Treatment of ST-Elevation Myocardial Infarction (STEMI)
Primary percutaneous coronary intervention (PCI) is the preferred reperfusion strategy for STEMI and must be performed immediately; if PCI cannot be delivered within 120 minutes of diagnosis, fibrinolytic therapy should be administered instead. 1
Immediate Reperfusion Strategy
The choice between primary PCI and fibrinolysis depends entirely on time to treatment:
- Reperfusion therapy is mandatory for all patients with symptoms <12 hours duration and persistent ST-segment elevation 1
- Primary PCI is superior to fibrinolysis when performed rapidly at experienced centers 2, 3
- If primary PCI cannot be performed in a timely manner after STEMI diagnosis, fibrinolytic therapy must be initiated within 12 hours of symptom onset 1
Primary PCI Pathway
Patients should bypass the emergency department entirely and go directly to the catheterization laboratory 1
- PCI-capable centers must provide 24/7 service without delay 1
- Regional networks should be designed to make primary PCI available to as many patients as possible 1
- The goal is door-to-device time that minimizes myocardial damage 2
Fibrinolysis Pathway (When PCI Unavailable)
Fibrinolytic therapy should be initiated as soon as possible after STEMI diagnosis, preferably in the pre-hospital setting, with a goal of within 10 minutes of diagnosis 1
- Use a fibrin-specific agent: tenecteplase, alteplase, or reteplase 1
- In patients ≥75 years, use half-dose tenecteplase 1
- All patients receiving fibrinolysis must be transferred immediately to a PCI-capable center 1
Antithrombotic Therapy
For Primary PCI
Aspirin (oral or IV if unable to swallow) must be given as soon as possible to all patients without contraindications 1
A potent P2Y12 inhibitor is required before (or at latest at the time of) PCI and continued for 12 months: 1
- Prasugrel or ticagrelor are preferred 1
- Clopidogrel only if prasugrel/ticagrelor unavailable or contraindicated 1
Fondaparinux is contraindicated for primary PCI 1
For Fibrinolysis
Aspirin (oral or IV) is mandatory 1
Clopidogrel must be added to aspirin 1
Anticoagulation is required until revascularization or for hospital stay up to 8 days: 1
- Enoxaparin IV followed by subcutaneous (preferred over unfractionated heparin) 1
- Unfractionated heparin as weight-adjusted IV bolus followed by infusion 1
- For streptokinase specifically: fondaparinux IV bolus followed by subcutaneous dose 24 hours later 1
Post-Fibrinolysis Management (Pharmacoinvasive Strategy)
Emergency angiography and PCI is mandatory in patients with heart failure or shock 1
Rescue PCI must be performed immediately when: 1
- Fibrinolysis has failed (<50% ST-segment resolution at 60-90 minutes)
- Hemodynamic or electrical instability occurs
- Worsening ischemia develops
Angiography and PCI of the infarct-related artery should be performed between 2-24 hours after successful fibrinolysis 1
Emergency angiography is required for recurrent ischemia or evidence of reocclusion 1
Long-Term Antithrombotic Management
Dual antiplatelet therapy (aspirin plus ticagrelor or prasugrel, or clopidogrel if others contraindicated) must continue for 12 months unless excessive bleeding risk exists 1
Low-dose aspirin (75-100 mg) is indicated indefinitely 1
Additional In-Hospital Management
Routine echocardiography during hospital stay is mandatory to: 1
- Assess left and right ventricular function
- Detect early post-MI mechanical complications
- Exclude left ventricular thrombus
Critical Pitfalls to Avoid
Do not perform routine PCI of an occluded infarct-related artery >48 hours after STEMI onset in asymptomatic patients 1
Do not use pre-hospital cooling with rapid infusion of large volumes of cold IV fluid after return of spontaneous circulation 1
Do not delay reperfusion therapy—time is myocardium 2, 4
Secondary Prevention
Smoking cessation interventions are mandatory, including repeated counseling, nicotine replacement, varenicline, and bupropion 1
Cardiac rehabilitation program participation is required 1