Management of Acute Coronary Syndromes
STEMI Management
For STEMI, immediate reperfusion with primary PCI within 120 minutes of presentation is the definitive treatment, reducing mortality from 9% to 7% 1. If PCI cannot be achieved within this timeframe, fibrinolytic therapy should be administered immediately, followed by transfer for PCI within 24 hours 1.
Reperfusion Strategy for STEMI:
- Primary PCI: Door-to-balloon time ≤120 minutes (preferred approach)
- Fibrinolytic therapy (if PCI unavailable within 120 minutes):
- Full dose alteplase, reteplase, or tenecteplase for patients <75 years
- Half dose for patients ≥75 years
- Transfer to PCI-capable facility within 24 hours after fibrinolysis 1
Immediate Medical Therapy:
- Aspirin indefinitely
- Anticoagulation (UFH, enoxaparin, fondaparinux, or bivalirudin)
- P2Y12 inhibitor loading dose (clopidogrel, prasugrel, or ticagrelor)
- Beta-blocker within 24 hours (unless contraindicated: heart failure signs, low-output state, cardiogenic shock risk, PR >0.24s, 2nd/3rd degree heart block, active asthma) 2
- ACE inhibitor within 24 hours if LVEF ≤0.40 or pulmonary congestion 2
- Sublingual nitroglycerin 0.4mg every 5 minutes × 3 doses, then IV if ongoing ischemia 2
NSTEMI/Unstable Angina Management
For high-risk NSTEMI/unstable angina, a routine invasive strategy with coronary angiography within 24-48 hours reduces death from 6.5% to 4.9% 1. The timing depends on risk stratification.
Risk-Based Invasive Strategy:
Immediate invasive strategy (<2 hours) for unstable patients with 3:
- Refractory or recurrent angina despite optimal medical therapy
- Hemodynamic instability
- Electrical instability (ventricular arrhythmias)
- Acute pulmonary edema or heart failure
- Worsening mitral regurgitation
Early invasive strategy (12-24 hours) for high-risk patients 4, 3:
- Elevated troponin
- Dynamic ST-segment or T-wave changes
- GRACE risk score >140
- Diabetes mellitus
- Renal insufficiency (CrCl <60 mL/min)
- LVEF <0.40
- Prior PCI or CABG
Selective invasive strategy for lower-risk patients 3:
- Normal or minimally elevated biomarkers
- No high-risk features
- Proceed with noninvasive stress testing or coronary CT angiography
- Angiography only if positive stress test or recurrent symptoms
Initial Medical Therapy (Before Angiography):
Antiplatelet therapy:
- Aspirin indefinitely 5
- P2Y12 inhibitor loading dose (clopidogrel 300-600mg, ticagrelor 180mg, or prasugrel 60mg) 6
- GP IIb/IIIa inhibitor (eptifibatide, tirofiban, or abciximab) for troponin-positive high-risk patients 5
Anticoagulation (choose one) 5:
- UFH: Continue for ≥48 hours or until discharge
- Enoxaparin: Continue for duration of hospitalization, up to 8 days
- Fondaparinux: Continue for duration of hospitalization, up to 8 days
- Bivalirudin: Discontinue or continue at 0.25 mg/kg/hr for up to 72 hours
Additional therapy:
- Beta-blocker within 24 hours (same contraindications as STEMI) 2
- ACE inhibitor if LVEF ≤0.40 or pulmonary congestion 2
- Nitroglycerin for ongoing ischemia 2
Post-Angiography Management Pathways
If PCI Selected:
- Continue aspirin 5
- Load with P2Y12 inhibitor if not given pre-angiography 5
- GP IIb/IIIa inhibitor for troponin-positive high-risk patients (can omit if bivalirudin used with clopidogrel ≥300mg given ≥6 hours prior) 5
- Discontinue anticoagulation after uncomplicated PCI 5
If CABG Selected:
- Continue aspirin 5, 7
- Discontinue P2Y12 inhibitor: 5-7 days for clopidogrel, 7 days for prasugrel/ticagrelor (unless urgent surgery required) 6
- Discontinue GP IIb/IIIa inhibitor 4 hours before CABG 5, 7
- Anticoagulation management 5, 7:
- Continue UFH
- Discontinue enoxaparin 12-24 hours before, switch to UFH
- Discontinue fondaparinux 24 hours before, switch to UFH
- Discontinue bivalirudin 3 hours before, switch to UFH
If Medical Therapy Selected:
- Continue aspirin 5
- Load with P2Y12 inhibitor if not given 5
- Discontinue GP IIb/IIIa inhibitor 5
- Continue anticoagulation 5:
- UFH for ≥48 hours or until discharge
- Enoxaparin/fondaparinux for duration of hospitalization, up to 8 days
- Bivalirudin: discontinue or continue at physician's discretion
If Conservative Strategy with No Angiography:
- Perform stress test if no recurrent symptoms/ischemia, heart failure, or serious arrhythmias 5
- If LVEF ≤0.40: proceed to angiography 5
- If LVEF >0.40: perform stress test; if not low-risk, proceed to angiography 5
Critical Pitfalls to Avoid
Do not delay reperfusion in STEMI waiting for biomarkers—ECG findings alone mandate immediate action 1, 8.
Do not use fibrinolytic therapy in NSTEMI/unstable angina—it is contraindicated and harmful 5.
Do not perform early invasive strategy in patients with extensive comorbidities (liver/pulmonary failure, cancer) where risks outweigh benefits 4.
Recognize STEMI equivalents (posterior MI, Wellens' syndrome, de Winter's T-waves) that require immediate reperfusion despite not meeting classic STEMI criteria 9.