• Journal of Chest Surgery
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• 제22권3호
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• pp.393-401
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• 1989

Between Dec. 1984, and May, 1988,96 prostheses were implanted in 80 patients at Dept. of Thoracic k Cardiovascular Surgery of National Medical Center. 43 patients had mitral valve replacement, 21 underwent aortic valve replacement, and 15 had double valve replacement [Mitral k Aortic], and 1 had tricuspid valve replacement. Seventy-one cases [88.8 %] were in NYHA Class III or IV. The mean duration of follow up was 22.1 months and follow-up information was available for 74 [92.5 %] of the patients. The overall actuarial survival rate at 45 months was 93.05 % and overall hospital mortality was 10 %, late Mortality was 5 %. The linearlized incidence of thromboembolism [2.4%/pt-yr], thrombotic valve obstruction [1.6 %/pt-yr], anticoagulant related bleeding [0.8 %/pt-yr]. There were no fatal valve related complications. The blood was studied in 40 patients 1 year after valve operation. Hgb and reticulocyte count were within normal values and Serum LDH value was slightly elevated but it was not of clinical significance. In conclusion, Monostrut Bjork-Shiley valve prosthesis to be a reliable valve substitute with an acceptable incidence of complications.

• Journal of Chest Surgery
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• 제25권5호
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• pp.518-525
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• 1992

50 months experience with St-Jude Medical Cardiac Valve Prosthesis The St. Jude Medical valve has become our mechanical valvular prosthesis of choice because of favorable hemodynamic results that associated with marked clinical improvement and low incidence of thromboembolism. The data for this study was collected from April 1986 to May 1990, four years period. There were total of 110 patients[female 53, male 58] in this series with 22 isolated aortic valve, 66 isolated mitral valve, 20 double valve, 2 tricuspid valve replacement. The mean follow up time was 23 months. Postoperatively, 77% of cases were in New York Heart Association[NYHA] functional class I, and mild and moderate symptoms[NYHA II ] were present in 20% and there were very few patients remaining in higher functional classifications. In postoperative echocardiographic study showed marked improved cardiac function. The overall early mortality was 5.4% and was higher after double[13.3%] and mitral valve replacement[5.6%] and the late mortality was one case after mitral valve replacement due to endocarditis. The cause of death in early mortality was attributed to heart failure, acute renal failure, sepsis, etc.

• Journal of Chest Surgery
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• 제21권2호
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• pp.351-365
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• 1988

During one year[1987], 110 cases of open heart surgeries were performed in the department of Thoracic and Cardiovascular Surgery, Pusan Paik Hospital, Inje Medical College. And the results were summarized as follows. 1. Among the 110 cases, there were 77 cases of congenital heart diseases and 33 cases of acquired heart diseases. Age range of the congenital patients was 8 months to 30 years with the mean age of 8 years, and acquired patients was 16 to 56 years with the mean age was 32 years. 2. The heart lung machine used for cardiopulmonary bypass was Sarns 7000, 5-head roller pump, and the number and type of oxygenators were 50 of membrane type and 60 of bubble type. For all cases GIK[glucose-insulin-potassium] solution was used as cardioplegic solution for myocardial protection during operation. 3. Among the 77 congenital anomalies, there were 67 cases of acyanotic patients[ASD: 12, VSD: 50, PS: 1, AP window: 1, Gerbode defect: 1, ECD: 2] and 10 cases of cyanotic patients[TOF: 10], and to all of which the appropriate radical operations were applied. 4. Among the 33 acquired diseases, there were one case of left atrial myxoma, one of annuloaortic ectasia, 20 of mitral valve diseases[MS: 2, MSr: 8, MR: 2, MRs: 8], 9 of double valve diseases[MRs+AR: 1, MRs+ARs: 2, MRs+TR: 1, MSr+TR: 3, MSr+ASr: 1, MSr+ARs: 1], 2 of triple valve diseases[MSr+AR+TR: 1, MSr+ASr+TR: 1]. The left atrial myxoma was removed well with right atriotomy and atrial septal approach. And to the annuloaortic ectasia, Bentall operation was applied with good result. Mitral valve replacement[MVR] was applied to 20 cases of mitral valve diseases, double valve replacement[MVR+AVR] was applied to 6 cases of double valve diseases, MVR & tricuspid annuloplasty[TVA] was applied to 3 cases of mitral 5. The number of replaced valve were 39 in 31 cases. In MVR, 5 of mechanical valves[St. Jude Medical Valve] and 26 of tissue valves[Carpentier-Edward valve] were used. In AVR, 3 of mechanical valves and 5 of tissue valves were used. 6. Postoperative complications were occurred in 23 cases, and among them 21 cases were recovered with intensive cares, but 2 cases were expired[mortality: 1.8%].

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.933-938
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• 2001

A 5-valve(intake 3-valve) engine has been developed to increase engine performance. These vehicles have a high power caused by the decrease of inertia mass of an intake valve and the increase of intake effective area. In this study, velocity profiles at near intake valves were inspected by using a two-color PIV and laser sheet method with tumble control valve(TCV). In addition, steady flow tests were performed to quantify tumble ratio on flow-fields generated with a TCV. These experimental results show that the tendency of the tunble ratio in intake 3-valve engine is different from the one in intake 2-valve engine. From this results, the intake flow characteristics around intake valves were made clear.

• 한국산업융합학회 논문집
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• 제19권3호
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• pp.160-166
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• 2016

This study proposes the development and performance evaluation of electronic proportional control valve having an LVDT. The electronic proportional control valve is composed of hydraulic valve, proportional solenoid and controller. LVDT is to reduce the steady state error for the reference input of the controller by the feedback signal to detect the displacement of the spool. Designed LVDT is applied to the common proportional valve. In order to evaluate the performance of the developed valve, the hydraulic test equipment was developed and flow tests were carried out. From experimental results, it was proved that the hysteresis was less than 1% based on the maximum flow rate.

• Journal of Chest Surgery
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• 제33권2호
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• pp.160-166
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• 2000

Background: The purpose of this study is to evaluate and analyze the surgical results in patients undergoing operations for multiple for multiple valvular heart diseases. Material and method: From April 1982 to June 1997 multiple valve replacement was performed in 150 patients mitral and aortic valve replacement were done in 135 patients mitral and tricuspid valve replacements in 10 patients triple replacements in 4 patients and aortic and tricuspid valve replacement in 1 patient. Of the valves implanted 157 were St. Jude 104 Duromedics 20 Carpenter-Edwards 6 Bjork-Shiley 6 Ionescu-Shiley and 2 Medtronics. Result: The hospital mortality rate was 10.7% (16/150) and the late mortality rate was 7.2% (8/134) The mortality rate was high in early operative period but decreased with time. The causes of death were low cardiac output in 9 sudden death in 3 congestive heart failure in 3 bleeding in 2 cerebral thrombosis in 1 leukemia in 1 multiorgan failure in 1 and so on . The actuarial survival rate excluding operative death was 83.1% at 15 years. Conclusion: With a follow-up now extending to 15 years the multiple valve replacement continues to be reliable procedure with relatively low mortality and morbidity.

• 한국가시화정보학회지
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• 제19권1호
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• pp.12-17
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• 2021

A three-dimensional slope valve component is used for controlling micro volume of liquid on a centrifugal force-based microfluidic disk platform, also called a lab-on-a-disk. The modeling factor of the slope valve component is determined to centrifugal force for liquid passing the crest of a slope valve via variation of slope length and angle as well as the radius to start point of slope valve. The centrifugal force is calculated by the equilibrium equation of the capillary and gravitational forces according to the microchannel surface roughness and the liquid volume, respectively. As a result, the slope valve is analyzed by the minimum angular velocity for liquid passing at crest point and the ratio between the length of micro liquid and slope length to obtain the factors for optimal slope angle modeling.

• Journal of Chest Surgery
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• 제31권11호
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• pp.1031-1036
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• 1998

연구배경 : Medtronic-Hall 기계판막은 세계적으로 흔히 쓰이고 있으나, 우리 나라에는 그에 대한 임상연구가 되어 있지 않다 재료 및 방법 : 1986년 3월부터 1990년 5월까지 Medtronic-Hall 기계판막을 이용한 인공 심장판막 치환 환자 50례를 대상으로 하였다. 환자의 평균 연령은 35세였고 남녀비는 17:33이었다. 결과 : 판막 병변의 원인은 류마티스성이 43례로 대부분을 차지했고 38명의 환자에서 승모판 치환술을 7명에서 중복판막치환술을 그리고 5명의 환자에서 대동맥판막 치환술을 시행하였다. 술전 NYHA 기능 분류는 Class III 혹은 Class IV가 91.5%였지만 술후는 ClassI혹은 Class II가 87.2%로 호전된 양상을 보였다. 심장초음파 검사상 좌심방내경, 수축말기 및 확장말기 좌심실내경은 술후 모두 감소하였고 심박출률은 증가하였다. 술후 합병증은 출혈 3례, 저심박출 증후군 2례, 혈전색전증 1례, 전격성 간염 1례가 있었고 병원 사망례는 3례였다. 혈전색전증의 발생률은 1.5%/환자.년이었고 5년 생존률은 93.65$\pm$0.71%, 10년 생존률은 88.27$\pm$6.4%였다. 결론 : 이상에서 Medtronic-Hall 기계판막은 판막에 관련된 합병증 발생률이 낮고 판막의 내구성도 뛰어나며 혈역학적 수행능력이 타 기계판막에 뒤떨어지지 않는 판막으로 확인되었다.

• Journal of Chest Surgery
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• 제34권9호
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• pp.686-691
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• 2001

배경: Duromedics 판막은 1982년부터 사용되어 왔으나 국내에서는 장기 임상 성적에 대한 보고가 없는 실정이다. 이에 본원에서 시행된 Duromedics 판막의 장기 임상 성적을 보고하는 바이다. 대상 및 방법: 1987년부터 1988년 사이에 23명의 성인 환자에게 Duromedics 기계판막을 이용하여 판막치환술을 시행하였다. 승모판막 치환이 8예, 대동맥판 치환이 5예, 삼첨판막 치환이 1예, 대동맥판막과 승모판막을 동시에 치환한 경우가 6예, 승모판막과 삼첨판막을 동시에 치환한 경우가 1예였다. 남자 환자가 12명, 여자 환자가 11명이었고 환자들의 평균 연령은 35$\pm$10(15~52) 세였다. 저자들은 이 환자들에게 치환된 Duromedics 기계 판막의 임상적인 결과를 추적 조사하였다. 결과: 조기 사망은 1예로서 4.3%(1/23)의 조기 사망률을 보였고 만기 사망도 1예로서 4.3%(1/23)의 만기 사망률을 보였다. 사망 원인은 저심박출 증후군과 구조적 판막실패였다. 평균 추적기간은 133$\pm$43개월(8~157)이었다. 재수술을 시행한 경우는 모두 3예가 있었는데 판막혈전증이 1예, 구조적 판막이상이 1예, 비구조적 판막 이상이 1예였다. 10년 생존율(actuarial survival rate)은 90.9%이었다. 결론: 비록 임상 연구를 하기에 충분한 환자 수는 아니었지만, Duromedics 판막의 장기 임상 성적은 다른 판막에 비해 우수하거나 비슷하였으며, 구조적 결함도 발견되지 않았다. 하지만 향후 좀더 연구가 이루어져야 할 것으로 생각된다.

• Journal of Chest Surgery
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• 제24권2호
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• pp.161-170
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• 1991

Clinical results with the Mechanical cardiac valves were reviewed for 261 patients who underwent cardiac valve replacement from September, 1985 to July, 1990. of the Mechanical valves used, 156 were Carbomedics, 109 Duromedics, 52 St. Jude and 11 Bjork-Shiley. Overall hospital mortality was 14 out of 261[5,36%]: 9 out of 159[5.66%] for MVR, 1 out of 35[2.86%] for AVR and 4 out of 67[5.96%] for DVR[AVR+MVR]. Two hundred and forty seven operative survivors were followed up for a total 466.8 patient-years, ranged from 1 month to 4.9 years [a mean 1.8 years] and the follow up was 96.0%. There were 12 valve-related complications: three from thromboembolism, three from valve thrombosis, three from prosthetic valve endocarditis, two from paravalvular leak and the other one from hemorrhage. Actuarial rate free from all valve-related complication at 4.9 years was 96$\pm$1.3%. There were 11 late deaths: two from thromboembolism, one from valve thrombosis, one from prosthetic valve endocarditis, one from hemorrhage and the others 6 from non-valve-related complications. Actuarial survival rate at 4.9 years was 94$\pm$2.0%. 96$\pm$3.0% for MVR, 94$\pm$4.2% for AVR and 91$\pm$3.7% for DVR[AVR+MVR]. And there are 7 reoperations: three from paraprosthetic leak, two from prosthetic valve endocarditis and two from valve thrombosis. Actuarial rate free from reoperation at 9 years was 96$\pm$2.9%. On the basis of this 4.9 years of experience, the pyrolytic carbon mechanical valves appears to be an excellent mechanical prosthesis for cardiac valve replacement, in terms of hemodynamic performance, low mortality and low thrombogenecity.