• 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.

• 한국임상약학회지
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• 제15권2호
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• pp.105-117
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• 2005

Following intracoronary stenting, antiplatelet therapy lead to greater protection from thrombotic complication. A few data are available about the effect of clopidogrel versus cilostazol, an antiplatelet commonly used after intracoronary stenting. To evaluate the efficacy and safety of clopidogrel plus aspirin compared with those of cilostazol plus aspirin in coronary stenting and to evaluate the efficacy of clopidogrel loading dose prior to coronary stealing in clopidogrel group. Data were retrospectively collected from medical charts of patients who had undergone coronary stenting and received either clopidogrel with or without loading 300 mg followed by 75 mg/d (n=58), or 200 mg/d cilostazol(n=72) for 1 year, between January 2000 and May 2002. All patients in both groups received aspirin 200 mg/d throughout the study. The primary endpoints at 7, 30, 180 and 365 days after stealing were the composite of death, Myocardial Infarction, stroke, angina, and revascularization in the intent to treat population and restenosis at follow up angiography. The secondary endpoints were the incidence of bleeding complications at 7, 30, and 365 days, and durg adverse effects at 365 days after stenting. At 180 and 365 days after stenting, the combined primary endpoints were significantly reduced in clopidogrel plus aspirin group (relative risk 0.39; 95% CI 0.17 to 0.92; p=0.021, RR 0.43; 95% CI 0.22 to 0.84; p=0.0085, respectively). However, the combined primary endpoints were not significantly different between the two groups at 7 and 30 days (p:1.00, p=0.79, respectively). Angiographic restenosis rate was 14.3% in clopidogrel plus aspirin uoup and 32.1% in cilostazol plus aspirin group (p=0.19). 300mg of clopidogrel loading dose did not significantly reduce the combined primary endpoints at 30 days after stenting (RR 0.14; 95% CI 0.01 to 2.65; p=0.23). The rate of bleeding complications and drug adverse effects were not different between the two groups. In patients undergoing intracoronary stenting, clopidogrel plus aspirin therapy is more beneficial than cilostazol plus aspirin in reducing major adverse cardiac events with similar rate of bleeding complication. A loading dose of clopidogrel did not lead to a statistically significant reduction in major adverse cardiac events.

• 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.

• 대한핵의학회:학술대회논문집
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• 대한핵의학회 2001년도 제40차 춘계학술대회 및 연수교육
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• pp.24-34
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• 2001

Restenosis remains a major limitation of percutaneous coronary interventions. Numerous studios including pharmacological approaches and new devices failed to reduce the restenosis rate except coronary stenting. Since the results of $BENESTENT^{1)}\;and\;STRESS^{2)}$ studies came out, coronary stenting has been the most popular interventional strategy in the various kinds of coronary stenotic lesions, although the efficacy of stenting was shown only in the discrete lesion of the large coronary artery. The widespread use of coronary stenting has improved the early and late outcomes after coronary intervention, but it has also led to a new and serious problem, e.g., in-stent restenosis. Intravascular radiation for prevention of restenosis is a new technology in the field of percutaneous coronary intervention. Recent animal experiments and human trials have demonstrated that local irradiation, in conjunction with coronary interventions, substantially diminished the rate of restenosis. This paper reviews basic radiation biology of intracoronary radiation and its role in the inhibition of restenosis. The current status of intracoronary radiation therapy using Re-188 liquid balloon is also discussed.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집E
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• pp.219-222
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• 2001

The objective of the present study is to evaluate the effects of the stenting shapes on flow velocity and wall shear stress in angulated coronary stenosis by computer simulation. Coronary angiogram and Doppler ultrasound measurement in the patients with angulated coronary stenosis were obtained. Inlet wave velocity distribution obtained from in vivo intracoronary Doppler data was used for the numerical simulation. Spatial pattern of blood flow velocity and recirculation area were drawn through out the selected segment of coronary models. Wall shear stresses in the intracoronary stent models were calculated from three-dimensional computer simulation. A negative shear stress region, which is consistent with re-circulation area on flow pattern, was noted on the inner wall of post-stenotic area of pre-stenting model. The negative shear stress was disappeared after stenting. Shear stress in the post-stenting model was markedly reduced up to about two orders of magnitude compared to that of the pre-stenting model.

• Journal of Chest Surgery
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• 제32권12호
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• pp.1127-1130
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• 1999

Percutaneous coronary intervention including intracoronary stenting is currently an accepted treatment modality in the treatment of coronary artery disease and is widely performed to treat the patient with multivessel disease with decreased morbidities and less cost compared with conventional coronary rtery bypass grafting(CABG), Repeated interventions due to restenosis even after successful angioplasty are the major disadvantage of the angioplsty especially when the lesion is located inthe left anterior descending artery(LAD) Recently CABG through left anterior small thoracotomy using the left internal thoracic artery to revascularize the LAD territory without cardiopulmonary bypass so called Minimally Invasive Direct Coronary Artery Bypass(MIDCAB) was intrduced and performed with comparable early outcomes. In this regard the integrated approach with percutaneous coronary intervention and minimally invasive direct coronary artery bypass surgery so called 'Hybrid CABG' was suggested to be an effective treatment in suitable patients with multivessel coronary artery disease. We report three cases of Hybrid CABG.

• 의료법학
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• 제18권2호
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• pp.163-194
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• 2017

관상동맥 질환은 2017년 고령사회로 진입한 우리나라에서 앞으로 더 많은 관심을 가질 것이다. 고령화가 될수록 고혈압, 당뇨 등 복합적인 질환이 합병되어 혈관상태도 상대적으로 더 나빠져 관상동맥 질환에 걸릴 가능성이 높기 때문이다. 심혈관 질병은 심장외과와 심장내과와의 긴밀한 협진이 필요하다. 따라서 협심증이나 심근경색증환자를 먼저 진료하게 되어 있는 우리나라의 임상현장에서 객관적인 심장내과 의사의 치료방침에 대한 판단은 매우 중요하다. 최근 심장내과의 비수술적 중재술이 발전하고 있지만 무리한 스텐트 시술로 의료사고도 발생하고 있다. 특히 관상동맥 3개혈관이 모두 막힌 삼중혈관이거나 석회화가 심해 혈관 상태가 좋지 않은 경우가 문제이다. 또한 심장외과 의사가 없는 병원에서 무리하게 경피적관상동맥중재술을 실시하다가 응급상황이 발생할 경우 관상동맥이식술 등 외과적 대처가 어려운 경우가 종종 발생한다. 최근 2년간 한국소비자원(소비자분쟁조정위원회) 의료분쟁 조정결정 8사례를 분석한 결과, 심장 중재술을 시행한 병원 중 심장외과 의사가 상주한 곳은 2곳으로 확인됐다. 8사례 모두 심장내과 진료 후 풍선확장술 및 스텐트 삽입한 경우로 7명이 사망했고 이중 5명은 시술 당일에 사망했다. 8사례 중에 3중혈관 환자는 5건이고, 나머지도 석회화가 심하거나 완전폐쇄로 혈관상태가 좋지 않은 상태였다. 2017년 심장내과 스텐트 시술 건수 조사 보고에 의하면 3개 이하 약물 방출 스텐트 시술이 98%로 보고됐다. 2015년 스텐트 시술 건수가 38,922건으로 약800건(2%)은 스텐트가 4개 이상 사용된 것으로 추정된다. 무리한 스텐트 시술로 마지막 여명에 급사함으로써 신변정리 기회상실은 물론 여명단축에 따른 손해로서 '지도 설명의무' 책임을 물어 전 손해에 대한 배상을 신중하게 고려할 필요가 있다. 최근 심평원 보험적용 스텐트 시술 개수 제한규제가 없어지면서 무리한 시술과 심장외과 의사 확충에 대한 문제가 있다. '다학제통합진료' 같은 병원차원의 해결방안은 물론 필수요원에 해당하는 심장외과를 공무원으로 확충하는 등 국가차원의 해결방안이 요구된다.