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

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

The treatment for NSTEMI should include immediate aspirin administration, anticoagulation, dual antiplatelet therapy, beta-blockers, and an early risk stratification to determine whether an invasive or conservative management strategy is appropriate. 1

Initial Management

• Administer aspirin 162-325 mg (non-enteric formulation, orally or chewed) immediately upon presentation 2, 1
• Admit to a monitored unit with continuous rhythm monitoring for at least 24 hours 1, 3
• Administer supplemental oxygen if arterial oxygen saturation is <90% 1, 3
• Consider nitroglycerin for ongoing ischemic symptoms unless contraindicated (systolic BP <90 mmHg, severe bradycardia, tachycardia without heart failure, right ventricular infarction, or recent use of phosphodiesterase inhibitors) 2, 1
• Initiate beta-blockers to reduce myocardial oxygen demand by decreasing heart rate, blood pressure, and myocardial contractility 1, 4

Antiplatelet Therapy

• Continue aspirin indefinitely (75-162 mg daily maintenance dose) 2
• Administer a P2Y12 receptor inhibitor in addition to aspirin:
  • Ticagrelor (preferred): 180 mg loading dose, then 90 mg twice daily 2
  • Clopidogrel: 300-600 mg loading dose, then 75 mg daily (when ticagrelor is contraindicated or unavailable) 2, 5
  • Prasugrel: 60 mg loading dose, then 10 mg daily (only after coronary anatomy is known and PCI is planned) 2
• For patients treated with stents, continue dual antiplatelet therapy for at least 12 months 2

Anticoagulant Therapy

• Administer one of the following anticoagulants as soon as possible 2, 1:
  • Enoxaparin: 1 mg/kg subcutaneously every 12 hours (reduce to once daily if CrCl <30 mL/min) 2
  • Unfractionated heparin: 60 IU/kg IV loading dose (maximum 4000 IU) with initial infusion of 12 IU/kg/hour (maximum 1000 IU/hour) adjusted per aPTT 2
  • Fondaparinux: 2.5 mg subcutaneously daily 2
  • Bivalirudin: 0.10 mg/kg loading dose followed by 0.25 mg/kg/hour (only in patients managed with early invasive strategy) 2
• Continue anticoagulation until PCI is performed or until hospital discharge for conservatively managed patients 2, 1

Management Strategy Selection

• Early invasive strategy (coronary angiography within 24-48 hours) is indicated for 2, 1:
  • Refractory angina
  • Hemodynamic or electrical instability
  • Elevated cardiac biomarkers
  • High GRACE or TIMI risk score
• Conservative strategy is appropriate for 1, 3:
  • Lower-risk patients without ongoing ischemia
  • Patients with significant comorbidities where risks of invasive approach outweigh benefits

Additional Pharmacologic Therapy

• Beta-blockers should be initiated for all patients unless contraindicated 2, 1
• ACE inhibitors should be initiated for patients with heart failure, LV dysfunction (LVEF <0.40), hypertension, or diabetes 2, 1
• ARBs should be considered for ACE inhibitor-intolerant patients 1, 3
• Consider high-intensity statins for all patients regardless of baseline LDL levels 1

Common Pitfalls and Caveats

• NSAIDs (except for aspirin) should be avoided during hospitalization due to increased risks of mortality, reinfarction, hypertension, heart failure, and myocardial rupture 2, 3
• Immediate-release dihydropyridine calcium channel blockers should not be administered without adequate beta-blockade 2, 3
• Intravenous ACE inhibitors should be avoided within the first 24 hours due to increased risk of hypotension 2, 3
• Nitrates should not be administered to patients who have recently taken phosphodiesterase inhibitors (sildenafil within 24 hours, tadalafil within 48 hours) 2, 3
• Fibrinolytic therapy is harmful in NSTEMI patients and should not be administered 2

Long-term Management

• Continue aspirin indefinitely 2, 1
• Continue P2Y12 inhibitor for up to 12 months 2
• Measure left ventricular ejection fraction before discharge 1
• Implement secondary prevention measures including smoking cessation, blood pressure control, diabetes management, and cardiac rehabilitation 1