Moffitt HemOnc Report 6/9/17

Thanks to Megan for presenting today at Hem-Onc report! We discussed a young woman with NICM s/p LVAD c/b drive line infxns on Coumadin transferred to UCSF for recurrent, nontraumatic intracranial hemorrhage. Hematology was consulted for two issues:  (1) how do we manage the bleeding, and (2) what was causing the bleeding?

Key Pearls:

  1. For an approach to non-traumatic bleeding, think about congenital and acquired issues with vessels, platelets, and the coagulation cascade.
  2. Patients with LVADS often have an acquired von Willebrand Disorder thought due to the high shear forces (see paper below).
  3. If you suspect an acquired form of vWD it’s appropriate to send the multimer studies concurrent with vWD screening tests.

************************************************************************************

BLEEDING AND CLOTTING WITH LVADS:

  • Thrombosis: varies by the particular model, but in general patients are treated with therapeutic anticoagulation. Even with anticoagulation, patients have risk for pump thrombosis, stroke and other thromboembolic events.
    • Risk factors: inadequate anticoagulation, atrial fibrillation, hypercoagulable states, coexistent infection
  • Bleeding: greatest risk is perioperatively, often related to the coagulopathic effect of extracorporeal circulation. As time goes on, usually at least a week in to LVAD therapy, a significant proportion of patients can develop an acquired vWD (thought due to the high intravascular shear forces) – similar to what we see in Heyde’s Syndrome with aortic stenosis.

General Approach to Bleeding

  • Vessel
    • Acquired:
      • infection, amyloid, vitamin C deficiency, vasculitis (and others!)
    • Inherited:
      • aneurysmal
  • Platelets
    • quantitative – low platelets
    • qualitative – malfunctioning platelets
  • Coagulation cascade
    • intrinsic – PTT (F VIII, IX, X, XIII)
    • extrinsic – PT (F VII)

Evaluation for vWD (Thank you, Pat, for this approach!)

  1. Initial screening tests:
    1. Plasma vWF antigen
    2. Plasma vWF activity (ristocetin cofactor activity)
    3. Factor VIII activity

NB: If the above tests are negative, but you still have a high index of suspicion, the tests should be repeated. If negative x2, start looking for another explanation of bleeding!  If you’re suspicion is for ACQUIRED DISEASE, as in this patient, you would skip the first step and go right to sending the multimers.

  1. Specialized assays (performed if one of the above tests is abnormal)
    1. vWF multimer distribution using gel electrophoresis
    2. Restocetin-induced platelet aggregation (RIPA)

Bleeding Rescue Products:

  • Kcentra AKA Prothrombin Complex Concentrate (PCC) – combination of vitamin K-dependent coagulation factors (II, VII, IX, and X).
    • has small risk of clotting
  • Novo7 – recombinant factor 7A.
    • has small risk of clotting
  • Humate – Human-plasma derived von Willebrand factor – (contains factor VIII)
    • has small risk of clotting
  • Cryoprecipitate – VIII, fibrinogen, and vWF
  • DDAVP

Resources:

Acquired von Willebrand syndrome associated with left ventricular assist device.https://www.ncbi.nlm.nih.gov/pubmed/27143258

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s