Implementation of Rapid CYP2C19 Genotyping to Guide Antiplatelet Therapy for Secondary Prevention of Ischemic Stroke and Transient Ischemic Attack.

CYP2C19

CYP2C19 variants alter clopidogrel bioactivation; intermediate and poor metabolizers are given ticagrelor, the others clopidogrel.

Clopidogrel is first-line for secondary stroke prevention, but its effectiveness depends on CYP2C19 genotype. This prospective observational quality-improvement cohort deployed rapid CYP2C19 testing across three comprehensive stroke centers of one health system between September 2024 and August 2025. Results were available for 467 patients, 451 (97%) before discharge, with a median turnaround of 5.2 hours. Among 296 patients with stroke or TIA discharged on a P2Y12 inhibitor, ticagrelor was prescribed in 87% of intermediate/poor metabolizers (89/102) versus 5.7% of the others (11/194; RR 15.4; 95% CI 8.6-27.4; P < 0.0001). Prescribing matched genotype-based recommendations in 92% of patients.

Synthesis written by Geno'X. For the full original abstract, please refer to the source publication.

The strength is the turnaround time: with a result within hours, testing fits within the hospital stay and genuinely changes prescribing. The endpoint, however, is prescribing alignment rather than vascular events: the study shows feasibility, not clinical benefit.

Analysis by Dr Thibaut Benquey