Current status and prospects of antiplatelet therapy in percutaneous coronary intervention in Japan: Focus on adenosine diphosphate receptor inhibitors

A Descriptive Analysis of Direct Oral Anticoagulant Drugs Dosing Errors Based on Spontaneous Reports from the EudraVigilance Database

Direct oral anticoagulant drugs (DOACs) interfere with the coagulation process, thus improving patient care for those who require anticoagulant treatment. This study presents a descriptive analysis of adverse reactions (ADRs) attributed to DOAC dosage errors (overdose, underdose, and improper dose). The analysis was performed based on the Individual Case Safety Reports from the EudraVigilance (EV) database. Results show that data reported for rivaroxaban, apixaban, edoxaban, and dabigatran are mostly regarding underdosing (51.56%) compared to overdosing (18.54%). The most dosage error reports were identified for rivaroxaban (54.02%), followed by apixaban (33.61%). Dabigatran and edoxaban had similar percentages (6.26% and 6.11%, respectively) regarding dosage error reports. Since coagulation issues can become life-threatening events, and factors such as advanced age and renal failure can influence the pharmacokinetics of drugs, the correct usage of DOACs is of utmost importance for the management and prevention of venous thromboembolism. Thus, the collaboration and the complementarity of knowledge of physicians and pharmacists may offer a reliable solution for DOAC dose management and improve patient care.

The ABCB1, CYP2C19, CYP3A5 and CYP4F2 genetic polymorphisms and platelet reactivity in the early phases of acute coronary syndromes

Background

The aim was to study seven polymorphic markers of genes encoding proteins involved in the absorption, metabolism and pharmacokinetics of clopidogrel among patients with an acute coronary syndrome (ACS), who have undergone percutaneous coronary intervention (PCI).

Methods

Eighty-one ACS and PCI patients older than 18 years and treated with dual antiplatelet therapy were enrolled in the study. Platelet function testing and ABCB1, CYP2C19, CYP3A5 and CYP4F2 genotyping were performed. The predictive role of categorical variables, such as genotypes (carriers and non-carriers of polymorphism), on platelet reactivity (platelet reactivity units [PRU] platelet inhibition [PI]) was assessed by logistic regression (for categorical outcomes) and linear regression (for continuous outcomes) analysis. A p-value<0.05 was considered significant. The allele frequencies were estimated by gene counting, and Hardy-Weinberg equilibrium was tested using the chi-square test.

Results

Regarding clopidogrel response, 62 patients (76.5%) were clopidogrel responders and 19 were non-responders (23.5%). Mean PRU value and the percentage of platelet inhibition were 170.0±50.9 PRU and 28.6±19.9%, respectively. The effects of the CYP2C19*2 polymorphisms on PRU (166.0±50.8 vs. 190.7±48.2, p<0.038) and PI (30.6±20.0 vs. 18.1±16.3, p<0.013) were observed, and the rates of high platelet reactivity (HPR) were lower in CYP2C19*1/*1 than those in CYP2C19*1/*2+CYP2C19*2/*2 (16.2% vs. 53.8% p<0.0067). In comparison, no significant difference in PRU value and PI was observed at <5 days between the rest of polymorphisms (p>0.05). Based on the logistic regression analysis, CYP2C19*2 (OR: 4.365, CI: 1.25–17.67, p=0.022) was an independent predictor of HPR at <5 days, as was the stent diameter (OR: 0.219, CI: 0.002–0.229, p=0.049). The remaining polymorphisms had no influence.

Conclusions

The reactivity of the on-clopidogrel platelet in the early phase of ACS is influenced primarily by the CYP2C19 polymorphisms. We believe that the findings of the present study could supply additional evidence regarding the clinical appropriateness of the CYP2C19 genetic testing for designing suitable antiplatelet therapy in the early phase of ACS.

Effect of Smoking Status on Clinical Outcome and Efficacy of Clopidogrel in Acute Coronary Syndrome

BACKGROUND

The "smoker's paradox" is an otherwise unexplained phenomenon in which the mortality of smokers after acute myocardial infarction is reduced, contrary to expectations. It has been suggested that an association with antiplatelet agents exists, but the true mechanism remains largely unidentified.

METHODS AND RESULTS

The analysis included 6,195 consecutive patients who underwent percutaneous coronary intervention (PCI) for acute coronary syndrome, registered in the Japanese multicenter PCI registry. Smokers were significantly younger and had less comorbidity than non-smokers. Unadjusted in-hospital mortality rate, general complication rate, and bleeding complication rate were lower in smokers than in non-smokers. After adjustment, the trend persisted and smoking was not associated with overall mortality (odds ratio [OR], 0.90; 95% confidence interval [CI]: 0.61-1.34; P=0.62), and was associated with lower overall (P=0.032) and bleeding complication events (P=0.040). Clopidogrel effectively reduced the occurrence of in-hospital complications and major adverse cardiac events in smokers compared with non-smokers (OR, 0.55; 95% CI: 0.53-0.98 vs. OR, 1.20; 95% CI: 0.87-1.67; and OR, 0.37; 95% CI: 0.20-0.70 vs. OR, 1.48; 95% CI: 0.90-2.43, respectively).

CONCLUSIONS

The smoker's paradox was largely explained by confounding factors related to the lower risk profile of smokers, and they benefited from a positive modification of the efficacy of clopidogrel. (Circ J 2016; 80: 1590-1599).

Comparison of peri-procedural platelet inhibition with prasugrel versus adjunctive cilostazol to dual anti-platelet therapy in patients with ST segment elevation myocardial infarction

BACKGROUND

It has been well known that the inhibition of platelet aggregation (IPA) by anti-platelet agents was important to reduce the thrombo-embolic events in patients with ST segment elevation myocardial infarction (STEMI). However, the peri-procedural IPA by anti-platelet agents was not well known.

METHODS

We compared the peri-procedural IPA between prasugrel and adjunctive cilostazol to dual anti-platelet therapy (triple anti-platelet therapy; TAP) in patients with STEMI undergoing primary percutaneous coronary intervention (PCI). We prospectively randomized 70 consecutive clopidogrel-naive patients with STEMI planned PCI to either prasugrel [loading dose (LD) 60 mg; 37 patients] or TAP (LD aspirin 300 mg, clopidogrel 600 mg, and cilostazol 200mg; 33 patients). Primary end points of the study were the platelet reactivity unit (PRU) or % inhibition by the VerifyNow P2Y12 assay at pre-PCI and pre-discharge.

RESULTS

The drug loading to pre-PCI time was similar between prasugrel and TAP groups (25.4 ± 10.42 min vs. 25.5 ± 10.56 min, p=0.957). PRU at pre-PCI was significantly lower in prasugrel than in TAP (269.1 ± 71.69 vs. 306.5 ± 48.67, p=0.012). The lower PRU and greater % inhibition also observed in prasugrel than in TAP at pre-discharge (108.2 ± 60.51 vs. 238.1 ± 73.40; 63.6 ± 18.51% vs. 16.8 ± 17.91%, p<0.001 respectively). No differences in in-hospital bleeding complications between the two groups were observed.

CONCLUSION

Our study demonstrates that prasugrel could produce a significantly greater peri-procedural as well as in-hospital IPA compared with TAP in patients with STEMI undergoing primary PCI.

Clinical outcomes following coronary stenting in Japanese patients treated with and without proton pump inhibitor

BACKGROUND

The aim of this study was to examine the effect of proton-pump inhibitor (PPI) on clinical outcomes in Japanese patients who undergo coronary stent implantation.

METHODS AND RESULTS

A total of 1,270 patients (males 915, 69 years) were enrolled and dual antiplatelet therapy of aspirin and a thienopyridine derivative was prescribed (clopidogrel 630, ticlopidine 640). Patients were divided into 2 groups treated with or without PPI. PPI was administered in 331 cases (26%), and non-PPI in 939 (74%). There were no significant differences in cardiovascular death (PPI vs. non-PPI: 5 vs. 11 cases), nonfatal myocardial infarction (3 vs. 5), and stroke (3 vs. 16) between PPI and non-PPI groups, but the ratio of gastrointestinal events had a higher tendency in non-PPI group compared with PPI group (1 vs. 17, P=0.08). In subgroup analysis of patients taking clopidogrel, or patients with acute coronary syndrome, there was no significant difference in the ratio of cardiovascular events (7 vs. 16, 6 vs. 17, NS). The non-PPI group had a tendency of an increased risk of gastrointestinal events compared with the PPI group (0 vs. 9, P=0.06; 1 vs. 7, P=0.14).

CONCLUSIONS

In contrast to the negative drug interaction of PPI reported elsewhere, in the present study the intake of PPI was not associated with an increased risk for adverse clinical outcomes in patients treated with stents.