Clopidogrel Use in CYP2C19 Loss-of-Function Carriers With High Bleeding Risk After Percutaneous Coronary Intervention.

BACKGROUND: It is not known whether clopidogrel use in cytochrome P450 (CYP) 2C19 loss-of-function (LOF) carriers with high bleeding risk (HBR) contributes to adverse outcomes after percutaneous coronary intervention (PCI).Methods and Results: This retrospective observational study included 618 consecutive patients with available CYP2C19 polymorphism information who underwent PCI between September 2014 and August 2021. Patients with HBR (319 [52%] met the Academic Research Consortium definition) were divided into 2 groups according to P2Y12inhibitor action, namely decreased (i.e., clopidogrel in CYP2C19 LOF carriers) and retained (i.e., clopidogrel in CYP2C19 LOF non-carriers or prasugrel regardless of CYP2C19 polymorphisms), and clinical outcomes at 1 year were compared using inverse probability-weighted Cox proportional hazard regression. The primary ischemic outcome (a composite of cardiovascular death, myocardial infarction, or ischemic stroke) was significantly higher in the decreased than retained group (10.2% vs. 3.0%; adjusted hazard ratio [aHR] 2.78; 95% confidence interval [CI] 1.40-5.52; P=0.004). The primary bleeding outcome (Bleeding Academic Research Consortium 3 or 5) did not differ significantly between the decreased and retained groups (3.4% vs. 6.9%, respectively; aHR 0.48; 95% CI 0.22-1.01; P=0.054). There were no interactions between the treatment groups and HBR status in primary ischemic and bleeding outcomes. CONCLUSIONS: Among patients with HBR, clopidogrel use in CYP2C19 LOF carriers was significantly associated with increased ischemic events after PCI.

Comparison Between Clopidogrel and Prasugrel Associated With CYP2C19 Genotypes in Patients Receiving Percutaneous Coronary Intervention in a Japanese Population.

BACKGROUND: The association between cytochrome P450 (CYP) 2C19 genotypes and adverse events in patients treated with clopidogrel or prasugrel after percutaneous coronary intervention (PCI) in the Japanese population is unclear.Methods and Results:This study consisted of 1,580 patients whoseCYP2C19genotypes were assessed at Shiga University of Medical Science Hospital, and 193 clopidogrel-treated and 217 prasugrel-treated patients who were followed more than 1 year after receiving PCI were analyzed. Among 1,580 patients, the prevalence of normal, intermediate, and poor metabolizers was 32%, 49%, and 17%, respectively. Overall incidence of the primary outcome, defined as a composite of cardiovascular death, myocardial infarction, definite stent thrombosis, ischemic stroke, or major bleeding was not significantly different between the clopidogrel and prasugrel groups (adjusted hazard ratio [HR] 1.98, 95% confidence interval [CI] 0.85-4.61, P=0.12). Among patients with theCYP2C19loss-of-function (LOF) allele, however, the incidence of the primary outcome was significantly higher in the clopidogrel group (adjusted HR 3.19, 95% CI 1.10-9.24, P=0.03), whereas no difference was observed among patients without theCYP2C19LOF allele (adjusted HR 0.67, 95% CI 0.14-3.26, P=0.62). CONCLUSIONS: Among patients with theCYP2C19LOF allele, the use of clopidogrel was significantly associated with increased adverse events. Thus, further investigation is needed to establish the practical use ofCYP2C19genotyping.

A challenge for mutation specific risk stratification in long QT syndrome type 1.

BACKGROUND: The relationship between mutation locations in KCNQ1 which is a major gene in long QT syndrome (LQTS) and phenotype has been analyzed and used for risk stratification. Mutations in the transmembrane region (TM) or cytoplasmic-loop (C-loop) are associated with more frequent cardiac events than those in other regions. However, accumulation of LQTS type 1 (LQT1) patients poses the question of whether the location specific risk stratification is really effective. METHODS: The study cohort consisted of 67 KCNQ1 mutation carriers and 13 family members who were suspected as having LQTS due to sudden cardiac death or syncope from 36 unrelated families. The KCNQ1 mutations were L250H, V254M, H258P, and R259C located in segment 4-5 linker (C-loop), G269S, and S277L in segment 5 (TM). RESULTS: More than half of the patients with V254M or S277L suffered sudden cardiac death or syncope. In contrast, those with other mutations showed mild phenotype. In these two mutations related to severe phenotype, gender frequency and the age of onset were contrasting, 14 out of 23 patients with V254M were male, 19 out of 22 patients with S277L were female. In the patients we could confirm the age of onset, all of the patients with V254M showed symptoms at less than 15 years old, while 5 out of 12 patients with S277L suffered symptoms after 16 years old. CONCLUSION: Clinical characteristics were not specific for mutation locations but specific for respective mutations in our LQT1 patients. Patients should be evaluated by their own mutations to prevent severe cardiac events.

Contribution of a KCNH2 variant in genotyped long QT syndrome: Romano-Ward syndrome under double mutations and acquired long QT syndrome under heterozygote.

BACKGROUND: Long QT syndrome (LQTS) presents two clinical phenotypes, congenital and acquired forms. This study aims to evaluate the genetic contribution of a KCNH2 variant for the two LQTS phenotypes. METHODS: From 1996 to 2014, genetic screening for LQTS probands was performed for five major genes: KCNQ1, KCNH2, SCN5A, KCNE1, and KCNE2 and 389 probands were found to be mutation carriers. We analyzed the clinical phenotypes of p.His492Tyr carriers in KCNH2. RESULTS: Heterozygous p.His492Tyr variant was identified in 10 LQTS families. Six probands (mean age, 26±23 years) carried another mutation, and two of six had syncope associated with emotional stress or telephone ringing. The remaining four probands were significantly older at diagnosis (mean age, 42±33 years) and carried no other compound mutations. All the four probands had fatal arrhythmic events in the presence of additional precipitating factors such as culprit drugs in 2, hypokalemia in 1, and bradycardia in 1. The QTc interval of carriers with p.His492Tyr alone was 445±10ms and significantly shorter than that in double mutation carriers (481±40ms, p=0.041). CONCLUSIONS: KCNH2 p.His492Tyr variant presented Romano-Ward syndrome in the presence of another mutation and heterozygous carriers had mild phenotypes while even heterozygous carriers should be cared for not to encounter secondary factors because incidental factors could manifest "latent" form of p.His492Tyr heterozygous carriers.