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

Medical Management for NSTEMI

The optimal management of Non-ST-Elevation Myocardial Infarction (NSTEMI) requires immediate anti-ischemic therapy, antithrombotic therapy, and risk stratification to guide invasive management timing. 1

Initial Management

Immediate Interventions

• Bed rest with continuous ECG monitoring for all NSTEMI patients during early hospital phase 1
• Supplemental oxygen only if arterial saturation <90%, respiratory distress, or high-risk features for hypoxemia 1, 2
• Sublingual nitroglycerin (0.4 mg) every 5 minutes for up to 3 doses for ongoing ischemic discomfort 1, 2
• Intravenous nitroglycerin for persistent ischemia, heart failure, or hypertension in first 48 hours 1

Antiplatelet Therapy

• Aspirin 162-325 mg (non-enteric, orally or chewed) immediately, then 75-162 mg daily indefinitely 1, 2
• P2Y12 inhibitor in addition to aspirin:
  • Ticagrelor (preferred for moderate to high-risk patients) 2
  • Prasugrel (for patients proceeding to PCI without contraindications) 2, 3
  • Clopidogrel (for patients who cannot receive ticagrelor or prasugrel) 2, 4

Anticoagulant Therapy

• Unfractionated heparin (UFH), low molecular weight heparin (LMWH), or fondaparinux 1, 2
• Continue UFH for 48 hours or LMWH/fondaparinux for duration of hospitalization (up to 8 days) 1

Anti-Ischemic Therapy

Beta-Blockers

• Oral beta-blockers within first 24 hours unless contraindicated 1
• IV beta-blockers may be reasonable for hypertension in selected patients without contraindications 1
• Contraindications: Signs of heart failure, low-output state, increased risk for cardiogenic shock, PR interval >0.24s, 2nd/3rd degree heart block, active asthma/reactive airway disease 1, 2

Calcium Channel Blockers

• Non-dihydropyridine calcium channel blockers (verapamil, diltiazem) for patients with continuing/recurring ischemia when beta-blockers are contraindicated 1
• Immediate-release dihydropyridine calcium channel blockers only with adequate beta-blockade for ongoing symptoms or hypertension 1

ACE Inhibitors/ARBs

• ACE inhibitors orally within 24 hours for patients with pulmonary congestion or LVEF ≤0.40 1
• ARBs for patients intolerant to ACE inhibitors with clinical/radiological signs of heart failure or LVEF ≤0.40 1
• Avoid IV ACE inhibitors within first 24 hours due to hypotension risk 1

Other Medications

• High-intensity statin therapy as early as possible 2
• Avoid NSAIDs (except aspirin) during hospitalization due to increased risks of mortality, reinfarction, hypertension, heart failure, and myocardial rupture 1

Risk Stratification and Invasive Management

Risk Assessment

• Determine timing of invasive strategy based on risk assessment 2:
  • Very high-risk: Immediate invasive strategy (<2h)
  • High-risk: Early invasive strategy (<24h)
  • Intermediate-risk: Invasive strategy (<72h)

Invasive vs. Conservative Strategy

• Invasive strategy recommended for high-risk patients (elevated troponins, clinical/hemodynamic instability, ST depression, diabetes mellitus) 5
• Conservative strategy with stress testing appropriate for low-risk patients 1

Mechanical Support

• Intra-aortic balloon pump (IABP) counterpulsation for severe ischemia despite intensive medical therapy, hemodynamic instability, or mechanical complications 1

Special Considerations

Medication Contraindications

• Nitrates: Avoid with SBP <90 mmHg, severe bradycardia (<50 bpm), tachycardia (>100 bpm) without symptomatic HF, right ventricular infarction, or recent use of phosphodiesterase inhibitors 1, 2
• Beta-blockers: Avoid IV administration in patients with contraindications, signs of HF, low-output state, or risk factors for cardiogenic shock 1, 2
• Prasugrel: Generally not recommended in patients ≥75 years or <60 kg due to bleeding risk 3

Discharge Planning

• Continue aspirin indefinitely 1
• Continue P2Y12 inhibitor for at least 1 month and ideally up to 1 year 1
• Discontinue IV GP IIb/IIIa inhibitor if started previously 1
• Continue anticoagulant therapy for duration of hospitalization, up to 8 days 1

Pitfalls to Avoid

• Administering immediate-release dihydropyridine calcium channel blockers without beta-blockers 1
• Using IV beta-blockers routinely in all patients 2
• Administering IV ACE inhibitors within first 24 hours 1
• Continuing NSAIDs during hospitalization 1
• Delaying invasive management in high-risk patients 2, 5
• Overlooking NSTEMI patients with total coronary occlusion who may benefit from immediate invasive strategy 6

The medical management of NSTEMI requires a systematic approach focusing on rapid diagnosis, risk stratification, and institution of therapies that restore coronary blood flow and reduce myocardial ischemia 7, with careful attention to contraindications and individual patient risk factors.