Introduction: Dual antiplatelet therapy is required for treatment of intracranial aneurysms using the Pipeline Embolization Device (PED). Platelet function testing (PFT) is often employed to assess the efficacy of the antiplatelet regimen prior to PED placement. The optimal impedance values for whole blood lumi-aggregometry (WBLA) in this setting have not been defined.
Methods: A retrospective review of a prospectively maintained database was performed for the years 2011-2015 to identify patients with intracranial aneurysms treated with the PED that underwent preoperative PFT using whole blood lumi-aggregometry. Clinical, radiographic, and laboratory data were analyzed to identify the optimal cutoff impedance value for clopidogrel responsiveness.
Results: Forty-nine patients underwent 53 endovascular procedures for the treatment of 76 aneurysms using the PED. The majority of these aneurysms were located in the anterior circulation (90.8%) and affected the internal carotid artery (89.5%). Thirty patients (56.6%) were identified as clopidogrel responders based on the manufacturer cutoff value (< 6 ohms). Thromboembolic complication occurred in 13 (24.5%) procedures; 6 (11.3%) were symptomatic with 3 (5.7%) ischemic strokes. Eleven of the 13 (84.6%) thromboembolic complications occurred in clopidogrel non-responders. The optimal electrical impedance value was identified as less than or equal to 6 ohms (sensitivity 61.5%, specificity 70.0%, LR+ 2.1, LR- 0.5) with an area under the curve of 0.66.
Conclusions: Thromboembolic complications are more common following placement of the PED in patients who do not respond to clopidogrel. The optimal cutoff value to categorize someone as a clopidogrel non-responder when using whole blood lumi-aggregometry is less than or equal to 6 ohms.
Patient Care: Our research highlights the importance of platelet function testing prior to use of the PED while validating the optimal cutoff value for clopidogrel responsiveness when using WBLA.
Learning Objectives: By the conclusion of this session, participants should be able to: 1) identify clopidogrel non responders using WBLA, 2) utilize this data to reduce risk of thromboembolic complications during PED treatment of aneurysms.