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

Management of NSTEMI

Immediate Actions Upon Presentation

All patients with suspected NSTEMI must be admitted to a monitored unit with continuous cardiac rhythm monitoring, receive aspirin 162-325 mg orally immediately, initiate parenteral anticoagulation, add a P2Y12 inhibitor, and undergo risk stratification to determine timing of invasive strategy within 24 hours. 1

First 10 Minutes

• Obtain 12-lead ECG within 10 minutes of arrival to distinguish STEMI from NSTE-ACS 2
• Administer aspirin 162-325 mg orally (non-enteric coated for faster absorption) 1, 3
• Establish continuous cardiac rhythm monitoring for at least 24 hours 1, 3
• Administer supplemental oxygen only if arterial oxygen saturation is <90% 2, 1

Anti-Ischemic Therapy

• Give sublingual or intravenous nitroglycerin for ongoing chest pain, unless systolic blood pressure <90 mmHg, severe bradycardia or tachycardia, right ventricular infarction, or recent phosphodiesterase inhibitor use within 24-48 hours 2, 1
• Initiate beta-blocker therapy within 24 hours to reduce myocardial oxygen demand by decreasing heart rate, blood pressure, and contractility, unless contraindicated by heart failure, low-output state, or risk factors for cardiogenic shock 4, 1
• Consider morphine sulfate intravenously for uncontrolled ischemic chest pain despite nitroglycerin, though use cautiously as it may delay P2Y12 inhibitor absorption 1, 3

Antithrombotic Strategy

Antiplatelet Therapy

• Continue aspirin 75-100 mg daily indefinitely 1, 3
• Add a P2Y12 inhibitor before diagnostic angiography (upstream administration): 1, 3
  • Ticagrelor is preferred (180 mg loading dose, then 90 mg twice daily) over clopidogrel due to superior outcomes 1, 3
  • Clopidogrel (300-600 mg loading dose, then 75 mg daily) is an alternative if ticagrelor is contraindicated 1, 3
  • Prasugrel (60 mg loading dose, then 10 mg daily) should only be given after coronary anatomy is established at time of PCI, not before angiography 5
• Continue P2Y12 inhibitor for at least 12 months after NSTEMI, regardless of whether a stent was placed 3

Anticoagulation Therapy

• Initiate parenteral anticoagulation immediately in all patients 1, 3, 6
• Agent selection based on strategy and renal function: 2, 1, 3
  • For early invasive strategy: unfractionated heparin or enoxaparin 2, 1
  • For conservative strategy: fondaparinux preferred due to lower bleeding risk 2, 1
  • For severe renal impairment (CrCl <30 mL/min): unfractionated heparin preferred 4, 3
• Duration of anticoagulation: 3
  • Unfractionated heparin: continue for at least 48 hours or until discharge 3
  • Enoxaparin or fondaparinux: continue for duration of hospitalization, up to 8 days 3
• Critical: Do not switch between anticoagulants as this increases bleeding risk 3
• If fondaparinux is used during PCI, add unfractionated heparin to prevent catheter thrombosis 3

GP IIb/IIIa Inhibitors

• Eptifibatide or tirofiban may be added upstream in very high-risk patients if delay to catheterization is anticipated 1
• Do not give abciximab upstream; use only if PCI is imminent 1
• Routine upstream use of GP IIb/IIIa inhibitors is not recommended due to increased bleeding risk without reduction in ischemic events 3

Risk Stratification and Timing of Invasive Strategy

Immediate Invasive Strategy (<2 hours)

Indicated for very high-risk patients with: 2, 1

• Refractory or recurrent angina despite medical therapy
• Hemodynamic instability or cardiogenic shock
• Life-threatening arrhythmias or cardiac arrest
• Mechanical complications of MI
• Acute heart failure
• Recurrent dynamic ST-segment or T-wave changes

Early Invasive Strategy (<24 hours)

Indicated for high-risk patients with: 2, 1, 3

• Elevated cardiac troponin with high-risk features
• Dynamic ST-segment or T-wave changes
• High GRACE score (>140) or TIMI score (≥3)
• Diabetes mellitus
• Renal insufficiency (eGFR <60 mL/min/1.73 m²)
• Left ventricular ejection fraction <40%
• Early post-infarction angina

Invasive Strategy (<72 hours)

Appropriate for intermediate-risk patients without recurrence of symptoms but with at least one intermediate-risk criterion 2

Conservative (Selective Invasive) Strategy

May be considered for low-risk patients who are initially stabilized, or those with significant comorbidities where risks of invasive approach outweigh benefits 1, 3

Post-Angiography Management

If PCI is Performed

• Continue aspirin indefinitely 1, 3
• Administer P2Y12 inhibitor loading dose if not given before angiography 1, 3
• Continue dual antiplatelet therapy for at least 12 months 3

If CABG is Selected

• Continue aspirin 1, 3
• Discontinue ticagrelor 5 days before elective CABG 3
• Discontinue prasugrel at least 7 days before elective CABG 3, 5
• Discontinue clopidogrel 5-7 days before elective CABG 1, 3

If Medical Therapy is Selected

• Continue aspirin indefinitely 3
• Administer P2Y12 inhibitor loading dose if not given before angiography 3

Long-Term Secondary Prevention

Mandatory Interventions

• High-intensity statin therapy (atorvastatin 80 mg or rosuvastatin 40 mg) regardless of baseline LDL cholesterol 1, 3
• Beta-blockers continued indefinitely 1, 3
• ACE inhibitors for patients with heart failure, left ventricular dysfunction (LVEF <0.40), hypertension, or diabetes 1, 3
• ARBs for ACE inhibitor-intolerant patients 1, 3

Risk Assessment

• Measure left ventricular ejection fraction in all patients 1, 3
• If LVEF ≤0.40, consider diagnostic angiography 1, 3
• If LVEF >0.40, consider stress test 1, 3

Patients Requiring Long-Term Anticoagulation

• Use triple antithrombotic therapy (oral anticoagulant + aspirin + clopidogrel) for shortest duration possible, typically 1 week to 1 month 3, 6
• After initial period, use dual therapy (DOAC + clopidogrel) for up to 1 year 6
• Then DOAC monotherapy thereafter 6
• Prefer DOAC over warfarin when possible 3, 6

Critical Pitfalls to Avoid

Medication Errors

• Never use NSAIDs (except aspirin) during hospitalization—they increase mortality, reinfarction, hypertension, heart failure, and myocardial rupture risk 1, 3
• Do not use immediate-release dihydropyridine calcium channel blockers (nifedipine) without adequate beta-blockade 3
• Avoid omeprazole and esomeprazole with clopidogrel due to reduced antiplatelet effect; use other PPIs if gastroprotection is needed 1
• Do not administer intravenous ACE inhibitors within first 24 hours due to increased risk of hypotension 3

Timing Errors

• Do not delay angiography in high-risk patients for "medical stabilization"—early invasive approach within 24 hours reduces ischemic events 1, 3
• For prasugrel specifically, do not administer loading dose until coronary anatomy is established; no clear benefit was observed when given prior to angiography compared to at time of PCI, but bleeding risk increased 5

Anticoagulation Errors

• Do not switch between anticoagulants—this increases bleeding risk 3
• If using fondaparinux during PCI, must add unfractionated heparin to prevent catheter thrombosis 3

Special Populations

• For patients <60 kg on prasugrel, consider lowering maintenance dose to 5 mg due to increased bleeding risk 5
• Prasugrel is generally not recommended for patients ≥75 years except in high-risk situations (diabetes or prior MI) 5
• For patients with severe renal impairment, prefer unfractionated heparin over enoxaparin or fondaparinux 4, 3

Bleeding Management

• Suspect bleeding in any patient who is hypotensive after coronary angiography, PCI, CABG, or other surgical procedures 5
• If possible, manage bleeding without discontinuing antiplatelet therapy 5
• Discontinuing antiplatelet therapy, particularly in first few weeks after ACS, increases risk of subsequent cardiovascular events 5