CYP2C19 Genotype and Early Ischemic Lesion Recurrence in Stroke Patients Treated with Clopidogrel

Background: Early recurrent ischemic lesions detected on diffusion-weighted imaging (DWI) have been proposed as a surrogate marker for clinical recurrence. We hypothesized that cytochrome P450 2C19 (CYP2C19) genotype influences the incidence of early recurrence on DWI in acute stroke patients treated with clopidogrel. Methods: We enrolled 76 Korean patients with acute ischemic stroke due to large artery atherosclerosis who were treated with clopidogrel. Early ischemic lesion recurrence was defined as new lesions separate from the index lesion. We compared the rates of early ischemic lesion recurrence on DWI based on the CYP2C19 genotypes. Results: Early recurrence on DWI was observed in 36 patients (47.4%). A total of 76 patients were classified into 3 phenotypic groups: extensive metabolizers (EMs; n = 27, 35.5%), intermediate metabolizers (IMs; n = 36, 47.4%), and poor metabolizers (PMs; n = 13, 17.1%). Early recurrence on DWI was more common in PMs (84.6%), followed by IMs (50.0%), and EMs (25.9%; P < .001). PMs had a significantly higher recurrence rate than EMs (P < .001). In multivariate analysis, CYP2C19 genotypes were independently associated with early DWI recurrence (for PMs: odds ratio, 19.3; 95% confidence interval, 3.15-117.56). Conclusions: CYP2C19 genotypes are significantly associated with early lesion recurrence in Korean acute stroke patients treated with clopidogrel.