• Journal of Chest Surgery
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• 제28권12호
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• pp.1122-1131
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• 1995

One hundred eighty-eight patients[August.23,1988,through July.30,1994 underwent aortic[AVR , mitral[MVR , or double [DVR valve replacement with the St.Jude Medical prosthesis. The author analyzed 100 patients with valvular heart disease,who underwent valve replacement with the St.Jude Medical prothesis from 1990 to 1994, at Hanyang University hospital Cardiovascular department. Information on volume and functional change of the heart chamber can be obtained by cardiac echocardiography and cartheterization. Out of 100 patients, 40 patients were male[40% and 60 patients were female [60% . Age ranged from 13 years to 68 years, with mean age of 42.6 years. Mean height was 160.3cm and mean body weight was 54.9Kg. According to NYHA functional classification, class III is most frequent and 60 patients could be classfied under it. MVR [involved Redo MVR was performed in 40 patients, AVR [involved Redo AVR was performed in 18 patients, and DVR [involved Redo DVR was performed in 42 patients. Warfarin [Coumadin anticoagulation was recommended for all patients. Life long warfarin anticoagulation was necessary to all patients who underwent valve replacement with St.Jude Medical prosthesis. Ideal prothrombin time was maintained about 30% during warfarinization. There were no case of mechanical failure. It followed a comparison of echocardiography before and after valve replacement at Hanyang University hospital [30 patients and a preoperative evaluation of cardiac catheterization and angiography [64 patients . The St.Jude Medical cardiac valve is a viable alternative in the surgical therapy of valvular heart disease.

• Journal of Chest Surgery
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• 제27권12호
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• pp.995-1001
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• 1994

The CarboMedics valve prosthesis is a relatively new. low profile bileaflet prosthesis. During a 6 year period from Aug. 1988 to July 1994. 158 patients had CarboMedics prostheses implanted in the mitral [n=94], aortic [n=25], or aortic and mitral [n=39] in National Medical Center. Hospital mortality was 9.4% and the main cause of death was low output syndrome. Follow up was 96% complete, with 365.4 patient-years and a mean follow up of 30 months [ range 1 to 72 months ] . The overall actuarial 6 year survival rate was 91.61 3.47% and actuarial 6year freedom from all valve related complications was 73.9 7.67%. The linearized incidence of vavle related complications was as follows: thromboembolism 1.37%/patient-year ; valve thrombosis 0.82%/ patient-year ; anticoagulant related hemorrhage 0.85%/patient-year ; perivalvular leakage 0.55%/paitent-year: prosthetic valve endocarditis 0.82%/patient-year ; reoperation 1.37%/patient-year. There were no instances of structural failure. We conclude that the Carbomedics valve has a low rate of complications that further improves the quality of life in patients with heart valve prostheses.

• Journal of Chest Surgery
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• 제28권9호
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• pp.817-821
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• 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
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• 제28권7호
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• pp.666-670
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• 1995

A total of and consecutive 87 patients underwent concomitant double mitral and aortic valve replacement with the St. Jude Medical prosthesis between January 1985 and December 1993. They were 44 males and 43 females with the ages ranging from 18 to 59 years[mean$\pm$SD: 40.9$\pm$9.5 years . Fifteen patients[17.2% had a history of previous cardiac valve replacement. There were 2 early deaths[2.3% , and 85 early survivors were followed up for a total of 352.6 patient-years[mean$\pm$SD: 4.1 $\pm$2.6 years . All were anticoagulated with coumadin keeping the target international normalized ratio within the range of 1.5 and 2.5. There was a single late death[late mortality of 0.284%/patient-year . Thromboembolism was the most frequent complication[1.985%/patient-year , and bleeding related to anticoagulation was experienced in one patient [0.284%/patient-year . The incidences of prosthetic valve endocarditis and of paravalvular leak were also low[0.284%/patient-year, respectively . The survival including operative mortality was 96.1%$\pm$2.2% at 10 years. The actuarial probabilities of freedom from thromboembolism and from all events were 77.9%$\pm$11.1% and 72.4%$\pm$10.7%, respectively, at 10 years. There was no structural failure of the prosthesis. Results from a series of clinical studies suggest strongly that the use of lower intensity of anticoagulation therapy lowers the thromboembolic as well as bleeding rates in patients with the ST. Jude Medical prosthesis.

• 대한의용생체공학회:의공학회지
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• 제19권3호
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• pp.291-296
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• 1998

설계방법론을 적용하여 새로운 기계식 인공심장판막을 설계 하였다. 심장판막의 기능을 정의하고 기능구조 결과에 따라 체계적인 설계변이 탐색을 수행하였으며, 이에 의하여 다양한 가능성을 검토하였다. 심장판막에 요구되는 제반 요구조건들을 기준으로 하여 최적 모델을 결정하였다. 설계된 심장판막의 시제품을 제작하여 모의순환계를 이용한 거동특성측정 실험을 수행하였다. 설계된 신규모델은 유량과 파형특성 및 거동특성면에서 대체로 양호한 결과를 보였다.

• 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 Mechanical Science and Technology
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• 제17권9호
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• pp.1316-1323
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• 2003

This paper presents a structural analysis on the rigid and deformed motion of the leaflet induced by the blood flow required in the design of a bileaflet mechanical heart valve (MHV) prosthesis. In the study on the design and the mechanical characteristics of a bileaflet mechanical heart valve, the fluid mechanics analysis on the blood flow passing through leaflets, the kinetodynamics analysis on the rigid body motion of the leaflet induced by the pulsatile blood flow, and the structural mechanics analysis on the deformed motion of the leaflet are required sequentially and simultaneously. Fluid forces computed in the previous hemodynamics analysis on the blood flow are used in the kinetodynamics analysis on the rigid body motion of the leaflet. Thereafter, the structural mechanics analysis on the deformed motion of the leaflet follows to predict the structural strength variation of the leaflet as the leaflet thickness changes. Analysis results show that structural deformations and stresses increase as the fluid pressure increases and the leaflet thickness decreases. Analysis results also show that the leaflet becomes structurally weaker and weaker as the leaflet thickness becomes smaller than 0.6 mm.

• Journal of Chest Surgery
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• 제50권6호
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• pp.467-470
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• 2017

Extensive mitral annulus calcifications are considered a contraindication for valve surgery. We describe the case of a 76-year-old female with severe mitral and aortic stenosis associated with extensive calcifications of the heart. The patient underwent an open mitroaortic valve replacement using transcatheter aortic valve implantation with an Edwards SAPIEN XT valve (Edwards Lifesciences Corp., Irvine, CA, USA) in the mitral position. The aortic valve was replaced using a stentless valve prosthesis (LivaNova S OLO; LivaNova PLC, London, UK). Postoperative echocardiography showed that the prosthetic valve was in the correct position and there were no paravalvular leaks. A bailout open transcatheter valve implantation can be considered a safe and effective option in selected cases with an extensively calcified mitral valve.

• 대한의용생체공학회:의공학회지
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• 제12권3호
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• pp.149-156
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• 1991

In this paper, fluttering behavior of mechanical bileaflet heart valve prosthesis was analyzed taking into consideration of the impact between valve plate and stopper Vibration system of the valve was modeled as a rotating system, and equations are induced by moment equilibrium equations. Lift force, drag force, gravity and buoyancy were considered as external forces acting on the valve plate/ The 4th order Runge-Kutta method was used to solve the equations. Valve plate does not come to the static equilibrium position at a stretch, but come to that position after under damping vibration. Damping ratio increases as the cardiac optput increases, and the mean damping ratio is in the range of 0.16~40.25. Fluttering frequency does not have any specific value, but varies as a function of time. It is in the range of 10~40Hz. Valve opening appears to be affected by the orientation of the of the valve relative to gravitational forces.

• Journal of Chest Surgery
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• 제46권5호
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• pp.380-382
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• 2013