CYP2C19 and transient ischemic attack: This meta-analysis aims to pool evidence on the effect of different antiplatelet strategies on outcomes according to CYP2C19 LoF status.<h4>Methods</h4>We conducted a systematic review and meta-analysis of RCTs to evaluate the interaction of CYP2C19 LoF allele on clopidogrel versus placebo or other antiplatelet agents in patients with cardiovascular disease or transient ischemic attack (TIA) or ischemic stroke.