R. D. Rodriguez1, B. W. Carr1, A. L. Patterson1, S. A. Savage1 1Indiana University,General Surgery,Indianapolis, IN, USA
Introduction: Platelet dysfunction is common in traumatic brain injury. While platelet transfusion is used to reverse dysfunction, there is not an established dose-response to measure effectiveness. Thromboelastogram Platelet Mapping (TEG-PM) quantifies dysfunction in the arachidonic acid (AA) and adenosine diphosphate (ADP) pathways. The purpose of this study was to examine the effect of platelet transfusion on TEG-PM in TBI patients on antiplatelet agents.
Methods: This retrospective observational study included trauma patients admitted to a Level 1 Trauma Center with TBI from 2014 through 2017. Inclusion criteria was transfusion of at least one unit of platelets, use of antiplatelet agent prior to admission, and TEG-PM measured before and after transfusion. Repeated measures analysis of variance (ANOVA) was used to define change in ADP and AA inhibition over time in light of platelet transfusions.
Results: Twenty-eight patients met screening criteria. Mean age was 74.6 with a median ISS of 25. 26 patients were on ASA, 12 on Plavix, 3 on ticargrelor, and 1 on dipyramidole. The median initial ADP inhibition was 66.6% and AA inhibition was 83.3%. Units of platelets transfused ranged from 1 to 6 with median 2. The change in inhibition over time, controlling for units of platelets transfused, was not statistically significant for ADP (p = 0.76) or AA (p = 0.09), see Table 1. Nine patients had expansion of hemorrhage, with 3 requiring operative intervention and 3 transitioned to hospice.
Conclusion: Transfusion of platelets to restore platelet function was not effective for patients on antiplatelet agents as measured by TEG-PM, potentially exposing patients to unnecessary risk. This may be attributed to insufficient transfusion dosing or dysfunction in stored platelets. Further work is ongoing to identify the best way to define dysfunction, determine if correction of dysfunction is possible with platelet transfusion, and establish effective dosing.
