• Journal of Chest Surgery
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• v.41 no.4
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• pp.430-438
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• 2008

Background: All the patients with mechanical valves require warfarin therapy in order to prevent them from developing thromboembolic complications. According to the ACC/AHA practice guidelines, after AVR with bileaflet mechanical prostheses in patients with no risk factors, warfarin is indicated to achieve an INR of 2.0 to 3.0. After MVR with any mechanical valve, warfarin is indicated to achieve an INR of 2.5 to 3.5. But in our clinical experience, bleeding complications (epistaxis, hematuria, uterine bleeding, intracerebral hemorrhage etc.) frequently developed in patients who maintained their INR within this value. So, we retrospectively reviewed the patients with bileaflet mechanical heart valve prosthesis and we determined the optimal anticoagulation value. Material and Method: From January 1984 to February 2007, 311 patients have been followed up at a national medical center. We classified the AVR patients (n=60) into three groups as follows: an INR from 1.5 to 2.0 in Group I, an INR from 2.0 to 2.5 in Group II and an INR from 2.5 to 3.0 in Group III. We classified the MVR (n=171) and DVR (n=80) patients into four groups as follows: an INR from 1.5 to 2.0 in Group I, an INR from 2.0 to 2.5 in Group II, an INR from 2.5 to 3.0 in Group III and an INR from 3.0 to 3.5 in Group III. We compared the groups for their thromboembolic and bleeding complications by means of the Kaplan Meier method. Result: In the AVR patients, 2 thromboembolic complications and 4 bleeding complications occurred and the log rank test failed to identify any statistical significance between the groups for thethromboembolic complication rate, but groups I and II had lower bleeding complication rates than did group III. Thirteen thromboembolic complication and 15 bleeding complication occurred in the MVR and DVR patients, and the log rank test also failed to identify statistical significance between the groups for the thromboembolic complication rate, but groups I and II had lower bleeding complication rates that did groups III and IV. Conclusion: The thromboembolic complication rate was not statistically different between groups I and II and groups III and IV, but the bleeding complication rates of groups I and II were lower than those of groups III and IV. So this outcome encouraged us to continue using our low intensive anticoagulation regime, that is, an INR of 1.5 to 2.5.

• Journal of Chest Surgery
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• v.37 no.7
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• pp.559-569
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• 2004

The CarboMedics mechanical valve has been reported to show acceptable valve-related complication rates. The aim of this study is to evaluate our clinical experience with the CarboMedics valve. Material and Method: Between August 1988 and September 1999, we implanted 1,144 CarboMedics valves in 850 patients (aortic 179; mitral 385; double-valve 234; tricuspid 52). The mean age was 44.5 $\pm$ 12.5 years. Follow-up was completed in 95.2% and median follow-up period was 7.9 years (6753 patient-years). Result: The overall hospital mortality rate was 3.4% and the mortality rate for each group was 1.7% for aortic group, 2.6% for mitral group, 4.7% for double-valve group, and 9.6% for tricuspid group, Tricuspid group showed significantly higher mortality rate than aortic and mitral group (p〈0.05). The actuarial survival at 10 years was 87.1 $\pm$ 2.6%, 88.9 $\pm$ 1.7%, 82.4 $\pm$ 2.9%, and 77.5 $\pm$ 7.0% for aortic, mitral, double, and tricuspid valve group, respectively. Age and tricuspid valve replacement were significant risk factors for long-term survival in multivariate analysis (p 〈 0.05). Freedom from valve thrombosis at 10 years was 99.4 $\pm$ 0.6%, 98.2 $\pm$ 0.8%, 99.2 $\pm$ 0.8%, and 87.6 $\pm$ 0.5% for aortic, mitral, double and tricuspid valve group. Tricuspid valve group showed significantly higher rate of valve thrombosis (p 〈 0.05). Conclusion: Long-term results of our experience demonstrated that CarboMedics valve showed acceptable incidence of valve-related complications. However, tricuspid valve replacement showed higher rate of early mortality and valve thrombosis than other valve replacement groups.

• Proceedings of the KTCVS Conference
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• 1995.10a
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• pp.49-49
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• 1995

• Proceedings of the KTCVS Conference
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• 1993.06a
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• pp.77-77
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• 1993

• Journal of Chest Surgery
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• v.36 no.5
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• pp.321-328
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• 2003

Background: The St. Jude Medical prosthesis is one of the popularly used artificial prosthesis, therefore the National Medical Center reports the long-term clinical results of patients who underwent prosthetic valve replacement with St. Jude medical valve for 18 years. Material and Method: Between January, 1984 and June, 2002, a series of 163 consecutive patients who had Implanted St. Jude prosthesis at the National Medical Center were reviewed. Mean age was 42.9$\pm$15.1 years and male to female ratio was 69:94. The operative procedure comprised of 87 MVR, 30 AVR, 45 DVR, and 1 TVR. The reoperative procedure comprised of 21 MVR, 2 AVR, and 14 DVR. Follow-up rate was 96.9%, and cumulative follow-up was 823.8 patient-years. Result: Early mortality rate was 7.9% (13 patients), late mortality rate was 8.7% (13 patients) and late mortality due to valve related complication was 47% (7 patients). Actual survival rate at 10 and 18 years were 91.7$\pm$2.1% and 91.0$\pm$1.9%. Linearized Incidence was as follows: thromboembolism, 1.09%/ patient-year; anticoagulant related hemorrhage, 0.36%/patient-year; valve thrombosis, 0.24%/patient-year; paravalvular leakage, 0.12%/patient-year; and prosthetic bacterial endocarditis, 0.12%/patient-year linearized incidence of over all valve related complication was 1.94%/patient-year. Freedom from valve related complication at 10 and 18 years were 89.1$\pm$3.3% and 88.4$\pm$3.9%. Freedom from valve related death at 10 and 18 years were 95.1$\pm$1.2% and 95.1$\pm$1.0%. Valve related complication was related the age of patient, especially anticoagulant related hemorrhage was more common in patients over 60 years of age. Valve related complication, death were higher in DVR than AVR or MVR, and valve related death was higher in reoperation. There was no relationship between valve related complication or death and implant valve of size. Conclusion: The long-term clinical results of patients implanted with St. Jude Mechanical prosthesis was quite satisfactory with a low incidence of valve related complication and mortality.

• Journal of Chest Surgery
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• v.37 no.4
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• pp.369-372
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• 2004

Acute myocardial infarction due to coronary occlusion by emboli originating from the prosthetic valve thrombosis is very rare but fatal disease which needs immediate diagnosis and urgent treatment. We report a case of acute myocardial infarction after left anterior descending embolic occlusion in whom had previous mitral valve replacement. Redo valve replacement following the interventional catheterization and anti platelet therapy lead to successful results.

• Journal of Chest Surgery
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• v.22 no.4
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• pp.677-679
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• 1989

Recently, we have experienced a case of acute thrombotic obstruction of the St. Jude Medical cardiac valve in the mitral position of the Heart. We will discuss about the incidence, recognition and preventive measurement of the thrombotic St. Jude Medical valve with the review of literatures.

• Journal of Chest Surgery
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• v.39 no.12 s.269
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• pp.891-899
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• 2006

Background: This study is to evaluate the safety of ATS valve by examining the clinical results of ten-years experience. Material and Method: From July 1995 to March 2005, we reviewed 305 patients with ATS valve implantation. Mean age was $49.8{\pm}11.7$ years and 140(45.6%) males were included. Etiologies were rheumatic diseases in 207 cases(67.4%), degenerative changes in 57 cases(18.6%), valve dysfunction in 23 cases(7.5%) and infective endocarditis in 14 cases(4.6%). AVR was performed in 72 patients(23.5%), MVR in 156 patients (50.8%), DVR(AVR+MVR) in 63 patients(20.5%) and TVR in 16 patients(5.2%). Result: There were 9 operative mortalities(2.9%). Follow up period was $56.5{\pm}34.0(0{\sim}115)$ months and 96.4% patients were followed up with 9 late deaths. Five and ten years survival rates were $94.9{\pm}1.3%,\;91.2{\pm}2.3%$ using Kaplan-Meier's methods. Valve related event free survival rates in 5 and 10 years were $90.8{\pm}2.0%$ and $86.9{\pm}3.2%$. There were 16 anticoagulation-related hemorrhages, 6 thromboembolisms, 3 prosthetic valve endocarditis and 1 paravalvular leakage. NYHA class improved after operation(p<0.05). Postoperative echocardiography showed significant decrease in LA size, LVEDD and IVESD(p<0.01). Patients with 19 and 21 mm valve showed significantly higher transvalvular pressure gradient in aortic position(p<0.001, p<0.001). Conclusion: ATS valve showed good hemodynamic results with few valve related complications and thus can be used with acceptable risk.

• 유체기계공업학회:학술대회논문집
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• 2002.12a
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• pp.504-512
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• 2002

Bileaflet mechanical valves have the complications such as hemolytic and thromboembolic events, leaflet damage, and leaflet break. These complications are related with the fluid velocity and shear stress characteristics of mechanical heart valves. This fact makes clear the importance of determining the fluid velocity and shear stress characteristics of mechanical heart valves, and requires a detailed understanding of these system properties and further substantial research. The first aim of current study is to introduce fluid-structure interaction method for calculation of unsteady and three-dimensional blood flow through bileaflet valve and leaflet behavior interacted with its flow, and to overcome the shortness of previous studies, where the leaflet motion has been ignored or simplified, by using FSI method. To accomplish this goal, a finite volume computational fluid dynamics code and a finite element structure dynamics code have been used concurrently to solve the flow and structure equations, respectively, to investigate the interaction between the blood flow and leaflet. Physiologic ventricular and aortic pressure waveforms were prescribed as flow boundary conditions. The interaction of aortic flow and valve motion were computed.

• Journal of Chest Surgery
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• v.29 no.10
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• pp.1090-1094
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• 1996

From February 1980 to September 1995, 31 children between 2 months and 15 years of age with mitral valve disease have undergone mitral valve replacement(MVR) at Yonsei Cardiovascular Center and com- plete follow-up has been obtained on 28 patients. There were 10 males and 18 females whose weight ranged from 4.9kg to 56kg. Two patients died early postopeiatively and the overall hospital mortality rate was 7.1%. These two were infants but there were no statistically significant difference in overall mortality among the age groups(p=0.13). The valve related complication rate was 57.1% in children younger than 5 years of age, which showed higher complication rate compared to older patients(p< 0.05). The bioprosthetic valve have been applied in 7 patients, and its 5-year valve failure-free survival rate was 50% . No mechanical valve failu e had occurred in 21 patients. In considering high re-replacement rate of bioprosthetic valve, mechanical valve is recommended despite its possibility of bleeding and thromboembolic complications. However, the consequences of increasing body size and long-term interposition of a rigid prosthesis in a growing heart will require second valve replacement. En conclusion, mitral valve replacement can be performed tilth satisfactory long-term survival in children, although younger mean age of the children has an important influence on early mortality and com- plication rate. And therefore mitral valve replacement in children younger than 5 years of age needs special consideration.