• Journal of Chest Surgery
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• 제47권6호
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• pp.504-509
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• 2014

Background: Most surgeons favor the pledgeted suture technique for heart valve replacements because they believe it decreases the risk of paravalvular leak (PVL). We hypothesized that the use of nonpledgeted rather than pledgeted sutures during mitral valve replacement (MVR) may decrease the incidence of prosthetic valve endocarditis (PVE) and risk of a major PVL. Methods: We analyzed 263 patients, divided into 175 patients who underwent MVR with nonpledgeted sutures from January 2003 to December 2013 and 88 patients who underwent MVR with pledgeted sutures from January 1995 to December 2001. We compared the occurrence of PVL and PVE between these groups. Results: In patients who underwent MVR with or without tricuspid valve surgery and/or a Maze operation, PVL occurred in 1.1% of the pledgeted group and 2.9% of the nonpledgeted group. The incidence of PVE was 2.9% in the nonpledgeted group and 1.1% in the pledgeted group. No differences were statistically significant. Conclusion: We suggest that a nonpledgeted suture technique can be an alternative to the traditional use of pledgeted sutures in most patients who undergo MVR, with no significant difference in the incidence of PVL.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 추계학술대회 논문집 학회본부
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• pp.91-94
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• 1996

A simulation procedure was developed for identifying Yungnam unit 2 excitation model parameters to improve the accuracy of stability simulation of KEPCO. First, generator model parameters are derived by using modified load rejection technique from measured load rejection test. For identifying excitation model parameters, switch was changed from MVR mode to AVR mode in Yungnam unit 2 excitation system instead of applying to a small step to the voltage reference($V_{ref}$) because of saving time and efforts, assuming the test result would show coincided result with applying to a small step to the $V_{ref}$. However, it was found that the response of switching from MVR to AVR is greatly different from it of applying small signal to the $V_{ref}$. A simulation procedure was needed to take into accounts of real AVR component status before and after switching from MVR to AVR. This paper reports the procedure which duplicated the measured response and addresses the merits of this test on conventional AVR step test.

• Journal of Chest Surgery
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• 제16권2호
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• pp.147-156
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• 1983

Over a period from May, 1977 to SEptember, 1982, 101 cases ofopen heart surgerywere done under cardiopulmonary bypass. There were 50 male and 51 female patients, and the ages of the patients ranged from 19 months to 48 years. Sixty-nine cases were congenital heart disease and 32 cases were acquired heart disease, which consisted of 30 valvular disease, 1 IVC obstruction, and 1 myxoma. Among the 30 cases of valvular disease, 12 MVR, 4 MVR+TAP, 2 MVT+AVR, 1 MAP, and 11 OMC were done. There were 3 operative deaths (17.5%) in 16 MVR, 1 in 2 MVR+AVR, and 1 in 11 OMC. Operative mortality in 69 congenital heart disease was 13.0% ; 3 deaths (6.7%) in 45 acyanotic and 6(25.0%) in 24 cyanotic cases. The overall mortality for 101 cases was 14.8%; 13.0% for congenital and 18.8% for acquired heart disease.

• Journal of Chest Surgery
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• 제18권4호
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• pp.711-717
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• 1985

Over a period from July 1984 to June 1985, 39 cases of open heart surgery were done under cardiopulmonary bypass. There were 23 male and 16 female patients, ranging in age from 18 months to 58 years. Thirty cases were valvular disease. The most common of congenital heart disease is VSD. Among the 9 cases of acquired valvular diseae,1 MAP, 5 MVR, 2 MVR+TAP, and 1 MVR+AVR were done. There were 1 operative death[11%] which was done MVR+TAP. Operative mortality in 30 congenital heart disease was 7%; 1 death [5%] in 22 acyanotic and 1[13%] in 8 cyanotic cases. Finally, overall mortality for 39 cases was 8%; 7% for congenital heart disease and 11% for acquired heart disease.

• 대한설비공학회지:설비저널
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• 제19권1호
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• pp.36-45
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• 1990

• Journal of Chest Surgery
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• 제17권2호
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• pp.223-230
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• 1984

Since January 1977 to the end of September 1982, total 60 Ionescu-Shiley pericardial xenograft heart valves were implanted for valve replacement in 50 patients at the Han Yang University Hospital. The operative procedures were as follow: Mitral valve replacement [MVR] in 25 patients, Mitral valve replacement [MVR] and Tricuspid valve [TV] annuloplasty in 7 patients, Aortic valve replacement [AVR] in 8 patients, Aortic valve replacement [AVR] and Mitral valve replacement [MVR] in 8 patients. Aortic valve replacement [AVR] and Mitral valve replacement [MVR] and Tricuspid valve [TV] annuloplasty in 2 patients. To evaluate the immediate hemodynamic changes after valve replacements, the pressures of each cardiac chamber and ulmonary artery were checked before and after valve replacement on the operation table. Right ventricle [RV] pressure was decreased from 52.09\ulcorner6.71 to 45.57\ulcorner5.03 mmHg, Pulmonary artery [PA] pressure was decreased from 45.97\ulcorner2.69 to 41.00\ulcorner3.99 mmHg, and Left atrium [LA] pressure was decreased from 30.33\ulcorner13.02 to 22.76\ulcorner.97 mmHg before and after valve replacement. In MVR group, RV pressure was decreased from 49.17\ulcorner7.89 to 43.14\ulcorner4.14 mmHg, PA pressure was decreased from 44.67\ulcorner3.18 to 38.67\ulcorner2.85 mmHg, and LA pressure was decreased from 31.46\ulcorner13.47 to 21.91\ulcorner.17 mmHg. In AVR group, RV pressure was decreased from 53.0\ulcorner7.44 to 44.71 \ulcorner3.24 mmHg, PA pressure was decreased from 34.83\ulcorner0.73 to 31.86\ulcorner.36 mmHg, and LA pressure was not changed. In double valve replacement [MVR and AVR] group, RV pressure was decreased from 57.50\ulcorner3.82 to 42.50\ulcorner.80 mmHg, PA pressure was decreased from 51.17\ulcorner1.42 to 43.33\ulcorner4.53mmHig, and LA pressure was decreased from 34.33\ulcorner2.09 to 25.50\ulcorner0.21 mmHg. But in the group where MVR and TV annuloplasty were performed, preoperative RV and PA pressure were markedly increased and no pressure decrease in RV and PA noticed after valve replacement. This study shows good immediate postoperative hemodynamic results after valve replacement using Ionescu-Shiley xenograft valve except in the cases of MVR and TV annuloplasty and advanced disease with pulmonary hypertension.

• Journal of Chest Surgery
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• 제16권4호
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• pp.602-614
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• 1983

Six hundred fourteen consecutive cases of bioprosthetic cardiac valve replacement performed during the period from March 1976 through December 1982 were reviewed. A total of 748 tissue valves [534 Ionescu-Shiley valves, 144 Hancock valves, 46 Angell-Shiley, and 24 Carpentier-Edwards] were implanted in 610 patients. Of these, 477 had single valve replacements [403 mitral, 60 aortic, and 14 tricuspid] including three REDO MVR and one REDO AVR. The remaining 129 had double valve replacements [95 AVR and MVR and 34 MVR and TVR] and 8 had triple valve replacement.592 cases were evaluated. Overall early mortality rate [within 30 days of operation] was 7.1% [6.2% in single valve replacement, 10.2% in double valve replacement, and 16.7% in triple valve replacement]. Leading causes of mortality were low cardiac output or myocardial failure and ventricular arrhythmias. The follow-up period was from one month to 7 years with a cumulative follow-up of 906.6 patient-years [mean 1.53 years]. The late mortality was 1.6%, 3.9%, 0%, 2.6%, 6.6% and 2.0% per patient-year for MVR, AVR, TVR or triple valve replacement, AVR+MVR, MVR+TVR and total, respectively. Actuarial analysis of late results including early mortalities indicates an expected survival rate of 87.6+1.8% at 3 years and 85.92.4% at 7 years for all cases. We also analyzed actuarial survival rate between groups of each valve replacement [AVR, TVR, Double valve, and Triple valve] and the tissue valve groups in MVR. We experienced 7 cases [0.77% per patient-year] of confirmed endocarditis, two of which were fatal. Valve failure-free rates calculated according to the confirmed cases were 97.5% at 4 years, 87.5% at 7 years, and 88.3% at 6 years for Ionescu-Shiley, Hancock and Angell-Shiley valves, respectively. The occurrence rate of thromboembolism was 2.0% per patient-year in total cases, although almost all the patients were given anticoagulant therapy for one year. The occurring rate in MVR was 1.5% and 2.7% per patient-year for Ionescu-Shiley and Hancock valve groups, respectively. The difference in actuarial rate free from thromboemboli between Ionescu-Shiley and Hancock groups was statistically significant [P value less than 0.001]. Thromboembolic events beyond the period of anticoagulation therapy mainly occurred in patients with atrial fibrillation. The actuarial thromboemboli free survival was 95.71.4% at 3 years and 80.17.3% at 7 years. The incidence of hemorrhagic complications was 1.2% per patient-year [fatality 0.55% per patient-year] for anticoagulated patients. Although our clinical data favorably compares with results from other reports, our results suggest that anticoagulant therapy be given on a short-term basis or not at all to hemodynamically stable patients. Long-term therapy with antiplatelet drugs is probably inevitable with patients who have thromboembolic risk factors [such as atrial fibrillation].

• Journal of Chest Surgery
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• 제29권10호
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• pp.1095-1101
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• 1996

1983년 7월부터 1995년 6월까지 전북대학교병원 흉부외과학 교실에서 승모판협착증으로 수술을 시행한 판막치환술 62예와 교련절개술 33예를 패상으로 하였다. 대동맥 판막이나 관상동맥 질환을 동반하거나 중등도 이상의 승모판 폐쇄부전증이 동반된 경우는 본 연구에서 제외하였으며 승모판 협착증에 대한 술식들을 합병증과 재수술, 사망율, 수술후 기능적인 변화에 따라 비교 분석 하였다. 수술전 대상환자의 특성 중 승모판 치환술군에서 심흉곽비가높았던 점 이외에 나이나 성별, NYHA 기능분류, 심전도상 심방세동의 유무, 심초음파 소견에서 두군 간에 의의 있는 차이는 없었다. 수술시 판막 병변의 병리학적 소견은 치환술군에서 더 심하였고(Sellors type IR, 35 in MVR, 1) in OMC 3 판엽의 석회화를 보이는 경우도 많았으나(35 in MVR, 11 in OMC), 판엽의 석 회화가 있었던 46 예 중 11예(23.9%)와 Sellor의 제3형 협착 61예 중 13예(27.1 %)에서 교련절개 술이 가능하였다. 수술후 조기 및 만기사망과 생존율에서 두군 간에 차이는 없었고, 출혈 및 혈전색전증과관련된 조기 및 만기 합병증이 치환술군에서 더 많았으며, 수술후 중장기 추적관찰시 N HA기능분류, EKG, 심흉 곽비, 심초음파 소견(EF, LAD, LWDs, LWDd) 등의 기능상의 변화에서는 두군간에 의의있는 차이를 발견할 수 없었다. 승모판 헙착증의 상호 보완적인 주요술식인 치환술과 교련절개술은 술식에 따른 기능상의 변화와 사망 및 생존율에 의의있는 차이는 없으나 출혈 및 혈전색전증과 관련된 합병증이 치환술군에서 많았고 고도의 협착 및 판막석회화가 존재하는 상황에서도 교련절개술이 가능하였으므로 자연판막의 보전을 위한 노력은 지속되어야 한다.

• Journal of Chest Surgery
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• 제24권4호
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• pp.404-420
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• 1991

Surgical treatment of congenital and acquired heart disease preceded the development of accurate techniques for diagnosis, heart lung machine and cardiopulmonary bypass, intraoperative myocardial protection, operative techniques and cardiac anesthesia. For 5 years from Sep. 1985 to Sep. 1990, six hundred cases of open heart surgeries [OHS] were performed in the department of Thoracic & Cardiovascular Surgery, Pusan Paik Hospital, College of Medicine, Inje University. The results were summarized as follows. 1. The annual number of OHS[cases per year] was above 100 since 1987, and the increasing rate of cases was 23.5% per year since 1986. 2. Among the total 600 cases, there were 470 cases of congenital heart diseases and 130 cases of acquired. Age range of the congenital patients was 8 months to 44 years with the mean age of 10 years, and acquired patients was 16 to 56 years with the mean age of 36 years. 3. Among the 470 congenital anomalies, there were 429 cases of acyanotic and 41 cyanotic patients. Totally, VSD was 286 cases[60.6%], ASD 103 cases[21.9%], TOF 35 cases [7.4%], PS 20 cases [4.1%], ECD 12 cases [2.0%], Ebstein`s anomaly 3 cases [0.6%], Valsalva sinus rupture 3 cases [0.6%] and others. The appropriate one stage radical operations were applied to the all congenital cases with the result of 2.6% immediate postoperative hospital mortality rate. 4. Among the 130 acquired cases, there were 122 cases of valvular heart diseases, 6 of heart tumors [5 myxoma, one malignant histiocytoma], one of LA thrombus and one of annuloaortic ectasia. Cardiac tumors and LA thrombus were removed through the atrial septal approach. Bentall procedure was adopted to the annuloaortic ectasia case. AVR, MVR and TVA [DeVega procedure] were applied to 120 valve diseases, and there were also one of OMC and one of MVA[Jerome-Kay procedure]. 5. Among the 120 valve replacement cases, there were 87 of single valve replacement cases [AVR: 8, MVR: 79], 11 of double valve replacement [AVR+MVR: 11], 12 of MVR+TVR and 10 of MVR+AVR+TVA. The total number of implanted prosthetic valves were 141. In MVR, 45 of St. Jude Medical valves, 63 of Carpentier-Edward valves and 4 of Ionescu-Shiley valves were used. In AVR, 18 of St. Jude Medical valves and 11 of Carpentier-Edward valves were used. in MVR, 29mm and 31mm sized valves were used mostly and In AVR, 23mm sized valves were used mostly. 6. Postoperatively many kinds of complications were occurred. Among them, wound problems [30 cases], low output syndrome [29 cases], arrhythmia [20 cases], pleural effusion and pneumothorax [13 cases] were occurred frequently. The postoperative immediate hospital mortality was 3.0% in total [congenital 2.6%, acquired 4.6%].

• 국제초고층학회논문집
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• 제11권4호
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• pp.315-320
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• 2022

With the rapid development of urbanization the problems of pedestrian-level wind comfort and natural ventilation of tall buildings are becoming increasingly prominent. The velocity at the pedestrian level ($\overline{MVR}$) and variation of wind pressure coefficients $\overline{{\Delta}C_p}$ between windward and leeward surfaces of tall buildings were investigated systematically through numerical simulations. The examined parameters included building density ρ, height ratio of building α_H, width ratio of building α_B, and wind direction θ. The linear and quadratic regression analyses of $\overline{MVR}$ and $\overline{{\Delta}C_p}$ were conducted. The quadratic regression had better performance in predicting $\overline{MVR}$ and $\overline{{\Delta}C_p}$ than the linear regression. $\overline{MVR}$ and $\overline{{\Delta}C_p}$ were optimized by the NSGA-II algorithm. The LINMAP and TOPSIS decision-making methods demonstrated better capability than the Shannon's entropy approach. The final optimal design parameters of buildings were ρ = 20%, α_H = 4.5, and α_B = 1, and the wind direction was θ = 10°. The proposed method could be used for the optimization of pedestrian-level wind comfort and natural ventilation in a residential area.