Thrombolysis in Acute PE

Today, we discussed the case of an elderly woman with paroxysmal afib, who presented to the ED with recurrent episodes of chest pain, and was eventually diagnosed with a massive (or “high risk”) pulmonary embolism. See below for pearls on utilization of thrombolysis in acute PE.

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TOP PEARLS

  • The only guideline-accepted indication for systemic thrombolysis for acute PE is hemodynamic instability.
  • Decision for systemic thrombolysis in acute PE is often a challenging question that often requires a multi-disciplinary discussion (primary team, cardiology, hematology, pulmonology, and IR). Some institutions have implemented a PE Response Team (PERT) to facilitate rapid multidisciplinary decision making (Check out this article in Chest regarding such a team at MGH –> PMID 27006156 ).

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Thrombolytic Therapy in Acute Pulmonary Embolism

  • Thrombolytic therapy leads to early hemodynamic improvement in acute PE, but at a cost of increased major bleeding. Often times, the decision for systemic thrombolysis is a difficult one, and many academic institutions have incorporated a “PERT (PE Response Team)” to facilitate this decision making. See related paper (PMID: 27006156).

  • Hemodynamic instability is the only guideline-accepted definite indication for systemic thrombolysis.
  • Possible Indications on a case-by-case basis:
    • Severe or worsening RV dysfunction without systemic hypotension (“submassive” or “intermediate risk”)
    • Cardiopulmonary arrest due to PE: case reports reported success from systemic thrombolysis during cardiopulmonary resuscitation when arrest is secondary to a PE
    • Extensive clot burden (large perfusion defects on VQ scan or extensive clot burden on CT)
    • Free-floating R atrial or ventricular thrombus
  • Contraindications for thrombolysis:
    • Absolute: intracranial neoplasm, recent (<2 mo) intracranial or spinal surgery/trauma, history of hemorrhagic stroke, active bleeding or bleeding diathesis, nonhemorrhagic stroke within previous 3 months
    • Relative: SBP > 200, DBP > 110, nonhemorrhagic stroke older than 3 months, surgery within the previous 10 days, pregnancy
  • How to administer?
    • Usually administered via a peripheral IV as an infusion:
      • tPA: 100 mg IV over 2 hours
      • Streptokinase: 250 K units IV over initial 30 min à then 100 K units/hr for 24 hours
      • Urokinase: 4400 units/kg IV for initial 10 min à 4400 units/kg/hr for 12 hours
    • Bolus infusion of thrombolytics may be effective, but it has not been directly compared to a 2 hour infusion of tPA.
    • Catheter-directed thrombolysis?
      • May be considered for patients with persistent hemodynamic instability despite systemic thrombolysis, or those at risk of death before systemic thrombolysis can manifest effective, and those at high risk of bleeding.
      • Reserved for use in centers with appropriate expertise (Miles Conrad at ZSFG performs them)
      • Potential benefit is that lower doses of lytic agent can be administered. However, data regarding this approach come from small prospective trials with mixed results!
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