• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.753-758
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• 2003

The purpose of the present study was to establish the mechanism of the generation of atherosclerosis by analyzing the hemodynamic variables in the coronary artery where atherosclerosis occurs frequently. From the previous results, the stenosis phenomena due to atherosclerosis were related to not only biochemical reaction between blood and blood vessel but also the hemodynamic factors like flow separation and oscillatory wall shear stress. The present study aimed to investigate the causes of the generation and progression of atherosclerosis in the coronary artery. This study also aimed to develop the softwares which generate automatically three dimensional vascular models obtained by the angiogram images and the computer vision techniques. In the present study, the flow patterns for full three-dimensional hemodynamic characteristics were analyzed. To understand the three-dimensional hemodynamic characteristics, the wall shear stress distributions and secondary flows were investigated quantitatively.

• 대한기계학회논문집B
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• 제34권10호
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• pp.893-899
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• 2010

박동유동조건에서 관상동맥 내의 유동특성과 혈류역학적 인자 분포를 선행연구에서 수행하여 혈류역학이 관상동맥 내의 협착현상과 연관관계가 있음을 밝혔다. 동맥경화증의 호발부위인 관상동맥 분지부에서 혈류역학적 변수를 분석하여 동맥경화증의 발생기전을 규명하는 것이 본 연구의 목적이다. 동맥경화증에 의한 협착현상은 혈액과 혈관벽 사이의 생화학 반응뿐 아니라 유동박리나 벽전단응력과 같은 혈류역학적 인자와도 관계 있음을 확인하였다. 관상동맥 분지부의 분지각이 증가할수록 분지부 단면에서의 재순환영역의 크기가 증가하고 교란유동이 발생하게 된다. 이 재순환영역이 관상동맥에서 동맥경화의 시작점으로 의심되는 영역이라 할 수 있다.

• 대한의용생체공학회:의공학회지
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• 제23권6호
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• pp.437-449
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• 2002

관상동맥은 체순환 동맥과 비교하여 매우 다른 유동조건을 갖는다. 본 연구에서는 이러한 관상동맥의 유동조건이 다른 혈관과 비교하여 동맥경화의 생성과 발전에 어떤 영향을 미치는지를 협착된 혈관 모델의 혈류역학적 전산유체해석을 통해 분석하였다. 연구 결과, 협착된 관상동맥 모델의 유동장과 벽면전단응력의 분포는 복부 대동맥 및 고동맥과 비교하여 큰 차이점을 보였다. 관상동맥은 혈관 지름이 혈류량에 비해 상대적으로 작으므로 큰 벽면전단응력값을 보이는 반면에, 혈관 협착부 목 후방부에 하나의 보텍스만 보이는 단순한 유동장 분포를 보였다. 한편, 복부대동맥과 고동맥 모델은 협착부 목 전반부와 후방부에 여러 개의 보텍스를 나타내는 복잡한 유동장을 형성하였다. 관상동맥 모델에서는 임피던스 페이즈앵글이 음의 큰 값을 가질 때에 벽면전단응력의 크기가 증가하고 재순환영역이 증가함이 관찰되었다. 그러므로 심장의 수축운동과 -110。에 이르는 관상동맥의 큰 음의 임피던스 페이즈앵글 값은 동맥경화를 촉진시키는 유동환경을 조성함을 알 수 있었다.

• Korean Journal of Radiology
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• 제25권6호
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• pp.518-539
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• 2024

Coronary computed tomography angiography (CCTA) has emerged as a pivotal tool for diagnosing and risk-stratifying patients with suspected coronary artery disease (CAD). Recent advancements in image analysis and artificial intelligence (AI) techniques have enabled the comprehensive quantitative analysis of coronary atherosclerosis. Fully quantitative assessments of coronary stenosis and lumen attenuation have improved the accuracy of assessing stenosis severity and predicting hemodynamically significant lesions. In addition to stenosis evaluation, quantitative plaque analysis plays a crucial role in predicting and monitoring CAD progression. Studies have demonstrated that the quantitative assessment of plaque subtypes based on CT attenuation provides a nuanced understanding of plaque characteristics and their association with cardiovascular events. Quantitative analysis of serial CCTA scans offers a unique perspective on the impact of medical therapies on plaque modification. However, challenges such as time-intensive analyses and variability in software platforms still need to be addressed for broader clinical implementation. The paradigm of CCTA has shifted towards comprehensive quantitative plaque analysis facilitated by technological advancements. As these methods continue to evolve, their integration into routine clinical practice has the potential to enhance risk assessment and guide individualized patient management. This article reviews the evolving landscape of quantitative plaque analysis in CCTA and explores its applications and limitations.

• Journal of Chest Surgery
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• 제20권2호
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• pp.384-392
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• 1987

The occlusive coronary artery disease presents a potential threat to a significant population in the United State. According to many case reports, the increasing incidence of coronary artery disease due to atherosclerosis is noted in Korean, recently. We experienced one case of coronary artery disease. He was a 68 year old male who had been suffered from hypertension since 1 5 years ago, and had intermittent conservative treatment at local clinic. He had been afflicted with severe chest pain on exertion, but this symptom was relieved on rest. Pre-operative EKG finding revealed no any other ischemic sign. Significant S-T segment depression was noted at lead II, aVF, V3, V4, and V5, and inverted T wave in V5 and V6 after Master`s test. Simple chest X-ray finding showed emphysematous field, bilaterally. Final pre-operative diagnosis was made by coronary angiogram, which showed almost 90% degree of occlusive lesion in the proximal part of left main coronary artery above the origin LAD artery. He was treated successfully by aorta-coronary saphenous vein graft under extra-corporeal circulation in May, 1987. He has been followed up with uneventful course.

• 대한영상의학회지
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• 제85권2호
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• pp.297-307
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• 2024

관상동맥 질환은 죽상동맥경화(atherosclerosis)로 인해 혈관의 내강이 좁아지면서 심근허혈 또는 경색까지 유발할 수 있는 질병이다. 이런 관상동맥 질환은 조기에 진단해서 치료하면 그만큼 예후가 좋기에 정확한 진단이 환자 관리에서 매우 중요하다. 전산화단층촬영 혈관조영술(CT angiography; 이하 CTA)은 높은 해상도와 대조도를 통해 혈관의 구조 및 협착 정도를 세밀하게 평가할 수 있는 비침습적 영상 진단법이다. 여러 임상시험들이 관상동맥 질환에 대한 조기 진단과 평가에 있어 관상동맥 CTA의 유용성을 보고하였다. 최근에 관상동맥 질환이 의심되는 환자들에 대한 보다 효과적인 처치를 위해 CTA에 기반한 관상동맥 질환 진단 분류 체계인 관상동맥 질환 판독과 자료 체계(coronary artery disease-reporting and data system; 이하 CAD-RADS)가 만들어졌다. 이런 CAD-RADS는 관상동맥 CTA를 기반으로 하지만 CAD-RADS는 CTA 결과만으로 관상동맥의 정확한 상태를 해석하는 것이 어려운 경계선 범주를 포함하고 있다. 본 종설은 침습적 관상동맥 조영술 진행 여부를 결정하기에 앞서 추가검사가 필요한 경계선상 CAD-RADS범주들의 CTA의 소견과 이들에 대한 대처를 논하고자 한다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.717-720
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• 2002

The present study is to evaluate the performances of flow velocity and wall shear stress in the stenosed coronary artery using human in vivo hemodynamic Parameters and computer simulation. Initial and follow-up coronary angiographics in the patients with angulated coronary stenosis are performed. Follow-up coronary angiogram demonstrated significant difference in the percent of diameter in the stenosed coronary between two groups ($Group\;1:\;40.3{\%},\;Group\;2:\;25.5{\%}$). Flow-velocity wave obtained from in vivo intracoronary Doppler ultrasound data is used for the boundary condition for the computer simulation. Spatial and temporal variations of flow velocity vector and recirculation area are drawn throughout the selected segment of coronary models. The WSS of pre- and post-intracoronary stenting are calculated from three-dimensional computer simulation. Then negative shear stresses area on 3D simulation we noted on the inner wall of the post-stenotic area before stenting. The negative WSS is disappeared after stenting. High spatial and temporal WSS before stenting fell into within physiologic WSS after stenting. This finding was prominent in Model 2. The present study suggest that hemodynamic forces exerted by pulsatile coronary circulation termed WSS might affect on the evolution of atherosclerosis within the angulated vascular curvature. The local recirculation area which has low or negative WSS, might lead to progression of atherosclerosis.

• Journal of Mechanical Science and Technology
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• 제19권6호
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• pp.1313-1320
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• 2005

Stenosed coronary artery may play an important role in various coronary heart diseases. However, it has not been known how much stenosed coronary artery affects coronary circulation system, quantitatively. The present study developed a mathematical model for microcirculation in the left common coronary artery (LCCA) with adopting a previously measured morphological data and mechanical properties of the coronary vessels. We examine the effect of percent diameter stenosis on blood flow rate and shear stress for two cases. Case I comprised of one-stenosed element at $10^{th}$ order ($\%$ diameter stenosis are 10, 30, and 50, respectively). Case II consisted of completely occluded element at $10^{th}$ order (number of occluded elements are 0, 1, and 2 out of 8, respectively). As the level of stenosis becomes severe, the shear stress increases significantly but the flow rate reduction was relatively small. However, for the occluded case, there was linearly proportional reduction of flow rate according to number of occluded elements. Either such high shear stress associated with coronary artery stenosis or reduced flow rate due to occlusion may cause atherosclerosis and myocardial ischemia.

• Journal of Chest Surgery
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• 제12권3호
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• pp.297-305
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• 1979

Occlusive coronary artery disease presents a potential threat to a significant population in the United States. According to many case reports, the increasing incidence of coronary artery disease due to atherosclerosis is noted in Korean, recently. Operative vascular procedures have increased steadily in number over the past 20 years in the United States. There have been many isolated case reports about coronary artery surgery, but these had little clinical impact. Nowadays, major three coronary bypass surgery has developed principally at three cardiac centers in the United States since 1967. Among three coronary bypass operation, the aorta-coronary artery saphenous vein bypass graft was first demonstrated by Favolaro and Effler at the Cleveland Clinic in 1967. We experienced one case of coronary artery disease, which was treated successfully by aorta-coronary saphenous vein graft with mild hypothermia under extracorporeal circulation in May, 1977. Saphenous vein was removed from above the knee and was 2.5 mm in diameter. The left ventricle was not vented for the left ventricle was not overdistended. Temporary artificial pace-maker-Medtronic-was implanted for the prevention and treatment of post-operative arrhythmia and heart block in post-operative first day. He is a 57 year old male businessman who had been suffered from hypertension [200 mmHg in systolic pressure] since 4 years ago, who had intermittent conservative treatment at local clinic. He had been afflicted with severe chest pain with choking sensation for 50 days. This symptom was aggravated exposing cold weather, or cold water, but was respond to rest. Pre-operative ECG revealed no any other ischemic sign except sinus bradycardia. Significant S-T segment depression was noted at lead II, AVF after double 5 minutes exercise, indicating positive Master`s test. Serum cholesterol was slight elevated to 253 mg/dl. Final pre-operative diagnosis was made by coronary arteriogram, which showed about 1.0-cm segmental 90 % occlusive atherosclerotic lesion in the proximal part of right coronary artery above the origin of acute marginal artery. Left coronary artery revealed good patency and there was no collateral circulation between right and left coronary artery .Hospital course was not eventful. He was discharged with good result on the post-operative day. He has been free from chest pain for longer than 2 years. And also the arterial flow in the coronary bypass graft is auscultated with the pocket-sized ultrasonic velocity detector, which shows the patency of the coronary bypass graft good.

• 대한의생명과학회지
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• 제8권4호
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• pp.257-268
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• 2002

Chronic infection and inflammation have recently been implicated as important etiologic agents of atherosclerosis. Several agents have been suggested as possible candidates including cytomegalovirus (CMV), herpes simplex vims type 1 (HSV-1), Epstein-Barr virus (EBV), Chlamydia pneumoniae, and Helicobacter pylori. We evaluated the relationship between cytornegalovirus infection and atherosclerosis by in situ hybridization and polymerase chain reaction (PCR). We examined 23 subjects with atherosclerosis and 10 matched control subjects without atherosclerosis. CMV was detected by in situ hybridization in 60.9% (14/23) of aorta and 42.9% (9/21) of coronary arteries in subjects with atherosclerosis. It was also detected by PCR in 65.2% (15/23) of aorta and 52.4% (11/21) of coronary arteries. CMV was detected on areas showing early or advanced atheromatous changes. Cells morphologically identical to smooth muscle cells, endothelial cells, lymphocytes, fibroblasts, and Schwann cells were positively reacted with the CMV probe. However. none of the cells to which the probe hybridized contained inclusion bodies, thus strongly suggesting that the arterial wall may be a site of CMV latency. This result Indicates that CMV may potentially play a direct or indirect role in the pathogenesis of human atherosclerosis.