• 대한의용생체공학회:의공학회지
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• 제16권1호
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• pp.61-66
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• 1995

We have developed a monoleaflet polymer valve as an inexpensive and viable alternative, especially for short-term use in the ventricular assist device or total artificial heart. The frame and leaflet of the polymer valve were made from polyurethane. To evaluate the hemodynamic performance of the polymer valve a comparative study of flow dynamics past a polymer valve and a St. Jude Medicals prosthetic valve under physiological pulsatile flow conditions in vitro was made. Comparisons between the valves were made on the transvalvular pressure drop, regurgitation volume and maximum valve opening area. The polymer valve showed smaller regurgitation volllme and transvalvular pressure drop compared to the mechanical valve at higher heart rate. The results showed that the functional characteristics of the polymer valve compared favorably with those of the mechanical valve at higher heart rate.

• Journal of Chest Surgery
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• 제11권2호
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• pp.213-226
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• 1978

One hundred cases of open heart surgery were done at this Department in 1977. There were 65 congenital anomaly and 35 acquired diseases. Out of 65 cases of congenital malformation 35 acyanotic and 30 cyanotic cases were found. Fifteen cases of ventricular septal defect and 29 tetralogy of Fallot were noted eight patients expired out of 65 congenital anomaly [12.3%] , 4 out of 35 acyanotic [11. 4%] and 4 among 30 cyanotic anomaly[13.3%]. Among 35 cases of acquired heart disease 3 atrial myxoma [2 left and one right] and 32 valvular lesions were noted. In two cases open mitral commissurotomy, and in 30 valve replacement were done. Twenty-two single valve and 8 double valve replacement were done. Seven patients expired out of 30 patients [23.3%]. Among 22 single valve replacement cases 2 and among 8 double valve 5 died. ~ In eighteen mitral valve replacement cases 2 deaths occurred. One mitral insufficiency patient who expired suffered from severe pulmonary` hypertension [PA=120/67mmHg], tricuspid insufficiency and a large ventricular septal defect. The patient underwent mitral valve replacement, tricuspid annuloplasty and patch closure of ventricular septal defect. Over all mortality rate for 100 open heart surgery cases was 15%. Since 1977 open heart surgery cases were done routinely in this institution and cases are increasing rapidly. With present rapid improvement of economical status and introduction of medical insurance system, open heart surgery will be firmly established in Korea in the very near future.

• 한국정밀공학회지
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• 제20권3호
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• pp.120-124
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• 2003

Monoleaflet polymer artificial heart valve was known to show remarkable improvement in antithrombosis and pressure drop compared with other type of artificial valve. In this investigation of monoleaflet heart valve the vertical and horizontal deflection pattern of polymer heart valve with three types of supporting members, straight member and two curved members were analysed using the large deformation nonlinear finite element method.

• Journal of Chest Surgery
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• 제18권4호
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• pp.655-662
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• 1985

From January 1985 to July 1985, prosthetic heart valves were replaced in 5 patients at Keimyung University Dongsan Medical Center. The patients included three women and two men ranging in age from 22 to 41 years. Three mitral valve replacements, one aortic valve replacement and one double valve replacement [mitral and aortic valve replacement] were done at the first valve operations. Reoperation were performed 2 to 76 months after the first operations, Prosthetic valve endocarditis occurred in 3 patients, early in one and late in two and primary valve failure occurred in 2 patients. In operative findings, vegetation in prosthetic valve endocarditis and calcification in primary valve failure were found. All except one had relatively successful operative results. One died of early fungal prosthetic valve endocarditis due to relapsed prosthetic valve endocarditis with heart failure and block.

• Journal of Chest Surgery
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• 제52권1호
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• pp.55-57
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• 2019

Robotically assisted mitral valve repair has proven its efficacy during the last decade. The most suitable approach for patients with difficult anatomies, such as morbid obesity, sternal deformities, cardiac rotation, or vascular anomalies, represents a current challenge in cardiac surgery. Herein, we present the case of a 71-year-old patient affected by severe degenerative mitral valve regurgitation with pectus excavatum and a right aortic arch with an anomalous course of the left subclavian artery who was successfully treated using a Da Vinci-assisted approach.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1992년도 춘계학술대회
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• pp.123-126
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• 1992

In this paper, a numerical simulation of steady laminar and turbulent flow in a two dimensional model for the total artificial heart is presented. A trileaflet polyurethane valve was simulated at the outflow orifice while the inflow orifice had a trileaflet or a flap valve. The numerical solutions of the simulated model show that regions of relative stasis and trapped vortices were smaller wi thin the ventricular chamber wi th the flap valve at the inflow orifice than that with the trileaflet valve. The predicted Reynolds stresses distal to the inflow valve within the ventricular chamber were also found to be smaller with the flap valve than with the trileaflet valve. Analysis of the numerical solutions suggests that geometries similar to the flap valve(or a tilting disc valve) results in a better flow dynamics within the total artificial heart chamber compared to a trileaflet valve.

• Journal of Chest Surgery
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• 제27권12호
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• pp.984-988
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• 1994

Between 1981 and 1992, 22 children from 1 to 15 years of age have undergone cardiac valve replacements at National medical center. The patients were composed of 14 males and 8 females and 7 patients had congenital heart disease and 15 patients had rheumatic heart disease. Three of these 15 patients have had second valve replacement due to prosthetic valve failure[PVF]. Single valve replacement were 20[Aortic 3 cases, Mitral 17 cases] and double valve replacments were 2. The overall mortality was 22.7 %. Actuarial survival rate was 77.28 $\pm$ 8.92 % and Complication free rate was 67.68$\pm$15.56%. The pediatric valve replacements can now be performed at a low operative risk although various problems are still remained and the choice of valve is prosthetic valve mainly due to its durability at the present time.

• 대한의용생체공학회:의공학회지
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• 제10권2호
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• pp.91-93
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• 1989

We have developed a monoleaflet polymer valve as an inexpensive and viable alternative, especially for short-term use in the ventricular assist device or total artificial heart. The frame and leaflet of the polymer valve were made from polyurethane, To evaluate the hemodynamic performance of the polymer valve a comparative study of flow dynamics past a polymer valve and a St. Jude Medical prosthetic valve under physiological pulsatile flow conditions in vitro was made. Comparisons between the valves were made on the transvalvular pressure drop, regurgitation volume and maximum valve opening area. The polymer valve showed smaller regurgitation volume and transvalvular pressure drop compared to the mechanical valve at higher heart rate. The results showed that the functional characteristics of the polymer valve compared favorably with those of the mechanical valve at higher heart rate.

• 한국CDE학회논문집
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• 제6권1호
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• pp.59-68
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• 2001

This paper investigates the structural analysis and design of mechanical heart valve through the numerical analysis methodology. In a numerical analysis methodology application to the thickness minimization structural design of mechanical heart valve, fluid analysis is performed for the blood flow through a bileaflet mechanical heart valve. Simultaneously the kinetodynamic analysis is carried out to obtain the appropriate structural condition for the structural analysis. Thereafter the structural static analysis is also carried out to confirm the thickness minimization structural condition(minimum thickness shape of leaflet).

• Journal of Chest Surgery
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• 제19권3호
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• pp.399-406
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• 1986

131 cases of open heart surgery were performed in the Department of Thoracic and Cardiovascular Surgery, Kyungpook National University Hospital in 1985. There were 116 congenital cardiac anomaly and 15 acquired heart diseases. Out of 116 congenital cardiac anomaly, 73 cases of acyanotic group and 43 cases of cyanotic group were noted. In 73 cases of acyanotic group, 17 ASD, 52 VSD and 4 other acyanotic anomaly were noticed. In 43 cases of cyanotic group, 4 Trilogy of Fallot, 34 TOF, 1 Pentalogy, 3 DORV and 1 DCRV were included. Of the 15 acquired valvular heart disease cases, individual incidence was in mitral valve 10, double valve 3, and simple aortic valve 2 cases. Total number of valve replaced was 16, and 13 for mitral, 2 for aortic, and 1 for tricuspid in position, including 1 cases of double valve replacement. Overall operative mortality for 131 cases of open heart surgery was 4.5%, and the operative mortality was 5.5% in congenital acyanotic group, 2.3% in congenital cyanotic group, 0% in TOF group and 6.7% in acquired group.