What are the guidelines for managing Non-ST-Elevation Myocardial Infarction (NSTEMI)?

Guidelines for Managing Non-ST-Elevation Myocardial Infarction (NSTEMI)

The management of NSTEMI requires an early invasive strategy (within 12-24 hours of admission) for high-risk patients, with dual antiplatelet therapy consisting of aspirin and a P2Y12 inhibitor, along with anticoagulation therapy. 1

Initial Assessment and Monitoring

• All NSTEMI patients should be admitted to a monitored unit with continuous rhythm monitoring until diagnosis is confirmed, even if symptoms have resolved 2
• Rhythm monitoring for at least 24 hours (or until PCI, whichever comes first) is recommended for NSTEMI patients at low risk for cardiac arrhythmias 2
• Extended monitoring (>24 hours) is recommended for patients at increased risk for cardiac arrhythmias 2
• High-sensitivity cardiac troponin (hs-cTn) should be measured serially for both diagnosis and prognostic assessment 2, 3
• Echocardiography should be performed to evaluate regional and global left ventricular function 2, 3

Antiplatelet Therapy

• Aspirin should be administered to all patients without contraindications at an initial oral loading dose of 150-300 mg (or 75-250 mg IV), followed by 75-100 mg daily for long-term treatment 2, 1
• A P2Y12 receptor inhibitor should be added to aspirin and maintained for 12 months unless contraindicated or there is excessive bleeding risk 2, 1
• Options for P2Y12 inhibitors include:
  • Clopidogrel: 300-600 mg loading dose, then 75 mg daily 1
  • 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 known and PCI is planned) 4
• Prasugrel is contraindicated in patients with prior history of stroke or TIA 4
• For patients <60 kg on prasugrel, consider lowering maintenance dose to 5 mg daily due to increased bleeding risk 4

Anticoagulation Therapy

• Parenteral anticoagulation is recommended for all patients in addition to antiplatelet therapy 2, 1
• Options include:
  • Unfractionated heparin (UFH): Continue for at least 48 hours or until discharge 1
  • Enoxaparin: Administer for the duration of hospitalization (up to 8 days) 1
  • Fondaparinux: Preferred in patients with increased bleeding risk when managed conservatively 1
  • Bivalirudin: Can be used during PCI, particularly when GP IIb/IIIa inhibitors are planned 1

Management Strategy Selection

Early Invasive Strategy (Angiography with Intent to Perform Revascularization)

• Indicated for patients with:
  • Refractory angina or hemodynamic/electrical instability 1
  • Elevated risk for clinical events 1
  • Positive troponin 1
• Reasonable to choose early invasive strategy (within 12-24 hours) over delayed invasive strategy for initially stabilized high-risk patients 1

Conservative (Selective Invasive) Strategy

• May be considered for initially stabilized patients with elevated risk for clinical events 1
• For patients managed conservatively:
  • Continue aspirin indefinitely 1
  • Continue clopidogrel for at least 1 month and ideally up to 1 year 1
  • Discontinue IV GP IIb/IIIa inhibitor if started previously 1
  • Continue UFH for 48 hours or administer enoxaparin/fondaparinux for the duration of hospitalization 1
• If recurrent symptoms/ischemia, heart failure, or serious arrhythmias subsequently appear, perform diagnostic angiography 1

Not Recommended for Early Invasive Strategy

• Patients with extensive comorbidities where risks outweigh benefits 1
• Patients with acute chest pain and low likelihood of ACS 1
• Patients who will not consent to revascularization regardless of findings 1

Post-Angiography Management

For Patients Undergoing PCI

• Continue aspirin indefinitely 1
• P2Y12 inhibitor (clopidogrel, prasugrel, or ticagrelor) should be given for at least 12 months for patients receiving drug-eluting stents (DES) and up to 12 months for patients receiving bare-metal stents (BMS) 1
• If bleeding risk outweighs benefits, consider earlier discontinuation of P2Y12 inhibitor therapy 1

For Patients Undergoing CABG

• Continue aspirin 1
• Discontinue clopidogrel 5-7 days before elective CABG 1
• Discontinue IV GP IIb/IIIa inhibitor 4 hours before CABG 1
• Manage anticoagulant therapy as follows:
  • Continue UFH 1
  • Discontinue enoxaparin 12-24 hours before CABG 1
  • Discontinue fondaparinux 24 hours before CABG 1
  • Discontinue bivalirudin 3 hours before CABG 1

Long-term Pharmacotherapy

• Beta-blockers are indicated for all patients recovering from NSTEMI unless contraindicated 2, 3
• ACE inhibitors should be given and continued indefinitely for patients with heart failure, LV dysfunction (LVEF <0.40), hypertension, or diabetes 2
• Angiotensin receptor blockers (ARBs) are recommended for ACE inhibitor-intolerant patients 2

Common Pitfalls and Caveats

• Dual antiplatelet therapy should not be discontinued prematurely, even if symptoms have resolved, as this increases risk of recurrent events 2
• Patients should not be discharged too early based solely on symptom resolution 2
• NSAIDs (except for aspirin) should be avoided during hospitalization 3
• Prasugrel should not be administered before diagnostic angiography in NSTEMI patients, as it increases bleeding risk without providing additional benefit 5
• Fibrinolytic therapy is not recommended for NSTEMI management 1
• Immediate-release dihydropyridine calcium channel blockers should not be administered without adequate beta-blockade 3