Abstract Number: PB1695
Meeting: ISTH 2020 Congress
Background: The procoagulant profile of platelet concentrates (PCs) following transfusion has been difficult to evaluate, lacking specific markers.
Aims: This study aimed to characterise procoagulant platelets in PCs and following transfusion, including cold-storage (2-6°C) and cryopreservation (-80°C with DMSO), using the novel, specific marker, GSAO.
Methods: Procoagulant platelets were assessed by flow cytometry (GSAO+/P-selectin+) at rest and after ex vivo thrombin 2U/mL ± collagen 10µg/mL stimulation in fresh whole blood collected pre- and one-hour post prophylactic platelet transfusion (n=6). Comparison was made with PCs: pooled buffy coat-derived PCs (12 donors each, n=6), apheresis PCs (n=3) and healthy control fresh whole blood (n=25). At production, each pooled PC was split for conventional storage, cold-storage and cryopreservation. Procoagulant platelets and thrombin generation were measured on days 1, 2, 5, 9 and 14.
Results: Buffy-coat and apheresis-derived PCs were equivalent, with both having significantly fewer procoagulant platelets before and after agonist stimulation than healthy control whole blood (mean±SD stimulated: 4.2±1.3%, 3.5±0.8% and 11.1±2.8%, respectively, p< 0.001). However, in post-transfusion samples, where most platelets were PC-derived, procoagulant platelet response was significantly increased (mean±SD: combined day 5 buffy coat and apheresis PCs 4.0±1.6%, transfused platelets 15.8±5.9%, p< 0.0001, figure 1). P-selectin expression following agonist stimulation was also blunted (mean±SD: combined day 5 PCs 77.0±7.8%; healthy control 99.3±0.4%; p< 0.0001), however, was not restored upon transfusion (79.4±13.9%, p< 0.0001). Cryopreserved PCs had marked increase in procoagulant platelets (unstimulated: day 1 conventional PC 0.3±0.2%; immediately post-thaw cryopreserved 25.6±1.8%; p< 0.0001) and thrombin generation (peak thrombin: day 1 conventional 67.1±6.5; cryopreserved 134.4±32.7; p=0.003). There was strong correlation between proportion of procoagulant platelets and thrombin generation: peak thrombin (r2=0.62, p< 0.0001), time to peak (r2=0.79, p< 0.0001, figure 2) and lagtime (r2=0.81, p< 0.0001).
Conclusions: Utilising the novel marker, GSAO, PCs have reduced procoagulant potential, but this significantly increases following transfusion.
To cite this abstract in AMA style:Tohidi-Esfahani I, Tan S, Tan CW, Johnson L, Marks D, Chen V. Platelet Procoagulant Potential Is Reduced in Platelet Concentrates ex vivo But Appears to Be Restored in vivo Following Transfusion [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/platelet-procoagulant-potential-is-reduced-in-platelet-concentrates-ex-vivo-but-appears-to-be-restored-in-vivo-following-transfusion/. Accessed September 29, 2023.
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