Fresh platelet concentrate (FRESH) must be stored under gentle agitation and has a 5-day shelf life. Because of expense and logistics, most veterinary institutions limit platelet transfusions to platelets in fresh whole blood. Lyophilized platelets (LYO), a recently developed product in which platelets are lyophilized and reconstituted with preservation of platelet structure and hemostatic function, can be stored for up to 24 months in the refrigerator.

In this preliminary clinical trial, 37 dogs with hemorrhage associated with thrombocytopenia (platelet count, <70,000/µL) were randomized to receive LYO (n = 22) or FRESH (n = 15). Outcome was assessed by determining bleeding score, response to transfusion, adverse reactions, hospitalization time, need for additional transfusions, survival to discharge, and 28-day survival. No difference in outcome was found between LYO and FRESH groups. Although efficacy of LYO compared with FRESH could not be determined because of small sample size, transfusion of LYO was found to be feasible and associated with low transfusion reaction rate. Human albumin was used in the formulation of LYO, but no type III hypersensitivity reactions were observed.

Commentary
Administering therapeutic platelet transfusions to bleeding with either thrombocytopenia or platelet dysfunction can be hampered by limited availability and accessibility of platelet products. Acquiring, processing, and administering fresh products in a timely manner can be challenging with life-threatening hemorrhage. To date, the only alternative has been cryopreserved platelets. While this product can be stored frozen and therefore be available for on-demand use, information on its clinical efficacy is scarce. This paper is the first to describe the use of LYO, an alternative product that might become available in the near future.—Gretchen Lee Schoeffler, DVM, DACVECC

Source
Use of fresh platelet concentrate or lyophilized platelets in thrombocytopenic dogs with clinical signs of hemorrhage: A preliminary trial in 37 dogs. Davidow EB, Brainard B, Martin LG, et al. JVECC 22:116-125, 2012.