• Introduction

    •  

    • Focus: Anticoagulation and thrombosis management in mechanical circulatory support (MCS), with emphasis on Impella devices and ECMO.

    • Discusses anticoagulation strategies, management of pump thrombosis, and thrombolytic therapy in ECMO/PE.

  • Impella Devices

    • Continuous antegrade blood flow pumps unloading the LV, improving forward flow.

    • Models: CP and 5.5 (most used for LV support), RP/RP Flex (RV support).

    • Duration originally 14 days, but often extended to weeks/months.

  • Anticoagulation & Purge Solutions

    • Heparin purge (25 units/mL) traditionally used to protect motor housing from thrombus.

    • Bicarbonate purge (25–50 mcg/mL NaHCO₃ in D5W): prevents protein denaturation/fibrin polymerization, reduces hemolysis, allows heparin-free strategy.

    • Systemic anticoagulation: ACT 160–180, Anti-Xa 0.3–0.6, APTT ~45–90s.

  • Survey Data (2019)

    • Most high-volume centers used heparinized purge solutions.

    • Alternatives: DTI (argatroban/bivalirudin) in purge or pure dextrose.

    • Routine hemolysis monitoring underused (<50%).

  • Heparin Exposure from Purge

    • Purge flow may deliver therapeutic systemic heparin even without IV infusion.

    • Strategies: adjust IV dose considering purge contribution, or manage IV infusion alone to avoid dosing errors.

  • Evidence on Anticoagulation Intensity

    • Lower APTT targets (40–60) reduced bleeding versus higher goals (60–80) without increasing thrombotic events.

    • Institutional practice: systemic bivalirudin with bicarbonate purge (safer, less bleeding, good survival).

    • Studies: Bivalirudin shows trend toward less bleeding and better therapeutic stability compared to heparin.

  • Pump Thrombosis Management

    • Signs: ↑ purge pressure, ↓ purge flow, ↑ motor current.

    • Therapy: Alteplase (0.04–0.08 mg/mL) infused via purge restores flow.

    • Institutional case series: 90% success, avg. 10 mg alteplase required.

  • ECMO in Pulmonary Embolism

    • VA ECMO used as a bridge to thrombectomy or CDT in massive PE/cardiac arrest.

    • Strategies:

      • Systemic thrombolysis + ECMO (higher bleeding risk).

      • ECMO + catheter-directed thrombolysis/thrombectomy (increasingly preferred).

    • Guidelines: CDT (fragmentation, aspiration, local lysis) reduces bleeding compared to systemic TPA.

    • Mortality higher with anticoagulation alone; ECMO + CDT shows best outcomes.

  • Emerging Concepts

    • Novel approaches: instilling Alteplase into ECMO oxygenator to delay exchange (experimental).

 

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