(1556) Thromboelastography Platelet Mapping Assay in Intracranial Hemorrhage Patients: Does Age Matter?

Introduction: Thromboelastography (TEG) is a whole blood measure of coagulation. Platelet mapping TEG detects derangements in platelet aggregation through the adenosine diphosphate (ADP) pathway. Inhibition of this pathway has been associated with mortality after traumatic intracranial hemorrhage (tICH). A threshold of ≥ 60% ADP inhibition has been adopted as a standard; however, its relationship with age is not well defined. The purpose of this study is to validate 60% ADP inhibition as a threshold for poor outcome in adult patients with tICH and by age. We hypothesized ≥ 60% ADP inhibition would be a strong discriminator of mortality.

Methods: TEG results for patients admitted to a Level 1 trauma center with tICH between December 2017 and June 2021 were reviewed. Receiver operating characteristic curves were used to test ≥ 60% ADP inhibition as a predictor of mortality. The area under the curve (AUC) is reported for the overall cohort stratified by age for the entire sample and then selected for a) patients with Glasgow Coma Scale (GCS) < 13 and then for b) patients with an injury severity score (ISS) of > 16.

Results: TEG results were reviewed on 169 patients with the following age distribution (15 – 39 years, 16.6%; 40 – 64 years, 29.7%; 65 – 74 years, 20.0%, 75+ years 33.8%) and head/neck injury severity 3.7±1.0. Mortality rate was 11.8% (n=20). Deaths accounted for 20% - 30% of patients within each age range: 15-39, 5(25%); 40-64, 6(30%); 65-74 4(20%); 75+, 5(25%).
For patients younger than 65 years, the AUC ranged from 0.33 -0.54 depending on the model and between 0.73- 0.88 for patients ≥ 65 years. AUCs are as follows for the entire cohort, for the cohort if GCS < 13, and for the cohort if ISS > 16 [15-39 years: 0.44, 0.41, 0.44; 40-64 years: 0.54, 0.33, 0.49; 65-74 years 0.77, 0.88, 0.75; 75+ years: 0.77, 0.73, 0.79].

Conclusions: In patients with intracranial hemorrhage, increased ADP inhibition discriminated mortality better if age was ≥ 65. Caution should be used when applying ADP inhibition to tICH patients of all ages.