Rapid detection of platelet inhibition and dysfunction in traumatic brain injury: A prospective observational study

Rapid platelet function testing is frequently used to determine platelet function in patients with traumatic intracranial hemorrhage (tICH). Accuracy and clinical significance of decreased platelet response detected by these tests is not well understood. We sought to determine whether VerifyNow and whole blood aggregometry (WBA) can detect poor platelet response and to elucidate its clinical significance for tICH patients. METHODS: We prospectively enrolled patients with isolated tICH between 2018 and 2020. Demographics, medical history, injury characteristics, and patient outcomes were recorded. Platelet function was determined by VerifyNow and WBA testing at the time of arrival to the trauma bay and 6 hours later. RESULTS: A total of 221 patients were enrolled, including 111 patients on no antiplatelet medication, 78 on aspirin, 6 on clopidogrel, and 26 on aspirin and clopidogrel. In the trauma bay, 29.7% and 67.7% of patients on no antiplatelet medication had poor platelet response on VerifyNow and WBA, respectively. Among patients on aspirin, 72.2% and 82.2% had platelet dysfunction on VerifyNow and WBA. Among patients on clopidogrel, 67.9% and 88.9% had platelet dysfunction on VerifyNow and WBA. Patients with nonresponsive platelets had similar in-hospital mortality (3 [3.0%] vs. 6 [6.3%], p = 0.324), tICH progression (26 [27.1%] vs. 24 [26.1%], p = 0.877), intensive care unit admission rates (34 [34.3%] vs. 38 [40.0%), p = 0.415), and length of stay (3 [interquartile range, 2–8] vs. 3.2 [interquartile range, 2–7], p = 0.818) to those with responsive platelets. Platelet transfusion did not improve platelet response or patient outcomes. CONCLUSION: Rapid platelet function testing detects a highly prevalent poor platelet response among patients with tICH, irrespective of antiplatelet medication use. VerifyNow correlated fairly with whole blood aggregometry among patients with tICH and platelet responsiveness detectable by these tests did not correlate with clinical outcomes. In addition, our results suggest that platelet transfusion may not improve clinical outcomes in patients with tICH. LEVEL OF EVIDENCE: Diagnostic tests, level II.