Management of Non-ST-Elevation Myocardial Infarction (NSTEMI)

Immediate Initial Management

The American College of Cardiology recommends administering aspirin 162-325 mg immediately as a non-enteric formulation, either chewed or taken orally, regardless of prior aspirin use 1, 2, 3
Patients with NSTEMI should be admitted to a monitored unit with continuous cardiac rhythm monitoring for at least 24 hours to detect arrhythmias 1, 2
Supplemental oxygen should be provided only if arterial oxygen saturation is <90%; routine oxygen is not indicated 1, 2
The American College of Cardiology suggests administering sublingual or intravenous nitroglycerin for ongoing ischemic chest pain, but avoid if systolic blood pressure <90 mmHg or ≥30 mmHg below baseline, severe bradycardia (<50 bpm) or tachycardia (>100 bpm without heart failure), right ventricular infarction, or phosphodiesterase inhibitor use within 24 hours (sildenafil) or 48 hours (tadalafil) 3
Beta-blocker therapy should be initiated (oral preferred over intravenous) to reduce myocardial oxygen demand by decreasing heart rate, blood pressure, and contractility, unless contraindications exist 1, 2

The American College of Cardiology recommends continuing aspirin 75-162 mg daily indefinitely after the initial loading dose 1, 2, 4
A P2Y12 receptor inhibitor should be added to aspirin for 12 months unless contraindicated or high bleeding risk 1, 4
Ticagrelor is the preferred agent, with a loading dose of 180 mg, then 90 mg twice daily—recommended regardless of invasive or conservative strategy 1, 4

Parenteral anticoagulation should be administered to all NSTEMI patients in addition to antiplatelet therapy 1, 2, 4
Unfractionated heparin (UFH) should be continued for at least 48 hours or until discharge if given before angiography 3, 2, 4
Enoxaparin should be continued for the duration of hospitalization, up to 8 days, if given before angiography 3, 2, 4

An early invasive strategy (angiography within 24-48 hours) is indicated for patients with refractory angina, hemodynamic instability, electrical instability, elevated cardiac biomarkers, or high GRACE or TIMI risk score 1, 2, 4
A conservative strategy is appropriate for lower-risk patients without ongoing ischemia or significant comorbidities where invasive risks outweigh benefits 2, 4

After PCI, aspirin should be continued, and a P2Y12 inhibitor loading dose should be administered if not given before angiography 3, 5, 2
After CABG, aspirin should be continued, and clopidogrel should be discontinued 5-7 days before elective CABG 5, 6, 2

Left ventricular ejection fraction (LVEF) should be measured in all patients 5, 2, 4
If LVEF ≤0.40, diagnostic angiography should be considered 5, 2, 4
ACE inhibitors should be initiated for patients with heart failure, LV dysfunction (LVEF <0.40), hypertension, or diabetes 1, 2, 4
Beta-blockers should be continued indefinitely in all NSTEMI patients without contraindications 4
High-intensity statin therapy should be initiated regardless of baseline LDL levels 2

NSAIDs (except aspirin) should not be administered during hospitalization due to increased mortality, reinfarction, hypertension, heart failure, and myocardial rupture 3, 1, 2
Immediate-release dihydropyridine calcium channel blockers should not be given without adequate beta-blockade 3, 1, 2
Intravenous ACE inhibitors should be avoided within the first 24 hours due to hypotension risk (exception: refractory hypertension) 3, 2
Intravenous beta blockers should not be administered to patients with contraindications, signs of heart failure, low-output state, or cardiogenic shock risk factors 3
Fibrinolytic therapy is contraindicated in NSTEMI patients without ST-segment elevation 5