• 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.

• 한국산업융합학회 논문집
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• 제26권3호
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• pp.411-419
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• 2023

In this paper, NIMONIC 86 material was tried to apply to exhaust valve for small-sized marine diesel engine. The both structural stability and thermal resistance in high temperature were needed to use the NIMONIC 86 material as exhaust valve for small-sized marine diesel eng ine. The purpose of this study is to investig ate the application of NIMONIC 86 material to exhaust valve of small-sized marine diesel engine by comparing, respectively, SUH 3 and STS 316 materials. As the results, NIMONIC 86 material has intermediate characteristics between SUH 3 and STS 316 materials in terms of the strength in condition of room temperature. Further NIMONIC 86 material was evaluated to have better characteristics than SUH 3 and STS 316 materials in terms of the thermal conductivity.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.828-831
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• 2003

The benefits of the pneumatic valve with piezoelectric element are faster response times, low energy consumption, and the ability to be used in hazardous environments and field bus systems. In this paper, PZT actuator, 2 and 3 stages pneumatic valve were designed and manufactured. Also. characteristics of the pneumatic valve with piezoelectric element were tested with a testing system. It is confirmed that the PZT actuator is useful one for controlling the direction of pilot valve.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.729-732
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• 2002

In this paper, poppet valve with cone type poppet and sharp edged seat was studied. In order to develope poppet valve which have a specification of 315(bar) and 3(lpm), effect of design parameter as valve seat diameter, poppet angle, spring stiffness and spring pre-load was evaluated. The validity of simulation was confirmed and basic data far poppet valve design was derived.

• 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.

• Journal of Chest Surgery
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• 제22권1호
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• pp.106-115
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• 1989

Clinical results with the xenograft cardiac valves were reviewed for 212 patients who underwent heart valve replacement from January 1981 to December 1987. One hundred and twenty-four Carpentier-Edwards k 88 Ionescu Shiley valves were used. Overall operative mortality was 11 out of 212[5.1%]: 5 out of 153[3.39o] for mitral valve replacement [MVR], 2 out of 34[5.9%] for aortic valve replacement [AVR], 0 out of 4[0%] for Tricuspid valve replacement [TVR], and 4 out of 21[19.1%] for double valve replacement [DVR;MVR+ AVR]. Two hundred and one operative survivors were followed up for a total of 824.3 patient-years [a mean 3.9*1.8 yrs], and the follow up was 78.1%. The linealized complication rates were 0.1% emboli / patient-year, 1.0% endocarditis/ patient-year and 2.2% overall valve failure / patient-year. A linealized rate of primary tissue failure was 0.7*/o/ patient-year. The actuarial survival rates including the operative mortality were 92*2.8% at 4 years and 85*4.3% at 7 years after surgery using the Xenograft cardiac valves. Probabilities of freedom from thromboembolism and overall valve failure were 73*11.0% and 69*2.4% at 7 years after surgery using the Xenograft cardiac valves respectively. The intrinsic durability of the Xenograft cardiac valves appears to be relatively well satisfactory over the long term [4 to 7 years] and the risk of failure appears well balanced by the advantages of a low incidence of thromboembolism and no mandatory anticoagulant therapy.

• Journal of Chest Surgery
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• 제26권9호
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• pp.677-685
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• 1993

Experience with bileaflet mechanical valve replacement at the Inha Hospital in 192 patients, operated on from June 1986 until April 1993. Two hundred fourty-one prostheses [51 Duromedics, 79 St.Jude Medical, and 111 CafboMedics]were implanted during the total 195 operations. Mitral valve replacment[MVR]was done in 113 cases, aortic valve replacement[AVR]in 34, tricuspid valve replacement[TVR]in 2, and double valve replacement[DVR]in 46 cases.Of the total patients, 63.0% were women and 37.0% were men. The mean age of the patients was 40.8 years, ranged from 14 to 67years. Overall early mortality was 9.2\ulcorner%[18 out of 195]; 9.7%[11 out of 113]for MVR, 14,7% [5 out of 34]for AVR, and 4.3%[2 out of 46]for DVR. All of the operative survors were followed over a period of one to 83 months with a mean of 37 months, for total 543 patient-years. So far, eleven patients[6.7% of the long-term survivors]were lost to follov-up after a mean postoperative follow-up of 22.8 months. There were nine late deaths; three deaths due to prostetic valve endocarditis, two due to persistent heart failure, one due to cerebral hemorrhage, one due to aortic dissection after Bentall oreration, and two sudden deaths. Actuarial survival rate at 6.9 years was 94.8%, There were seventeen valve-related complications; three prosthetic valve thromboses, three thrombembolisms, three instances of prosthetic valve endocarditis, two paravalvular leakages, and six hemorrhagic complications related to anticoagulation. The actuarial rate of freedom from all valve-related complications at 6.9years was 91.3%. There were significant decreases in the heart size postoperatively that can be demonstrated by comparison of cardio-thoracic ratios on simple chest X-ray and left ventricle dimensions on echocardiography. We conclude that this midterm follow-up shows good results in terms of hemodynamics and durability although further long-term evaluations are mandatory.

• 한국가스학회지
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• 제17권3호
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• pp.14-19
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• 2013

본 연구에서는 특수가스용기용 밸브의 안전성에 관한 실험적 연구를 수행하였다. 시험용 밸브는 특수가스용기에 부착되었던 것을 무작위로 수거한 것으로 가스누출 및 작동 안전성에 대한 시험을 실시하였다. 실험결과에 의하면, 밸브의 몸체, 나사 체결부, 안전판, 방출구, 스템부, 핸들에서 가스누출 안전성에 영향을 미칠 정도의 크랙, 마모, 부식, 변형이 발생하지 않았다. 다만, 핸들의 페인트 일부가 벗겨지고, PT나사와 몸체에서 녹이 국부적으로 형성되어 있지만, 가스누출 안전성에 영향을 미칠 정도는 아니었다. 또한, 탈거한 밸브에서 가스누출은 발생되지 않았다. 다만, 밸브스템의 영구변형과 오링의 마찰표면 일부에서 손상이 관찰되었다. 따라서, 탈거된 밸브의 가스누출 안전성을 보장하기 위해서 밸브시트와 오링 교체하는 것이 바람직함을 알 수 있다. 또한, 핸들의 조임력을 주기적으로 점검하는 것이 필요함을 알 수 있었다.

• Journal of Chest Surgery
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• 제25권2호
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• pp.149-157
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• 1992

Total 145 cases mitral vlave replacement were performed in Department of Thoracic and Cardiovascular Surgery in Chungnam National University Hospital during the period from May 1983 to July 1991. Sixty-one patients were male and 84 patients were female and the range of age was from 12 to 66 years old with the mean of 37.9[$\pm$11.6] years. Valvular lesions were 49 cases of mitral stenosis, 18 cases of regurgitation and 78 cases of combined lesion. Used valve were Ionescu-Shiley[42 cases], Bjork-Shiley[49 cases], Inact[6 cases], St. Jude Medical[11 cases] and CarboMedics[37 cases]. Mean size of valve was 29.8$\pm$1.68mm. Early morality was 13.8%[20 cases] and low output syndrome was most common cause[9 cases]. Age, functional classification and biventricular hypertrophy were risk factors. All survived cases were followed up without missing. Mean follow up period were 3 years and 3 months. Total 14 cases of death[9.7%] were observed and heart failure, unexplained sudden death and bleeding were the causes in that order. Common late complications were heart failure and bleeding related with anticoagulation. Actuarial survival rate at 5 years was 83$\pm$5.4% in overall, 78$\pm$7.2% in tissue valve group, 87$\pm$6.8% in mechanical valve group. The actuarial freedom rate from thromboembolism at 7 years was 89$\pm$8.3% in overall, 86$\pm$9.9% in tissue valve group and 97$\pm$1.9% in mechanical valve group. Actuarial freedom rate from bleeding at 5 years with anticoagulation was 88.9$\pm$4.2% in overall, 96$\pm$3.9% in tissue valve group, 86$\pm$4.6% in mechanical valve group. Reoperation was done in 3 cases with heart failure with tricuspid regurgitation and thromboembolism in 2 cases. The functional status of survived cases was I or II.

• Journal of Chest Surgery
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• 제57권5호
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• pp.496-499
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• 2024

Calcification of the mitral valve annulus is common in patients on dialysis. The growing number of individuals receiving dialysis has been accompanied by an increase in cases necessitating surgical intervention for mitral valve annulus calcification. In this report, we present a severe case characterized by bulky calcification of the mitral annulus, which was managed with mechanical mitral valve replacement. A 61-year-old man on dialysis presented with chest pain upon exertion that had persisted for 3 months. Cardiac echocardiography revealed severe mitral stenosis and regurgitation, accompanied by cardiac dysfunction. During surgery, an ultrasonic aspiration system was employed to remove the calcification of the mitral valve annulus to the necessary extent. Subsequently, a mechanical mitral valve was sutured into the supra-annular position. To address the regurgitation, the area surrounding the valve was sewn to the wall of the left atrium. Postoperative assessments indicated an absence of perivalvular leak and demonstrated improved cardiac function. The patient was discharged on postoperative day 22. We describe a successful mitral mechanical valve replacement in a case of extensive circumferential mitral annular calcification. Even with severe calcification extending into the left ventricular myocardium, we were able to minimize the decalcification process. This approach enabled the performance of mitral mechanical valve replacement in a high-risk patient on dialysis, thus expanding the possibilities for cardiac surgery.