What is the recommended treatment with TNK (tenecteplase) for a patient with cardiac arrest?

TNK (Tenecteplase) for Cardiac Arrest

Direct Recommendation

Tenecteplase may be considered for cardiac arrest when pulmonary embolism (PE) is the suspected or confirmed cause, but it is NOT recommended for routine use in undifferentiated cardiac arrest. 1, 2

Evidence-Based Treatment Algorithm

When TNK Should Be Administered

For PE-Related Cardiac Arrest:

• Administer tenecteplase when PE is the known cause of cardiac arrest (weak recommendation based on very-low-quality evidence) 1
• Consider tenecteplase when PE is strongly suspected as the cause based on clinical presentation (sudden onset dyspnea, risk factors for thromboembolism) 1, 2
• Dosing: Weight-adjusted single IV bolus over 5 seconds (30-50 mg based on body weight) 3, 4

Specific Weight-Based Dosing:

• <60 kg: 30 mg 3
• 60-<70 kg: 35 mg 3
• 70-<80 kg: 40 mg 3
• 80-<90 kg: 45 mg 3
• ≥90 kg: 50 mg 3

When TNK Should NOT Be Used

Contraindicated in undifferentiated cardiac arrest:

• Controlled trials demonstrate lack of mortality benefit and potential harm in patients without confirmed or suspected PE 2
• The largest randomized trial (TROICA) showed no survival benefit at 30 days in undifferentiated cardiac arrest 1
• Increased bleeding risk without corresponding survival benefit 2

Critical Absolute Contraindications During Cardiac Arrest

Even when PE is suspected, do not administer TNK if any of the following are present:

• Any prior intracranial hemorrhage 5, 3
• Known structural cerebral vascular lesion (AV malformation) 5
• Known intracranial neoplasm 5
• Ischemic stroke within 3 months 5
• Suspected aortic dissection 5
• Significant closed-head or facial trauma within 3 months 5
• Active internal bleeding 4

Relative Contraindications Requiring Risk-Benefit Assessment

Traumatic or prolonged CPR (>10 minutes) is a relative contraindication that must be weighed against the mortality of untreated massive PE 5, 3

Clinical Context and Supporting Evidence

Evidence Quality Assessment

The recommendation for PE-related cardiac arrest is based on:

• Very-low-quality evidence from observational studies showing improved ROSC rates (81.0% vs 42.9%, p=0.03 in one retrospective analysis) 1
• One small RCT (TROICA substudy) showing non-significant trend toward improved 30-day survival in suspected PE (13.3% vs 0%, p=0.31) but underpowered 1
• Case series demonstrating successful outcomes in confirmed PE cases 6, 2, 7

The recommendation against routine use in undifferentiated arrest is based on:

• Five controlled trials involving 1,544 patients showing no mortality reduction 2
• Increased bleeding complications without survival benefit 2
• The TROICA trial design specifically for out-of-hospital cardiac arrest of presumed cardiac origin 8

Practical Implementation During Resuscitation

If administering TNK during cardiac arrest:

1. Continue high-quality CPR throughout and after administration 1
2. Administer as single IV bolus over 5 seconds via established IV access 4
3. Flush dextrose-containing lines with 0.9% saline before and after (TNK precipitates with dextrose) 4
4. Continue CPR for at least 60-90 minutes after administration to allow drug circulation and clot lysis 1, 7
5. Monitor for ROSC, which may occur 13-30 minutes post-administration 6, 7

Observational Data on Outcomes

In selected cardiac arrest patients receiving empiric TNK:

• ROSC achieved in 26% vs 12.4% controls (p=0.04) 7
• Survival to admission: 12% vs 0% (p=0.0007) 7
• Survival to discharge: 4% with good neurological outcome (CPC 1-2) 7
• One intracranial hemorrhage (2%) in 50 patients 7

These outcomes occurred after mean 30 minutes of failed ACLS and eight medication doses, suggesting potential benefit in refractory arrest with suspected PE 7

Common Pitfalls and How to Avoid Them

Pitfall 1: Using TNK in Undifferentiated Cardiac Arrest

Avoid: Do not administer TNK routinely without strong clinical suspicion of PE or acute MI as the underlying cause 2

Pitfall 2: Inadequate CPR Duration Post-Administration

Avoid: Stopping resuscitation too early—continue CPR for at least 60-90 minutes after TNK to allow time for thrombolysis and reperfusion 1, 7

Pitfall 3: Dextrose Incompatibility

Avoid: Administering through dextrose-containing IV lines causes precipitation—always flush with normal saline 4

Pitfall 4: Ignoring Absolute Contraindications

Avoid: The mortality risk of untreated PE must be weighed against catastrophic bleeding (particularly intracranial hemorrhage) in patients with recent stroke, head trauma, or known vascular malformations 5, 4

Special Considerations for Cardiac Arrest Context

TNK has theoretical advantages over other fibrinolytics during cardiac arrest:

• Single bolus administration (vs 90-minute alteplase infusion) 1, 9
• Longer half-life (17-24 minutes initial phase) allows continued effect during prolonged resuscitation 9
• No antibody formation, permitting re-administration if needed 10
• Room temperature stable before reconstitution 6

However, these pharmacologic advantages have not translated to proven mortality benefit in undifferentiated cardiac arrest 1, 2

Divergent Evidence Requiring Clinical Judgment

Conflicting data exists:

• Small observational studies suggest benefit in refractory arrest 7
• Larger controlled trials show no mortality benefit overall 1, 2
• Resolution: Restrict use to cases with high clinical suspicion or confirmation of PE, where the underlying pathophysiology is directly addressed by thrombolysis 1, 2

Post-ROSC Management if TNK Administered

If ROSC achieved after TNK:

• Transfer to PCI-capable center immediately 3
• Avoid additional invasive procedures for several hours due to bleeding risk 4
• Monitor for reperfusion arrhythmias (bradycardia, accelerated idioventricular rhythm, VT) 4
• CT imaging to confirm PE if suspected 2
• Consider therapeutic hypothermia per standard post-cardiac arrest care 2