• Journal of Chest Surgery
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• v.16 no.3
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• pp.301-309
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• 1983

Twenty-three patients with aneurysm were operated between Jan. 1956 to July 1983 at the Department of Thoracic surgery, Seoul National University Hospital. There were 18 males and 5 females in this series. The age ranged from 14 to 68 years with the mean age of 41 years. The etiology of aortic aneurysms was atherosclerosis in 10, trauma in 2, annuloaortic ectasia in 4, syphilis in 1, and unknown etiology in six cases. Among the 4 patients with ascending aortic aneurysm, aortic valve replacement with aneurysmorrhaphy in three patients and Bentall operation in one patient were performed successfully. One patient with entire aortic arch aneurysm was received Dacron graft replacement with anastomosis of brachiocephalic arteries separately under cardiopulmonary bypass. There was no complication. Among 6 patients involving the descending thoracic aorta, three patients were managed by prosthetic bypass graft and aneurysm resection, and another three patients were also managed by prosthetic graft replacement. There were three hospital deaths. There were two thoracoabdominal aortic aneurysm. One patient in shock state due to preoperative rupture died from cardiac arrest during operative procedure. In another patient who had extensive involvement from the midportion of descending thoracic aorta to the terminal abdominal aorta, the aneurysm was successfully repaired with Dacron graft. In this instance celiac axis, superior and inferior mesenteric arteries and right renal artery were anastomosed separately. Eight of the 10 abdominal aortic aneurysms was replaced with prosthetic graft. One saccular aneurysm was treated by resection and primary closure. In another patient, cardiac arrest occurred during operation before definitive procedure. There was one another hospital death in the patient with preoperative rupture.

• Journal of Chest Surgery
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• v.40 no.1 s.270
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• pp.1-7
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• 2007

Backgound: It has been shown that the endothelium of cardiac valves and adjacent great vessels have a reduced immune reaction compared to other vessels. We investigated the clinical feasibility of using immunologically untreated xenogenic valves, in a pig-to-goat pulmonary valve conduit implantation model. Material and Method: Porcine pulmonary valve conduits were prepared without specific immunologic treatment and implanted into the right ventricular outflow tract of goats while undergoing cardiopulmonary bypass. Two goats each were assigned to the following observation time intervals: one day, one week, three months, six months and twelve months. Echo-cardiographic examinations were performed prior to sacrifice of the goat to evaluate pulmonary valve function. After the xenograft specimens were retrieved, histological changes were evaluated microscopically. Result: Ten of the twelve animals survived the predetermined observation time intervals. Aneurysmal dilatations, of the anterior wall of the implanted pulmonary artery, were observed at each of three and twelve month-survival animals. A variable degree of pulmonary valve regurgitation was observed on echocardiography. However, valve stenosis, thrombotic occlusion and vegetation were not seen. Microscopically, the nuclei of the donor tissue disappeared as a result of pyknosis and karyolysis; however the three components of the implanted xenografts (the pulmonary artery, the valve and the infundibulum) were gradually replaced by host cells over time, while maintaining their structural integrity. Conclusion: Immunologically untreated xenogenic pulmonary valve conduits were replaced by host cells with few observed clinical problems in a pig to goat pulmonary valve implantation model. Therefore, they might be an alternative bioprosthesis option.

• Journal of Yeungnam Medical Science
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• v.13 no.2
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• pp.225-233
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• 1996

From August 1992 to July 1996, 63 consecutive patients underwent coronary artery bypass surgery. The mean age of these patient was 57 years(range form 30 to 71years). There were 44 men and 19 women. Preoperative 12 patients had stable angina pectoris and 23 patients were unstable angina pectoris. 8 patients had previous myocardial infarctation history and emergency or urgent myocardial revascularization were performed in 9 cases. In the risk factors of coronary atherosclerosis, 25 patients(40%) were hypercholesterolemia, 38 patients(60%) have smoking history and 19 patients(30%) have hypertension history. In the patterns of disease, 9 patients were single vessel disease, 18 patients were two vessele disease and 33 patients were three vessel disease. We performed total 284 distal anastomosis(mean 3.5 anastomosis per patient) and performed one case of ascending aorta graft interposition, two cases of mitral valve replacement, one case of aortic valve replacement, one case of ventricular septal defect repair and one case of atrial septal defect repair and the mean aortic cross clamp time was 115.3 minutes. The common complications were arrhythmia(7cases), wound infection(5cases), perioperative myocardial infarction(4cases), reoperation for bleeding control(4cases) and stroke(4cases). There were six hospital deaths due to low cardiac output syndrome, ventricular arrhythmia and respiratory failure. In the evaluation of operative risk factors, preoperative intravenous nitroglycerin requirement and prolonged aortic cross clamp tirne(>2hours) were found to be predective factor of morbidity and old age(>65years) was found to be predective factor of mortality.

• Journal of Chest Surgery
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• v.25 no.3
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• pp.232-239
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• 1992

Acute renal failure is a well known serious complication following open heart surgery and is associated with a significant increase in morbidity and mortality rate. From 1984 to 1990, 33 patients who had acute renal failure following cardiopulmonary bypass received renal replacement therapy. PD[Peritonial dialysis] was employed in 11 patients and CAVH[continous arteriovenous hemofiltration] was employed in 22 patients. Their age ranged from 3 months to 64 years[mean 25.5$\pm$7.8 years]. The disease entities included congenital cardiac anomaly in 18, valvular heart disease in 15 and aorta disease in 2 cases. Low cardiac output was thought as a primary cause of ARF except two redo valve cases who showed severe Aemolysis k depressed renal function preoperatively. Mean serum BUN and creatinine level at the onset renal replacement therapy were 65$\pm$8 mg/dl and 3.5$\pm$0.4 mg/dl respectively, declining only after reaching peak level 7&10 days following the onset of therapy. Overall hospital mortality was 72.7%[24/33]; 81%[9/11] in PD group and 68.2% [15/22] in CAVH group respectively. The primary cause of death was low cardiac output & hemodynamic depression in all the cases. The fatal complications included multiorgan failure in 7, disseminated intravascular coagulation and sepsis in 6, neurologic damage in 4 and mediastinitis in 3 cases. No measurable differences were observed between CAVH and PD group upon consequence of acute renal failure and disease per se. The age at operation, BUN/Cr level at the onset of bypass and highest BUN/Cr level and the consequence of low output status were regarded as important risk factors, determining outcome of ARF and success of renal replacement therapy. Thus, we concluded that althoght the prognosis is largely determined by severity of low cardiac output status and other organ complication, early institution of renal replacement therapy with other intensive supportive measures could improve salvage rate in established ARF patients following CPB.

• Journal of Chest Surgery
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• v.29 no.2
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• pp.185-190
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• 1996

The effect of low-dose aprotinin on hemostasis in patients undergoing cardiopulmonary bypass (CPB) for repeat valve replacement and coronary artery bypass operations were investigated. Thirty patients undergoing elective CPB from February 1993 through February 1995 at Catholic Medical Center were studied. the patients were randomly divided into two groups(15 patients per group) : group 1, receive 1, 000, 000 KIU/kg aprotinin in the CPB priming volume and 20, 000 KIU/kg aprotinin intravenously each hour during CPB ; group 2, without aprotinin administration served as the controls. The result showed that the early postoperative (during the first 24 hours) and mean postoperative total blood loss of the aprotinin group were significantly reduced than the control group (317.2 $\pm$ 89.6ml in the aprotinin group versus 821.3 $\pm$ 441.2rnl in the control group, p<0.01 ; 767.2 $\pm$ 214.1 ml in the aprotinin group versus 1562.5 $\pm$ 735.2 rnl in the control gorup, p<0.01). Total use of packed red ells and fresh frozen plasma was higher in control group(1.22 $\pm$ 0.3 units versus 4.21 $\pm$ 1.7units of packed red cells, p<0.01 : and 2.37 $\pm$ 0.4units versus 6.72 $\pm$ 0.88uni1s of fresh prozen plasma, p<0.05). We conclude the low-dose aprotinin was positive influence on postoperative blood loss in undergoing highly bleeding potency cardiac operation.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.2
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• pp.111-119
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• 2011

Recently, the performances of speed and accuracy are enhanced in machine tools. The high speed of the machine tools usually causes harmful thermal displacements on the objects. To reduce the thermal displacements, machine tools generally adopt oil coolers with precise temperature control function. This study aims at precise control of oil outlet temperature in the oil coolers with hot-gas bypass manner based on PI control logic. The control system was designed for obtaining steady state error within ${\pm}0.1^{\circ}C$ and maximum overshoot with 0.8% even though abrupt disturbances are added to the system. We showed that the PI gains could be easily decided by numerical simulations using practical transfer function which got experiments. Also, transient characteristics could be improved significantly by reflecting the inlet temperature of an evaporator to the output of a controller feedforwardly considering periodic abrupt disturbances. Through some experiments, excellent control performances were established by the suggested control.

• Journal of Chest Surgery
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• v.55 no.6
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• pp.442-451
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• 2022

Background: This meta-analysis was conducted to evaluate the effect of fractional flow reserve (FFR) on clinical outcomes after coronary artery bypass grafting (CABG). Methods: Five online databases were searched for studies that (1) enrolled patients who underwent isolated CABG or CABG with aortic valve replacement and (2) demonstrated the effect of an FFR-guided strategy on major adverse cardiac events (MACE) after surgery based on a randomized controlled trial or adjusted analysis. MACE included cardiac death, acute myocardial infarction (MI), and repeated revascularization. The primary outcomes were all MACE outcomes and a composite of all-cause death and MI, and the secondary outcomes were the individual MACE outcomes. Publication bias was assessed using a funnel plot and the Egger test. Results: Six articles (3 randomized and 3 non-randomized studies: n=1,027) were selected. MACE data were extracted from 4 studies. The pooled analyses showed that the risk of MACE was not significantly different between patients who underwent FFR-guided CABG and those who underwent angiography-guided CABG (hazard ratio [HR], 0.80; 95% CI, 0.57-1.12). However, the risk of the composite of death or MI was significantly lower in patients undergoing FFR-guided CABG (HR, 0.62; 95% CI, 0.41-0.94). The individual MACE outcomes were not significantly different between FFR-guided and angiography-guided CABG. Conclusion: FFR-guided CABG might be beneficial in terms of the composite outcome of death or MI compared with angiography-guided CABG although data are limited.

• Journal of Chest Surgery
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• v.37 no.5
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• pp.410-415
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• 2004

Background: In the operation for coronary artery stenosis, the procedures for mitral regurgitation are restricted to cases of more than moderate mitral regurgitation or for the lesions in leaflets. This is based on the belief that the less than mild regurgitation are a form of reversible change results from ischemia with coronary artery stenosis. We studied the changes and prognostic factors of mitral regurgitation in patients with coronary artery stenosis and mitral regurgitation who underwent coronary artery bypass surgery alone. Material and Method: We reviewed the medical records of 90 patients with coronary artery stenosis and mitral regurgitation who underwent coronary artery bypass surgery alone by a single surgeon from Jan. 1995 to Dec. 2002, We grouped the patients according to the postoperative changes of mitral regurgitation, and then we statistically compared the findings of echocardiogram between preoperative and last follow up. Result: There were 24 cases with progression of mitral regurgitation, 12 cases without changes, 54 cases with improvements of mitral regurgitation in total 90 patients. The bypass to LAD was proven as the significant prognostic factor of mitral regurgitation. The preoperative end diastolic left ventricular volume index were higher in aggravated group with 105.38$\pm$38.89 $m\ell$ compared to 71.75$\pm$28,45 $m\ell$ in improvement group, and 84.00$\pm$11.66 $m\ell$ in no change group. The grade of preoperative mitral regurgitation did not show significant differences among the groups. Conclusion: The mitral regurgitation in patient with coronary artery stenosis can be improved after the coronary artery bypass surgery alone. However, the expectation of improvements based on the degree of preparative mitral regurgitation can not be justified, therefore, the procedures for mitral regurgitation should be aggressively considered even in the cases of mild mitral regurgitation. Also, further study should be performed to identify the exact prognostic factors of mitral regurgitation including the left ventricular volume index, and whether the left anterior descending artery has been bypassed.

• Journal of Chest Surgery
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• v.33 no.9
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• pp.723-728
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• 2000

Background: Minimally invasive techniques for open heart surgery are widely accepted in these days. There are minimally invasive approaches by the right or left parasternal incision and another approaches by mini-sternotomy of upper or lower half or sternum. We report the safety and efficacy of minimally invasive technique with right parasternal incision compared with the routine full sternotomy. Material and Method: From April 1997 through February 1999, 20 patients(Group A) underwent minimally invasive cardiac operations. We chose 41 patients(Group B) whose preoperative diagnosis were the same and general conditions were similar and who underwent routine full sternotomy before April 1997. We compared A group and B group in many aspects. We performed routine full median sternotomy in B group but we did a minimally invasive technique through a small right parasternal incision in A group. Result: mean age was 36.1 years in both groups. In disease entities, there were 11 cases of ASD, 9 cases of mitral valve disease in group A, and 16 cases of ASD, 25 cases of mitral valve diseases in group B. In ASD, operation time, cardiopulmonary bypass time of aortic occulusion time were 263 min, 82 min, and 41 min in group A and 180 min, 53 min, and 32 min in group B. In mitral valve disease, operation time, cardiopulmonary bypass time and aortic occlusion time were 267min, 106 min, and 70min in A group and were 207 min, 82 min, and 69 min in group B. There were significant differences in operation time, CPB time, and ACC time between group A and group B. There was a significant difference in the amount of bleeding in postoperative day 1 between group A and group B of mitral diasease. However, there was no significant difference in the amount of bleeding in other comparisons. Mean length of incision was 8.7 cm in group A. There was no significant difference in postoperative complications between A group and B group. There was no mortality in either group. Conclusion: We conclude that this minimally invasive technique with right parasternal incision is cosmetically excellent but it is not effective in reducing operative time and there was no significant difference in recovery time and postoperative complications compared with routine full sternotomy.

• Journal of Chest Surgery
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• v.29 no.2
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• pp.171-176
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• 1996

From March, 1983 to June, 1994, twenty-two patients underwent coronary artery and combined operations. The ages of the patients ranged from 42 years to 72 years (mean 60.4$\pm$8.2 years). There were 17 male and 5 female patients. The left ventricular (LV) ejection fraction ranged from 25% to 65% (mean 46.9$\pm$14.2%). Nine patients had mechanical complication of myocardial infarction (MI), of which 5 were LV aneurysm, 3 ventricular septal defect and 1 mitral regurgitation. Nine patients had rheumatic valvular heart disease of whom 7 with aortic valve disease and 2 with mitral valve disease. Two other patients had left atrial thrombi, only one with atrial septal defect a d another with aneurysm of ascending aorta. An average of 2.1$\pm$1.0 bypasses was done, ranging from one to four. There were 3 postoperative complications; 2 perioperative MI and 1 leg wound infection. Among complicated patients, mortality was 1 patient (4.5%) due to low cardiac output syndrome after perioperative MI. With 3 to 136 months follow-up (mean 41.1$\pm$40.2 months), late mortality was 1 patient due to cerebral vascular accident. Among long-term survivors, all patients are in New York Heart Association functional class I or II. Although the number of patients was small, our surgical results were favorable. Therefore we think that coronary revascularization combined with heart operation does not increase the operative risk when associated coronary artery disease is present, and it reduces the occurrence of late death.