Carotid artery stenting outcomes: do they correlate with antiplatelet response assays?

Objective Limited data exist regarding the use of antiplatelet response assays during neuroendovascular intervention. We report outcomes after carotid artery stenting (CAS) based on aspirin and P2Y12 assays. Methods We retrospectively identified patients who had aspirin and P2Y12 assays at the time of stenting. Aspirin (325mg) and clopidogrel (75mg) were started 7-10days pre-intervention. If not possible, aspirin (650mg) and clopidogrel (600mg) loading doses were given pre-intervention. Assays were checked on postoperative day 0/1. Outcomes included neurological ischemic sequela at 30days, 1 and 2years, as well as 30 day death/hemorrhage/myocardial infarction. Results 449 patients were included. Mean P2Y12 reaction unit (PRU) values were higher in patients with an ipsilateral ischemic event (stroke/transient ischemic attack (TIA)) or stroke (alone) at 1 and 2years than in patients with no events: ischemic event versus no event at 1year, 252 vs 202 (p=0.008); stroke versus no stroke at 1year, 252 versus 203(p=0.029); ischemic event versus no event at 2years, 244 vs 203 (p=0.047); stroke versus no stroke at 2years, 243 versus 203 (p=0.082). Ischemic event free survival (stroke/TIA, p=0.0268) and overall survival (p=0.0291) post-CAS were longer in patients with PRU 198 compared with an initial threshold of PRU 237. Mean PRU values were higher in patients who died from all causes at 30days than in survivors (p=0.031). No correlation was found between lower PRU values and hemorrhage. Aspirin reaction units did not correlate with outcome. Conclusions PRU 198 may be associated with a lower incidence of ischemic neurological sequela and death post-CAS. Prospective studies are needed to validate the relationship between antiplatelet assays and outcomes post-CAS.