Clopidogrel Hyperresponsiveness and Hemorrhagic Complications Using On-Label Clopidogrel Dosing after Pipeline Embolization

<b>Introduction:</b> Clopidogrel hyperresponsiveness is a timely topic, with wide ranging reports of hemorrhagic complications, using various clopidogrel dosing strategies following neuroendovascular procedures. This study serves to investigate hemorrhagic complications using standard clopidogrel doses and timing of these complications in relation to the procedure. <b>Materials and Methods:</b> Retrospective cohort of consecutive adult patients undergoing flow diversion with Pipeline Embolization Device (PED) at an academic medical center, receiving on-label clopidogrel doses. Patients with clopidogrel hyperresponsiveness (VerifyNow^TM P2Y12 reaction unit (PRU) ≤ 70) were compared to those who were normoresponsive. The primary outcome is the rate of hemorrhagic complications between groups. <b>Results:</b> Of 148 included patients, 54 (36.5%) were identified as clopidogrel hyperresponsive (PRU ≤ 70) and 94 (63.5%) as clopidogrel normoresponsive (PRU 71 - 194). There were no hemorrhagic complications observed in patients who were clopidogrel hyperresponsive, with 5 occurring in patients who were normoresponsive (<i>P</i> = 0.09). Three (60%) of the hemorrhages were intracranial with most occurring intra-procedure or within the first week of the procedure. Age > 60 years was the only candidate predictor for hemorrhagic complications (<i>P</i> = 0.004). <b>Conclusion:</b> Our findings are contradictory, with lower hemorrhagic complications in clopidogrel hyperresponders than prior literature, and most occurring intra-op or in the immediate acute post-op phase.