• Journal of Biomedical Engineering Research
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• v.34 no.2
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• pp.69-72
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• 2013

The goal of this study is to develop test method for evaluating the drug eluting properties of drug eluting stents (DES). PBS and the detergent solutions, presented by each DES manufacturer, were used for drug release of DES coated with paclitaxel, zotarolimus and everolimus. The drugs which are coating DES were not released by PBS but released by the detergent solutions, finally paclitaxel 83.38%, zotarolimus 103.85% and everolimus 115.78%. It seems that the use of the detergents is necessary in order to release the drugs because those drugs are extremely hydrophobic. In conclusion, using of detergent solutions presented by each manufacturer were suitable for evaluating the drug eluting property of drug eluting stent.

• Korean Journal of Clinical Pharmacy
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• v.22 no.2
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• pp.113-122
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• 2012

ACC/AHA/SCAI Guideline recommends for administration dual antiplatelet therapy after drug-eluting stent (DES) to prevent restenosis and stent thrombosis in patients with percutaneous coronary intervention (PCI). Recently triple antiplatelet therapy including cilostazol is known to reduce restenosis and stent thrombosis significantly after DES implantation. However, there is lack of data providing the efficacy of triple antiplatelet therapy. The purpose of this study is to evaluate the clinical effects of the triple therapy after DES implantation compared with the dual therapy. This retrospective study collected data from medical charts of 251 patients who received DES implantation between Jul 2006 and Jun 2008. They received either dual antiplatelet therapy (N = 154 clopidogrel and aspirin; Dual group) or triple antiplatelet therapy (N = 97 cliostazol, clopidogrel and aspirin; Triple group). Major adverse cardiac event rates (MACE, included total death, myocardial infarction, target lesion revascularization) at 12 months, 24 months, stent thrombosis, rates of bleeding complications and adverse drug reactions were compared between these two groups. Compared with the dual group, the triple group had a similar incidence of the MACE rates at 24months (12.3% vs. 12.4%, p = 0.99). There is no difference in overall stent thrombosis between two groups (Dual group 2.6% vs. Triple group 4.1%, p = 0.5). Subgroup analysis showed that diabetic patients got more benefit in reducing MACE rates but, there is no statistical difference. Bleeding complications and adverse drug effects were not different significantly. As compared with dual antiplatelet therapy, triple antiplatelet therapy did not reduce the 12-months, 24-months MACE rates and stent thrombosis. Bleeding complications and adverse drug effects were not different.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.10
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• pp.1053-1060
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• 2011

This study is performed to determine the drug concentration profiles of drug-eluting stents (DES) for an ideal circular ring stent and intertwined stent models for various Reynolds numbers (Re = 200, 400, and 800). The Navier.Stokes equations coupled with the advection-diffusion equation are solved numerically in order to determine how the flow patterns and drug deposition are affected in the in-stent and post-stent regions where flow separation and recirculation occur. The presence of DES within the arterial segment affects the local drug distribution in the flow field. As a result, the drug concentration for the intertwined stent is higher over the in-stent region in comparison with the ideal stents. For a given stent geometry, the local drug concentration in the in-stent region decreases with Reynolds number, while for a given Reynolds number, the local drug concentration is relatively insensitive to the stent geometry. The results show that drug concentration along the arterial wall is significantly higher within the in-stent and post-stent regions for the intertwined stent geometry than for the ideal stent geometries.

• Journal of radiological science and technology
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• v.37 no.2
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• pp.109-116
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• 2014

Many studies have suggested that in the era of Drug-Eluting Stents(DES) are one of the causes of In-Stent Restenosis(ISR) of Stent Fracture(SF). The present study sought to evaluate clinical characteristics of patients with stent fracture after successful DES implantation. The 4,701 patients were selected for analysis who underwent a follow-up coronary angiography irrespective of ischemic symptoms. The overall incidence of SF was 32 patients(male:female=19:13, Av. age $62.44{\pm}9.8$year, 0.68%). Fractures of Sirolimus-Eluting Stents(SES), Paclitaxel-Eluting Stents(PES), Biolimus A9-Eluting Stents(BES), Everolimus-Eluting Etents(EES), Endothelial Progenitor Cell Capture Stent(EPC) and Zotarolimus-Eluting Stents(ZES) are accounted for 19(59.4%), 9(28.1%), 2(6.3%), 1(3.1%), 1(3.1%) and 0(0%) respectively. SF developed in the left Anterior Dscending(LAD) artery in 16 patients(50%) and in complex(type B2, C) lesions in 25 patients(69.4%). Ten patients were treated with heterogenous DES, the rest being treated with either homogenous DES(3 patients), plain old balloon angioplasty(3 patients), or conservative medical treatment(17 patients). None of the patients with SF suffered from cardiac death during a follow-up period of $32.9{\pm}12.4$ months. The overall rate of DES fracture over up to 3.7 years of follow-up was 0.68% with higher incidence in SES than in PES. SF frequently occurred in the LAD artery and in complex lesions. Of the patients with SF, coronary intervention was performed only when the binary restenosis lesion was significant. During the follow-up, patients with SF have continued on combination antiplatelet therapy. There is a very low rate of major adverse cardiac events(post-detection of SF), especially cardiac death associated with SF.

• The Journal of the Korea Contents Association
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• v.13 no.12
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• pp.880-892
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• 2013

Stent thrombosis after successful drug-eluting stent(DES) implantation has been reported in around 1% of patients in clinical trials. However, the increased risk of ST associated with DES remains a matter of concern. From 1 June 2003 to 30 June 2013, we investigated clinical characteristics, in-hospital outcomes in 10,273 patients who underwent percutaneous coronary intervention in the Heart Center of CNUH. Overall incidence of ST was 1.30% (134 patients). The incidence of ST according to the stent generations and the timing of ST (n=total, early vs. late vs. very late) were 0.79% (n=81, 26 vs. 12 vs. 43) in first-generation, 0.38% (n=39, 21 vs. 9 vs. 9) in second-generation and 0.14% (n=14, 8 vs 3 vs. 3) in third-generation, (p=0.70). The mortality from ST was significantly higher in early ST group compared to the late and very late ST groups (18.2% vs. 8.3% vs. 3.6%, p=0.042). Overall incidence of ST after DES implantation was 1.30% (134 patients). The in-hospital mortality was significantly higher in early ST group compared to the late and very late ST groups.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.10a
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• pp.223-224
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• 2006

• Polymer(Korea)
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• v.35 no.5
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• pp.483-487
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• 2011

For the preparation of effective non-vascular drug eluting stent (DES), pullulan acetate (PA) was investigated as a coating material for polytetrafluorethylene (PTFE)-covered stent. PA was coated on PTFE-covered stent (PTFE-stent) by dip coating technique, and then its surface morphology, drug release behavior and cellular toxicity were tested. Field emission-scanning electron microscopy (FE-SEM) result indicated that its surface was smoother after PA coating without any cracking. The sustained release behavior of paclitaxel from PA-coated PTFE membrane was observed for 80 days. Also, the biological stability of paclitaxel in the membrane was confirmed by annexin V binding assays. Furthermore, the antitumor activity was demonstrated by an in vivo test against CT-26 murine colorectal tumors. From the results, we concluded that PA was expected as a useful coating material to design an effective non-vascular DES.

• Journal of the Korean Society of Radiology
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• v.13 no.3
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• pp.381-389
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• 2019

Although the development of Drug-eluting stent (DES) improved the ISR significantly more than the Bare metal stent (BMS), the coronary stent restenosis (ISR) treatment still has a high recurrence rate. This study is compared the efficacy of DEB with that of DES implantation in patients with ISR. Among 4,316 patients who underwent coronary stent implantation at the Chonnam National University Hospital between November 2012 and December 2016, 187 patients developed ISR on follow-up coronary angiography ($66.3{\pm}11.0years$, 123 males) were enrolled and divided into two groups according to revascularization method as group I (DEB group; n=127) and group II (DES group; n=60). Primary end point was defined as major adverse cardiac events (MACEs), composite of cardiac death (CD), myocardial infaction (MI), target lesion revascularization (TLR) and stent thrombosis (ST) during two-year follow-up between the two groups. There were no differences in the baseline characteristics and angiographic findings except that prevalence of device length was shorter ($21.1{\pm}5.3$ vs. $25.3{\pm}9.6 mm$, p<0.002) in group I.Two-year MACE were not different in the two groups (8.7%vs.10.0%, p=0.789). The incidences of cardiac death (0%vs.0%, p=1.000), MI (1.6%vs.6.7%, p=0.085), TLR(8.7% vs. 10.0%, p=0.789) and ST (0% vs. 0%, p=1000). DEB demonstrated comparable risk reduction for MACEs compared with DES in patients with ISR during two-year follow-up. DEB might be good alternative for the treatment of ISR in patients with ISR.

• Bulletin of the Korean Chemical Society
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• v.28 no.3
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• pp.397-402
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• 2007

Restenosis after percutaneous coronary intervention (PCI) continues to be a serious problem in clinical cardiology. To solve this problem, drug eluting stents (DES) with antiproliferative agents have been developed. Variable local drug delivery systems in the context of stenting require the development of stent manufacture, drug pharmacology and coating technology. We have worked on a system that integrates electrophoretic deposition (EPD) technology with the polymeric nanoparticles in DES for local drug delivery and a controlled release system. The surface morphology and drug loading amount of DES by EPD have been investigated under different operational conditions, such as operation time, voltage and the composition of media. We prepared poly-D,L-lactide-co-glycolic acid (PLGA) nanoparticles embedded with curcumin, which was done by a modified spontaneous emulsification method and used polyacrylic acid (PAA) as a surfactant because its carboxylic group contribute negative charge to the surface of CPNPs (?53.5 ± 5.8 mV). In the process of ‘trial and error' endeavors, we found that it is easy to control the drug loading amount deposited onto the stent while keeping uniform surface morphology. Accordingly, stent coating by EPD has a wide application to the modification of DES using various kinds of nanoparticles and drugs.

• The Journal of the Korea Contents Association
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• v.12 no.7
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• pp.273-283
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• 2012

Drug-eluting stents (DES) have significantly reduced in-stent restenosis, compared to bare-metal stents (BMS). However, there remains concern for the increased risk of stent thrombosis (ST) associated with DES. The present study sought to evaluate the incidence, clinical characteristics and outcome of ST in patients with acute myocardial infarction (MI) during a 1-year follow-up. 80 patients who developed ST were divided into 2 groups according to stent type: group I (DES-ST, n = 57 ) and group II (BMS-ST, n = 23 ). There were no differences between group I and II in the overall incidence of ST (2.7% vs. 4.3%, p=0.064) and in the incidence of each type of ST: acute ST (8.8% vs. 2.3%), subacute ST (50.9% vs. 60.9%), late ST (19.3% vs. 8.7%), and very late ST (21.1% vs. 17.4%) (p=0.605). Predictors of 1-year mortality were the occurrence of ST (OR 8.12, 95% CI 2.83-23.61, p<0.001), left ventricular ejection fraction<40% (OR 6.41, 95% CI 2.42-16.96, p<0.001), and age${\geq}$75 years (OR 4.98, 95% CI 1.95-12.74, p=0.001).