Thrombolytic Therapy Protocol for STEMI
Initiate fibrinolytic therapy immediately when primary PCI cannot be performed within 120 minutes of STEMI diagnosis, using a fibrin-specific agent (tenecteplase, alteplase, or reteplase) preferably in the pre-hospital setting, combined with aspirin, clopidogrel, and enoxaparin anticoagulation. 1
When to Use Fibrinolysis
Administer fibrinolytic therapy when primary PCI is not available within 120 minutes of STEMI diagnosis in patients presenting within 12 hours of symptom onset with persistent ST-segment elevation and no contraindications (Class I, Level A). 1
The benefit is greatest within the first 3 hours of symptom onset, with every minute of delay increasing myocardial necrosis. 2
Primary PCI remains the preferred reperfusion strategy when it can be delivered within the appropriate time window. 1, 3
Fibrinolytic Agent Selection
Use a fibrin-specific thrombolytic agent: tenecteplase, alteplase, or reteplase (Class I, Level B). 1
These agents achieve epicardial infarct-artery patency in approximately 50% of patients within 90 minutes. 4
Essential Adjunctive Medications
Antiplatelet Therapy
Aspirin: Administer oral or IV aspirin (if unable to swallow) as soon as possible (Class I, Level B). 1
Clopidogrel: Give clopidogrel immediately in addition to aspirin when fibrinolysis is the reperfusion strategy (Class I, Level A). 1, 5
- Critical distinction: Clopidogrel is specifically indicated for fibrinolytic therapy, NOT prasugrel or ticagrelor initially. 5
Anticoagulation
Enoxaparin is preferred: IV bolus followed by subcutaneous administration (preferred over unfractionated heparin, Class I, Level A). 1, 5
Alternative: Weight-adjusted unfractionated heparin IV bolus followed by infusion (Class I, Level B). 1
Continue anticoagulation until revascularization or for hospital stay duration up to 8 days. 1, 5
Absolute Contraindications to Fibrinolysis
Fibrinolytic therapy is contraindicated in patients with: 6
- Active internal bleeding
- History of cerebrovascular accident
- Intracranial or intraspinal surgery/trauma within 2 months
- Intracranial neoplasm, arteriovenous malformation, or aneurysm
- Known bleeding diathesis
- Severe uncontrolled hypertension
Post-Fibrinolysis Management Strategy
Immediate Transfer
Transfer ALL patients to a PCI-capable center immediately after fibrinolysis (Class I, Level A). 1, 5
Patients should bypass the emergency department and proceed directly to the catheterization laboratory when appropriate. 1
Timing of Angiography Based on Clinical Scenario
Routine angiography: Perform between 2-24 hours after successful fibrinolysis (Class I, Level A). 1, 5
Emergency angiography (immediate): 1, 5
- Heart failure or cardiogenic shock
- Hemodynamic or electrical instability
- Recurrent ischemia or evidence of reocclusion
Rescue PCI (immediate): When fibrinolysis has failed, defined as <50% ST-segment resolution at 60-90 minutes (Class I, Level A). 1, 5
Transition to Potent P2Y12 Inhibitor
At the time of PCI, switch from clopidogrel to prasugrel or ticagrelor and maintain for 12 months unless contraindications exist (Class I, Level A). 5, 2
Critical pitfall: Do not continue clopidogrel after PCI is performed—escalate antiplatelet therapy at the time of coronary intervention. 5
Monitoring and Safety Considerations
Bleeding Precautions
Avoid intramuscular injections and minimize patient handling during the first few hours. 6
Perform arterial and venous punctures carefully; avoid internal jugular and subclavian sites. 6
If arterial puncture is necessary, use upper extremity vessels accessible to manual compression and apply pressure for at least 30 minutes. 6
Bleeding requiring transfusion occurs in approximately 5% of patients, with stroke risk approximately 1.8%. 4
Arrhythmia Management
- Have anti-arrhythmic therapy available for bradycardia and ventricular irritability, as reperfusion arrhythmias (sinus bradycardia, accelerated idioventricular rhythm, ventricular tachycardia) commonly occur. 6
Assessment of Reperfusion Success
Monitor for rapid resolution of ST-segment elevation within 60-90 minutes, which correlates with angiographic patency, smaller infarct size, and better clinical outcomes. 7
Perform routine echocardiography during hospital stay to assess LV/RV function, detect mechanical complications, and exclude LV thrombus. 1
Critical Pitfalls to Avoid
Do not use prasugrel or ticagrelor as the initial P2Y12 inhibitor with fibrinolytic therapy—clopidogrel is specifically indicated in this setting. 5
Do not delay transfer to a PCI-capable center—all patients require angiography regardless of apparent lysis success. 5
Do not miss the 2-24 hour window for routine angiography after successful fibrinolysis. 5
Do not combine fibrinolysis with planned immediate PCI—choose one primary reperfusion strategy, as combined therapy shows trends toward worse outcomes including increased mortality (6.7% vs 4.9%), cardiogenic shock, and recurrent MI. 6
Do not use fondaparinux for primary PCI (Class III, Level B). 1