When should fibrinolytic therapy be administered in ST-Elevation Myocardial Infarction (STEMI)?

From the Guidelines

Fibrinolytic therapy should be administered in STEMI patients as soon as possible after diagnosis, preferably in the pre-hospital setting, when primary percutaneous coronary intervention (PCI) cannot be performed within 120 minutes of first medical contact. The decision to administer fibrinolytic therapy is based on the timing of symptom onset and the availability of PCI. According to the 2017 ESC guidelines for the management of acute myocardial infarction in patients presenting with ST-segment elevation 1, fibrinolysis is recommended when the anticipated first medical contact (FMC) to device time at a PCI-capable hospital exceeds 120 minutes.

The benefits of fibrinolytic therapy in STEMI patients are well established, with a time-dependent reduction in both mortality and morbidity rates during the initial 12 hours after symptom onset 1. The preferred agents for fibrinolytic therapy include tissue plasminogen activator (tPA) such as alteplase, reteplase, or tenecteplase, which should be administered with antiplatelet therapy including aspirin and clopidogrel, as well as anticoagulation with unfractionated heparin or enoxaparin.

Some key points to consider when administering fibrinolytic therapy include:

• The timing of administration, with the goal of initiating treatment as soon as possible after STEMI diagnosis
• The choice of fibrinolytic agent, with a fibrin-specific agent such as tenecteplase, alteplase, or reteplase recommended 1
• The use of antiplatelet therapy, including aspirin and clopidogrel, in addition to fibrinolytic therapy
• The need for anticoagulation, with enoxaparin or unfractionated heparin recommended until revascularization or for the duration of hospital stay up to 8 days 1
• The importance of transferring patients to a PCI-capable facility after fibrinolysis for either rescue PCI if reperfusion fails or routine angiography within 24 hours.

Contraindications to fibrinolytic therapy include prior intracranial hemorrhage, known cerebrovascular lesion, ischemic stroke within 3 months, active bleeding, suspected aortic dissection, significant closed head trauma within 3 months, or uncontrolled hypertension (>180/110 mmHg). Overall, the goal of fibrinolytic therapy in STEMI patients is to rapidly restore blood flow to the affected myocardium, reducing morbidity and mortality.

From the FDA Drug Label

Initiate treatment as soon as possible after the onset of STEMI symptoms. Fibrinolytic therapy with tenecteplase should be administered as soon as possible after the onset of STEMI symptoms [ 2 ].

• The dosage is individualized based on the patient's weight.
• It is administered as a single bolus over 5 seconds.

From the Research

Fibrinolytic Therapy Administration in STEMI

• Fibrinolytic therapy should be administered in patients with STEMI when primary percutaneous coronary intervention (PPCI) cannot be delivered within 90-120 minutes from the patient's first medical contact 3.
• Fibrinolytic therapy is recommended for patients presenting early after symptom onset and without contraindications, especially when PPCI is not available in a timely manner 3, 4.
• The therapy should preferably be started in the pre-hospital setting to minimize delays 3.
• Following fibrinolytic therapy, patients should be transferred to a PCI-center for rescue PCI or routine coronary angiography with PCI as indicated 3.

Timing of Fibrinolytic Therapy

• The American College of Chest Physicians recommends that fibrinolytic therapy be administered promptly after contact with the healthcare system for patients with ischemic symptoms characteristic of acute MI of ≤ 12 hours in duration and persistent STE 5.
• The door-to-needle (DTN) time for fibrinolytic therapy should be ≤ 30 minutes, but this target is often not met, with a median DTN time of 34 minutes reported in one study 6.
• Timely fibrinolysis (DTN time ≤ 30 minutes) is associated with a decreased risk of a composite outcome of death, shock, or stroke 6.

Considerations for Fibrinolytic Therapy

• Fibrinolytic therapy should always be considered when timely primary PCI cannot be delivered appropriately 7.
• Clinicians should promptly recognize the signs of fibrinolytic therapy failure and consider rescue PCI 7.
• When fibrinolytics are used, coronary angiography and revascularization should not be conducted within the initial 3 hours after fibrinolytic administration 7.