• Proceedings of the Computational Structural Engineering Institute Conference
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• 한국전산구조공학회 2008년도 정기 학술대회
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• pp.152-155
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• 2008

The blood flow characteristics have been closely related to various cardiovascular diseases, it is very important to predict them accurate enough in an efficient way. Thus, this paper proposes a one-dimensional spectral element model for the blood flow through blood vessels. The spectral element model is formulated by using the variational method. The nonlinear terms in spectral element model are all treated as the pseudo-force and an iterative solution method is applied in the frequency domain.

• Journal of Chest Surgery
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• 제38권1호
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• pp.13-22
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• 2005

It has been known that pulsatile flow is physiologic and more favorable to tissue perfusion than nonpulsatile flow. The purpose of this study is to directly compare the effect of pulsatile versus nonpulsatile blood flow to renal tissue perfusion in extracorporeal circulation by using a tissue perfusion measurement system. Material and Method: Total cardiopulmonary bypass circuit was constructed to twelve Yorkshire swines, weighing 20$\~ $30 kg. Animals were randomly assigned to group 1 (n=6, non pulsatile centrifugal pump) or group 2 (n=6, pulsatile T-PLS pump). A probe of the tissue perfusion measurement system $(QFlow^{TM}-500)$ was inserted into the renal pa­renchymal tissue. Extracorporeal circulation was maintained for an hour at a pump flow of 2 L/min after aortic cross-clamping. Tissue perfusion flow of the kidney was measured at baseline (before bypass) and every 10 minutes after bypass. Serologic parameters were collected at baseline and 60 minutes after bypass. Result: Baseline parameters were not different between the groups. Renal tissue perfusion flow was substantially higher in the pulsatile group throughout the bypass (ranged 48.5$\~$ 64 in group 1 vs. 65.8$\~$88.3 mL/min/100 g in group 2, p=0.026$\~$ 0.45) The difference was significant at 30 minutes bypass $(47.5{\pm}18.3\;in\;group\;1\;vs.\;83.4{\pm}28.5$ mL/min/100 g in group 2, p=0.026). Serologic parameters including plasma free hemoglobin, blood urea nitrogen, and creatinine showed no differences between the groups at 60 minutes after bypass (p=NS). Conclusion: Pulsatile flow is more beneficial to tissue perfusion of the kidney in short-term extracorporeal circulation. Further study is suggested to observe the effects to other vital organs or long-term significance.

• Clinical and Experimental Pediatrics
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• 제48권3호
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• pp.321-326
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• 2005

Kawasaki disease is an acute systemic vasculitis of unknown origin. Giant coronary aneurysm is one of the most serious complications, although peripheral artery vasculitis can produce life-threatening events. Myocardial ischemia and infarction can be caused by coronary artery stenosis, aneurysm, and stagnation of blood flow in coronary arteries which triggers thromboembolism. Atypical presentation in young infants often interferes with prompt diagnosis and timely treatment, resulting in poor outcomes. We describe a 3-month-old infant with multiple giant coronary aneurysms with flow stagnation, stenosis and large mural thrombus due to Kawasaki disease. He presented with a prolonged course of severe coronary involvement in spite of all measures to reduce coronary complications. Finally, surgical intervention was tried because of the worsening coronary artery abnormalities. The patient died of acute cardiorespiratory failure shortly after weaning from cardiopulmonary bypass.

• The Journal of Internal Korean Medicine
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• 제21권3호
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• pp.417-424
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• 2000

Objective : The purpose of this study was to investigate the effects of Sasim-tang water extract on the cardiovascular systems including changes of blood pressure and regional cerebral blood flow volume (rCBF) in male Sprague-Dawely rats. Methods : The changes of blood pressure were recorded by data acquisition system composed of MacLab and Macintosh computer. The changes of rCBF were observed by Laser-Doppler flowmetry through a opened cranial window. Results : 1. The changes of blood pressure was not affected by Sasim-tang extract intravenous injection in rats. 2. After pretreatment with propranolol(3mg/kg), L-NNA(10mg/kg) and 000(10mg/kg), the changes of blood pressure was not affected by Sasim tang extract intravenous injection in rats. 3. The changes of rCBF was increased in dose-dependent manner by Sasim-tang extract intravenous injection in rats. 4, After pretreatment with propranolol(3mg/kg), ODQ(10mg/kg) and L-NNA(10mg/kg), rCBF was significantly decreased in dose- dependent manner by Sasim-tang extract intravenous injection in rats. Conclusions : These results suggest that Sasim-tang was related to the regulation of the sympathetic nerve system, nitric oxide synthesis and synthesis of cyclic GMP.

• Korean Circulation Journal
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• 제54권7호
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• pp.382-394
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• 2024

Background and Objectives: Fractional flow reserve (FFR) is an invasive standard method to identify ischemia-causing coronary artery disease (CAD). With the advancement of technology, FFR can be noninvasively computed from coronary computed tomography angiography (CCTA). Recently, a novel simpler method has been developed to calculate onsite CCTA-derived FFR (CT-FFR) with a commercially available workstation. Methods: A total of 319 CAD patients who underwent CCTA, invasive coronary angiography, and FFR measurement were included. The primary outcome was the accuracy of CT-FFR for defining myocardial ischemia evaluated with an invasive FFR as a reference. The presence of ischemia was defined as FFR ≤0.80. Anatomical obstructive stenosis was defined as diameter stenosis on CCTA ≥50%, and the diagnostic performance of CT-FFR and CCTA stenosis for ischemia was compared. Results: Among participants (mean age 64.7±9.4 years, male 77.7%), mean FFR was 0.82±0.10, and 126 (39.5%) patients had an invasive FFR value of ≤0.80. The diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of CT-FFR were 80.6% (95% confidence interval [CI], 80.5-80.7%), 88.1% (95% CI, 82.4-93.7%), 75.6% (95% CI, 69.6-81.7%), 70.3% (95% CI, 63.1-77.4%), and 90.7% (95% CI, 86.2-95.2%), respectively. CT-FFR had higher diagnostic accuracy (80.6% vs. 59.1%, p<0.001) and discriminant ability (area under the curve from receiver operating characteristic curve 0.86 vs. 0.64, p<0.001), compared with anatomical obstructive stenosis on CCTA. Conclusions: This novel CT-FFR obtained from an on-site workstation demonstrated clinically acceptable diagnostic performance and provided better diagnostic accuracy and discriminant ability for identifying hemodynamically significant lesions than CCTA alone.

• Journal of Acupuncture Research
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• 제21권1호
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• pp.111-118
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• 2004

Background and purpose: Opposing-needling technique involves selecting acupoints at unaffected limb. The aim of this study was to evaluate the effect of LI4-LI11 electrical acupuncture at unaffected limb on the cerebral blood flow in ischemic stroke patients using SPECT Methods: We selected 9 ischemic stroke patients. Baseline brain SPECT was done with triple head gamma camera(MultiSPECT3, Siemens, USA) after intravenous administration of 925 MBq of Tc-99m ECD). Fifteen-minute electro-acupuncture at Hapgok(LI 4) and Gokji(LI 11) were applied on unaffected upper limb of subjects. The same dose of Tc-99m ECD was injected during the electro-acupuncture, and the second SPECT images were obtained. Using the computer software(ICON 7.1, Siemens, USA), 3 SPECT slices(upper, middle, lower) surrounding the brain lesion were selected and each slice was divided by 10-16 brain regions. Asymmetry indexes were analyzed in each brain region. We regarded$\geq$10% changes of asymmetry index between before and after electro-acupuncture as significance. Results: Seven Patients(77.8%) had significantly increased perfusion and 2(22.2%) didn't show increased perfusion in post-acupuncture scans compared to pre-acupuncture scans(baseline). The regions of CBF improvement were mostly frontal lobes and anterior temporal lobes. Conclusions: This study demonstrated that LI4-LI11 electro-acupuncture at unaffected limb increased regional cerebral blood perfusion to the corresponding brain areas in ischemic stroke patients.

• Journal of Chest Surgery
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• 제54권6호
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• pp.543-546
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• 2021

A 55-year-old woman who had received an implantable left ventricular assist device 3 months earlier presented with dyspnea and a low-flow alarm of the device. Computed tomography and log-file analysis of the device system suggested inflow cannula obstruction. Since the patient had cardiogenic shock due to pump failure, venoarterial extracorporeal membrane oxygenation (ECMO) was initiated. With ECMO, surgical exchange of the pump was considered. However, the obstruction spontaneously resolved without surgical intervention. It turned out that an obstructive thrombus was washed out by rebooting the pump. Moreover, the thrombus was embolized in the patient's left subclavian artery. The patient underwent heart transplantation 4 months after the pump obstruction accident and continued to do well.

• Proceedings of the KOSOMBE Conference
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• 대한의용생체공학회 1994년도 춘계학술대회
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• pp.111-114
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• 1994

Three component velocity measurements with a refractive index-matching technique was used to investigate the flow characteristics in the atrio-pulmomnary (AP) Fontan connection under the steady flow condition. A strong swirl was observed in the extra-cardiac conduit and the main pulmonary artery (MPA). Maximum velocity magnitude in the MPA was about 0.8 m/s near the posterior wall at 6 liter/min. Swirling motion of the flow as well as geometric abnormalities of the connection are important factors in energy loss across Fontan connections.

• Proceedings of the KSMRM Conference
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• 대한자기공명의과학회 1997년도 춘계학술대회 초록집
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• pp.136-142
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• 1997

• 순환기질환의공학회:학술대회논문집
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• 순환기질환의공학회 2004년도 춘계학술강연회
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• pp.71-76
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• 2004