Comparison of a novel viscous platelet additive solution and plasma: preparation and in vitro storage parameters of buffy-coat-derived platelet concentrates

Background and Objectives  We developed a viscous platelet additive solution (PAS) based on MacoPharma's SSP+ but containing hydroxyethyl starch to address the poor osmotic balance and low yield associated with conventional PAS for the storage of buffy-coat platelet concentrates (PC).
Materials and Methods  Pools of four buffy-coats were made into leucoreduced PCs ( n  = 5) suspended either in plasma or viscous PAS. After determination of platelet recoveries, the PCs were stored under standard conditions. On days 1, 2, 3, 5, 7 and 9, PCs were tested for mean platelet volume, platelet concentration, soluble protein concentration, CD62 expression, platelet morphology, partial pressure of oxygen and partial pressure of carbon dioxide, glucose and lactate concentration, pH, extent of shape change, and hypotonic shock response (HSR).
Results  Platelets were prepared with greater ease using the viscous PAS and had improved platelet yield. PCs stored in either plasma or viscous PAS displayed similar storage characteristics to day 9. On days 7 and 9 of storage, platelets stored in viscous PAS displayed significantly lower ( P <  0·05) CD62 expression and higher HSR scores than those stored in plasma.
Conclusion  Alteration of the viscosity of PAS improves platelet recovery during processing and may prolong platelet quality at the later stages of storage.