In particular, Dr. Brandt was troubled by the number of patients who did not have a history of aspirin therapy, but were aspirin inhibited, and said it is unclear whether this is a function of other comorbidities or of the test itself. She asked whether ADT testing should be conducted in all TBI patients and whether it is practical to do so based on cost and turnaround time.
Dr. Bautz explained that the high number of patients without an aspirin history in the study is likely because these patients were unable to provide a history upon presentation for TBI. "It is in this setting, that we feel our test is of the most value," he said.
The test typically takes 40 minutes, including laboratory and transport time, and costs about $40 per test, he said.
Audience member Dr. Jonathan Saxe, professor of surgery at Wright State University in Dayton, Ohio, said that brain injury itself has been known to cause issues with aspirin testing and asked whether the brain injuries in the cohort could be causing the platelet test to be abnormal rather than the aspirin. He also pointed out that his group published a similar study finding no impact on mortality with platelet transfusion in elderly TBI patients taking aspirin or clopidogrel (Am. Surg. 2009;75:1100-3). "So I’m wondering, if giving platelets really does anything," he said.
Dr. Bautz said that the ADT test has demonstrated a sensitivity of almost 100% and specificity of 88% at his institution for showing aspirin inhibition. "So it is our belief these patients are on aspirin and that is the cause of their platelet inhibition."
A randomized controlled trial using objective measures of platelet inhibition is necessary to quantify platelet administration in patients presenting with TBI, he said.
The authors reported no conflicts of interest.