What is the management of Non-ST-Elevation Myocardial Infarction (NSTEMI)?

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

The management of NSTEMI requires immediate administration of aspirin 162-325 mg, anticoagulation with unfractionated heparin or low-molecular-weight heparin, risk stratification to determine appropriate strategy (early invasive vs. conservative), 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, 2
• Administer supplemental oxygen if arterial oxygen saturation is <90% 1, 2
• Consider nitroglycerin for ongoing ischemic symptoms unless contraindicated (systolic BP <90 mmHg, severe bradycardia, tachycardia without heart failure, right ventricular infarction, or recent phosphodiesterase inhibitor use) 1, 2
• Initiate beta-blockers to reduce myocardial oxygen demand by decreasing heart rate, blood pressure, and myocardial contractility 1, 2
• Perform risk stratification using cardiac biomarkers, ECG findings, and clinical risk scores (GRACE, TIMI) 1, 3

Antiplatelet Therapy

• Continue aspirin indefinitely at a dose of 75-162 mg daily 4, 1
• Administer a loading dose of clopidogrel (300 mg) if an early conservative strategy is selected or if PCI is planned 4, 1
• For patients undergoing PCI, consider prasugrel (60 mg loading dose followed by 10 mg daily) or ticagrelor as alternatives to clopidogrel 5
• Note that prasugrel is contraindicated in patients with prior history of stroke or TIA 5
• Consider lower maintenance dose (5 mg) of prasugrel for patients weighing <60 kg 5

Anticoagulant Therapy

• Administer one of the following anticoagulants 4, 1:
  • Unfractionated heparin (UFH) - continue for at least 48 hours or until discharge if given before diagnostic angiography
  • Enoxaparin - continue for duration of hospitalization, up to 8 days
  • Fondaparinux - continue for duration of hospitalization, up to 8 days
  • Bivalirudin - either discontinue or continue at 0.25 mg/kg/h for up to 72 hours at physician's discretion

Management Strategy Selection

• An early invasive strategy (angiography within 24-48 hours) is indicated for patients with 4, 1:
  • Refractory angina
  • Hemodynamic or electrical instability
  • Elevated cardiac biomarkers
  • High GRACE or TIMI risk score
• A conservative strategy may be appropriate for 4, 1:
  • Lower-risk patients without ongoing ischemia
  • Patients with significant comorbidities where risks of invasive approach outweigh benefits

Post-Angiography Management

If PCI is Selected:

• Continue aspirin 4, 1
• Administer a loading dose of P2Y12 inhibitor if not started before diagnostic angiography 4, 1
• Consider administering an intravenous GP IIb/IIIa inhibitor for troponin-positive and other high-risk patients 4
• Discontinue anticoagulant therapy after PCI for uncomplicated cases 4

If CABG is Selected:

• Continue aspirin 4
• Discontinue clopidogrel 5-7 days before elective CABG 4, 1
• Discontinue anticoagulants before CABG according to the following schedule 4:
  • UFH: 4-6 hours
  • Enoxaparin: 12-24 hours
  • Fondaparinux: 24 hours
  • Bivalirudin: 3 hours

If Medical Therapy is Selected:

• Continue aspirin 4
• Administer a loading dose of clopidogrel if not given before diagnostic angiography 4
• Discontinue intravenous GP IIb/IIIa inhibitor if started previously 4
• Continue anticoagulant therapy as described above 4

Long-term Management

• Measure left ventricular ejection fraction (LVEF) 4, 1
• If LVEF ≤0.40, consider diagnostic angiography 4, 1
• If LVEF >0.40, consider a stress test 4, 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 6
• Implement lifestyle modifications 4:
  • Smoking cessation
  • Weight management (target BMI 18.5-24.9 kg/m²)
  • Regular physical activity (30-60 minutes per day, at least 5 days per week)
  • Cardiac rehabilitation programs

Common Pitfalls and Caveats

• Avoid NSAIDs (except for aspirin) during hospitalization due to increased risks of mortality, reinfarction, hypertension, heart failure, and myocardial rupture 2
• Do not administer immediate-release dihydropyridine calcium channel blockers without adequate beta-blockade 2
• Avoid intravenous fibrinolytic therapy in NSTEMI patients as it has no significant beneficial effect and may increase the risk of MI 4
• Do not discontinue dual antiplatelet therapy prematurely, even if symptoms have resolved, as this increases risk of recurrent events 3
• Avoid discharging patients too early based solely on symptom resolution; continuous monitoring is still required for at least 24 hours 3