• 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.

• Advances in biomechanics and applications
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• 제1권4호
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• pp.279-292
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• 2014

This paper presents some simulations of fluxes and pressures in the coronary network, in the case of very severe coronary disease (several stenoses on the left branches and total occlusion of the right coronary artery). In that case, coronary artery bypass graft surgery is the commonly performed procedure. However, the success of the intervention depends on many factors. Modeling of the coronary circulation is thus important since it can help to understand the influence of all these factors on the coronary haemodynamics. We previously developed an analog electrical model that includes the eventual presence of collateral flows, and can describe the different revascularization strategies (two grafts, three grafts, ...). The aim of the present work is to introduce in our simulations the time-dependence of the coronary microvascular resistances, in order to better represent the effect of the systolic ventricular contraction (which induces an elevation of the resistances because the vessels are squeezed).

• Journal of Nutrition and Health
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• 제25권7호
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• pp.597-607
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• 1992

The present study examined effects of caffeine on coronary circulation myocardial oxygen me-tabolism and calcium release in isolated perfused guinea pig hearts. Intracoronary caffeine({{{{ {10 }^{-5 } }}}}∼{{{{ { 10}^{-3 } }}}}M) was employed for 10 minutes to measure coronary perfusate flow(CF) and coronary vascular sresistance(CVR) at a constant coronary perfusion pressure of 80 cmH2O Perfusate myocardial oxygen consumption(MVO2) and percent oxygen extraction(%EC2) were calcula-ted. In addition calcium contents in both perfusate samples were measured to calculate calcium release in coronary venous effluent. Caffeine significantly decreased CF and increased CVR during 10 minutes of caffeine perfusion regardless of dose of caffeine perfused exhibiting time-response. While % EO2 was significantly enhanced with caffeine MVO2 was markedly reduced. The coronary venous perfusate pH dcreased during the perfusion with caffeine. These changes were consistent with caffeine-induced metabolic acidosis. Calcium release appeared to be dose-dependent and high dose of caffeine greatly increased venous calcium release even 2 minutes after perfusion with carffeine. These finding in dicate that caffeine produced coronary vasoconst-riction with increased calcium release in isolated perfused guinea pig hearts. Additionaly this vasoconstrictor response mignt be due tin part to the direct actions of caffeine.

• 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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• 제55권3호
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• pp.243-245
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• 2022

True aneurysms of the coronary artery after aortic root replacement in Marfan syndrome patients are very rare. An anomalous origin of the right coronary artery (RCA) from the left sinus of Valsalva adds complexity during aortic root surgery. We present a case of a 37-year-old male patient with Marfan syndrome who had an RCA anomaly and a 4.5-cm true aneurysm of the common coronary button 14 years after a previous Bentall procedure. A redo Bentall operation and hemi-arch replacement were successfully performed. The anomalous origin of the RCA from the left sinus of Valsalva was safely divided and anastomosed as separate coronary buttons to the prosthetic composite valve graft. To prevent coronary button aneurysms after aortic root surgery in Marfan patients, the coronary buttons and the corresponding side holes on the prosthetic graft must be reduced to the maximum possible extent.

• Anatomy and Cell Biology
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• 제57권1호
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• pp.61-69
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• 2024

Hypogonadism is associated with an increased risk of coronary artery disease. This study sought to describe the histomorphology of the left coronary arteries of the adult male rabbit following orchiectomy and subsequent testosterone administration. We included 20 adult male rabbits, divided into a baseline group (n=2), an interventional group subjected to castration only (n=6), an intervention group subjected to castration followed by testosterone injection (n=6), and a control group (n=6). Key variables under investigation were serum testosterone levels, the intima-media thickness of coronary arteries, smooth muscle cell density, and adventitial collagen fiber density. The mean coronary arteries' intimal medial thickness was significantly higher in the castrated group than in controls (0.488 mm and 0.388 mm, respectively), while the testosterone-injected group had a mean of 0.440 mm. Mean smooth muscle cell density was significantly lower in the castrated rabbits vs. controls (26.96% and 47.80%, respectively), this observation being reversed with testosterone injection (47.53%). Mean adventitial collagen fiber density was significantly higher in the castrated group than in controls (66.6% and 36.1%, respectively), with a marginal difference after testosterone injection (65.2%). This study demonstrates that castrationinduced hypogonadism causes morphological changes in the coronary arteries that are partly reversible using testosterone injections. These findings provide a morphological basis for understanding the role of testosterone in coronary arteries.

• 한국방사선학회논문지
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• 제17권7호
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• pp.1033-1039
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• 2023

폐 스크리닝 검사로 이용되고 있는 저선량 흉부 CT는 Scan 범위 내에 관상동맥 석회화에 대한 정보도 함께 포함하고 있어 이를 이용한 관상동맥 석회화 판별의 유용성을 알아보고자 한다. 저선량 흉부 CT 검사와 관상동맥 석회화 점수(CACS) 검사를 같은 날 시행 받은 자들을 대상으로 하였다. 관상동맥 석회화 점수 검사 결과를 Coronary artery calcium score categories and risks 분류법을 참고하여 4개 그룹(Low: 1〈CACS〈10, Mild: 10〈CACS〈100, Moderate: 100〈CACS〈400, High: 400〈CACS)으로 각각 30명을 선정한 후 관상동맥 석회화 수치 측정 업무에 종사하고 있는 경력 15년차 이상 5명의 방사선사가 저선량 흉부 CT 영상에서 관상동맥 석회화 유무를 후향적으로 분석하였다. 저선량 흉부 CT 영상에서 5명의 관찰자가 통일되게 판독한 결과가 관상동맥 석회화점수 CT 검사 결과와 일치한 경우는 Low 그룹: 56%, Mild 그룹: 96.6%, Moderate 그룹: 100%, High 그룹: 100%로 나타났다. Low 그룹에서 5명의 관찰자 모두가 석회화를 관찰한 것은 30건 중 17건이었으며, 5명이 모두 판별 불가로 결정한 경우 7건이었다. 무증상 성인을 대상으로 저선량 흉부 CT 검사에서 석회화 점수가 15 이상인 경우에는 관상동맥 석회화를 100% 관찰할 수 있었다. 판별이 가능한 최소 석회화 수치는 1로, 피검자의 체형이 작거나 심장의 움직임이 최소가 되는 시점에서 스캔이 이루어지는 경우 매우 작은 석회화까지도 판별할 수 있다는 것을 알 수 있었다.

• Journal of Chest Surgery
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• 제34권9호
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• pp.720-723
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• 2001

우관상동맥 폐쇄증을 동반한 Marfan 증후군환자를 보고한다. 환자는 45세 여자로 약 1년 전에 Marfan 증후군으로 진단받고, 최근 흉통을 주소로 내원하였다. 환자는 손가락과 발가락이 긴 지주증과 돌출흉이 있고 몸통에 비해 사지가 긴 전형적인 외형을 갖고 있었다. 시력이 매우 약하고 수정체의 아탈구가 있었다. 심초음파상 대동맥판막 폐쇄부전증은 경도로 있었고, 좌심실의 중등도 확장과 심박출율의 중등도 저하가 있었다. 수술시에 우관상동맥의 폐쇄증을 발견하였다. 대동맥판막 폐쇄부전증과 대동맥 확장증에 대해서 SJM 27mm composite graft를 이용하여 좌관상동맥에는 Bentall 술식과 우관상동맥에는 PTFE 6mm를 이용하여 변형된 Piehler 식 방법으로 수술을 하였다. 원래의 우관상동맥구로 추정되는 부분부터 우관상동맥 원위부의 혈류가 있는 곳까지의 결손부위는 약 4cm 가량 되었다. 관상동맥 폐색증과 Marfan 증후군의 조합은 매우 드문 질환으로 양측 관상동맥의 혈류 재건을 위하여 각기 다른 술식으로 수술하였다.

• Journal of Chest Surgery
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• 제43권3호
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• pp.296-299
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• 2010

거대 우관상 동맥류를 동반한 우관상 동맥에서 좌심실로 유출되는 관상 동맥루는 매우 드문 질환이며 동맥류 파열과 심부전, 심내막염으로의 진행 가능성이 있으므로 수술적 치료가 요구되는 질환이다. 본 증례는 47세 남자 환자가 3개월 전부터 시작된 운동 시 호흡 곤란을 주소로 내원한 환자로 흉부 전산화 단층 촬영과 관상동맥 조영술을 통해 거대 우관상동맥류 및 관상동맥-좌심실루로 진단되어 거대 관상동맥류 절제술 및 관상동맥 우회술을 시행하여 성공적으로 치험하였기에 보고하는 바이다.

• 대한영상의학회지
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• 제85권2호
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• pp.258-269
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• 2024

관상동맥병 환자의 치료에 풍선팽창스텐트 치료는 현재 가장 흔히 시행되는 관상동맥재개통 치료법이다. 그러나 경피적 관상동맥 중재술 이후 재협착은 여전히 주요 합병증으로 남아 있다. 스텐트 재협착을 진단하기 위한 도구로서 관상동맥 CT 조영술(coronary CT angiography; 이하 CCTA)는 과거에는 주로 번짐허상과 움직임허상으로 인해 내강을 정확히 판단하기 어려워 그 역할이 제한적이었다. 따라서 정확한 확인을 위해서 침습적인 고식적 관상동맥 조영술로 넘어가는 경우가 많았다. 그러나 근래 CT 기술의 발달로 민감도와 특이도가 모두 개선되면서 그 역할이 중요해지고 있으며, 특히 일관되게 음성예측도가 높게 보고되고 있다. 본 종설에서는 CCTA를 이용한 관상동맥 스텐트 재협착 진단의 과거와 현재, 그리고 최신 동향에 대해 알아보고자 한다.