Treatment of Acute ST-Elevation Myocardial Infarction (STEMI)
Primary percutaneous coronary intervention (PCI) is the preferred reperfusion strategy for STEMI patients when it can be performed in a timely manner (within 90 minutes of first medical contact), while fibrinolytic therapy should be administered immediately when PCI cannot be performed within 120 minutes of STEMI diagnosis. 1, 2
Initial Diagnosis and Management
- Obtain 12-lead ECG within 10 minutes of first medical contact 1, 2
- Establish continuous ECG monitoring with defibrillator capacity immediately 1, 2
- Administer 162-325 mg of aspirin (non-enteric coated, chewed) immediately 2
- Add a loading dose of a P2Y12 inhibitor:
- Start anticoagulation immediately:
Reperfusion Strategy Selection
Primary PCI Strategy
- Preferred when PCI can be performed within 90 minutes of first medical contact 1
- Absolute goal: First medical contact-to-device time ≤90 minutes 1
- For high-risk patients with large infarct area: Target ≤60 minutes 1
- Transfer patients to PCI-capable centers, bypassing emergency departments when possible 1
Fibrinolytic Therapy
- Indicated when anticipated time from STEMI diagnosis to PCI exceeds 120 minutes 1, 2
- Should be administered within 30 minutes of hospital arrival (door-to-needle time) 1, 2
- Preferred agents: Fibrin-specific agents (tenecteplase, alteplase, or reteplase) 2
- After fibrinolysis:
Pharmaco-invasive Strategy
- For patients receiving fibrinolysis who are transferred to PCI centers 4, 5
- Early PCI (within 24 hours after successful fibrinolysis) improves cardiovascular outcomes 5
- This strategy has been shown to be non-inferior to primary PCI in areas with long transfer delays 4
Special Considerations
Cardiogenic Shock
- Primary PCI is the preferred strategy regardless of time delay 1
- Consider complete revascularization (non-infarct related arteries) during the index procedure 1
Late Presenters (>12 hours)
- Primary PCI is indicated if there is evidence of ongoing ischemia 1
- May be considered in stable patients presenting 12-24 hours after symptom onset 1
- Not recommended for totally occluded arteries >24 hours after symptom onset in stable patients without signs of ischemia 1
Post-Cardiac Arrest
- Patients with ST-elevation on post-resuscitation ECG should undergo a primary PCI strategy 1
- For patients without ST-elevation but with high suspicion of ongoing ischemia, urgent angiography should be performed within 2 hours 1
Post-Reperfusion Care
- Monitor all patients for at least 24 hours after reperfusion therapy 1, 2
- Perform echocardiography to assess LV/RV function and detect complications 2
- Continue dual antiplatelet therapy (DAPT) for at least 12 months 2
- Initiate secondary prevention measures:
Common Pitfalls to Avoid
- Delaying ECG acquisition beyond 10 minutes of first medical contact
- Failing to recognize STEMI equivalents (hyperacute T-waves, posterior MI, multilead ST depression with ST elevation in aVR)
- Administering oxygen to patients with normal oxygen saturation (SaO2 ≥90%), which may be harmful 1
- Delaying transfer to PCI-capable centers for unnecessary testing
- Premature discontinuation of DAPT, which increases risk of stent thrombosis 2
- Using fondaparinux for primary PCI (contraindicated) 2
The time-sensitive nature of STEMI treatment requires coordinated systems of care similar to trauma systems, with clear protocols for rapid diagnosis, triage, and treatment to minimize total ischemic time and improve patient outcomes 1, 6.