• Proceedings of the KTCVS Conference
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• 1996.10a
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• pp.48-48
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• 1996

• Journal of the Korean Society for Precision Engineering
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• v.22 no.3 s.168
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• pp.154-161
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• 2005

In this study, the leaflet motion of a mechanical heart valve and the characteristics of two-dimensional transient blood flow in an elastic blood vessel have been numerically investigated by using fluid-structure interaction method. Here, blood has been assumed as a Newtonian, incompressible fluid. Pressure profiles have been used as boundary conditions at the ventricle and the aorta. As a result, closing motion of the leaflet is faster than opening one. While opening angles of leaflet grow up, vortex is detected at the sinus and backward of the leaflets. When the leaflet is fully closed, vortex is detected at the ventricle and at that moment maximum displacement of the elastic blood vessel is observed in the vicinity of the sinus region. Maximum displacement is caused in association with the blood flow that is oriented toward the elastic blood vessel.

• Journal of Chest Surgery
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• v.29 no.6
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• pp.651-654
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• 1996

Recently, we report a surgical experience of one case of acute prosthetic valve failure due to throe- bosis. The patient was 39-year old male who complained of dyspnea and orthopnea for 3 days before admission. The patient had not taken anticoagulant therapy for recent 4 months against medical ad- vice. The limitation of valve motion was revealed on echocardiography. We performed emergency reoperation with thrombectomy and prosthetic valve replacement. The patient had anuncomplicated postoperative course and have been followed up.

• Journal of Chest Surgery
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• v.34 no.1
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• pp.91-93
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• 2001

기계판막의 비구조적 기능이상은 판막 치환 후 생길 수 있는 심각한 합병증 중의 하나이다. 이러한 기계판막의 비구조적 기능이상은 일반적으로 1) pannus나 조직 혹은 봉합물질에 의한 장애 2) 치환 판막 주위의 틈 3) 부적절한 판막의 크기나 위치, 판막 삽입시의 잘못 등에 의해 생긴다. 저자들은 상대적으로 작은 판막륜을 가진 환자에서 치환 판막의 잘못된 위치로 야기된 pannus 형성에 의한 판막의 기능부전을 경험하였으며, 이 환자에 대해 pannus 제거 후 판막륜 확장술(닉스 술식, Nicks procedure)을 포함한 판막 재치환술을 성공적으로 시행하여 이를 보고하는 바이다.

• Journal of Chest Surgery
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• v.37 no.4
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• pp.328-334
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• 2004

There are only limited numbers of reports about long-term results of tricuspid valve replacement(TVR) with bioprosthetic and mechanical prostheses. We analyzed risk factors for tricuspid valve replacement and compared long-term clinical results of bioprosthetic and mechanical valves in tricuspid position. Material and Method: We reviewed 77 cases of TVR, which were performed between October 1978 and December 1996. Mean age was 38.8 15.9 years. Bioprostheses were implanted in 26 cases and mechanical prostheses were implanted in 51 cases. Result The operative mortality was 15.6% and late mortality was 12.3%. Survival for bioprosthetic and mechanical valve group at 5, 10 and 13 years was 81.3% vs. 100%, 66.1% vs. 100%, 60.6% vs. 100% (p=0.0175). Free from valve related re-operation for bioprosthetic and mechanical valve group at 5, 10 and 13 years was 100% vs. 93.9%, 100% vs. 93.9% and 58.3% vs. 93.9% (p=0.3274). Linealized incidences of valve related re-operation for bioprosthetic and mechanical valve group was 2.27 %/patient-years and 1.10 %/patient-years. Risk factor analysis showed that presence of preoperative ascites, hepatomegaly larger than 2 finger breaths, poor preoperative NYHA functional class and number of tricuspid valve replacement were risk factors for early mortality, and the use of bioprosthetic valve and number of open heart surgery were risk factors for late mortality. Conclusion: Long-term survival of mechanical valve was superior to bioprosthetic valve in tricuspid position. We recommend mechanical valve in tricuspid position if the patient can be closely followed up.

• Journal of Chest Surgery
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• v.30 no.7
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• pp.663-669
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• 1997

This is a report on the clinical outcome and hemodynamic profile of the ATSwcardiac valve prosthesis, which is a recently introduced pyrolytic carbon bileaflet prosthesis. We retrospectively reviewed the early outcome of 100 consecutive patients who underwent isolated cardiac valve replacement with the ATS(w prosthesis from October 1994 through June 1996 at our hospital. All patients were evaluated with Doppler echocardiography before discharge from the hospital. The mean age of the patients was 48.6 years(range: 2 to 74). A tota of 124 prosthesis were implanted; 71 mitral, 46 aortic, and 7 tricuspid. The two most frequently used sizes were 27 mm(40.8%) and 29 mm(35.2%) in the mitral position, and 23 mm(30.4%) and 21 mm(28.3%) in the aortic position. There was no early or late death. The total follow-up period was 950 patient-months with 99% follow-up rate. Serious late morbidity occurred in three patients; reoperation in two patients for late rupture of Sinus of Valsava in one and for endocarditis with prosthetic dehiscence in the other, and intracranial hemorrhage due to hypertension in one patient. There has been no thromboembolic complication or structural valval deterioration. In the mitral position, the average values of peak and mean transprosthetic pressure gradients and valve area calculated from pressure half time were 6.9$\pm$2.8 mmHg, 2.6$\pm$ 1.5 mmHg, and 2.7 $\pm$0.8 cm2 respectively. In the aortic position, the peak and mean pressure gradients'were 26.4 $\pm$ 15.9 mmHg and 14.2 $\pm$ 7.9 mmHg. For the mitra prostheses larger than 25-mm size, there was no significant difference among prosthetic sizes in terms of transprosthetic gradients, whereas there was a significant negative correlation between the prosthesis size and the transprosthetic gradients for the aortic valves. The peak and mean Pressere pradients were 52.2 $\pm$ 17.6 tmHg and 26.9$\pm$ 7.4 mmHg across the 19-mm aortic Prostheses, and 27.1 $\pm$ 11.9 mmHg and 13.3$\pm$6.6 mmHg across the 21-mm size. Above results can lead to the conclusion that the early clinical outcome of the ATS valve prosthesis is quite satisfactory, And the hemodynamic characteristics are comparable, if not better, with other bileaflet prostheses.

• 순환기질환의공학회:학술대회논문집
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• 2002.11a
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• pp.27-28
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• 2002

• Journal of Chest Surgery
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• v.29 no.9
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• pp.971-976
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• 1996

From March 1988 to October 1992, 201 CarboMedics cardiac valve prostheses (150 mitral, 50 aortic and 1 tricuspid) were implanted in 166 consecutive patients (mean age 38 years, male/female 66/100) by one surgical team operating on adult cardiac patients at Kyungpook University Hospital. Total follow up represen:toed 6646 patient-months (mean 40mon1hs) and follow up rate was 96%. One hundred and twenty-four patients (74.7 %) were in NYHA functional class 111 or tV preoperatively and 164 patients (98.7 %) were in class I or ll postoperatively. Hospital mortality was 4.2 % and late death was 4.2%. The actuarial survival at 78 months was 89.4%. The linearized incidence of valve related death, prosthetic valve thrombosis, anticoagulant related hemorrhage, non-structural dysfunction and reoperation was 0.72%/pt-yr, 0.18%/pt-yr, 0.18%trapt-yr, 0.18 %/pt-yr and 0. 36%/pt-yr respective y. The 78 month rates of freedom from valve related death, prosthetic valve thrombosis, anticoagulant related hemorrhage, non-structural dysfunction and reoperation were 94.9%, 99.4%, 99.4%, 98.6 % and 97.9 % respectivly. The 78 month rate of freedom from all valve related complications and deaths including hospital mortality was 90.9%. These fact suggest that the CarboMedics cardiac valve has execellent result, low incidence of valve-ie-lated complications and no structural deterioration, and long term follow up study is necessary.

• Journal of Chest Surgery
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• v.38 no.11 s.256
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• pp.761-772
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• 2005

Background: Following the implantation of heart valve prostheses, it is important to maintain therapeutic INR to reduce the risk of thromboembolism. The objective of this study was to suggest a practical dosing guideline for Korean outpatients with prosthetic heart valves managed by a pharmacist-run anticoagulation service (ACS). Material and Method: A retrospective chart review was completed for all patients enrolled in the ACS at Seoul National University Hospital from March, 1997 to September, 2000. Patients who were at least 6 months post-valve replacement and had nontherapeutic INR value (less than 2.0 or greater than 3.0) were included. The data on 688 patients (1,782 visits) requiring dosing adjustment without any known drug or food interaction with warfarin were analyzed. The amount of adjusted dose and INR changes based on the INR at the time of the event were calculated. Aortic valve replacements (AVR) patients and mitral or double valve replacement (MVR/DVR) patients were evaluated separately. Result: Two methods for the warfarin dosage adjustment were suggested: Guideline I (mg-based total weekly dose (TWD) adjustment), Guideline II (percentage-based TWD adjustment). The effectiveness of Guideline 1 was superior to Guideline II overall in patients with both AVR and MVR/DVR. Conclusion: The guideline suggested in this study could be useful when the dosage adjustment of wafarin is necessary in outpatients with mechanical heart valves.

• Journal of Chest Surgery
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• v.29 no.4
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• pp.444-448
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• 1996

Hemolytic anemia due to tiny prosthetic paravalvular leakage is one of a complication of prosthetic valve replacement. Mild Hemolysls usually occurs after aortic valve replacement with mechanical valve but rarely occurs in mitral valve position especially in case of tissue valve. Cardiac valves fabricated from biologic material are associated with a reduced incidence of hemolytic anemia. Hemolysis was reported in patients with an lonescu-Shiley bovine pericardial xenograft prosthesis in the aortic position but not in the mitral site. A 41-year-old female patient was admitted due to sudden development dark colored urine. About 10 years ago the patient was underwent MVR (Mitral Valve Re lacement) with fTmm lonescu-Shiley valve due to MR (Mitral regurgitation). Echocardiographic examination showed mild degree of mitral regurgitation with valvular thickening. However, there was no definitive evidence of paravalvular leakage. The peripheral blood smear showed nomochromic normocytic anemia, but the hematologic and urinary examination revealed severe hemolytic evidence. Mitral valve replacement with St. Jude Medical valve (27mm) was done and intraoperatively, a tiny paravalvular leakage was found which was regarded as the point of hemolysis. The hemolytic evidence completely disappeared. We are reporting a case of severe hemolytic anemia due to tiny prosthetic paravalvular leakage with a review of the literature.