procedures to reduce mortality and prevent serious adverse outcomes. 1

Initial Management

• Administer aspirin 162-325 mg (non-enteric formulation, orally or chewed) immediately upon presentation 1, 2
• Admit to a monitored unit with continuous cardiac rhythm monitoring for at least 24 hours 1, 3
• Provide supplemental oxygen if arterial oxygen saturation is <90% 2
• Administer sublingual or IV nitroglycerin for ongoing chest pain unless contraindicated (systolic BP <90 mmHg, severe bradycardia, tachycardia without heart failure, right ventricular infarction) 1, 2
• Initiate beta-blocker therapy to reduce myocardial oxygen demand unless contraindicated 1

Antithrombotic Therapy

Antiplatelet Therapy

• Aspirin 162-325 mg loading dose followed by 75-162 mg daily indefinitely 1
• Add a P2Y12 receptor inhibitor and maintain for up to 12 months 1:
  • Clopidogrel: 300-600 mg loading dose, then 75 mg daily 1, 4
  • Ticagrelor: 180 mg loading dose, then 90 mg twice daily 1
  • Prasugrel: 60 mg loading dose, then 10 mg daily (only after coronary anatomy is defined and PCI is planned; contraindicated in patients with prior stroke/TIA) 1, 2

Anticoagulant Therapy

• Initiate parenteral anticoagulation in addition to antiplatelet therapy 1
• Options include:
  • Unfractionated heparin (UFH): 60 U/kg IV bolus (max 4,000 U), then maintenance infusion 1
  • Enoxaparin: 30 mg IV bolus followed by 1 mg/kg SC every 12 hours 1
  • Fondaparinux: 2.5 mg SC once daily 1
  • Bivalirudin: 0.1 mg/kg bolus, 0.25 mg/kg/hr infusion (primarily for early invasive strategy) 1

Risk Stratification and Management Strategy

• Perform serial high-sensitivity cardiac troponin measurements 1, 3
• Conduct echocardiography to evaluate regional and global left ventricular function 1, 3
• Based on risk assessment, select one of the following strategies 1:

Invasive Strategy

• Immediate invasive strategy (<2 hours): For patients with ongoing ischemia, hemodynamic instability, or other very high-risk features 1
• Early invasive strategy (<24 hours): For patients with at least one high-risk criterion 1
• Invasive strategy (<72 hours): For patients with at least one intermediate-risk criterion 1

Conservative Strategy

• For low-risk patients without recurrent symptoms 1
• Perform non-invasive stress testing before discharge 1

Post-Acute Management

Pharmacotherapy

• Continue aspirin indefinitely 1
• Continue P2Y12 inhibitor for up to 12 months 1:
  • For medically managed patients without stenting: clopidogrel or ticagrelor for up to 12 months 1
  • For patients receiving stents: clopidogrel, prasugrel, or ticagrelor for at least 12 months with DES and up to 12 months with BMS 1
• Continue beta-blockers indefinitely unless contraindicated 1
• Initiate ACE inhibitors for patients with heart failure, LV dysfunction (LVEF <0.40), hypertension, or diabetes 1, 3
• Consider ARBs for ACE inhibitor-intolerant patients 1, 3
• Initiate high-intensity statin therapy 1

Important Contraindications and Precautions

• Do not administer:
  • Nitrates to patients with systolic BP <90 mmHg, severe bradycardia, or right ventricular infarction 1
  • Nitrates within 24-48 hours of phosphodiesterase inhibitor use 1
  • Immediate-release dihydropyridine calcium channel blockers without beta-blockers 1
  • IV ACE inhibitors within first 24 hours (increased hypotension risk) 1
  • NSAIDs (except aspirin) during hospitalization due to increased mortality and complication risks 1
  • IV beta-blockers to patients with contraindications, heart failure, or risk factors for cardiogenic shock 1
  • Prasugrel to patients with prior stroke/TIA 1, 2

Special Considerations

• For patients on warfarin, delay initiating anticoagulant therapy until INR <2.0, but start antiplatelet therapy regardless 1
• Consider lower maintenance doses of prasugrel (5 mg) for patients weighing <60 kg or aged ≥75 years 1
• For patients requiring triple therapy (dual antiplatelet plus oral anticoagulation), carefully balance bleeding versus thrombotic risk 1