Transfusion medicine
Transfusion therapy
Cold stored platelets


Topic Completed: 26 March 2020

Minor changes: 7 April 2020

Copyright: 2020, PathologyOutlines.com, Inc.

PubMed Search: Cold stored platelets[TIAB]

Hope Hastings, M.D.
Jose A. Cancelas, M.D., Ph.D.
Page views in 2020 to date: 235
Cite this page: Hastings H, Cancelas JA. Cold stored platelets. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/transfusionmedcoldstoredplatelets.html. Accessed July 8th, 2020.
Definition / general
  • Platelets may be stored at 1 - 6°C without agitation for up to 3 days for usage in actively bleeding trauma patients (21 CFR 640.24 and 640.25)
  • A 2019 variance by the FDA allows for apheresis platelets to be stored at 1 - 6°C for 14 days without agitation for use in military settings including actively bleeding patients or in the absence of available room temperature platelets
Essential features
  • Cold platelets undergo cytoskeletal rearrangements that allow for priming of the platelet and provide a hemostatic advantage over room temperature platelets in the actively bleeding patient
  • Circulation of cold stored platelets is reduced
    • Room temperature autologously transfused platelets have a survival of 6 - 7 days while the survival of allogeneic transfused platelets is 3 - 4 days
    • Autologously transfused cold stored platelets have a survival of 2 - 3 days and allogeneically transfused cold stored platelets circulate for one day or less (Transfusion 2017;57:2836)
  • Currently approved to be stored at 1 - 6°C without agitation for up to 3 days for use in actively bleeding trauma patients
Terminology
  • COLD-PLT(S): cold stored platelets
  • RT-PLT(S): room temperature platelets
  • CCI: corrected count increment
Pathophysiology
  • Cold stored platelets are activated during storage, offering the advantage of improved clotting and hemostatic effects
  • Ultrastructurally, refrigeration results in cytoskeletal rearrangements causing increased actin filaments and loss of microtubule banding
  • Shortly after starting refrigeration (< 16°C), membrane flipping of the platelet results in the release and exposure of P selectin from the alpha granules, which facilitates platelet-platelet binding as well as increasing platelet-leukocyte-endothelial interactions (Curr Opin Hematol 2018;25:500)
  • Increased intracellular calcium and exposure of negatively charged phosphatidylserine contribute to initiation of coagulation cascade
  • Other procoagulatory changes that occur in cold stored platelets include microparticle formation, increased degranulation, pseudopod formation and CD40L ligand expression (Transfusion 2019;59:1467)
  • In vitro analysis shows enhanced clot formation in cold stored platelets
  • At approximately 24 hours, the effects of refrigeration become irreversible and platelets will show permanent disc to sphere configuration and rapid clearance by the liver after transfusion
  • Increased removal of cold stored platelets from circulation is multifactorial and involves the following mechanisms (see Diagrams / tables) (Curr Opin Hematol 2018;25:500, Transfusion 2019;59:1467):
    • Glycoprotein Ibα clustering, which induces 14-3-3 protein associated apoptosis
    • Cold induced removal of sialic acid, causing exposure of galactose, which in turn leads to increased removal by hepatic macrophages via the Ashwell-Morell receptor
    • Exposure of phosphatidylserine resulting in macrophage induced phagocytosis
Diagrams / tables

Contributed by Jose A. Cancelas, M.D., Ph.D.

Mechanisms of apoptosis and clearance

Clinical features
Treatment
  • Administered in patients with trauma induced coagulopathy
Board review style question #1
Cold stored platelets are currently approved by the FDA. Which of the following is one of the current properties or criteria for transfusion of cold stored platelets?

  1. In vivo circulation of 6 - 7 days
  2. Prophylactic platelet transfusion
  3. Require continual agitation
  4. Stored up to 5 days at 1 - 6°C
  5. Trauma induced coagulopathy
Board review answer #1
E. Trauma induced coagulopathy. Due to activation of platelets during refrigeration, they are rapidly removed from circulation within 48 hours by macrophages and hepatocytes and thus currently are not approved for patients requiring prophylactic platelet transfusion. While room temperature platelets still offer better recovery beyond 48 hours, cold stored platelets offer the benefit of shortened bleeding times and faster clot formation, making this product desirable for the bleeding patient. Cold stored platelets are only approved for up to 3 days when stored at 1 - 6°C without agitation for trauma patients; however, a recent variance from the FDA has permitted the military to allow usage of cold stored platelets for up to 14 days without agitation.

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