• 한국기계기술학회지
• /
• 제13권1호
• /
• pp.81-88
• /
• 2011

The triple eccentric butterfly valve has metal sheet and this study about butterfly valve ceiling is an innovative approach. But it is affected by the static pressure as well as cross-current. The damage at the valve on the pipe resulted from the reflux is due to valve leakage. This study is investigated on the triple eccentric disk and it is applied with angle and the static pressure in all cases to develop cross-current triple eccentric butterfly valves. The disc with the diameter of 300A is valve against flow velocity. The entrance pressure by flow characteristics is performed with numerical analysis. As the result, valve torque production is reduced more than the conventional triple eccentric valve and entrance pressure is decreased on the increase of valve open angle. And flow coefficient can be known to be increased.

• 대한조선학회논문집
• /
• 제46권5호
• /
• pp.545-551
• /
• 2009

In naval architecture and offshore engineering, the development and a broad use has been achieved in the field of flow control valves for pipe system. Butterfly valves are also widely used for flow control, but there are not many studies for triple-eccentric butterfly valves. Moreover, if the fluid of pipeline flows in the bi-direction then it makes more complicate to adapt triple-eccentric butterfly valves to flow control. In this study, we are trying to develop a bi-directional triple-eccentric butterfly valve through sealing mechanism and stem design study. Digital mockup using 3D CAD was constructed for shape interference check and structural analysis was conducted for structural safety. Also we performed leakage test to check out the durability of the bi-directional pressure for the developed valve.

• Journal of Chest Surgery
• /
• 제28권9호
• /
• pp.817-821
• /
• 1995

The CarboMedics 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 after it,s uses. The data for this study was collected from August 1988 to July 1993,five years period. There were total of 57 patients[female 40,male 17 in this series with 4 isolated aortic valve,26 isolated mitral valve,11 double valve and a triple valve replacement. The mean follow up time was 32 months. Postoperatively,58% of cases were in New York Heart Association[NYHA functional class I,and mild and moderate symptoms[NYHA class II were present in 36% and there were very few patients remaining in higher functional classes. In postoperative echocardiographic study, showed marked improved cardiac function. The overall early mortality was 3.5% and the late mortality was one case after triple valve replacement due to sudden death. The causes of early death were attributed to early prosthetic valve endocarditis and heart failure.

• Journal of Chest Surgery
• /
• 제13권2호
• /
• pp.92-99
• /
• 1980

From 1958 up to the end of April 1980, during the period of 12 years 1640 cardiac surgery cases including 1069 open heart surgery and 304 valve replacement cases, were operated in this Department. There were 1070 congenital anomaly and 570 acquired disease cases. In 1070 congenital anomaly cases 673 acyanotic and 397 cyanotic anomaly patients were noted. In acquired diseases 94 pericardial and 456 valvular cases were found. Among 456 valve cases 189 mitral stenosis, 133 mitral insufficiency, 30 aortic valve lesion, 97 double valve, and 7 triple valve lesion patients were noted. Among 304 valve replacement cases 209 mitral, 34 aortic, 5 tricuspid, 34 aortic with mitral, 20 mitral with tricuspid, and 2 triple valves were replaced. Annual increase `of open heart surgery cases and decrease of operative deaths were remarkable in recent years. In recent years Shiley** oxygenator in pump-oxygenator set up and Ionescu** bovine pericardial xenograft bioprosthesis were used for valve replacement mainly.

• Journal of Chest Surgery
• /
• 제16권4호
• /
• pp.602-614
• /
• 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
• /
• 제13권2호
• /
• pp.100-104
• /
• 1980

Simultaneous triple valve replacements were performed in two patients on January and April 1980 at Seoul National University Hospital. The first case was 17 years old male patient with a history of exertional dyspnea for 7 years. He was in class III by the NYHA functional classification and diagnosed as aortic insufficiency, mitral steno-insufficiency and tricuspid insufficiency. The second case was 46 years old male patient suffered from exertional dyspnea for 5 years, He was in class IV and diagnosed as aortic stenoinsufficiency, mitral stenoinsufficiency and tricuspid insufficiency. Triple valve replacements were performed under the deep hypothermia and pharmacologic cardiac arrest with aortic cross clamping for 80 minutes to 159 minutes. Total extracorporeal circulation time were 197 and 176 minutes respectively. The postoperative courses were uneventful.

• 한국산업융합학회 논문집
• /
• 제25권2_2호
• /
• pp.279-287
• /
• 2022

Butterfly valves installed on ships use valves with up to triple offset to improve tightness. However, the triple offset valve has structural problems such as disc deformation and seat separation. Accordingly, interest in quadruple offset butterfly valves with added offset is increasing. In this study, the structural safety of the quadruple offset butterfly valve was examined through numerical analysis. In addition, we intend to evaluate the performance of the valve through flow coefficient analysis.

• Journal of Chest Surgery
• /
• 제18권3호
• /
• pp.446-455
• /
• 1985

A total and consecutive 156 patients have undergone cardiac valve surgery including 13 closed mitral commissurotomy, 13 open mitral commissurotomy, one mitral annuloplasty, 75 mitral valve replacement, one aortic annuloplasty, 24 aortic valve replacement, 3 tricuspid valve replacement, 25 double valve replacement and one triple valve replacement. 155 prosthetic valves were replaced in a period between September 1976 and August 1985. There were 68 males and 88 females with age range from 8 to 69 yrs [mean 36.5 yr]. Out of replaced valves, 61 was tissue valve including 54 Carpentier-Edwards, and 4 was mechanical valves including 74 St. Jude Medical, and the position replaced was 101 valves for mitral, 46 for aortic and 8 for tricuspid. Single valve replacement in 102 cases, double valve replacement in 25 cases [17 for AVR+MVR, and 8 for MVR+TVR], and only one case was noted in the triple valve replacement. Early mortality within 30 days after operation was noted in 11 cases [7%]; 7 after MVR, 2 after DVR, and each one after open mitral commissurotomy and mitral annuloplasty. Cause of death was valve thrombus, cerebral air embolism, low output syndrome, uncontrollable arrhythmia, parapneumonic sepsis, acute cardiac tamponade and left atrial rupture. 7 late deaths were noted during the follow-up period from 1 to 104 months [average 48 month]; three due to valve and left atrial thrombus formation, two due to CVA from overdose of warfarin, and each one due to congestive heart failure and chronic constrictive pericarditis, Anticoagulants after prosthetic valve replacement were maintained with warfarin, dipyridamole and aspirin to the level of around 50% of normal prothrombin time in 79 cases, and Ticlopidine with aspirin in 47 cases to compare the result of each group. There were 11 major thromboembolic episodes including 3 deaths in the warfarin group. Two cases of CVA due to overdose of warfarin was noted in the warfarin group. In the ticlopidine group, there was only one left atrial thrombus confirmed at the time of autopsy. Among the survived 138 cases, nearly all cases[136 cases] were included in NYHA functional class I and II during the follow-up period. In conclusion, surgical treatment of the cardiac valve disease in 156 clinical cases revealed excellent result with acceptable operative risk and late mortality. Prevention of thrombus formation with anti-platelet aggregator Ticlopidine has better result than warfarin group presently with no specific side effect such as bleeding or gastrointestinal trouble.

• Journal of Chest Surgery
• /
• 제38권10호
• /
• pp.675-679
• /
• 2005

배경: 삼중 판막 대치술의 임상적 결과에 대한 문헌들은 매우 드물다. 대랄 및 방법. 1992년 1월부터 2003년 12월까지 38명의 환자가 연세 심장혈관 병원에서 삼중 판막에 대한 대치술을 시행받았다. 평균 나이는 $49.5\pm10.7 (28\~69)$세였으며 24명이 여자였다. 류마치스성 심장 판막 질환이 가장 흔한 원인이었고(n=37), 수술 전 New York Heart Association (NYHA) functional class는 II가 4명, III가 24명, IV가 10명이었다. 15명의 환자는(group 1) 최초의 수술에서 삼중 판막 대치술을 시행 받은 경우였고, 23명의 환자는(group 2) 이전에 일회 이상의 심장 수술을 받았으며 한 명을 제외하고는 삼첨 판막 대치술을 제일 나중에 시행 받은 경우였다. 7명의 환자는 최초 수술에서 삼첨 판막 성형술을 받은 후 삼첨 판막 대치술을 시행 받은 환자들이었다. 걸과 수술 사망은 6명$(15.8\%)$이었으며 모두 group 2에 속하는 환자들이었다. 최초 수술에서 삼중 판막 대치술을 시행 받은 15명의 환자는 수술 사망 없이 모두 퇴원하였다. 평균 $66.0\pm40.7$개월의 추적 관찰 기간 중에 만기 사망은 3명$(9.4\%)$에서 있었으며 대부분의 환자에서 NYHA functional class의 향상을 보였다. 4명의 환자에서 인공 판막과 관련된 합병증이 있었으며, 10년 생존율은 $68.8\%$였고, 생존자에 있어서 재수술을 포함한 10년 무사고 생존율은 $85.5\%$였다. 결론: 삼중 판막 대치술 후에 대부분의 환자에서 증상의 호전을 보였다. 그리고 추적 관찰기간 중에 인공 판막과 관련된 합병증 발생 및 생존율은 만족할 만한 결과를 보였다. 따라서 적응이 되는 경우에는 환자의 상태가 더 나빠지기 전에 삼중 판막 대치술을 적극적으로 고려해야 할 것이다.

• Journal of Chest Surgery
• /
• 제13권4호
• /
• pp.422-434
• /
• 1980

Since 1968 up to the end of October 1980, 448 valves were replaced in 354 patients in Seoul National University Hospital. There were 238 mitral, 38 aortic, 7 tricuspid, 45 aortic with mitral, 23 tricuspid with mitral, and 3 triple valve replacement aortic mitral and tricuspid cases. Annual increase of mitral valve replacement cases and decrease of operative maortality were remarkable. Recently operative mortality of mitral valve replacement is about 5%. Sex ratio of mitral valve replacement is almost equal and there were 12 cases of pediatric patients (5%) among 238 cases, and patients under the age of 20 years were 34 (14.3%). Mitral valve replacement was done for 199 single mitral, 38 double valve and one triple valve lesions. Among 238 mitral valve replacement paients left atrial thrombus in 23(9.7%), atrial fibrillation in 132 (55.5%), and reoperation after blind mitral commissurotomy in 12(5%) cases were noted. In recent cases bioprosthetic valves, mainly lonescu-shiley valve were utilized to overcome the difficulties of postoperative late complications in anticoagnuation, especially for the rural patients and pediatric cases, in addition to the hemodynamic advantages of lonesocu valve. Among 354 patients 16 cases were congenital heart anomaly related, 5 ventricular septal defect related aortic and 4 Ebstein related tribuspid valve replacement cases. There were 2 congenital anomaly related mitral valve replacements, one for congenital mitral insufficiency of 7 years old boy and one for corrected transposition of the great vessels associated with mitral insufficiency. Among total 354 valve replacements 49 operative deaths (13.3%) were noted and in 238 mitral valve replacement 24 operative deaths occurred (10.1%). In 39 patients among 354 total valve replacements late complications were found. In 238 mitral valve replacement cases late complications were noted in 26 patients, among whom 16 cases expired. Main late complications were thrombe-embolism, subacute becteerial endocarditis, arrythmia cerebral hemorrhage due to unsatisfactory anticoagulation, and congestive heart failure in the incipient period of valve replacement were also noted. In mitral valve replacement cases long-term survival rate was 83.2% who showed marked clinical improvement. Ther were no evidences of calcification during the 2 years follow-up period for the lonescu-valve replacement cases among 19 pediatric patients. In conclusion 238 cases of mitral valve replacement were done with 24 operative deaths and 26 late complication cases among whom 16 expired. The long term survival was 83.2% of the cases. In pediatric cases in place of coumadin anticoagulation Persantin **** 75 and aspirin were administered after valve replacement. In adult cases who have difficulaties with coumadin anticoagulation and for those even with bioprosthetic heart valve replacement who needs long-term or permanent anticoagulation persantin 75 and aspirin combination regimen were administered with antisfactory results.