NSTEMI Acute Management and Early Treatment Strategy
All patients with NSTEMI should receive immediate dual antiplatelet therapy (aspirin plus a P2Y12 inhibitor) and parenteral anticoagulation, with the timing of invasive coronary angiography determined by risk stratification—immediate (<2 hours) for very high-risk features, early (<24 hours) for high-risk features, or within 72 hours for intermediate-risk features. 1, 2
Initial Evaluation and Monitoring
ECG must be obtained within 10 minutes of first medical contact to confirm NSTEMI diagnosis and exclude STEMI. 1 Continuous cardiac rhythm monitoring should be initiated immediately. 1
Key assessment parameters include:
- Chest pain characteristics: duration, persistence, and response to initial therapy 1
- Hemodynamic status: systolic blood pressure, heart rate, Killip classification 1
- 12-lead ECG findings: ST-segment depression, T-wave inversions, or transient ST-elevation 1
- High-sensitivity troponin levels: to confirm myocardial necrosis 1, 3
Immediate Pharmacological Management
Antiplatelet Therapy
Aspirin should be administered immediately to all patients without contraindications (loading dose followed by 81 mg daily maintenance). 1, 2
For P2Y12 inhibitor selection:
- Ticagrelor (180 mg loading, 90 mg twice daily) is the preferred agent for moderate-to-high risk patients, regardless of management strategy 1, 2
- Clopidogrel (300-600 mg loading, 75 mg daily) is indicated when ticagrelor is contraindicated or oral anticoagulation is required 2, 4
- Prasugrel should NOT be given until coronary anatomy is defined at angiography 1, 2
Parenteral Anticoagulation
All patients require parenteral anticoagulation in addition to dual antiplatelet therapy from the time of diagnosis. 2 Selection depends on planned management strategy:
For early invasive strategy (angiography planned):
- Unfractionated heparin (UFH): 60 IU/kg bolus (max 4000 IU), then 12 IU/kg/hour infusion (max 1000 IU/hour), adjusted to aPTT 1
- Enoxaparin: 0.10 mg/kg loading dose, then 0.25 mg/kg/hour until angiography 1
- Bivalirudin: 0.10 mg/kg loading, 0.25 mg/kg/hour (only with provisional GP IIb/IIIa use) 1
For initial conservative/delayed invasive strategy:
- Fondaparinux: 2.5 mg subcutaneous daily is preferred 1, 2
- Critical warning: If fondaparinux is used and patient subsequently undergoes PCI, administer UFH bolus at time of procedure to prevent catheter thrombosis 1, 2
Anti-Ischemic Therapy
- Sublingual or IV nitroglycerin for persistent chest pain 1
- Beta-blockers (oral within 24 hours if no contraindications) 2
- High-intensity statin therapy should be initiated immediately 2
Risk Stratification and Timing of Invasive Strategy
Risk stratification determines the urgency of coronary angiography, not whether to perform it. 5 The 2020 ESC guidelines provide the most current framework:
Immediate Invasive Strategy (<2 hours)
Indicated for patients with at least one very high-risk criterion: 1, 6
- Refractory or recurrent chest pain despite medical therapy 1, 6
- Hemodynamic instability or cardiogenic shock 1, 6
- Life-threatening arrhythmias (sustained ventricular tachycardia/fibrillation) 1, 6
- Acute heart failure or pulmonary edema 1
- Mechanical complications (acute mitral regurgitation, ventricular septal defect) 1
Early Invasive Strategy (<24 hours)
Indicated for patients with at least one high-risk criterion: 1, 5
- GRACE risk score >140 1, 5
- Dynamic or new ST-segment/T-wave changes suggesting ongoing ischemia 1, 2
- Transient ST-segment elevation 1
- Elevated troponin levels (confirming NSTEMI diagnosis) 1, 2
- TIMI risk score >4 5
The 2020 ESC guidelines and recent evidence favor early invasive strategy within 24 hours over delayed approach for high-risk patients, as this reduces recurrent ischemia and improves outcomes. 1, 5, 6
Invasive Strategy (<72 hours)
Indicated for patients with at least one intermediate-risk criterion: 1
- Diabetes mellitus 1, 2
- Renal insufficiency (eGFR <60 mL/min/1.73 m²) 2
- Left ventricular ejection fraction <40% 1
- Prior PCI within 6 months 1
- Prior coronary artery bypass surgery 1
Ischemia-Guided (Selective Invasive) Strategy
May be considered for low-risk patients (normal troponin, no high-risk features, GRACE score <140) who stabilize with medical therapy. 1 These patients should undergo noninvasive stress testing before discharge to identify high-risk coronary disease. 5
However, many initially conservatively managed patients will cross over to invasive angiography due to recurrent ischemia, heart failure, or development of high-risk features. 5
Technical Aspects of Invasive Management
Radial artery access is the recommended standard approach for coronary angiography and PCI, as it reduces bleeding complications. 1
Drug-eluting stents are recommended over bare-metal stents for any PCI, regardless of clinical presentation or anticipated duration of dual antiplatelet therapy. 1
Revascularization strategy (culprit-only PCI, multivessel PCI, or CABG) should be based on:
- Patient clinical status and comorbidities 1
- Disease severity and distribution 1
- Angiographic lesion characteristics (SYNTAX score) 1
Routine immediate revascularization of non-culprit lesions is NOT recommended in patients with cardiogenic shock. 1
Common Pitfalls and Caveats
Do not delay invasive angiography in high-risk patients to perform noninvasive testing first—this represents inappropriate risk stratification and delays definitive therapy. 5
Do not administer fibrinolytic therapy to NSTEMI patients—this is contraindicated and associated with harm. 1
Adjust anticoagulant and antiplatelet dosing for renal function and age to minimize bleeding risk. 1
Do not use abciximab (GP IIb/IIIa inhibitor) unless PCI is planned; eptifibatide or tirofiban are preferred for upstream use in high-risk patients. 1
Maintain aspirin dose at 81 mg daily when used with ticagrelor to optimize efficacy and minimize bleeding. 1
Continue dual antiplatelet therapy for at least 12 months after NSTEMI, regardless of whether revascularization was performed. 1, 2