Abstract WMP27: Prevalence of Non-responsiveness to Antiplatelet Therapy in Patients Undergoing Treatment of Cerebral Aneurysms Utilizing Flow Diversion with the Pipeline Embolization Device

Introduction: Flow-diversion has emerged as a novel treatment for complex cerebral aneurysms. Although preliminary reports suggest flow-diverting devices are safe and effective, the risk of thromboembolic and hemorrhagic complications must be balanced with the added risk of dual antiplatelet therapy. Although the prevalence of antiplatelet therapy non-responsiveness (NR) has been associated with adverse cardiac events in patients with acute coronary syndrome (ACS), it has has not been studied in patients treated with these devices. Methods: All patients received clopidogrel 75mg and aspirin 325mg prior to modified light transmittance platelet aggregometry (LTA) using 4 agonists (ADP 5 and 20 uM, arachidonic acid (ACA), and U46619). NR was defined as a maximum amplitude (MA) > 60% with ADP 20uM and 40% with ADP 5uM for clopidogrel and a MA >20% with ACA for aspirin. Patients were also assessed for known drug interactions. Chi-square or Fisher’s exact tests were used for univariate analyses, and logistic regression was used to identify potential predictors of NR. Results: 79 patients with 98 cerebral aneurysms were treated with the pipeline embolization device (PED). The prevalence of clopidogrel and aspirin NR was 27.6% and 30.3%, respectively. In univariate and multivariate analyses, age, gender, race, presence of drug interactions, history of hypertension, diabetes, ischemic stroke, subarachnoid hemorrhage and smoking were not significant predictors of NR. Conclusions: In our cohort, the prevalence of clopidogrel and aspirin NR was high and similar to that reported in ACS patients. As a result of the rate of NR, patients were evaluated by a virtual antiplatelet clinic and patients with suboptimal LTA results underwent modification of a drug interaction, received double doses of clopidogrel and/or aspirin, or were transitioned to an alternative P2Y12 inhibitor (prasugrel or ticagrelor). The mechanisms underlying antiplatelet NR remain to be further explored to minimize the risk of hemorrhagic complications if more potent antiplatelet therapy is required.