Does the Degree of Platelet Adenosine Diphosphate and Arachidonic Acid Receptor Inhibition Correlate With the Severity of Injury in Non-Brain-Injured Trauma Patients?

BACKGROUND: Direct correlations between platelet adenosine diphosphate (ADP) and arachidonic acid (AA) receptor inhibition have been described in the traumatic brain injury (TBI) population. Our goal was to evaluate the percent inhibition of ADP receptor inhibition (ADPri) and AA receptor inhibition (AAri) receptors in non-TBI patients and correlate injury severity and outcomes. METHODS: We performed a retrospective review of non-TBI patients admitted to our trauma center, who received thromboelastography with platelet mapping prior to blood transfusion. Exclusion criteria included patients younger than 18 years, current antiplatelet therapy, or history of renal failure. Univariate descriptive statistics and bivariate comparisons were performed on patient demographic and outcomes. Multivariable linear regression models were constructed to quantify any association between ADPri and AAri with injury outcomes. High ADP inhibition was defined >20% and high AA inhibition >7%. RESULTS: 117 patients met inclusion criteria. Mean age was 53 years with 61% male. Mean ADPri was 64% and AAri 42%. On bivariate analysis, no statistically significant differences with respect to injury severity measures or outcomes were identified. On multivariable linear regression, AAri was associated with longer hospital length of stay. DISCUSSION: There was a high degree of platelet dysfunction in this cohort of severely injured patients without TBI. Despite this, the only correlation identified between injury severity and outcomes was AAri correlating with hospital length of stay. Irrespective of injury severity or outcomes, these patients' results were far from reported "normal" values. Further, research is needed to determine the significance and clinical implications of thromboelastography with platelet mapping use in trauma care.