• 한국정밀공학회지
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• 제22권9호
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• pp.179-187
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• 2005

The characteristics of blood flow and the interaction between the blood vessel and blood flow play important roles in plaque cap rupture and the growth of atherosclerosis which may lead directly to a heart attack or a stroke. In this study, carotid arteries with different stenoses have been numerically simulated to investigate the wall shear stress(WSS) and the elastic motion of the vessel. Blood flow has been treated as physiological, laminar and incompressible flow. To model the shear thining behavior of the blood, the Carreau-Yasuda model has been employed but the viscoelasticity of blood has not been considered. The results show that the WSS of $severe(75\%)$ stenosis is much higher than those of $25\%\;and\;50\%$ stenosis in the region of stenosis. With the increase in the stenosis thickness, the expansion ratio of the center of the stenosis decreases while the expansion ratio of the upstream region of the stenosis increases.

• Journal of Chest Surgery
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• 제45권4호
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• pp.251-253
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• 2012

We report a redo coronary artery bypass grafting (CABG) in a 55-year-old man. Angina recurred 7 years after the initial surgery. Coronary angiography showed all patent grafts except a faint visualization of the in situ right gastroepiploic artery (RGEA) graft, which was anastomosed to the posterior descending coronary artery, associated with celiac axis stenosis. Redo-CABG was performed at postoperative 10 years because of aggravated angina and decreased perfusion of the inferior wall in the myocardial single photon emission computed tomography. The saphenous vein graft was interposed between the 2 in situ grafts used previously; the right internal thoracic artery and RGEA grafts. Angina was relieved and myocardial perfusion was improved.

• Journal of Korean Neurosurgical Society
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• 제41권3호
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• pp.200-203
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• 2007

We describe a case that showed augmention of the superficial temporal artery [STA] pedicle's patency 15 months after extracranial to intracranial [EC-IC] bypass surgery for a carotid artery occlusion with contralateral intracranial internal carotid artery stenosis. It is rare that meager patency of the STA pedicle in the early postoperative angiogram can be become well augmented with time where most branches of the middle cerebral artery [MCA] are robustly filled with blood from the STA. A 28-year-old woman with a history of a previous left hemispheric stroke presented with slurred speech after several bouts of seizure. Magnetic resonance imaging showed a new infarct on the right hemisphere in addition to an old infarct on the left hemisphere. Carotid angiography revealed stenosis of the right carotid siphon and occlusion of the left carotid artery. The patient underwent EC-IC bypass on the right side. Even though the early postoperative angiogram showed meager filling of MCA with no significant stenotic lesion change, a subsequent angiogram taken 15 months later, demonstrated a widely patent STA pedicle with occlusion of the previous intracranial stenotic lesion. Selected cases with an inaccessible intracranial stenotic lesion can benefit from EC-IC bypass surgery; however, its clear indication should first be established.

• 대한기계학회논문집B
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• 제32권11호
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• pp.891-896
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• 2008

In the present computational study, simple stenotic artery models using pulsatile flow condition were investigated. A 1 Hz non-reversing sinusoidal velocity for pulsatile flow was imposed at the flow inlet and the corresponding Womersley number based on the vessel radius is 2.75. The simple stenotic geometries have been used that consist of 25%, 50% and 75% semicircular constriction in a cylindrical tube. In this paper, numerical solutions are presented for a first harmonic oscillatory flow using commercial software ADINA 8.4. As stenosis and Reynolds number increase, the maximum wall shear stress(WSS) increases while the minimum WSS decreases. As the stenotic rate increases, the pressure drop at the throat severely decreases to collapse the artery and plaque. It is found that the fluid mechanical disturbances due to the constriction were highly sensitive with rate of stenosis and Reynolds number. When Reynolds number and stenosis increase, the larger recirculation region exists. In this recirculation region the possibility of plaque attachment is increasingly higher. The present results enhance our understanding of the hemodynamics of a stenotic artery.

• Journal of Cerebrovascular and Endovascular Neurosurgery
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• 제20권4호
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• pp.235-240
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• 2018

The safety and feasibility of simple coil embolization and stent deployment for the treatment of posterior inferior cerebellar artery (PICA) aneurysms, as well as their radiologic and clinical results, have not been adequately understood. Especially, if dissecting aneurysm of proximal PICA is associated with small caliber PICA and stenosis of ipsilateral vertebral artery orifice (VAO), endovascular coiling with saving of PICA is not always easy. This 64-year-old man presented with subarachnoid hemorrhage due to a ruptured dissecting aneurysm of left proximal PICA. The aneurysm was irregularly fusiform in nature with a shallow PICA orifice (1.4 mm) and narrow caliber (0.9-1.5 mm). Moreover, the ipsilateral VAO showed severe stenosis (1.8 mm). We performed bifemoral puncture and chose additional route from right vertebral artery to left vertebrobasilar junction for retrograde approach and deployment of LVIS Jr. intraluminal support at proximal PICA. And then, the antegrade approach and coiling of aneurysm was done. Despite of transient thrombus of PICA, the aneurysm was successfully secured with preservation of whole PICA course. For preservation of narrow PICA with ipsilateral VAO stenosis, the contralateral approach and deployment of LVIS Jr. intraluminal support may be considered.

• Journal of Korean Neurosurgical Society
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• 제46권5호
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• pp.488-491
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• 2009

A 31-year-old man presented with right hemiparesis, and magnetic resonance imaging revealed a small infarct at left basal ganglia. Digital subtraction angiography showed left cervical internal carotid artery (ICA) occlusion and severe stenosis of the ipsilateral external carotid artery (ECA) with collateral cerebral circulation fed by ECAs. Based on the results of a functional evaluation of cerebral blood flow, we performed preventive ECA angioplasty and stenting for advanced ECA stenosis to ensure sufficient blood flow to the superficial temporal artery. Eight weeks later, superficial temporal artery to middle cerebral artery (STA-MCA) anastomosis was performed. His postoperative course was uneventful and no additional transient ischemic attacks have occurred. To our knowledge, this is the first report of preventive angioplasty and stenting for advanced narrowing of an ECA before STA-MCA anastomosis for ipsilateral ICA occlusion.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.1987-1992
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• 2004

Hemodynamics behavior of the blood flow is influenced by the presence of the arterial stenosis. If stenosis is present in an artery, normal blood flow is disturbed. In the present study, characteristics of steady and pulsatile flow of non-Newtonian fluid, the effects of stenosised geometry are analyzed by numerical simulation. One interesting point is that non-symmetric solutions were obtained at severity stenosis, although the stenosis and the boundary condition were all axisymmetric.

• 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.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.707-708
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• 2002

Catheters are used to measure translesional pressure gradients in the stenosed coronary arteries. Catheter insertions during coronary angioplasty cause flow obstructions. A narrowed flow cross section with catheter present effectively introduced a tighter stenosis than the enlarged residual stenoses after balloon angiplasty. In general, the form of stenoses are no uniform. Sometimes, these are occurred the irregularly eccentricity If the analyses are conducted for uniform stenosed artery, the results will be underestimated. Thus, in this study, three dimensional computer simulations are conducted to investigate the flow blockage effects due to the catheter insertion during the coronary angioplasty. The results for the eccentric stenosed artery are compared with those of the concentric stenosed artery.

• 대한방사선기술학회지:방사선기술과학
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• 제45권1호
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• pp.19-29
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• 2022

The study is conducted with the subjects who have under gone coronary angiography to examine the influential factors for the severity of coronary stenosis. Four indicators related to hypertension, diabetes, dyslipidemia, obesity of metabolic syndrome were used as influential factors. As a result of the study, metabolic syndrome such as diabetes and dyslipidemia had 3.3 times and 7.7 times higher chance to lead to 1VD, respectively. In 2VD, diabetes showed 2.9 times higher risk, and dyslipidemia showed 8.5 times higher risk. In 3VD, diabetes was found to be 5 times higher and dyslipidemia was 17.5 times higher in risk. Therefore, it was confirmed that dyslipidemia showed the highest correlation among metabolic syndromes. According to this study, it was confirmed that dyslipidemia and diabetes were closely related to the influential factors for coronary artery stenosis.