Platelet function testing in acute severe settings

Introduction: Platelet dysfunction in severe acute hemorrhage or trauma patients is a critical and often overlooked component, notoriously difficult to reliably study. This study aims to assess in vitro platelet activation and function in acute severe settings to improve patient-specific management strategies by understanding the prevalence and impact of platelet dysfunction.

Method: We prospectively studied 43 patients in Dijon Bourgogne Hospital, France, between January 2022 and April 2023 with severe hemorrhage (brain or intestinal), trauma situation or hemorrhagic surgery along with twenty healthy donors. They should not have taken an antiplatelet drug within the previous 7 days. Blood was collected as soon as possible after the trauma without exceeding twenty-four hours or during the acute hemorrhage phase. We used platelet functional tests (PFT) panel with unadjusted citrated platelets rich plasma (PRP) such as light transmission aggregometry with collagen HORM from Takeda (final concentrations 5µg/mL and 1µg/mL), ADP from Stago (final concentration 20µM), TRAP-6 from Stago (final concentration 20µM); ATP release in response to collagen; flow cytometry (CD62p, PAC1, Annexin V).

Results: Patients exhibited significantly lower platelet counts, hemoglobin, hematocrit, and higher INR than controls, indicating impaired coagulation. Four patients fulfilled criteria of trauma-induced coagulopathy (TIC). Most of patients had INR≥1.2 (n=27) and≥1.4 (n=15). Twenty-one patients were in hemorrhagic shock. Platelet function tests revealed reduced aggregation in response to ADP, TRAP, and collagen, alongside decreased ATP secretion. Flow cytometry showed lower CD62p and PAC1 responses, while basal Annexin V binding indicated higher exposure of procoagulant phospholipids. Multivariate analysis identified three predictors of hemorrhagic severity: TRAP induced aggregation LTA, ATP secretion in response to collagen 5µg/mL, percentage of PAC1 positive response to TRAP ([Fig. 1]).

Fig. 1 LTA, Flow Cytometry, ATP Secretion Results. All data reported as means (interquartile range).^† Kruskall-Wallis test. Of note, for lack of plasma, ATP secretion was done for 25 patients in response to collagen 1 µg/mL and 27 in response to collagen 1 µg/mL.

Conclusion: Our study demonstrates the feasibility of platelet phenotyping even in case of low platelet counts, and further highlights platelet dysfunction, showing that a streamlined laboratory process is suited to such acute life-threatening settings. The widespread alterations with abnormal ATP release point to an alteration of shared signaling pathways, including intracellular calcium. The next step is a multicenter descriptive study with shared management algorithms, repeated blood collections, breakdown into the clinical groups, focusing on trauma.

Conflict of Interest:

No conflict.

Publication History

Article published online:
13 February 2025