title: Use of Aspirin and P2Y12 Response Assays in Detecting Reversal of Platelet Inhibition With Platelet Transfusion in Patients With Traumatic Brain Injury on Antiplatelet Therapy.
abstract: At present, guidelines are lacking on platelet transfusion in patients with a traumatic intracranial bleed and history of antiplatelet therapy. The aspirin and P2Y 12 response unit (ARU and PRU, respectively) assays detect the effect of aspirin and P2Y 12 inhibitors in the cardiac population.
  
  
  
  To describe the reversal of platelet inhibition after platelet transfusion using the ARU and PRU assays in patients with traumatic brain injury.
  
  
  
  Between 2010 and 2015, we conducted a prospective comparative cohort study of patients presenting with a positive head computed tomography and a history of antiplatelet therapy. ARU and PRU assays were performed on admission and 6 hours after transfusion, with a primary end point of detection of disinhibition after platelet transfusion.
  
  
  
  One hundred seven patients were available for analysis. Seven percent of patients taking aspirin and 27% of patients taking clopidogrel were not therapeutic on admission per the ARU and PRU, respectively. After platelet transfusion, 51% of patients on any aspirin and 67% of patients on any clopidogrel failed to be reversed. ARU increased by 71 ± 76 per unit of apheresis platelets for patients taking any aspirin, and PRU increased by 48 ± 46 per unit of apheresis platelets for patients taking any clopidogrel.
  
  
  
  A significant percentage of patients taking aspirin or clopidogrel were not therapeutic and thus would be unlikely to benefit from a platelet transfusion. In patients with measured platelet inhibition, a single platelet transfusion was not sufficient to reverse platelet inhibition in almost half.
authors.affiliation: University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.
authors.forename: Phillip A
authors.initials: PA
authors.lastname: Choi
authors.affiliation: Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.
authors.forename: Phillip V
authors.initials: PV
authors.lastname: Parry
authors.affiliation: Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.|St. George's University School of Medicine, Grenada, West Indies.
authors.forename: Joshua S
authors.initials: JS
authors.lastname: Bauer
authors.affiliation: University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.
authors.forename: Benjamin E
authors.initials: BE
authors.lastname: Zusman
authors.affiliation: Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.
authors.forename: David M
authors.initials: DM
authors.lastname: Panczykowski
authors.affiliation: Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.
authors.forename: Ava M
authors.initials: AM
authors.lastname: Puccio
authors.affiliation: Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.
authors.forename: David O
authors.initials: DO
authors.lastname: Okonkwo
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001241:Aspirin / Q000627:therapeutic use*; D001792:Blood Platelets / Q000187:drug effects; D000070642:Brain Injuries, Traumatic / Q000628:therapy*; D000077144:Clopidogrel; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use*; D017713:Platelet Transfusion; D058925:Receptors, Purinergic P2Y12; D013988:Ticlopidine / Q000031:analogs & derivatives* / Q000627:therapeutic use
chemical_list: C548576:P2RY12 protein, human; D010975:Platelet Aggregation Inhibitors; D058925:Receptors, Purinergic P2Y12; D000077144:Clopidogrel; D013988:Ticlopidine; D001241:Aspirin
keywords: Antiplatelet therapy; Aspirin; Aspirin response unit; Clopidogrel; P2Y12 response unit; Platelet transfusion; Traumatic brain injury