Implementation of Onsite Rapid CYP2C19 Assay for Genotype Guided Dual Antiplatelet Therapy After Acute Ischemic Stroke

Dual antiplatelet therapy (DAPT) with clopidogrel and aspirin is the standard of care (SOC) for secondary prevention of non-cardioembolic minor acute ischemic stroke (AIS) and high-risk transient ischemic attack (TIA); however, clopidogrel has limited effectiveness in CYP2C19 loss-of-function (LOF) allele carriers. Recent studies have demonstrated the superiority of ticagrelor over clopidogrel in CYP2C19 LOF allele carriers, especially when started within 24 hours of presentation. However, despite evidence of improved efficacy and advances in rapid genotyping technology, clinical care has been slow to adopt this form of precision medicine. To address this gap, an implementation study will be conducted in adult patients with cerebrovascular disease to determine the feasibility and acceptability of rapid CYP2C19 genotyping in an acute inpatient setting and to analyze the impact of this clinical implementation on DAPT prescribing patterns. To accomplish these aims, patients undergoing evaluation for AIS/TIA in the Emergency Department will be consented for in-house rapid quantitative polymerase chain reaction (qPCR) genotyping of CYP2C19. Genotype results will be recorded in the electronic health record and active clinical decision support alerts will be built to inform prescribers of any recommended DAPT changes.