• International Journal of Vascular Biomedical Engineering
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• 제1권1호
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• pp.13-23
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• 2003

Backgrounds: The present study in angulated coronary stenosis was to evaluate the influence of velocity and wall shear stress (WSS) on coronary atherosclerosis, the changes of hemodynamic indices following coronary stenting, as well as their effect of evolving in-stent restenosis using human in vivo hemodynamic parameters and computed simulation quantitatively and qualitatively. Methods: Initial and follow-up coronary angiographies in the patients with angulated coronary stenosis were performed (n=80). Optimal coronary stenting in angulated coronary stenosis had two models: < 50 % angle changed(model 1, n=43), > 50% angle changed group (model 2, n=37) according to percent change of vascular angle between pre- and post-intracoronary stenting. Flow-velocity wave obtained from in vivo intracoronary Doppler study data was used for in vitro numerical simulation. Spatial and temporal patterns of velocity vector and recirculation area were drawn throughout the selected segment of coronary models. WSS of pre/post-intracoronary stenting were calculated from three-dimensional computer simulation. Results: Follow-up coronary angiogram demonstrated significant difference in the percent of diameter stenosis between two groups (group 1: $40.3{\pm}30.2$ vs. group 2: $25.5{\pm}22.5%$, p<0.05). Negative WSS area on 3D simulation, which is consistent with re-circulation area of velocity vector, was noted on the inner wall of post-stenotic area before stenting. The negative WSS was disappeared after stenting. High spatial and temporal WSS before stenting fell into within physiologic WSS after stenting. This finding was prominent in Model 2 (p<0.01) Conclusions: The present study suggests that hemodynamic forces exerted by pulsatile coronary circulation termed as WSS might affect on the evolution of atherosclerosis within the angulated vascular curvature. Moreover, geometric change, such as angular difference between pre / post-intracoronary stenting might give proper information of optimal hemodynamic charateristics for vascular repair after stenting.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1306-1309
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• 2003

In the present paper, finite element analyses were carried out to evaluate the most important feature of a stent, that is. high radial strength and flexibility. Palmaz-Schatz 154 stent and two new models(stent A, stent B) were selected because they are the most representatives of tubular stents. Finite element analyses for the stent system were performed using ABAQUS/Explicit code. As a result, Palmaz-Schatz 154 stent shows sufficient radial strength but it needs some improvement in general properties such as high flexibility, low elastic recoil, low longitudinal contraction and low metal coverage area. Other two models show that sufficient flexibility, foreshortening and longitudinal recoil.

• Journal of Chest Surgery
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• 제42권2호
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• pp.252-255
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• 2009

58세 남자 환자가 좌쇄골하동맥협착이 동반된 관상동맥 질환으로 하이브리드술식을 시행받았다. 쇄골하동맥에 대한 스텐트 삽입과 좌내흉동맥의 좌전하행지 문합을 포함한 심폐 바이패스 없이 관상동맥 우회술을 시행하였다. 수술 후 시행한 관상동맥 조영술과 컴퓨터 단층촬영(CT)상에서 이식편의 개방성은 양호하였고 스텐트의 삽입부위는 적절한 것으로 보였고 개방성도 양호하였다. 술 후 8일째 퇴원하였고, 현재 6개월째 외래 경과관찰 중이다.

• Bulletin of the Korean Chemical Society
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• 제30권5호
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• pp.1085-1087
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• 2009

Bare metal stents which were used to treat coronary artery disease have several biochemical problems. Polymerbased drug-eluting stents (DES) have opened up a new paradigm in the treatment of in-stent restenosis. Many studies and research programmes have proved that DES can prevent restenosis. In our study, paclitaxel-loaded poly (lactic-co-glycolic acid) (PLGA) nanoparticles have been deposited along the three dimensional scaffold of coronary stents by a method using self-assembling properties of colloidal particles. We found that the nanoparticles were deposited uniformly and closely packed. The amount of paclitaxel was easily controlled by the drug content of the nanoparticles and the deposition count.

• Korean Journal of Radiology
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• 제20권4호
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• pp.621-630
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• 2019

Objective: To study the prevalence and clinical characteristics of decreased myocardial blood flow (MBF) quantified by dynamic computed tomography (CT) myocardial perfusion imaging (MPI) in symptomatic patients without in-stent restenosis. Materials and Methods: Thirty-seven (mean age, 71.3 ± 10 years; age range, 48-88 years; 31 males, 6 females) consecutive symptomatic patients with patent coronary stents and without obstructive de novo lesions were prospectively enrolled to undergo dynamic CT-MPI using a third-generation dual-source CT scanner. The shuttle-mode acquisition technique was used to image the complete left ventricle. A bolus of contrast media (50 mL; iopromide, 370 mg iodine/mL) was injected into the antecubital vein at a rate of 6 mL/s, followed by a 40-mL saline flush. The mean MBF value and other quantitative parameters were measured for each segment of both stented-vessel territories and reference territories. The MBF_ratio was defined as the ratio of the mean MBF value of the whole stent-vessel territory to that of the whole reference territory. An MBF_ratio of 0.85 was used as the cut-off value to distinguish hypoperfused from non-hypoperfused segments. Results: A total of 629 segments of 37 patients were ultimately included for analysis. The mean effective dose of dynamic CT-MPI was 3.1 ± 1.2 mSv (range, 1.7-6.3 mSv). The mean MBF of stent-vessel territories was decreased in 19 lesions and 81 segments. Compared to stent-vessel territories without hypoperfusion, the mean MBF and myocardial blood volume were markedly lower in hypoperfused stent-vessel territories (77.5 ± 16.6 mL/100 mL/min vs. 140.4 ± 24.1 mL/100 mL/min [p < 0.001] and 6.4 ± 3.7 mL/100 mL vs. 11.5 ± 4 mL/100 mL [p < 0.001, respectively]). Myocardial hypoperfusion in stentvessel territories was present in 48.6% (18/37) of patients. None of clinical parameters differed statistically significantly between hypoperfusion and non-hypoperfusion subgroups. Conclusion: Decreased MBF is commonly present in patients who are symptomatic after percutaneous coronary intervention, despite patent stents and can be detected by dynamic CT-MPI using a low radiation dose.

• Korean Circulation Journal
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• 제54권6호
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• pp.339-350
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• 2024

Background and Objectives: Ultimaster^TM, a third-generation sirolimus-eluting stent using biodegradable polymer, has been introduced to overcome long term adverse vascular events, such as restenosis or stent thrombosis. In the present study, we aimed to evaluate the 12-month clinical outcomes of Ultimaster^TM stents in Korean patients with coronary artery disease. Methods: This study is a multicenter, prospective, observational registry across 12 hospitals. To reflect real-world clinical evidence, non-selective subtypes of patients and lesions were included in this study. The study end point was target lesion failure (TLF) (the composite of cardiac death, target vessel myocardial infarction [MI], and target lesion revascularization [TLR]) at 12-month clinical follow up. Results: A total of 576 patients were enrolled between November 2016 and May 2021. Most of the patients were male (76.5%), with a mean age of 66.0±11.2 years. Among the included patients, 40.1% had diabetes mellitus (DM) and 67.9% had acute coronary syndrome (ACS). At 12 months, the incidence of TLF was 4.1%. The incidence of cardiac death was 1.5%, MI was 1.0%, TLR was 2.7%, and stent thrombosis was 0.6%. In subgroup analysis based on the presence of ACS, DM, hypertension, dyslipidemia, or bifurcation, there were no major differences in the incidence of the primary endpoint. Conclusions: The present registry shows that Ultimaster^TM stent is safe and effective for routine real-world clinical practice in non-selective Korean patients, having a low rate of adverse events at least up to 12 months.

• Journal of Yeungnam Medical Science
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• 제22권1호
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• pp.90-95
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• 2005

관상동맥파열은 중재시술시 간헐적으로 발생하는 합병증이지만 급성 심장눌림증으로 진행하여 치명적일 수 있다. 일반적으로 중재시술시 사용하는 유도철선에 의한 천공은 자연방누되는 경우가 많으나 본 예와 같이 풍선이나 죽상판 제거술 등으로 인한 천공은 매우 급격히 진행하여 생명이 위험할 수 있다. 과거에는 젤라틴이나 자가혈전을 이용하여 파열된 부위를 막거나 수술적 교정을 하였으나 시술이 매우 복잡하고 시술지연에 따른 문제가 많이 발생한다. 이식판 그물망은 동맥류의 치료를 위해 개발되어 유용하게 이용되어 지고 있다. 본 예와 같이 관동맥 성형술 중에 관동맥이 천공되어 위급한 경우에도 이식판 그물망은 유용한 치료법으로 이용될 수 있다.

• 한국콘텐츠학회논문지
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• 제13권12호
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• pp.880-892
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• 2013

약물방출 스텐트 (drug-eluting stents, DES)는 일반금속 스텐트에 비하여 재협착을 현저하게 줄었지만, DES의 구조적인 특성으로 인한 스텐트 혈전증 (stent thrombosis, ST)이 증가한다고 알려져 있다. 혈전증 유형의 정의는 Early ST ; (EST)은 30일 이내, Late ST ; (LST)은 31일 이상에서 1년 이내 그리고 Very late ST ; (VLST)은 1년 이상으로 분류 하였다. 스텐트 세대별 (시장 출시와 스텐트 디자인, Polymer 향상에 따른) ST발생빈도, 임상 양상 및 예후를 알아보았다. 2003년 6월부터 2013년 6월까지의 전남대학교병원 심혈관센터에서 경피적 관상동맥 중재술을 시행 받은 10,273명 중 ST 발생은 134명 (1.30%) 이었다. 세대별 발생빈도는 1세대에서 81명 (0.79%)으로 높았으며, 세대별 ST 유형은 1세대에서는 VLST의 발생률이 높았고 (p=0.002), 2세대에서는 EST와 LST의 발생률이 높았지만 (p=0.025), 3세대에서는 유의한 차이가 없었다(p=0.278). ST로 인하여 사망한 14명은 EST 10명 (18.2%), LST 2명 (8.3%), VLST 2명 (3.6%)로서 EST에서 사망률이 높았다 (p=0.042). DES 시술 후 발생하는 ST는 1.3% 이였고, VLST는 1세대 스텐트에서 많았으며, 입원 중 사망률은 EST에서 높았다.

• Korean Journal of Radiology
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• 제23권11호
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• pp.1044-1054
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• 2022

Objective: This study aimed to investigate whether a deep learning reconstruction (DLR) method improves the image quality, stent evaluation, and visibility of the valve apparatus in coronary computed tomography angiography (CCTA) when compared with filtered back projection (FBP) and hybrid iterative reconstruction (IR) methods. Materials and Methods: CCTA images of 51 patients (mean age ± standard deviation [SD], 63.9 ± 9.8 years, 36 male) who underwent examination at a single institution were reconstructed using DLR, FBP, and hybrid IR methods and reviewed. CT attenuation, image noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and stent evaluation, including 10%-90% edge rise slope (ERS) and 10%-90% edge rise distance (ERD), were measured. Quantitative data are summarized as the mean ± SD. The subjective visual scores (1 for worst -5 for best) of the images were obtained for the following: overall image quality, image noise, and appearance of stent, vessel, and aortic and tricuspid valve apparatus (annulus, leaflets, papillary muscles, and chordae tendineae). These parameters were compared between the DLR, FBP, and hybrid IR methods. Results: DLR provided higher Hounsfield unit (HU) values in the aorta and similar attenuation in the fat and muscle compared with FBP and hybrid IR. The image noise in HU was significantly lower in DLR (12.6 ± 2.2) than in hybrid IR (24.2 ± 3.0) and FBP (54.2 ± 9.5) (p < 0.001). The SNR and CNR were significantly higher in the DLR group than in the FBP and hybrid IR groups (p < 0.001). In the coronary stent, the mean value of ERS was significantly higher in DLR (1260.4 ± 242.5 HU/mm) than that of FBP (801.9 ± 170.7 HU/mm) and hybrid IR (641.9 ± 112.0 HU/mm). The mean value of ERD was measured as 0.8 ± 0.1 mm for DLR while it was 1.1 ± 0.2 mm for FBP and 1.1 ± 0.2 mm for hybrid IR. The subjective visual scores were higher in the DLR than in the images reconstructed with FBP and hybrid IR. Conclusion: DLR reconstruction provided better images than FBP and hybrid IR reconstruction.

• Journal of Korean Neurosurgical Society
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• 제51권3호
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• pp.155-159
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• 2012

The treatment of bilateral vertebral artery dissecting aneurysms (VADAs) presenting with subarachnoid hemorrhage (SAH) is still challenging. The authors report a rare case of bilateral VADA treated with coil trapping of ruptured VADA and covered stents implantation after multiple unsuccessful stent assisted coiling of the contralateral unruptured VADA. A 44-year-old woman was admitted to our hospital because of severe headache and sudden stuporous consciousness. Brain CT showed thick SAH and intraventricular hemorrhage. Cerebral angiography demonstrated bilateral VADA. Based on the SAH pattern and aneurysm configurations, the right VADA was considered ruptured. This was trapped with endovascular coils without difficulty. One month later, the contralateral unruptured VADA was protected using a stent-within-a-stent technique, but marked enlargement of the left VADA was detected by 8-months follow-up angiography. Subsequently two times coil packing for pseudosacs resulted in near complete occlusion of left VADA. However, it continued to grow. Covered stents graft below the posterior inferior cerebellar artery (PICA) origin and a coronary stent implantation across the origin of the PICA resulted in near complete obliteration of the VADA. Covered stent graft can be used as a last therapeutic option for the management of VADA, which requires absolute preservation of VA flow.