Tailored Adjunctive Cilostazol Therapy Based on CYP2C19 Genotyping in Patients With Acute Myocardial Infarction - The CALDERA-GENE Study

P2Y12 Reaction Units and Clinical Outcomes in Acute Large Artery Atherosclerotic Stroke: A Multicenter Prospective Study

AIMS

We aimed to determine the association between acute platelet reactivity and clinical outcome in acute ischemic stroke (AIS) or transient ischemic attack (TIA) with large-artery atherosclerosis (LAA).

METHODS

In this prospective, 16-multicenter study, we enrolled AIS/TIA patients with LAA receiving clopidogrel. We assessed the association of P2Y12 reaction units (PRU) 24 hours after initiation of antiplatelets with the CYP2C19 genotype and recurrent ischemic stroke within 90 days, and the difference between acute (≤ 7 days) and subacute (8-90 days) phases.

RESULTS

Among the 230 AIS/TIA patients enrolled, 225 with complete outcome data and 194 with genetic results were analyzed. A higher PRU was significantly associated with recurrent ischemic stroke within 90 days (frequency, 16%), and within 7 days (10%). Twenty-nine patients (15%) belonged to a CYP2C19 poor metabolizer group (CYP2C19^＊2/^＊2, ^＊2/^＊3, or ^＊3/^＊3). Multivariable receiver-operating characteristic analysis showed a greater area-under-the-curve (AUC) in predicting recurrence within 7 days, compared to 8-90 days (AUC, 0.79 versus 0.64; p=0.07), with a cut-off PRU of 254. Multivariable analysis showed high PRU (≥ 254), which had a comparable predictive performance for recurrent ischemic stroke within 7 days (odds ratio, 6.82; 95% CI, 2.23-20.9; p＜0.001) to the CYP2C19 poor metabolizer genotype. The net reclassification improvement, calculated by adding high PRU (≥ 254) to a model including the CYP2C19 poor metabolizer genotype in the prediction of recurrence within 7 days, was 0.83 (p＜0.001).

CONCLUSIONS

Acute PRU evaluation possesses predictive value for recurrent ischemic stroke, especially within 7 days in AIS/TIA with LAA.

Differential Impact of Clinical and Genetic Factors on High Platelet Reactivity in Patients with Coronary Artery Disease Treated with Clopidogrel and Prasugrel

AIM

High platelet reactivity (HPR) is associated with increased risks of thrombotic events in patients with coronary artery disease. The recently developed ABCD-GENE score identified five clinical and genetic factors (age, body mass index, chronic kidney disease, diabetes, and the CYP2C19 loss-of-function allele) for HPR, although the significance of various stages of each factor is unclear.

METHODS

Four prospective studies were pooled, in which platelet reactivity was measured using the VerifyNow assay with clopidogrel and prasugrel; genotyping of CYP2C19 was also performed. Each component of the ABCD-GENE score was divided into three subcategories. VerifyNow P2Y12 reactivity units ＞208 were defined as HPR.

RESULTS

A total of 184 patients were included, of which 111 (60%) and 51 (28%) had HPR with clopidogrel and prasugrel. Chronic kidney disease had an impact on HPR on both clopidogrel and prasugrel, whereas the impact of diabetes was more evident in patients treated with prasugrel. Although the number of CYP2C19 loss-of-function alleles was clearly associated with a likelihood of HPR with clopidogrel, P2Y12 reactivity units with prasugrel treatment were also significantly and progressively higher in patients with more CYP2C19 loss-of-function alleles.

CONCLUSIONS

Clinical and genetic factors had a differential effect on a P2Y12 inhibitor reactivity with clopidogrel and prasugrel in patients with coronary artery disease. The severity of the factors also had a different impact on HPR.

Update on Cilostazol: A Critical Review of Its Antithrombotic and Cardiovascular Actions and Its Clinical Applications

Cilostazol, a phosphodiesterase III inhibitor, has vasodilating and antiplatelet properties with a low rate of bleeding complications. It has been used over the past 25 years for improving intermittent claudication in patients with peripheral artery disease (PAD). Cilostazol also has demonstrated efficacy in patients undergoing percutaneous revascularization procedures for both PAD and coronary artery disease. In addition to its antithrombotic and vasodilating actions, cilostazol also inhibits vascular smooth muscle cell proliferation via phosphodiesterase III inhibition, thus mitigating restenosis. Accumulated evidence has shown that cilostazol, due to its "pleiotropic" effects, is a useful, albeit underutilized, agent for both coronary artery disease and PAD. It is also potentially useful after ischemic stroke and is an alternative in those who are allergic or intolerant to classical antithrombotic agents (eg, aspirin or clopidogrel). These issues are herein reviewed together with the pharmacology and pharmacodynamics of cilostazol. Large studies and meta-analyses are presented and evaluated. Current guidelines are also discussed, and the spectrum of cilostazol's actions and therapeutic applications are illustrated.

Cilostazol: a Review of Basic Mechanisms and Clinical Uses

Primarily used in the treatment of intermittent claudication, cilostazol is a 2-oxyquinolone derivative that works through the inhibition of phosphodiesterase III and related increases in cyclic adenosine monophosphate (cAMP) levels. However, cilostazol has been implicated in a number of other basic pathways including the inhibition of adenosine reuptake, the inhibition of multidrug resistance protein 4, among others. It has been observed to exhibit antiplatelet, antiproliferative, vasodilatory, and ischemic-reperfusion protective properties. As such, cilostazol has been investigated for clinical use in a variety of settings including intermittent claudication, as an adjunctive for reduction of restenosis after coronary and peripheral endovascular interventions, and in the prevention of secondary stroke, although its widespread implementation for indications other than intermittent claudication has been limited by relatively modest effect sizes and lack of studies in western populations. In this review, we highlight the pleiotropic effects of cilostazol and the evidence for its clinical use.

Temporal trends in coronary intervention strategies and the impact on one-year clinical events: data from a Japanese multi-center real-world cohort study

Percutaneous coronary intervention (PCI) has significantly advanced over the last 40 years, but it is not clear whether there have been any changes in prognosis in recent years. The Kumamoto Intervention Conference Study Real-World Registry is a multi-center registry that enrolls consecutive patients undergoing PCI in 17 centers in Kyushu, Japan. To elucidate the clinical impact of recent changes in treatment strategies, 8841 consecutive participants (historical PCI: n = 4038, enrolled between January 2013 and December 2014, and current PCI: n = 4803, between January 2015 and March 2017) with 1-year follow-up data were analyzed. The incidences of major adverse cardiovascular and other clinical events were comparable between historical PCI and current PCI, even though complex lesions were more frequent during the more recent period. During this period, the use of radial approaches, drug eluting stents, and coronary imaging was greater. The use of prasugrel was more frequent (P < 0.001) during the time periods. Comparable event rates were associated with the use of clopidogrel (52.7%) and prasugrel (47.3%). In the sub-analysis for acute coronary syndrome (n = 5047), similar clinical event rates were recorded for historical and current PCI. Although the lesions to be treated are becoming more severe and complex, equivalent clinical outcomes have been maintained in recent years, possibly due to advances in the devices and medication used.

Efficacy and Safety of Adjunctive Cilostazol to Clopidogrel-Treated Diabetic Patients With Symptomatic Lower Extremity Artery Disease in the Prevention of Ischemic Vascular Events

Background Type 2 diabetes mellitus is a risk factor for lower extremity arterial disease. Cilostazol expresses antiplatelet, anti-inflammatory, and vasodilator actions and improves the claudication intermittent symptoms. We investigated the efficacy and safety of adjunctive cilostazol to clopidogrel-treated patients with type 2 diabetes mellitus exhibiting symptomatic lower extremity arterial disease, in the prevention of ischemic vascular events and improvement of the claudication intermittent symptoms. Methods and Results In a prospective 2-arm, multicenter, open-label, phase 4 trial, patients with type 2 diabetes mellitus with intermittent claudication receiving clopidogrel (75 mg/d) for at least 6 months, were randomly assigned in a 1:1 ratio, either to continue to clopidogrel monotherapy, without receiving placebo cilostazol (391 patients), or to additionally receive cilostazol, 100 mg twice/day (403 patients). The median duration of follow-up was 27 months. The primary efficacy end point, the composite of acute ischemic stroke/transient ischemic attack, acute myocardial infarction, and death from vascular causes, was significantly reduced in patients receiving adjunctive cilostazol compared with the clopidogrel monotherapy group (sex-adjusted hazard ratio [HR], 0.468; 95% CI, 0.252-0.870; P=0.016). Adjunctive cilostazol also significantly reduced the stroke/transient ischemic attack events (sex-adjusted HR, 0.38; 95% CI, 0.15-0.98; P=0.046) and improved the ankle-brachial index and pain-free walking distance values (P=0.001 for both comparisons). No significant difference in the bleeding events, as defined by Bleeding Academic Research Consortium criteria, was found between the 2 groups (sex-adjusted HR, 1.080; 95% CI, 0.579-2.015; P=0.809). Conclusions Adjunctive cilostazol to clopidogrel-treated patients with type 2 diabetes mellitus with symptomatic lower extremity arterial disease may lower the risk of ischemic events and improve intermittent claudication symptoms, without increasing the bleeding risk, compared with clopidogrel monotherapy. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT02983214.

Acute thrombosis of everolimus-eluting platinum chromium stent caused by impaired prasugrel metabolism due to cytochrome P450 enzyme 2B6*2 (C64T) polymorphism: a case report

BACKGROUND

Dual antiplatelet therapy with aspirin and P2Y12 receptor inhibitor is an important option for preventing acute stent thrombosis after percutaneous coronary intervention (PCI).

CASE SUMMARY

A 72-year-old man was admitted to our hospital with ST-segment elevation myocardial infarction. Emergent coronary angiography identified the occlusion in the proximal left anterior descending artery. This lesion was successfully treated by thrombus aspiration and an everolimus-eluting platinum chromium stent implantation with loading of aspirin 200 mg and prasugrel 20 mg. However, acute closure of the stent occurred 1 h after PCI. P2Y12 reaction units (PRU) measured using VerifyNow assay was 282, suggesting high platelet reactivity on prasugrel. After adding cilostazol 200 mg, recanalization was successfully obtained by thrombus aspiration and ballooning under intra-aortic balloon pump. Thereafter, PRU decreased to 266 at 4 h after PCI, and 49 the next day, implying full inhibition of platelet reactivity on prasugrel. Fortunately, no stent thrombosis has recurred since then. Genotype analysis of cytochrome P450 enzyme (CYP) demonstrated CYP2B6*1/*2 polymorphism leading to impaired metabolism of prasugrel. Based on these findings, acute stent thrombosis in the present case might have been caused by delayed expression of prasugrel effects due to CYP2B6*2 (C64T) polymorphism.

DISCUSSION

In cases of stent thrombosis, we should consider the possibility of poor response to P2Y12 receptor inhibitors due to CYP polymorphism. Assessment of platelet aggregation and CYP genotype may be warranted.