How to manage thrombocytopenia in patients with Impella (Intra-Aortic Balloon Pump) devices?

Management of Thrombocytopenia in Patients with Impella Devices

For patients with Impella devices who develop thrombocytopenia, the anticoagulation strategy should be modified based on platelet count, with bivalirudin being the preferred alternative when heparin-induced thrombocytopenia (HIT) is suspected. 1, 2

Initial Assessment of Thrombocytopenia

• Determine severity of thrombocytopenia:

  • Significant thrombocytopenia: <100,000/μL or >50% drop in platelet count 1
  • Severe thrombocytopenia: <50,000/μL

• Rule out pseudothrombocytopenia:

  • Examine peripheral blood smear for platelet clumping
  • Collect blood in a tube containing sodium citrate and repeat platelet count 1

• Evaluate for HIT:

  • Calculate 4T score for probability of HIT
  • Consider HIT with >50% drop in platelet count during heparin therapy, typically 5-10 days after starting heparin 1
  • Order platelet factor-4 IgG ELISA test and serotonin release assay if HIT is suspected 2

Management Based on Platelet Count

For Platelet Count <50,000/μL:

• Modify anticoagulation:
  • Reduce heparin dose to 50% of therapeutic dose or use prophylactic dose only 1
  • Consider alternative anticoagulants if bleeding risk is high

For Platelet Count <25,000/μL:

• Hold heparin anticoagulation 1
• Consider platelet transfusion if active bleeding or high bleeding risk

For Suspected HIT:

• Immediately discontinue all heparin products, including heparin in the Impella purge solution 3, 4, 2
• Switch to alternative anticoagulation:

  1. Bivalirudin: Both systemic infusion and in purge solution 2

     • Systemic infusion: Start at 0.2 μg/kg/min
     • Purge solution: Low concentration bivalirudin (can be added to purge solution) 2

  2. Argatroban: Alternative option 3, 4

     • Systemic infusion: Start at 0.2 μg/kg/min
     • Purge solution: Argatroban 0.05 mg/mL 3

Monitoring and Adjustment

• Monitor activated partial thromboplastin time (aPTT):

  • Target intermediate aPTT range (40-60s) rather than therapeutic range (60-80s) to reduce bleeding risk 5
  • Recent evidence suggests lower aPTT targets may reduce major bleeding events without increasing thromboembolic complications 5

• Monitor Impella device parameters:

  • Track purge flow and pressure
  • Be aware that alternative anticoagulants may affect purge dynamics:
    • Bivalirudin use may result in decreased purge flow (up to 76%) and increased purge pressure (up to 89%) 2
    • Watch for signs of device malfunction or thrombosis

• Monitor for bleeding complications:

  • Higher ACT levels (>168s) have been associated with increased 30-day mortality 6
  • Consider using low-dose heparin purge solution in patients with high bleeding risk 6

Common Pitfalls and Considerations

• Do not continue heparin in patients with confirmed or strongly suspected HIT

• Do not overlook the need to modify both systemic anticoagulation and purge solution anticoagulation

• Avoid excessive anticoagulation as higher ACT levels (>168s) are associated with increased mortality 6

• Be aware that thrombocytopenia in Impella patients may be due to:

  • HIT
  • Device-induced hemolysis
  • Underlying critical illness
  • Other medications

• For patients with confirmed HIT requiring Impella support, bivalirudin has demonstrated safety and efficacy as an alternative to heparin 2

• Consider platelet transfusions for severe thrombocytopenia (<10,000/μL) with active bleeding 1