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

NSTEMI Treatment

The treatment of Non-ST-Elevation Myocardial Infarction (NSTEMI) requires immediate administration of aspirin 162-325 mg, anticoagulation with unfractionated heparin or alternatives, and risk stratification to determine whether an early invasive or conservative strategy is appropriate, followed by dual antiplatelet therapy and secondary prevention measures. 1

Initial Management

• Administer aspirin 162-325 mg (non-enteric formulation, orally or chewed) immediately upon presentation 1, 2
• Admit patient to a monitored unit with continuous rhythm monitoring for at least 24 hours 1
• 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) 1, 2
• Initiate beta-blockers to reduce myocardial oxygen demand by decreasing heart rate, blood pressure, and myocardial contractility 1, 3
• Consider morphine sulfate intravenously for uncontrolled ischemic chest discomfort despite nitroglycerin 1

Antiplatelet Therapy

• Continue aspirin indefinitely at a dose of 75-162 mg daily 1, 2
• Add a P2Y12 receptor inhibitor to aspirin for 12 months, unless contraindicated or at high risk of bleeding 3, 1:
  • Ticagrelor (loading dose 180 mg, 90 mg twice daily) regardless of the planned treatment strategy 2, 3
  • Prasugrel (loading dose 60 mg, standard dose 10 mg/day, 5 mg/day for patients ≥75 years or with weight <60 kg) in patients undergoing invasive coronary procedures 2, 3
  • Clopidogrel (loading dose 300-600 mg, daily dose 75 mg) when prasugrel or ticagrelor are not available or contraindicated 2, 3, 4

Anticoagulant Therapy

• Administer parenteral anticoagulation to all NSTEMI patients in addition to antiplatelet therapy 1, 3
• Options include:
  • Unfractionated heparin (UFH) for at least 48 hours or until discharge if given before diagnostic angiography 1, 2
  • Enoxaparin for the duration of hospitalization, up to 8 days, if given before diagnostic angiography 1, 2
  • Fondaparinux for the duration of hospitalization, up to 8 days, if given before diagnostic angiography 1, 2
  • Bivalirudin (can be continued at 0.25 mg/kg/h for up to 72 hours at physician's discretion) 2

Management Strategy Selection

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

Post-Angiography Management

• If PCI is selected:
  • Continue aspirin (Level of Evidence: A) 1, 2
  • Administer a loading dose of P2Y12 inhibitor if not started before diagnostic angiography 1, 2
  • Continue anticoagulation during the procedure 2
• If CABG is selected:
  • Continue aspirin 1, 2
  • Discontinue clopidogrel 5-7 days before elective CABG 1, 2
  • Discontinue prasugrel at least 7 days before surgery 2
  • Discontinue ticagrelor at least 5 days before surgery 3
• If medical therapy is selected:
  • Continue aspirin 1, 2
  • Administer a loading dose of clopidogrel if not given before diagnostic angiography 1, 2
  • Continue anticoagulant therapy as outlined above 2

Long-term Management

• Measure left ventricular ejection fraction (LVEF) 1, 3
• If LVEF ≤0.40, consider diagnostic angiography 1
• If LVEF >0.40, consider a stress test 1, 3
• 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 regardless of baseline LDL levels 1
• Implement aggressive risk factor modification (smoking cessation, blood pressure control, diabetes management) 1

Common Pitfalls and Contraindications

• Avoid NSAIDs (except for aspirin) during hospitalization due to increased risks of mortality, reinfarction, hypertension, heart failure, and myocardial rupture 1, 2
• Do not administer immediate-release dihydropyridine calcium channel blockers without adequate beta-blockade 1, 2
• Avoid intravenous ACE inhibitors within the first 24 hours due to increased risk of hypotension 1, 2
• Do not administer nitrates to patients who have received phosphodiesterase inhibitors (sildenafil within 24 hours, tadalafil within 48 hours) 2
• Use caution with intravenous beta-blockers in patients with contraindications to beta blockade, signs of heart failure, low-output state, or risk factors for cardiogenic shock 2