Effect of bedside filtration on aggregates from cold-stored whole blood-derived platelet-rich plasma and apheresis platelet concentrates

Background: The current approach to manufacture cold-stored platelets (CSP) replicates that of room temperature-stored platelets (RSP). However, this production method is associated with aggregate formation in CSP, a major pitfall that leads to significant wastage. We hypothesized that isolating platelets from whole blood as platelet-rich plasma (PRP) and storing them at a lower concentration reduces aggregates and that conventional bedside transfusion filtration removes CSP aggregates.

Methods: We collected platelets from healthy humans by apheresis (AP) and by phlebotomy, from which we generated platelet-rich plasma (PRP). We split each AP and PRP platelets into two equal aliquots, storing one at 22°C (RT-PRP and RT-AP) and the other at 4°C (4C-PRP and 4C-AP). We evaluated platelets on day 0 and day 7 of storage. After storage, we measured platelet counts, aggregates, and other key characteristics before and after filtration by a bedside filter.

Results: After storage, the 4C-AP platelet counts decreased significantly. 4C-PRP preserved glucose better and prevented a significant increase in lactate contrary to 4C-AP. Filtration led to significantly lower platelet counts in both 4C-PRP and 4C-AP but not in their RT counterparts. Post filtration, we observed 50% fewer aggregates only in 4C-AP, whereas 4C-PRP showed an unexpected but significant increase in aggregates. Testing confirmed activation during storage but filtration did not further activate platelets.

Conclusion: We provide evidence that 4C-PRP is an alternative to 4C-AP and that bedside filters reduce aggregates from 4C-AP. Further studies are needed to evaluate the hemostatic potential of 4C-PRP and the management of aggregates.