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

NSTEMI Management Guidelines

The management of Non-ST-Elevation Myocardial Infarction (NSTEMI) requires immediate administration of aspirin 162-325 mg, anticoagulation with unfractionated heparin or alternatives, and risk stratification to determine whether an early invasive or conservative strategy is appropriate, followed by dual antiplatelet therapy and secondary prevention measures. 1

Initial Management

• Admit patients to a monitored unit with continuous rhythm monitoring for at least 24 hours 1
• Administer aspirin 162-325 mg (non-enteric formulation, orally or chewed) immediately upon presentation 1, 2
• Provide supplemental oxygen if arterial oxygen saturation is <90% 1, 2
• Administer sublingual or IV nitroglycerin for ongoing ischemic symptoms unless contraindicated (systolic BP <90 mmHg, severe bradycardia, tachycardia without heart failure, right ventricular infarction, or recent use of phosphodiesterase inhibitors) 2
• Initiate beta-blockers to reduce myocardial oxygen demand by decreasing heart rate, blood pressure, and myocardial contractility 1, 2
• Consider morphine sulfate intravenously if there is uncontrolled ischemic chest discomfort despite nitroglycerin 3

Risk Stratification

• Measure high-sensitivity cardiac troponin (hs-cTn) serially for both diagnosis and prognostic assessment 4
• Perform echocardiography to evaluate regional and global left ventricular function 4
• Assess hemodynamic stability, presence of ongoing ischemia, and risk factors for adverse outcomes 2
• Consider GRACE or TIMI risk scores to guide management strategy 1, 5

Antiplatelet Therapy

• Administer aspirin 162-325 mg initially, followed by 75-162 mg daily indefinitely 3, 1
• Add a P2Y12 inhibitor to aspirin for dual antiplatelet therapy 1, 4:
  • Clopidogrel: 300-600 mg loading dose, then 75 mg daily 3
  • Ticagrelor: 180 mg loading dose, then 90 mg twice daily 4
  • Prasugrel: 60 mg loading dose, then 10 mg daily (only for patients undergoing PCI, contraindicated in patients with prior stroke/TIA) 6

Anticoagulant Therapy

• Administer parenteral anticoagulation in addition to antiplatelet therapy 4, 7
• Options include 1, 4:
  • Unfractionated heparin (UFH): preferred in patients with planned invasive strategy or high bleeding risk due to short half-life and reversibility 2
  • Enoxaparin: continue for duration of hospitalization, up to 8 days 1
  • Fondaparinux: continue for duration of hospitalization, up to 8 days 1
  • Bivalirudin: particularly for patients undergoing PCI 1, 4

Management Strategy Selection

• Early invasive strategy (angiography within 24-48 hours) is indicated for 1, 4:
  • Refractory angina
  • Hemodynamic or electrical instability
  • Elevated cardiac biomarkers
  • High GRACE or TIMI risk score
  • Recurrent symptoms
• Conservative strategy is appropriate for 1, 2:
  • Lower-risk patients without ongoing ischemia
  • Patients with significant comorbidities where risks of invasive approach outweigh benefits

Post-Angiography Management

• If PCI is performed 3, 1:
  • Continue aspirin indefinitely
  • Continue P2Y12 inhibitor for at least 12 months (clopidogrel, ticagrelor, or prasugrel)
  • For bare-metal stents: aspirin 162-325 mg daily for at least 1 month, then 75-162 mg indefinitely
  • For drug-eluting stents: aspirin 162-325 mg daily for at least 3-6 months (depending on stent type), then 75-162 mg indefinitely
• If CABG is performed 3, 4:
  • Continue aspirin
  • Discontinue clopidogrel 5-7 days before elective CABG
  • Discontinue ticagrelor 3-5 days before elective CABG
  • Discontinue prasugrel 7 days before elective CABG

Long-term Management and Secondary Prevention

• Continue aspirin 75-162 mg daily indefinitely 3, 1
• Continue P2Y12 inhibitor for at least 1 month and ideally up to 1 year for medically managed patients 3
• Administer beta-blockers to all patients unless contraindicated 3, 4
• Initiate ACE inhibitors for patients with heart failure, LV dysfunction (LVEF <0.40), hypertension, or diabetes 3, 4
• Consider ARBs for ACE inhibitor-intolerant patients 3, 2
• Initiate high-intensity statin therapy regardless of baseline LDL levels 1, 8
• Measure left ventricular ejection fraction (LVEF) 3, 4
• Provide education on lifestyle modifications (diet, exercise, smoking cessation) 3, 1
• Enroll patients in cardiac rehabilitation programs 3

Common Pitfalls and Contraindications

• Avoid NSAIDs (except for aspirin) during hospitalization due to increased risks of mortality, reinfarction, hypertension, heart failure, and myocardial rupture 3
• Do not administer immediate-release dihydropyridine calcium channel blockers without adequate beta-blockade 3
• Avoid intravenous ACE inhibitors within the first 24 hours due to increased risk of hypotension 3
• Do not administer nitrates to patients who have received PDE5 inhibitors (sildenafil within 24 hours, tadalafil within 48 hours) 3
• Prasugrel is contraindicated in patients with prior history of stroke or TIA 2, 6
• Consider lower maintenance dose (5 mg) of prasugrel in patients weighing <60 kg due to increased bleeding risk 6