The impact of residual coronary lesions on clinical outcomes after percutaneous coronary intervention: Residual SYNTAX score after percutaneous coronary intervention in patients from the Efficacy of Xience/Promus versus Cypher in rEducing Late Loss after stENTing (EXCELLENT) registry

BACKGROUND

The SYNTAX score (SS) is used in preprocedural evaluation for percutaneous coronary intervention (PCI); it assesses the complexity of coronary lesions and predicts PCI outcome. However, the usefulness of the residual SS (rSS), which can be calculated after PCI and may reflect the completeness of revascularization, has not been fully investigated in an enriched PCI population.

METHODS AND RESULTS

The baseline SS and rSS were determined in 5,088 patients (3,046 everolimus-eluting stents and 2,042 sirolimus-eluting stents) from the EXCELLENT registry. The primary end point was 1-year patient-oriented composite end point (POCE), comprising all-cause death, myocardial infarction, and repeat revascularization. The mean baseline SS was 13.6 ± 9.1 and rSS was 4.7 ± 6.5. Residual SS tertiles were defined as rSS = 0 (42.7%), 0 < rSS < 7 (29.9%), and rSS ≥ 7 (27.4%). Increasing rSS tertiles had increasing 1-year POCE rates (5.2%, 8.1%, 12.4%; P < .001) mainly caused by the increase in repeat revascularization. Also, rSS was an independent predictor of 1-year POCE after multivariate analysis (P for trend < .001) and had better predictability in simple coronary lesions (baseline SS < 16). The clinical rSS, calculated by multiplying the rSS to a modified age, creatinine clearance, and ejection fraction score (age/ejection fraction + 1 for each 10 mL the creatinine clearance <60 mL/min), was also associated with 1-year POCE, with predictability similar to rSS (area under curve 0.610 vs 0.607, P = .634).

CONCLUSION

Greater residual coronary lesions after PCI with "limus" drug-eluting stent, as quantified by the rSS and the clinical rSS, are associated with increased risk of adverse cardiac events.

Effect of intermittent hypoxia on rat INS-1 cells and the protective effect of melatonin

OBJECTIVES

This study aimed to observe the influence of intermittent hypoxia on rat INS-1 cells and the protective effect of melatonin (MT).

MATERIALS AND METHODS

Intermittent hypoxia condition was induced in rat INS-1 cells. The supernatants were used to detect oxidative stress indicators, and the cells were used to detect JNK1 mRNA and JNK1/2 protein. After different dose-dependent interventions of MT, the cells were harvested to observe corresponding oxidative stress indicators and JNK1/2 protein change.

RESULTS

With prolonged exposure time, malondialdehyde (MDA) increased in cultured supernatants whereas superoxide dismutase (SOD) activity decreased. Cells with intermittent hypoxia showed significantly increased JNK1 mRNA expression, whereas phosphorylated JNK1 was highly expressed on the third day. With increased MT dose, MDA in cultured supernatants decreased whereas SOD activity increased. In the group dosed with 100 µM MT, phosphorylated JNK1 protein expression significantly decreased.

CONCLUSIONS

Intermittent hypoxia can cause oxidative damage to INS-1 cells possibly by increasing the JNK1 transcription level and protein activation. A high dose of MT (100 µM) can protect INS-1 cells from oxidative damage induced by intermittent hypoxia.

Improved quality and diagnostic confidence achieved by use of dose-reduced gadolinium blood-pool agents for time-resolved intracranial MR angiography

BACKGROUND AND PURPOSE

Time-resolved MRA with the use of bolus injection of paramagnetic agents has proved valuable in neurovascular imaging. Standard contrast agents have limited blood-pool residence times, motivating the development of highly protein-bound blood-pool agents with greater relaxivity and longer intravascular residence, affording improved image quality at lesser doses. This study represents the first comparison of blood-pool agents to standard agents in time-resolved cerebral MRA.

MATERIALS AND METHODS

One hundred datasets were acquired at 1.5 T by use of a standardized, time-resolved MRA protocol. Patients received either unit dosing of a standard extracellular agent at 0.1 mmol/kg or a blood-pool agent at 0.03 mmol/kg. Peak arterial and venous enhancement phases were identified and subsequently scored qualitatively by use of a 4-point Likert scale, with attention to 6 vascular segments: 1) intracranial ICA; 2) MCA M1; 3) MCA M2; 4) MCA M3; 5) deep cerebral veins; and 6) dural venous sinuses.

RESULTS

Fifty MR angiographies were acquired with each agent. No significant differences were found between agents in generation of uncontaminated arteriograms. Blood-pool agents, at 67% dose reduction, were of significantly greater quality across most vascular segments, including ICA (P = .019), M2 (P = .003), and M3 (P < .01). Superiority in the M1 segment approached significance (P = .059). Significantly better venographic quality was noted for deep venous structures (P = .016) with the use of blood-pool agents.

CONCLUSIONS

Blood-pool agents provide superior demonstration of most intracranial vessels in time-resolved MRA compared with standard agents, at reduced doses. The greater relaxation enhancement and more favorable dosing profile make blood-pool agents superior to standard agents for use in cerebral time-resolved MRA.

Thermostability of seven hepatitis C virus genotypes in vitro and in vivo

Hepatitis C virus (HCV) is transmitted primarily through percutaneous exposure to contaminated blood especially in healthcare settings and among people who inject drugs. The environmental stability of HCV has been extrapolated from studies with the bovine viral diarrhoea virus or was so far only addressed with HCV genotype 2a viruses. The aim of this study was to compare the environmental and thermostability of all so far known seven HCV genotypes in vitro and in vivo. Incubation experiments at room temperature revealed that all HCV genotypes showed similar environmental stabilities in suspension with viral infectivity detectable for up to 28 days. The risk of HCV infection may not accurately be reflected by determination of HCV RNA levels. However, viral stability and transmission risks assessed from in vitro experiments correlated with viral infectivity in transgenic mice containing human liver xenografts. A reduced viral stability for up to 2 days was observed at 37 °C with comparable decays for all HCV genotypes confirmed by thermodynamic analysis. These results demonstrate that different HCV genotypes possess comparable stability in the environment and that noninfectious particles after incubation in vitro do not cause infection in an HCV in vivo model. These findings are important for estimation of HCV cross-transmission in the environment and indicate that different HCV genotypes do not display an altered stability or resistance at certain temperatures.

Impact of anticoagulation on coronary flow in patients with non-ST elevation acute coronary syndrome

The effect of anticoagulation by heparin on patients with non-ST elevation acute coronary syndrome (NSTE-ACS), receiving early dual antiplatelet therapy, has not been fully evaluated. We classified 355 patients with NSTE-ACS according to the adequacy of anticoagulation (percentage of low activated partial thromboplastin time [APTT] level). The 6-hour APTT level was optimal in only 23.1% of the patients treated with unfractionated heparin. The rate of poor preprocedural coronary blood flow (thrombolysis in myocardial infarction grade <3, 39.1%, 30.5%, 30.3%, and 33.9% in the 100% low-, 99%∼50% low-, 49%∼1% low-, and 0% low-APTT group, respectively, P = .632) and bleeding events did not differ between the groups. Instead, in multivariate analysis, the diagnosis of myocardial infarction was the only independent predictor of poor coronary flow. For bleeding events, the usage of glycoprotein IIb/IIIa inhibitor appeared to be a sole risk factor. In conclusion, inadequate preprocedural anticoagulation was not associated with adverse outcomes in patients with NSTE-ACS treated with dual antiplatelet agents.

Astrocytes release D-serine by a large vesicle

Long-term potentiation (LTP) of synaptic transmission in the CA1 region of the hippocampus depends on the activation of N-methyl-D-aspartate receptors (NMDARs), which can be regulated by Ca²⁺-dependent release of D-serine from astrocytes. The detailed mechanism underlying astrocytic d-serine release is still unknown. In hippocampal slices prepared from Sprague-Dawley rats, we found that clamping astrocytic [Ca²⁺] at 100-150 nM or puffing artificial cerebrospinal fluid (ACSF) into the extracellular space (weak mechanical stimulation) enhanced the synaptic activation of NMDARs. The enhancement was blocked by the NMDAR glycine site antagonist 5,7-dichlorokynurenic acid, glycine saturation, and infusion of astrocytes with D-amino acid oxidase and the serine racemase inhibitor L-erythro-3-hydroxyaspartate, suggesting the involvement of astrocytic D-serine release. Intracellular 100-150 nM [Ca²⁺] or puffing ACSF stimulated astrocytes to generate D-serine-containing large vesicles (1-3 μm), exocytotic fusion of which released D-serine. The formation of astrocytic large vesicles involved the intracellular fusion of small vesicles and/or other organelles. Spontaneous fusion of large vesicles occurred occasionally in astrocytes at rest, contributing to baseline D-serine levels, which increased the rising slope of NMDAR post-burst potentiation (PBP) without altering the PBP peak amplitude. Thus, under physiological conditions, astrocytic D-serine release by large vesicles facilitated weak theta-burst (TBS consisting of five bursts), but not strong TBS (TBS consisting of 10 bursts) stimulation-induced LTP.

Paraoxonase 1 gene polymorphism does not affect clopidogrel response variability but is associated with clinical outcome after PCI

Background

Paraoxonase (PON) is a high-density-lipoprotein (HDL) associated enzyme with antioxidative and anti-atherogenic property. Its function is associated with coronary artery disease and its activity genetically controlled. We evaluated whether genetic variation of PON-1 is associated with clinical outcome in a large cohort of Korean patients with drug-eluting stents implantation.

Methods

A total of 1676 patients with drug-eluting stent implantation were enrolled in the prospective CROSS-VERIFY cohort from June 2006 to June 2010. We genotyped the PON1-Q192R gene, measured clopidogrel on-treatment platelet reactivity (OPR), and analyzed lipid profiles. The primary endpoint was the composite of cardiac death, myocardial infarction, and stent thrombosis at 12 months.

Results

PON-1 genotyping data were available in 1336 patients. Since the Q-allele is associated with decreased PON-activity, we analyzed the outcome between patients with QQ/QR (815 patients, 61%) and those with RR-genotype (521 patients, 39%). After adjustment for common cardiac risk factors, the QQ/QR-genotype was an independent predictor of the primary thrombotic endpoint with an 11-fold increased risk (HR 11.6, 95% CI: 1.55–87.0), but not repeat revascularization (HR 1.12, 95% CI: 0.78–1.61). The QQ/QR-genotype was not associated with OPR (QQ/QR: 231±86 PRU vs. RR 236±82 PRU, p = 0.342) but higher small-dense LDL levels (1.20±0.12 mg/dL vs. 0.76±0.15 mg/dL, p = 0.027). The increased risk of thrombotic outcomes was more profound in acute coronary syndrome (ACS) patients compared with non-ACS patients.

Conclusion

PON1 Q-allele is an independent predictor of worse cardiovascular outcome independent of platelet function and is associated with significantly higher levels of small dense LDL-C.

CYP3A4 genetic status may be associated with increased vulnerability to the inhibitory effect of calcium-channel blockers on clopidogrel

BACKGROUND

Calcium-channel blockers (CCBs) inhibit the CYP3A4 enzyme, which is involved in clopidogrel activation. Studies have shown conflicting results regarding the effect of concomitant CCB administration on clopidogrel response. We investigated the relationship between CYP3A4 genotype and the inhibitory effect of CCBs on clopidogrel response.

METHODS AND RESULTS

Clopidogrel on-treatment platelet reactivity (OPR) was measured and CYP3A4 (IVS10+12G>A) genotyped in 1,247 consecutive patients with drug-eluting stent implantation. The mean OPR was 231±83 (P2Y12 reaction units: PRU). In total, 332 (26.6%) CCB users had higher OPR compared with 915 (73.4%) non-CCB users (245±84 vs. 227±83 PRU, P=0.001). The distribution of CYP3A4 (IVS10+12G>A) genotype was 63.6%, 32.6% and 3.8% for GG, GA and AA genotypes, respectively. After adjustment for possible confounding factors, the number of A-alleles was associated with increased vulnerability to CCB use (effect of CCB use ΔPRU: +8 PRU, P=0.210, +24 PRU, P=0.012, +50 PRU, P=0.025, for patients with 0, 1, and 2 A-alleles, respectively, +24 PRU, P=0.005 for GA/AA genotypes). Furthermore, only in the GA/AA-genotype did CCB use result in a significantly increased risk for high-OPR (odds ratio 1.84, 95% confidence interval 1.15-2.92, P=0.010).

CONCLUSIONS

CCB use is associated with increased OPR. The number of CYP3A4 (IVS10+12G>A) A-alleles may be associated with an increased vulnerability to the effects of CCBs on clopidogrel response variation. 

Using a Ludic Simulation to Make Learning of Middle School Space Science Fun

In this paper, the authors describe a ludic simulation designed for middle school space science and examine its use to support students’ learning and motivation. The participants were 383 sixth graders and 447 seventh graders. The findings of this study showed that sixth- and seventh-graders perceived the simulation as having substantial ludic characteristics and educational value. The results indicated that having a playful experience is important for this age group and that participating in a ludic simulation can help motivate students to learn school subjects. Results also indicated that incorporating ludus into the learning experience can improve students’ attitudes toward the subject matter. Implications of policy, research, and practice with regard to using ludic simulations to support classroom-based learning were discussed.

Genetic determinants of clopidogrel responsiveness in Koreans treated with drug-eluting stents

BACKGROUND

Variations of genes encoding cytochrome enzymes, drug transporters, and paraoxonase have recently been reported to be associated with clopidogrel response variability besides the well-known CYP2C19 loss-of-function (LOF) alleles. We determined whether newly reported genetic variations are associated with clopidogrel on-treatment platelet reactivity (OPR) in Korean patients.

METHODS

OPR was measured in 1264 consecutive patients who underwent percutaneous coronary intervention using the VerifyNowP2Y12 assay system and genotyping of PON-1 Q192R, ABCB1 C3435T, CYP1A2*1F, CYP2B6*6, CYP2C19*2, CYP2C19*3, CYP2C19*17, CYP3A4 (IVS10+12G>A), and CYP3A5*3 was performed. We applied two different cutoffs, i.e. 240 P2Y12 reaction units (PRU) and 253 PRU, to define high OPR.

RESULTS

Mean OPR of the entire population was 231±83 PRU. Genetic variations of ABCB1 and PON-1 genes as well as that of CYP1A2, 2B6, 3A4, and 3A5 were not associated with clopidogrel response variability. As for CYP2C19, patients were classified into 4 metabolism genotypes: 0.6% ultrarapid (UM), 40.3% extensive (EM), 48.8% intermediate (IM), and 10.3% poor metabolizers (PM). After adjustment for possible confounders, CYP2C19 metabolism genotype was associated with a significant increase in OPR: effect on OPR-difference: +27 PRU, p=0.015 for EM, +53 PRU, p<0.001 for IM, and +74 PRU, p=0.006 for PM compared with UM. In multivariable analysis, the CYP2C19 genotype was the only independent predictor of high-OPR among genetic variations using two different cutoffs.

CONCLUSIONS

Among genes postulated to be involved in clopidogrel metabolism, only the CYP2C19 genotype is associated with response variability and emerged as an independent predictor of high-OPR using two different cutoffs. PON-1 and ABCB1 genetic variants do not affect clopidogrel OPR in Korean patients.