• Journal of Chest Surgery
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• v.29 no.8
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• pp.850-860
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• 1996

Oxygen free radicals and their metabolites have been implicated as possible causes of reperrusion injury In animal models. Their role in the clinical setting is still controversial. The aim of this study was to evaluate the degree of tissue damage, oxidative stress. and changes in the antioxidant enzyme system in patients undergoing cor nary artery bypass graft operations(CABG) with myocardial protection by cold blood cardioplegia. In patients undergoing CABG(n:10). the levels of lactate dehydrogenate(LDH), creatine phosphokinase MB fraction(CK-MB), and malondialdehyde(M DA) were measured In the coronary sinus effluent before aortic cross clamping and 20 minutes after reperfusion. At the same time, the myocardial tissue activities of superoxide dismutase(SOD). catalase(CAT), glutathione peroxiddse(GSHPX), glutathione reductase (GSSGRd), and glucose 6-phosphate dehydrogenate(GfPDH ) were determined in the right atrial auricle excised before aortic cross clamping and in the left atrial auricle excised 20 minutes after reperfuslon. The levels of increased significantly after reperrusion(p< U.05). There were no significant changes in CAT and CfPDH levels. Western blot analysis was performed to study the induction of antioxidant enzyme and demonstrated increased amount of Cu,Zn-SOD.

• Journal of Biomedical Engineering Research
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• v.21 no.4
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• pp.363-372
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• 2000

The present study investigated flow dynamics of a straight elastic blood vessel under sinusoidal flow conditions in order to understand influence of wall motion and impedance phase angle(time delay between pressure and flow waveforms) on wall shear stress distribution using computational fluid dynamics. For the straight elastic tube model considered in the our method of computation. The results showed that wall motion induced additional terms in the axial velocity profile and the pressure gradient. These additional terms due to wall motion reduced the amplitude of wall shear stress and also changed the mean wall shear stress. Te trend of the changes was very different depending on the impedance phase angle. As the wall shear stress increased. As the phase angle was reduced from 0$^{\circ}$to -90$^{\circ}$for ${\pm}$4% wall motion case, the mean wall shear stress decreased by 10.5% and the amplitude of wasll shear stress increased by 17.5%. Therefore, for hypertensive patients vulnerable state to atherosclerosis according to low and oscillatory shear stress theory.

• Clinical and Experimental Pediatrics
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• v.53 no.2
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• pp.248-252
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• 2010

Anomalous origins of coronary arteries are a rare type of disease among children. These anomalies can be categorized into 3 types according to the anatomical relationship of the aorta and pulmonary trunks. Among these types, the interarterial type, as observed in our case, needs early diagnosis and treatment, because it can increase the risk for the patient, causing sudden cardiac death in young individuals. Although there are controversies concerning the management of anomalous origins of the left coronary artery (LCA) in children, the result can be very beneficial, if treated accurately. Three well-known methods for correction of anomalous origins of LCA are re-implantation, coronary arterial bypass grafting (CABG), and unroofing. We report on the case of a 12-year-old girl who had chest discomfort and syncope with physical exercise and was later diagnosed with an anomalous origin of LCA by transthoracic echocardiography (TTE) and heart computed tomography (CT). She underwent a corrective operation by re-implantation, CABG, and unroofing.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.1
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• pp.18-28
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• 2001

The present study investigates flow dynamics between two dimensional compliant plates under sinusoidal flow conditions in order to understand influence of wall motion, impedance phase angle (time delay between pressure and flow waveforms), and non-Newtonian fluid on wall shear stress using computational fluid dynamics. The results showed that wall motion induced additional terms in the streamwise velocity profile and the pressure gradient. These additional terms due to wall motion reduced the amplitude of wall shear stress and also changed the mean wall shear stress. The trend of the changes was very different depending on the impedance phase angle. As the impedance phase angle was changed to more negative values, the mean wall shear stress decreased while the amplitude of wall shear stress increased. As the phase angle was reduced from 0°to -90°under $\pm$4% wall motion, the mean wall shear stress decreased by 12% and the amplitude of wall shear stress increased by 9%. Therefore, for hypertensive patients who have large negative phase angles, the ratio of amplitude and mean of the wall shear stress is raised resulting in a more vulnerable state to atherosclerosis according to the low and oscillatory shear stress theory. We also found that non-Newtonian characteristics of the blood protect atherosclerosis by decreasing the oscillatory shear index.

• Journal of Chest Surgery
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• v.41 no.1
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• pp.102-105
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• 2008

An anomalous origin of the coronary artery with subsequent coursing between the great vessels is a rare congenital heart defect that may cause myocardial ischemia and sudden death. Several surgical techniques have been described to address this defect. An extended unroofing procedure to create an alternative ostium for the right coronary artery was successfully carried out in a patient having an anomalous origin of the right coronary artery. The newly constructed orifice was widely patent 3 months later, without any episodes of myocardial ischemia or aortic regurgitation.

• Clinical and Experimental Pediatrics
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• v.49 no.3
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• pp.287-291
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• 2006

Purpose : Aneurysms of sinus valsalva are rare anormalies thought to be primarily congenital in origin, progressing into death by acute heart failure in cases of rupture. Surgical correction is the only method of treatment. With these clinical implications, we reviewed the clinical characteristics and surgical results of patients with ruptured sinus of valsalva aneurysm. Methods : Between January 1991 and February 2004, 17 patients with ruptured sinus of valsalva aneurysm were retrospectively reviewed for their clinical symptoms, physical findings, past history, coexistent cardiac anormalies, surgical results, and mid-term prognosis. Results : The 17 patients included 13 men and four women, with a mean age of 30 years(10-59 years). Preoperatively accompanying cardiac anormalies were ventricular septal defect(VSD, eight cases of doubly committed juxta-arterial VSD) and aortic insufficiency(11 cases). During operations, patterns of fistulous tracts were found to be right colonary sinus-right ventricle in 13 patients, right coronary sinus-right atrium in one, noncoronary sinus - right ventricle in two, noncoronary sinus - right atrium in one, and VSD was noticed in 14 patients(all were doubly committed juxta-arterial in type). The defects were closed with a patch in 13 patients, without a patch in four, with concommitant aortic valve replacement in four and with aortic valvuloplasty in two. There were no mortalities during operations or the mid-term follow-up periods($40{\pm}49$ months). Conclusion : Because, at least in Orientals, VSD(especially doubly committed juxta-arterial) was accompanied in large numbers of patients with aneurysms of sinus valsalva, preoperative evaluations of this congenital heart disease should be made very careful. And we may need to revise the algorithm of treatment policy in small sized doubly committed juxta-arterial VSD.

• Journal of Chest Surgery
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• v.30 no.2
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• pp.158-163
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• 1997

From July 1994 to August 1995, 32 patients underwent coronary artery bypass surgery. There were 14 men and 18 women. The mean age was 59 years (range from 37 to 81 years). Preoperatively 26 patients had unstable angina pectoris and 6 patients had stable angina pectoris. Nine patients had previous myocardial infarction hi tory. Five patients had preoperative left ventricular ejection fraction of 40% or less, The involved risk factors were as follows ; smoking 19 cases, hypertension 16 cases, hypercholesterolemia 14 cases, diabetes mellitus 6 cases, and obesity 3 cases.21 patients had three-vessel disease, 7 patients had two-vessel disease, 2 patients had one-vessel disease and 2 patients had left main coronary artery disease. We performed 103 distal bypasses out of 32 cases, and the mean number of grafts per patients is 3.22. We used arterial grafts (left internal mammary artery,)1, radial artery; 2) in 32% of total grafts. Postoperative complications were low cardiac output, perioperative myocardial infarction, respiratory failure and atrial fibrillation, etc. Early mortality was 6.25% (2/32). The causes of deaths were low cardiac output (1), and perioperative myocardial infarction(1).

• Journal of Biomedical Engineering Research
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• v.21 no.3 s.61
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• pp.261-271
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• 2000

The present study investigated flow dynamics of a two-dimensional abdominal aortic bifurcation model under sinusoidal flow conditions considering wall motion. impedance phase angle(time delay between pressure and flow waveforms), and non-Newtonian fluid using computational fluid dynamics. The wall shear stress showed large variations in the bifurcated region and the wall motion reduced amplitude of wall shear stress significantly. As the impedance phase angle was changed to more negative values, the mean wall shear stress (time-averaged) decreased while the amplitude (oscillatory) of wall shear stress increased. At the curvature site on the outer wall where the mean wall shear stress approached zero. influence of the phase angle was relatively large. The mean wall shear stress decreased by $50\%$ in the $-90^{\circ}$ phase angle (flow wave advanced pressure wave by a quarter period) compared to the $0^{\circ}$ phase angle while the amplitude of wall shear stress increased by $15\%$. Therefore, hypertensive patients who tend to have large negative phase angles become more vulnerable to atherosclerosis according to the low and oscillatory shear stress theory because of the reduced mean and the increased oscillatory wall shear stresses. Non-Newtonian characteristics of fluid substantially increased the mean wall shear stress resulting in a less vulnerable state to atherosclerosis.

• Journal of Chest Surgery
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• v.36 no.11
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• pp.828-833
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• 2003

Background: It has been reported that the recently developed intermittent antegrade warm blood cardioplegia (IAWBC) has better myocardial protective effects during coronary artery bypass surgery than cold blood cardioplegia or continuos retrograde cold blood cardioplegia. The aim of this study is to evaluate the safety and usefulness of IAWBC by comparing it retrospectively with intermittent retrograde cold blood cardioplegia (lRCBC). Material and Method: From April 2001 to Feb. 2003, fifty seven patients who underwent isolated coronary surgery were divided into two groups (IAWBC vs. IRCBC). The two group had similar demographic and angiographic characteristics. There were no statistical differences in age, sex, Canadian Cardiovascular Society Functional Classification for angina, ejection fraction, and number of grafts. Result: Aortic cross clamping time and total pump time in IAWBC (99$\pm$23 and vs. 126$\pm$32 min) were shorter than those of IRCBC (118$\pm$32 min. and 185$\pm$48 min.)(p<0.05). The reperfusion time (13$\pm$7 min) in IAWBC was shorter than that of IRCBC (62$\pm$109 min.)(p<0.05). CKMB at 12 hours and 24 hours (16$\pm$15 and 9$\pm$13) in IAWBC was lower than that of IRCBC (33$\pm$47 and 17$\pm$26)(p<0.05). The awakening time in IAWBC (2$\pm$1 hour) was shorter than that of IRCBC (4$\pm$3)(p<0.05). The number of spontaneous heart beat recovery in IAWBC (85%) was more than that of IRCBC (35%)(p<0.05). The cardiac index after discontinuing cardio-pulmonary bypass was significantly elevated in the IAWBC group. The prevalence of perioperative myocardial infarction in IAWBC (4%) was lower than that of IRCBC group (20%)(p<0.05). Conclusion: Intermittent antegrade warm blood cardioplegia is a safe, reliable, and effective technique for myocardial protection. It can also provide simpler and economic way than the retrograde cold cardioplegia by shortening of cardiopulmonary bypass time and avoiding retrograde cannulation for coronary sinus.

• Journal of Chest Surgery
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• v.34 no.6
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• pp.454-464
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• 2001

Background: It has been recognized that systemic inflammatory reaction and oxygen free radical formed by activated leukocyte in the procedure of cardiopulmonary bypass(CPB) frequently produce postoperative cardiac and pulmonary dysfunction. The purpose of this study was to evaluate the efficacy of leukocyte-depleting filters in the cardiopulmonary bypass circuit for patients undergoing open heart surgery(OHS). Material and method: The study involved 15 patients who underwent OHS with a Leukoguard-6 leukocyte filter placed in the arterial limbs of the bypass circuit(filter group, n=15) and 15 patients who did not have the filter(control group, n=15). We analyzed the differences between the groups in intraoperative changes of peripheral blood leukocyte and platelet counts, pre- and postbypass changes of malondialdehyde(MDA), troponin-T(TnT), 5'-nucleotidase(5'-NT) in coronary sinus blood, spontaneous recovery rate of heart beat after CPB, pre-and postoperative cardiac index(Cl) and pulmonary vascular resistance(PVR), and the amounts of postoperative bleeding and sternal wound complication. Result: During CPB, total leukocyte count of the filter group(9,567$\pm$ 842/㎣) was significantly less than that of the control group(13,573+1,167/㎣) (p<0.01), but there was no significant difference in platelet count between the groups. Postoperative levels of MDA(3.78+0.32 $\mu$mol/L vs 5.86+0.65 $\mu$mo1/L, p<0.01), TnT(0.40$\pm$0.04 ng/mL vs 0.59$\pm$0.08 ng/mL, p<0.05) and 5'-NT(3.88$\pm$0.61 U/L vs 5.80$\pm$0.90 U/L, p<0.05) were all significantly lower in the filter group than the control group. Postoperative Cl was higher in the filter group than the control group(3.26$\pm$0.18 L/$m^2$min vs 2.75$\pm$0.17 L/$m^2$/min, p=0.05). PVR of the filter group was lower than that of the control group(65.87$\pm$7.59 dyne/sec/cm$^{5}$ vs 110.80+12.22 dyne/sec/cm$^{5}$ , p<0.01). Spontaneous recovery rate of heart beat in the filter group was higher than that in the control group(12 patients vs 8 patients, p<0.05). Postoperative wound infection occurred in one case in the filter group and 4 case in the control group(p<0.05). Postoperative 24 hour blood loss of the filter group was more than that of the control group (614$\pm$107 mL vs 380+71 mL, p=0.05).