Does the clopidogrel CYP2C19 genotype assay predict postprocedure stenosis in cerebral aneurysms treated with a flow diverter?

Flow diverters have emerged as a popular modality for treating cerebral aneurysms but require dual antiplatelet therapy (DAPT) after placement. Clopidogrel is a common choice but is a prodrug that some patients may not convert into an active metabolite. The CYP2C19 genotype assay is used to predict activation speed; however, limited data exist showcasing whether this genotype accurately predicts postprocedure complications after flow diversion treatment of cerebral aneurysms. Therefore, the authors sought to characterize whether CYP2C19 genotype correlated with the development of postprocedure intimal hyperplasia (stenosis) after flow diverter placement.Medical records were reviewed for patients who underwent flow diverter treatment of cerebral aneurysm at a single academic institution between January 1, 2012, and May 31, 2020. Patient demographics and comorbidities were reviewed alongside CYP2C19 genotype assay, DAPT regimen, and postprocedure angiogram data. Stenosis was defined based on review of angiogram data by two independent physicians.In this review of 120 unique cerebral aneurysms, 102 received DAPT with clopidogrel and 18 received DAPT with an alternative agent. Stenosis was present on 3-month follow-up angiogram for 35/102 (34.3%) aneurysms receiving DAPT with clopidogrel and in 11/18 (61.1%) aneurysms receiving an alternative DAPT regimen (p = 0.031). The CYP2C19 genotype did not correlate with postprocedure stenosis (p = 0.35).Clopidogrel was a significantly more effective DAPT agent for preventing stenosis when compared to nonclopidogrel DAPT regimens. The clopidogrel CYP2C19 genotype did not predict postprocedure stenosis in this cohort of 120 cerebral aneurysms treated with a flow diverter.