Differences in Optimal Platelet Reactivity after Potent P2Y12 Inhibitor Treatment in Acute Coronary Syndrome Patients Undergoing Percutaneous Coronary Intervention.

Background: East Asian patients receiving treatment with the potent P2Y12 inhibitors prasugrel or ticagrelor experience more potent platelet inhibition than with clopidogrel. Methods: This study investigated differences in OPR rates with reduced doses of prasugrel (n = 38) or ticagrelor (n = 40) for maintenance therapy in 118 Korean ACS patients who had undergone PCI, in comparison to conventional-dose clopidogrel (n = 40). We assessed drug responses at one- and three-months post-PCI with VerifyNow and multiple electrode aggregometry assays. Results: At the one-month period, patients receiving standard-dose prasugrel or ticagrelor had lower platelet reactivity as determined by the three assays than those receiving the conventional dose of clopidogrel (VN: p = 0.000; MEA: p = 0.000; LTA: p = 0.000). At the 3-month point, platelet reactivity was lower in those receiving reduced-dose prasugrel or ticagrelor than the clopidogrel-treated patients (VN: p = 0.000; MEA: p = 0.012; LTA: p = 0.002). Prasugrel resulted in significantly lower platelet inhibition than ticagrelor as determined by VN and LTA (VN: p = 0.000; LTA: p = 0.003). At three months, there was a significant overall difference in OPR among the three groups when measured by VN (p < 0.001), but not when measured by MEA (p = 0.596). OPR in the reduced-dose prasugrel group was not significantly different to the clopidogrel group at three months (VN: p = 0.180; MEA: p = 0.711). OPR in the reduced-dose ticagrelor group was similar to clopidogrel as determined by MEA at three months, but was different when assessed by VN (VN: p = 0.000; MEA: p = 0.540). Compared to standard-dose, the reduced-dose prasugrel OPR rate was significantly increased (VN: p = 0.008; MEA: p = 0.020). Conclusions: OPR values for reduced-dose prasugrel and conventional-dose clopidogrel at three months were similar but higher than for reduced-dose ticagrelor as determined by VN, but no differences were noted by MEA. The MEA assay might have less sensitivity and consistency than the VN assay. Further studies are needed to explore this discrepancy.

Mechanical Properties and Failure Behavior of 3D-SiCf/SiC Composites with Different Interphases.

Continuous silicon carbide fiber-reinforced silicon carbide ceramic matrix composites (SiCf/SiC) are promising as thermal structural materials. In this work, the microstructure and static mechanical properties of 3D-SiCf/SiC with PyC, SiC, and PyC/SiC and without an interface prepared via polymer infiltration and pyrolysis (PIP) were investigated systematically in this paper. The results show that the microstructure and static mechanical properties of SiCf/SiC with an interphase layer were superior to the composites without an interlayer, and the interface debondings are existing in the composite without an interphase, resulting in a weak interface bonding. When the interphase is introduced, the interfacial shear strength is improved, the crack can be deflected, and the fracture energy can be absorbed. Meanwhile, the shear strength of the composites with PyC and PyC/SiC interfaces was 118 MPa and 124 MPa, respectively, and showing little difference in bending properties. This indicates that the sublayer SiC of the PyC/SiC multilayer interface limits the binding state and the plastic deformation of PyC interphase, and it is helpful to improve the mechanical properties of SiCf/SiC.

Optimal antithrombotic therapy in patients with atrial fibrillation following percutaneous coronary intervention: A systemic review and meta-analysis.

A challenge for antithrombotic treatment is patients who present with atrial fibrillation (AF) and acute coronary syndrome, particularly in patients who have undergone coronary percutaneous intervention with stenting (PCIS). In the present study, a total of nine observational trials published prior to July 2017 that investigated the effects of dual antiplatelet therapy (DAPT; aspirin + clopidogrel) and triple oral antithrombotic therapy (TOAT; DAPT + warfarin) among patients with AF concurrent to PCIS were collected from the Medline, Cochrane and Embase databases and conference proceedings of cardiology, gastroenterology and neurology meetings. A meta-analysis was performed using fixed- or random-effect models according to heterogeneity. The subgroups were also analyzed on the occurrence of major adverse cardiac events (MACE), stroke and bleeding events in the two treatment groups. Analysis of baseline characteristics indicated that there was no significant difference in the history of coexistent disease or conventional therapies between the DAPT and TOAT groups. The primary end point incidence was 2,588 patients in the DAPT group (n=13,773) and 871 patients in the TOAT group (n=5,262) following pooling of all nine trials. There was no statistically significant difference in the incidence of primary end points between the DAPT and TOAT groups. Odds ratio (OR)=0.96, 95% confidence interval (CI)=0.73-1.27, P=0.79, with heterogeneity between trials (I2=82%, P<0.00001). Subsequently, on subgroup analysis, the results indicated no increased risk of major bleeding or ischemic stroke in the DAPT or TOAT group. However, compared with the TOAT group, there was an apparent increased risk of MACE plus ischemic stroke in the DAPT group (OR=1.62, 95% CI=1.43-1.83, P<0.00001) with heterogeneity between trials (I2=70%, P=0.01). In conclusion, the present meta-analysis suggests that TOAT (aspirin + clopidogrel + warfarin) therapy for patients with AF concurrent to PCIS significantly reduced the risk of MACE and stroke compared with DAPT (aspirin + clopidogrel) therapy. Further randomized controlled clinical trials are required to confirm the efficacy of the optimal antithrombotic therapy in patients with AF following PCIS.

Oral N-acetylcysteine for prophylaxis of contrast-induced nephropathy in patients following coronary angioplasty: A meta-analysis.

It is acknowledged that contrast-induced nephropathy (CIN) is a common cause of acute renal insufficiency after cardiac catheterization and affects mortality and morbidity. To date, it is unknown whether oral N-acetylcysteine (NAC) is able to prevent contrast-induced nephropathy (CIN) in patients undergoing coronary angioplasty. A meta-analysis of randomized controlled trials was performed to assess the effects of NAC in the prevention of CIN in patients following coronary angioplasty. A total of 19 studies published prior to January 2015 that investigated the efficacy of oral NAC for the prevention of CIN were collected from Medline, Cochrane and Embase databases and conference proceedings from cardiology and nephrology meetings. The primary point of investigation was CIN, and the secondary points were renal failure requiring dialysis, mortality and length of hospitalization. The meta-analysis was performed using fixed- or random-effect models according to heterogeneity. Up to January 2015, 19 randomized placebo-controlled clinical trials met the inclusion criteria for the meta-analysis, including 4,514 patients. The pooled data showed that oral NAC did not reduce the CIN incidence [relative risk 0.84, 95% confidence interval (CI) 0.65-1.10; P=0.20], without heterogeneity among trials (I2=29%). Thus, the present meta-analysis suggests that oral NAC therapy is not effective as an alternative treatment to prevent CIN in patients following angioplasty. Further high quality randomized clinical controlled trials are required to confirm the usage and availability of this treatment.

Loading effect of 200 mg cilostazol on platelet inhibition in patients undergoing percutaneous coronary intervention.

To date, most studies conducted on cilostazol have examined its effects as an agent of maintenance-dose therapy, but its loading effects on platelet inhibition have never been reported. This study aimed to determine the loading effects of 200 mg cilostazol in addition to aspirin and clopidogrel on platelet inhibition in patients undergoing percutaneous coronary intervention.Sixty consecutive patients undergoing coronary intervention were enrolled and assigned to receive 300 mg of aspirin and clopidogrel with or without 200 mg of cilostazol. All loading doses were given at least 3 hours before percutaneous coronary intervention and followed by dual or triple maintenance-dose therapy. Platelet function tests were performed just before and at 24 hours and 30 days after percutaneous coronary intervention by light transmittance aggregometry and VerifyNow® P2Y12 assay.There were no significant differences in baseline or angiographic characteristics between the 2 groups. The results of platelet function tests revealed that the adjunctive loading dose of 200 mg of cilostazol induced more potent platelet inhibition compared to a dual regimen at each time point. Cilostazol reduced the incidence of high post-treatment platelet reactivity (HPPR).Adjunctive 200 mg cilostazol can improve platelet responsiveness to clopidogrel in the pre- and postprocedural phases, reducing the prevalence of HPPR.

Identification of HZF1 as a novel target gene of the MEF2 transcription factor.

The MADS box-containing transcription factors MEF2A-D regulate the expression of most skeletal and cardiac muscle structural genes. Recently, a zinc finger protein called HZF1 was identified as a transcription factor, and found to be highly expressed in cardiac muscle. By screening the transcription regulatory region of HZF1, we found that myocyte enhancer factor 2 (MEF2) potentially recognizes and binds the regulatory region of the HZF1 gene. We also found that the knockdown of MEF2A endogenous expression in human aortic smooth muscle cells decreases the expression of HZF1, while the enforced expression of MEF2A in turn promotes the expression of HZF1. Furthermore, we employed the luciferase reporter system and chromatin immunoprecipitation (ChIP) to demonstrate that MEF2A does in fact bind the regulatory region of HZF1, which suggests that HZF1 is the direct target of MEF2A. Based on the fact that MEF2 proteins function as essential regulators of cardiac development and as important pathological factors for certain cardiac diseases, our finding that MEF2 positively regulates the expression of HZF1 may contribute to further research investigating the role of the zinc finger protein HZF1 in cardiac development and disease.