• Journal of Chest Surgery
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• v.24 no.3
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• pp.265-270
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• 1991

Since advent of the prosthetic cardiac valve replacement, much efforts for accurate assessing value function in-vivo have been attempted. To evaluate the postoperative functional and morphological status of the replaced cardiac valve prosthesis, 33 patients with valve replacement were studied by transthoracic and transesophageal 2-dimensional echocardiac imaging as well as by color Doppler flow velocity imaging. Twenty four patients had mitral valve replacement. 6 patients had aortic valve replacement and 3 patients had both mitral and aortic valve replacement. There were 34 mechanical and 2 biological prosthesis. Comparing to transthoracic echocardiography, transesophageal approach showed transvalvular regurgitant jet flow amid the prosthetic mitral valve ring during. systole and much clear visualization of cardiac chamber behind prosthesis which could give shadowing effect to ultrasound beam. According to the quantitative grading by the length and area of mitral regurgitant flow, 24 out of 27 mitral valves revealed mild degree regurgitation considered as physiological after prosthetic bileaflet valve replacement and the other 3 valves including 2 biological prosthesis had moderate degree regurgitation which was regarded as pathologic one. 2 cases of left atrial thromboses and 1 case of paravalvular leakage which were not visible by transthoracic approach were identified by transesophageal echocardiography in patients with mitral valve replacement and patients with aortic valve replacement respectively. We conclude that in patients with prosthetic mitral valve replacement, transesophageal 2-dimensional imaging with color Doppler can suggest reliable information beyond that available from the transthoracic access even though it gives patient some discomfort to proceed.

• Journal of Chest Surgery
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• v.51 no.3
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• pp.161-166
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• 2018

Patient-prosthesis mismatch (PPM) is a controversial issue in current clinical practice. PPM has been reported to have a negative impact on patients' prognosis after aortic valve replacement in several studies, showing increased all-cause and cardiac mortality. Moreover, a close relationship has recently been described between PPM and structural valve deterioration in biological prostheses. In patients at risk for PPM, several issues should be considered, and in the current era of cardiac surgery, preoperative planning should consider the different types of valves available and the various surgical techniques that can be used to prevent PPM. The present paper analyses the state of the art of the PPM issue.

• Journal of Chest Surgery
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• v.28 no.12
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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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• v.25 no.5
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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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• v.28 no.7
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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.

• Journal of Chest Surgery
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• v.28 no.9
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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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• v.16 no.3
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• pp.265-271
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• 1983

• Journal of Chest Surgery
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• v.25 no.7
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• pp.750-755
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• 1992

We report a case of leaflet embolization of central leaflet fracture a 31mm mitral Edw-ards-Duromedics prosthesis. A leaflet was fractured to two segments, a larger one embolized to right common iliac artery and a smaller one to left femoral artery, respectively. Patient was reoperated with 29mm mitral Carbomedics prosthesis and incidentally found of smaller segment in left femoral artery at cannulation site. The embolectomy was done 15 days after cardiac operation through midline abdominal incision, Leaflet escape of a mitral Edward-Duromedics prosthesis is a rare, potentially curable mode of valve failure. After mechanical valve replacement, unexplained heart failure and acute pulmonary edema, mechanical valve failure should be suspected. Correct interpretation of clinical signs, symptoms and fluroscopy should allow early diagnosis of leaflet escape and prompt surgical therapy.

• Journal of Biomedical Engineering Research
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• v.12 no.3
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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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• v.54 no.1
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• pp.25-30
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• 2021

Background: Life-long anticoagulant therapy is mandatory for patients who undergo heart valve replacement with implantation of a mechanical prosthesis. The aim of this study was to investigate the effects of a nurse-led patient educational program concerning oral anticoagulant therapy intake after heart valve replacement surgery on patients' knowledge of important parameters of anticoagulant administration. Methods: In this single-center study, 200 patients who underwent surgical implantation of a mechanical prosthesis were divided into 2 groups. The control group received the basic education concerning oral anticoagulants, while the intervention group received a personalized educational program. Results: Personalized education was correlated with a better regulation of therapeutic international normalized ratio (INR) levels and adequate knowledge among patients. Therapeutic levels of INR were achieved in 45% of the patients during the first month, 71% in the third month, and 89% in the sixth month after discharge in the intervention group, compared to 25%, 47%, and 76% in the control group, respectively. Patients' satisfaction with the information was higher in the intervention group than in the control group. The percentage of satisfaction reached 80% for the intervention group versus 37% for the patients of the control group. Conclusion: The implementation of the nurse-led educational programs was associated with improved clinical results and increased adherence to oral anticoagulant treatment.