High‐Dose Clopidogrel versus Ticagrelor in CYP2C19 intermediate or poor metabolizers after percutaneous coronary intervention: A Meta‐Analysis of Randomized Trials

What is known and objective For patients after percutaneous coronary interventions (PCI), clopidogrel combined with aspirin is a conventional dual antiplatelet therapy (DAPT) method. Because the genetic polymorphism of CYP2C19 gene leads to clopidogrel resistance, guidelines for antiplatelet recommendations in CYP2C19 of ultrarapid metabolizers (UM), extended metabolizers (EM) and poor metabolizers (PM) are clear. However, there is no clear recommendation as to whether ticagrelor or double dose clopidogrel is the best antiplatelet regimen for CYP2C19 of intermediate metabolizers (IM). To evaluate the efficacy and safety of ticagrelor (combined with aspirin) and high-dose clopidogrel (combined with aspirin) in patients after PCI with CYP2C19 loss-of-function (LOF) alleles. Methods We searched the following databases to select RCTs of comparing ticagrelor with high-dose clopidogrel in patients after PCI with CYP2C19 LOF alleles: CNKI, Wanfang Data, PubMed, Clinical trials, Cochrane, Web of Science and Embase. Major adverse cardiovascular events (MACEs), platelet function and TIMI bleeding event were defined as the outcomes. revman 5.3 software was used to perform meta-analysis. Results and discussion A total of 14 RCTs with 2351 patients were enrolled. Meta-analysis showed that compared with high-dose clopidogrel, ticagrelor had reduced incidence of MACEs (OR = 0.32, 95% Cl: 0.23–0.44, p < 0.00001), stent thrombosis (OR: 0.24, 95%CI: 0.13–0.44, p < 0.00001), myocardial infarction OR: 0.42, 95%CI: 0.22–0.80, p = 0.008), revascularization (OR: 0.29, 95%CI: 0.10–0.82, p = 0.02) and unstable angina (OR: 0.47, 95%CI: 0.29–0.77, p = 0.003) in patients after PCI with CYP2C19 LOF alleles. A subgroup analysis showed that ticagrelor reduced the risk of MACEs compared with high-dose clopidogrel regardless of the type of metabolizer. Compared with high-dose clopidogrel, ticagrelor significantly reduced the risk of MACE with longer follow-up period (more than 3 months) without increasing the risk of bleeding (OR: 0.89, 95%CI: 0.53–1.49, p = 0.30), while elevated dyspnoea (OR: 5.62, 95%CI: 3.07–10.28, p < 0.00001). What is new and conclusions For patients carrying CYP2C19 LOF alleles after PCI, ticagrelor may be better than high-dose clopidogrel in reducing the risk of MACEs, while dyspnoea incidents should be alerted.