What is the initial management for a patient presenting with Non-ST-Elevation Myocardial Infarction (NSTEMI)?

Initial Management of NSTEMI

Immediately administer aspirin 162-325 mg (non-enteric formulation, chewed or oral) upon presentation, initiate anticoagulation therapy, and begin dual antiplatelet therapy while performing risk stratification to determine whether an early invasive or conservative strategy is appropriate. 1, 2, 3

Immediate Actions (First 10-30 Minutes)

Antiplatelet Therapy

• Aspirin 162-325 mg immediately (non-enteric, chewed or oral), then continue 75-162 mg daily indefinitely 1, 2, 3
• Add a P2Y12 inhibitor loading dose before diagnostic angiography (upstream therapy): 1
  • Ticagrelor 180 mg (preferred, regardless of invasive vs. conservative strategy) 1, 4
  • Clopidogrel 300-600 mg (if ticagrelor unavailable or contraindicated) 1
  • Prasugrel 60 mg only after coronary anatomy is defined and PCI is planned (NOT before angiography unless bleeding risk is low and CABG unlikely) 1

Critical Pitfall: Avoid prasugrel in patients with prior stroke/TIA—it is potentially harmful in this population 1. Also avoid prasugrel before knowing coronary anatomy, as it cannot be used if CABG is needed 1.

Anticoagulation Therapy

Initiate one of the following immediately: 1, 2, 3

• Enoxaparin (preferred over UFH for conservative strategy) 1, 4
• Fondaparinux (preferred if increased bleeding risk) 1, 4
• Unfractionated heparin (UFH) 1, 4
• Bivalirudin (if early invasive strategy planned) 1

Continue anticoagulation for at least 48 hours or until discharge for medically managed patients, or up to 8 days for hospitalization duration 1, 3, 4.

Supportive Measures

• Admit to monitored unit with continuous rhythm monitoring for at least 24 hours 3
• Supplemental oxygen only if arterial oxygen saturation <90% 3
• Nitroglycerin for ongoing ischemic symptoms (sublingual or IV), unless contraindicated by: 1, 3
  • Systolic BP <90 mmHg or ≥30 mmHg below baseline
  • Severe bradycardia (<50 bpm) or tachycardia (>100 bpm without heart failure)
  • Right ventricular infarction
  • Phosphodiesterase inhibitor use within 24h (sildenafil) or 48h (tadalafil)
• Beta-blockers (oral, not IV initially) to reduce myocardial oxygen demand 3, 5

Critical Pitfall: Do NOT give IV beta-blockers to patients with signs of heart failure, low-output state, or risk factors for cardiogenic shock 1. Do NOT give immediate-release dihydropyridine calcium channel blockers without adequate beta-blockade 1.

Risk Stratification and Strategy Selection (Within 2-24 Hours)

Early Invasive Strategy (Angiography Within 24-48 Hours)

Indicated for patients with: 2, 3, 4

• Refractory angina despite medical therapy
• Hemodynamic instability or cardiogenic shock
• Electrical instability (ventricular arrhythmias)
• Elevated cardiac troponin
• High GRACE or TIMI risk score (≥2)
• Recurrent ischemia, heart failure, or serious arrhythmias

Conservative Strategy

Appropriate for: 2, 3, 4

• Low-risk patients (TIMI score <2) without ongoing ischemia
• Patients with significant comorbidities where invasive risks outweigh benefits
• Initially stabilized patients without high-risk features

If conservative strategy selected: Continue aspirin + clopidogrel (or ticagrelor) + anticoagulation for at least 1 month, ideally up to 1 year 1. Perform stress testing before discharge if no recurrent symptoms 1.

Additional Pharmacotherapy During Invasive Strategy

GP IIb/IIIa Inhibitors (Selective Use)

• Consider adding eptifibatide or tirofiban in high-risk patients (elevated troponin, diabetes, significant ST-depression) already on aspirin + P2Y12 inhibitor who are selected for invasive strategy and NOT at high bleeding risk 1
• Do NOT use abciximab if PCI is not planned 1
• Can omit GP IIb/IIIa inhibitor if bivalirudin is selected as anticoagulant AND at least 300 mg clopidogrel was given ≥6 hours before catheterization 1

Critical Pitfall: Do NOT use upstream GP IIb/IIIa inhibitors in low-risk patients (TIMI <2) or those at high bleeding risk 1.

Post-Angiography Management

If PCI Performed

• Continue aspirin indefinitely 1
• Continue P2Y12 inhibitor for at least 12 months: 1
  • Clopidogrel 75 mg daily, OR
  • Prasugrel 10 mg daily (5 mg if weight <60 kg or age ≥75 years), OR
  • Ticagrelor 90 mg twice daily

If CABG Planned

• Continue aspirin 1
• Stop clopidogrel 5-7 days before surgery 1, 3
• Stop prasugrel ≥7 days before surgery 4
• Stop ticagrelor ≥5 days before surgery 4

Long-Term Secondary Prevention

• Beta-blockers for all patients without contraindications 2, 3
• ACE inhibitors for patients with heart failure, LVEF <0.40, hypertension, or diabetes 2, 3, 4
• High-intensity statin therapy regardless of baseline LDL 3
• Measure LVEF and consider further risk stratification 1, 3, 4

Critical Pitfall: Avoid NSAIDs (except aspirin) during hospitalization—they increase mortality, reinfarction, hypertension, heart failure, and myocardial rupture risk 1, 3. Avoid IV ACE inhibitors within first 24 hours due to hypotension risk 1, 3.