Is Tenecteplase (TNK) indicated in late ST-Elevation Myocardial Infarction (STEMI) with cardiac arrest?

Tenecteplase (TNK) in Late STEMI with Cardiac Arrest

In late STEMI with cardiac arrest, tenecteplase (TNK) should be administered only when primary PCI cannot be performed in a timely manner and there is evidence of ongoing ischemia, hemodynamic instability, or a large area of myocardium at risk. 1, 2

Reperfusion Strategy in Late STEMI with Cardiac Arrest

• A primary PCI strategy is recommended in patients with resuscitated cardiac arrest and an ECG consistent with STEMI, as this is the preferred reperfusion approach 3
• For patients with STEMI in cardiac arrest where primary PCI cannot be performed in a timely manner, fibrinolytic therapy with TNK is indicated if symptoms of ischemia have been present for ≤12 hours 3
• In late presenting STEMI (>12 hours after symptom onset) with cardiac arrest, routine PCI of an occluded infarct-related artery is not indicated unless there is evidence of ongoing ischemia or hemodynamic instability 3

TNK Administration in Cardiac Arrest Setting

• Emergency angiography and PCI is indicated in patients with heart failure/shock following cardiac arrest, regardless of time from symptom onset 3, 2
• When fibrinolysis is the chosen reperfusion strategy, it should be initiated as soon as possible after STEMI diagnosis, preferably in the pre-hospital setting 3, 4
• A fibrin-specific agent like tenecteplase is recommended over non-fibrin specific agents 3, 4
• For patients ≥75 years old, a 50% dose reduction of TNK is recommended to reduce the risk of intracranial hemorrhage 4, 5

Adjunctive Therapy with TNK

• Oral or IV aspirin should be administered immediately to all patients without contraindications 3, 4
• Clopidogrel should be added to aspirin when using fibrinolytic therapy 3, 4
• Anticoagulation should be administered until revascularization or for the duration of hospital stay (up to 8 days) 3
• Enoxaparin IV followed by subcutaneous administration is preferred over unfractionated heparin 3, 4

Post-Fibrinolytic Management

• Transfer to a PCI-capable center following fibrinolysis is indicated in all patients immediately after fibrinolysis 3, 4
• Rescue PCI is indicated immediately if fibrinolysis has failed (<50% ST-segment resolution at 60-90 minutes) or in the presence of hemodynamic or electrical instability 3, 4
• Angiography and PCI of the infarct-related artery is recommended between 2-24 hours after successful fibrinolysis 3, 4

Contraindications and Cautions

• TNK is contraindicated in patients with active internal bleeding, history of cerebrovascular accident, intracranial or intraspinal surgery or trauma within 2 months, intracranial neoplasm, arteriovenous malformation or aneurysm, known bleeding diathesis, or severe uncontrolled hypertension 6, 1
• Carefully assess the risk-benefit ratio in cardiac arrest patients, as there is an increased risk of bleeding complications, particularly intracranial hemorrhage 1, 7
• Small observational studies suggest that empiric TNK in cardiac arrest patients unresponsive to standard ACLS interventions may increase return of spontaneous circulation and short-term survival 7

Clinical Decision Algorithm

1. Determine time from symptom onset:

   • If ≤12 hours: Consider TNK if primary PCI cannot be performed within 120 minutes 3
   • If >12 hours: TNK is generally not indicated unless there is evidence of ongoing ischemia, hemodynamic instability, or large area of myocardium at risk 3, 1

2. Assess for absolute contraindications to TNK 6

3. If TNK is administered:

   • Use weight-adjusted dosing (30-50 mg based on weight) 4
   • Consider 50% dose reduction in patients ≥75 years 4, 5
   • Administer appropriate adjunctive therapy (aspirin, clopidogrel, anticoagulation) 3, 4
   • Arrange immediate transfer to a PCI-capable center 3, 4

4. Monitor for reperfusion success (symptom relief, hemodynamic stability, ≥50% ST-segment resolution at 60-90 minutes) 4, 2

5. Perform rescue PCI if fibrinolysis fails or if there is hemodynamic/electrical instability 3, 4