• Journal of Chest Surgery
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• 제26권10호
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• pp.753-760
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• 1993

The CarboMedics valve is a bileaflet prosthesis with excellent hemodynamic characteristics, but the long term surgical experience with this valve, its durability and its biocompatibility are unknown. During a 5 year period from october 1988 to July 1993, 748 prostheses [402 mitral, 261 aortic, 58 tricuspid, 27 pulmonic] were inserted in 552 patients [mean age 40.2 years]. The operative mortality was 6.6% [37/560, 13.2% in age group below 15 years and 5.7% above 15 years]. and the main causes of death were complex congenital malformation and left ventricular failure. Follow up was totaled 1182 patient- years and mean follow up was 28.3 months/patient. No structural failure has been observed. Hemorrhage was the most frequent valve related complication[1.78% / Patient-year]. Embolism occurred at a rate of 0.93% / Patient-year. There were 5 cases of valve thrombosis [0.42% / Patient-year, two fatal]. There occurred 11 late deaths[6 valve related] and 42 valve related complications. Actuarial survival at 5 years is 97.18 0.94% and actuarial complication free survival at 5 years is 89.07 1.54%. In summary, the CarboMedics valve stands for a durable valve substitute, with low valve related complications.

• 대한기계학회논문집
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• 제19권2호
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• pp.443-450
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• 1995

An analysis of the dynamics of a mechanical monoleaflet heart valve prosthesis in the closing phase is presented. Employing the moment equilibrium principles on the occluder motion and the squeeze film dynamics of the fluid between the occluder and the guiding strut at the instant of impact, the velocity of the occluder tip and the impact force were computed. The dynamics of fluid being squeezed between the occluder and the guiding struts is accounted for by Reynold's equation. The effect of the fluid being squeezed between the occluder and the guiding strut was to reduce the velocity of the occluder tip at the instant of valve closure as well as dampen the fluttering of the occluder before coming to rest in the fully closed position. The squeeze film fluid pressure changed rapidly from a high positive value to a relatively large negative value in less than 1 msec. The results of this study may be extended for the analysis of cavitation inception, mechanical stresses on the formed elements and valve components as well as to estimate the endurance limits of the prosthetic valves.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1993년도 추계학술대회
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• pp.77-80
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• 1993

• Journal of Chest Surgery
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• 제21권5호
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• pp.889-893
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• 1988

We experienced a case of infective endocarditis of aortic valve and tricuspid valve associated with a fistula between aorta and right ventricle. The patient was 35 years old woman and showed severe congestive heart failure. Large and multiple vagetations were found on the valvular surfaces and a fistula was present between aorta and right ventricle. Probably infective endocarditis of aortic valve resulted in annular abscess and as it healed, a fistula was formed and tricuspid valve endocarditis followed. We replaced the aortic valve and tricuspid valve with St. Jude mechanical prostheses, and closed the fistula opening with suture. The postoperative course was smooth and the patient has no problems till now 4 months after operation.

• Journal of Chest Surgery
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• 제20권2호
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• pp.223-229
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• 1987

Doppler echocardiography provides valuable information regarding prosthetic heart valve function rather than structure. There are three methods of expressing the severity of mitral valve obstruction: the transvalvular pressure gradient, effective valve area, and pressure half-time. Of these, the transvalvular pressure gradient [~p] can be determined by the measurement of maximum transvalvular blood flow velocity [V] according to the modified Bernoulli`s equation [gp=4V*]. Eleven patients, who underwent mitral valve replacement with Duromedics mechanical prostheses, and 17 normal persons were investigated. There were significantly higher calculated pressure gradients in prosthetic than normal mitral valves [9.*10*2.22mmHg-vs-3.26*0.99mmHg:p<0,01], and there was a inverse relationship between pressure gradient and prosthetic valve size [11.17*0.%mmHg in size 27mm and 29mm -v- 7.38*1.12mmHg in size 31mm and 33mm; r=0.85, p<0.01] The noninvasive Doppler technique should be useful in the diagnosis of prosthetic valve obstruction.

• Journal of Chest Surgery
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• 제37권4호
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• pp.328-334
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• 2004

삼첨판막대치술의 장기 결과에 대한 연구결과는 보고된 바가 많지 않다. 이에 저자들은 삼첨판막대치술의 위험인자를 분석해 보고, 삼첨판막대치술의 장기 결과를 알고자 연구를 시행하였다. 대상 및 방법: 대상 환자들은 1978년 10월부터 1996년 12월까지 삼첨판막대치술을 시행 받은 환자 70명을 대상으로 후향적인 연구를 진행하였는데, 7명의 환자들은 2차례의 삼첨판막대치술을 시행 받아 총 77예의 삼첨판막대치슬을 시행하였다. 환자들의 평균 나이는 38.8$\pm$15.9세였으며, 26예에서는 조직판막을, 51예에서는 기계판막을 이식하였다. 결과: 수술 사망률은 15.6%였고, 만기 사망률은 12.3%였다. 5년, 10년 그리고 13년에서의 생존율은 조직판막과 기계판막이 각각 81.3% vs. 100%, 66.1% vs. 100%, 60.6% vs. 100%였다(p=0.0175).판막과 관련된 재수술이 없을 확률은 5년, 10년 그리고 13년에서 조직판막과 기계판막이 각각 100% vs. 93.9, 100% vs. 93.9% 그리고 58.3% vs. 93.9%였다(p=0,3274). 판막과 관련된 재수술을 시행할 확률은 조직판막이 2.27%/환자-년이었고, 기계판막이 1.10%/환자-년이었다. 수술 사망과 관련된 위험인자 분석상, 수술 전 복수, 간비대, NYHA class가 나쁠수록, 그리고 삼첨판막대치술을 여러 번 받는 경우가 유의한 위험인자로 분석되었고, 조직판막의 사용과 심장수술을 여러 번 받는 경우가 만기 사망과 관련된 유의한 위험인자로 분석되었다. 걸론: 기계판막을 이용하여 삼첨판막대치술을 시행한 환자들의 장기간 생존율이 조직판막을 이용한 환자들보다 우수하였다. 따라서 수술 후에 적절한 추적관찰이 가능하다면, 기계판막을 이용하여 삼첨판막대치술을 시행하는 것이 필요하리라 생각한다.

• Journal of Chest Surgery
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• 제26권9호
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• pp.677-685
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• 1993

Experience with bileaflet mechanical valve replacement at the Inha Hospital in 192 patients, operated on from June 1986 until April 1993. Two hundred fourty-one prostheses [51 Duromedics, 79 St.Jude Medical, and 111 CafboMedics]were implanted during the total 195 operations. Mitral valve replacment[MVR]was done in 113 cases, aortic valve replacement[AVR]in 34, tricuspid valve replacement[TVR]in 2, and double valve replacement[DVR]in 46 cases.Of the total patients, 63.0% were women and 37.0% were men. The mean age of the patients was 40.8 years, ranged from 14 to 67years. Overall early mortality was 9.2\ulcorner%[18 out of 195]; 9.7%[11 out of 113]for MVR, 14,7% [5 out of 34]for AVR, and 4.3%[2 out of 46]for DVR. All of the operative survors were followed over a period of one to 83 months with a mean of 37 months, for total 543 patient-years. So far, eleven patients[6.7% of the long-term survivors]were lost to follov-up after a mean postoperative follow-up of 22.8 months. There were nine late deaths; three deaths due to prostetic valve endocarditis, two due to persistent heart failure, one due to cerebral hemorrhage, one due to aortic dissection after Bentall oreration, and two sudden deaths. Actuarial survival rate at 6.9 years was 94.8%, There were seventeen valve-related complications; three prosthetic valve thromboses, three thrombembolisms, three instances of prosthetic valve endocarditis, two paravalvular leakages, and six hemorrhagic complications related to anticoagulation. The actuarial rate of freedom from all valve-related complications at 6.9years was 91.3%. There were significant decreases in the heart size postoperatively that can be demonstrated by comparison of cardio-thoracic ratios on simple chest X-ray and left ventricle dimensions on echocardiography. We conclude that this midterm follow-up shows good results in terms of hemodynamics and durability although further long-term evaluations are mandatory.

• Journal of Chest Surgery
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• 제25권6호
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• pp.661-671
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• 1992

From March 1988 to May 1991, 140 CarboMedics cardiac valve prostheses[75 mitral, 9 aortic and 28 double aortic-mitral] were implanted in 112 consecutive patients[mean age 36.7$\pm$11.6 years, male/female 48/76] by one surgical team operating on adult cardiac patients at Kyoungpook University Hospital Associated Surgical procedures were performed in 19 patients[16.9%]. Total follow up represented 2,345 patient-months[mean 22.4 months] and was 100% complete. Eighty-two patients[73%] were in NYHA functional class IIIor IV preoperatively and 102 patients [95%] were in class I or II postoperatively. Hospital[30 day] mortality was 4.4%, [3/75 mitral, 1/9 aortic, 1/28 double valve replacement] and late death was 1.7%. [1 /74 mitral, 1 /28 double valve replacement] The actuarial survival at 36 months was 94.0% after mitral, 80% after aortic, 92% after double valve replacement, and 93.2% for the total group. The linearized incidence of valve relater death, prosthetic valve thrombosis, anticoagulant related hemorrhage, and reoperation was 1.00%/pt-yr, 0.51%/pt/yr, 0.51%/pt-yr, and 0.51%/pt-yr respectively. The 36 month rates of freedom from valve replated death, thromboembolism, endocarditis, anti-coagulant related hemorrages, and reoperation were 98.75%, 99.08%, 100%, 99.04%, and 99.08% respectively. The 36 month rate of freedom from all valve related complications and deaths including hospital mortality was 90.2%. These fact suggest that the CarboMedics heart valve has excellent short-term result, low incidence of valve-related complications and valve dysfunction, and additional long term follow up study is necessary.

• Journal of Chest Surgery
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• 제33권6호
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• pp.502-506
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• 2000

Background: Anticoagulant therapy can be required during pregnancy with prosthetic heart valves. Warfarin and heparin provide real protection against thromboembolic phenomena, but they also carry serious risks for the fetus and the mother. In an attempt to identify the best treatment for pregnant women with cardiac valve prostheses who are receiving anticoagulant, we studied 19 pregnancies, the warfarin was discontinued and heparin was administered every 12 hours by subcutaneous injection in doses adjusted to keep the midinterval aPTT in the therapeutic range(at least 2-2.5 control) from the conception to the 12th week of gestation and oral antiocagulant was then administered until the middle of the third trimester in the therapeutic range(at least 2 INR), and heparin therapy was restared until delivery. Also in order to avoid an anticoagulant effect during delivery, it has been our practice to instruct women to either discontinue their heparin injections with the onset of labur or to stop heparin injections 12 hours prior to the elective induction of labour. Result: The outcome of 19 pregnancies managed with above protocol was spontaneous abortion in 3 cases, voluntary termination in 2 cases, premature delivery at 35 weeks in 1 case and delivery at full-term in 14 cases. There was no maternal morbidity and moratality and fetopathy. Conclusion: We conclude that in the second and third trimester of pregnancy, warfarin provide effective protection against thromboembolism, Oral antiocagulant therapy should be avoided in 2 weeks before delivery because of the risk of serious perinatal bleeding caused by the trauma of delivery to the anticoagulated fetus. However, the substitution of heparin at first trimester and 2 weeks before delivery reduce the incidence of complications.

• Journal of Chest Surgery
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• 제56권6호
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• pp.394-402
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• 2023

Background: The optimal choice of valve substitute for aortic valve replacement (AVR) in pediatric patients remains a matter of debate. This study investigated the outcomes following AVR using mechanical prostheses in children. Methods: Forty-four patients younger than 15 years who underwent mechanical AVR from March 1990 through March 2023 were included. The outcomes of interest were death or transplantation, hemorrhagic or thromboembolic events, and reoperation after mechanical AVR. Adverse events included any death, transplant, aortic valve reoperation, and major thromboembolic or hemorrhagic event. Results: The median age and weight at AVR were 139 months and 32 kg, respectively. The median follow-up duration was 56 months. The most commonly used valve size was 21 mm (14 [31.8%]). There were 2 in-hospital deaths, 1 in-hospital transplant, and 1 late death. The overall survival rates at 1 and 10 years post-AVR were 92.9% and 90.0%, respectively. Aortic valve reoperation was required in 4 patients at a median of 70 months post-AVR. No major hemorrhagic or thromboembolic events occurred. The 5- and 10-year adverse event-free survival rates were 81.8% and 72.2%, respectively. In univariable analysis, younger age, longer cardiopulmonary bypass time, and smaller valve size were associated with adverse events. The cut-off values for age and prosthetic valve size to minimize the risk of adverse events were 71 months and 20 mm, respectively. Conclusion: Mechanical AVR could be performed safely in children. Younger age, longer cardiopulmonary bypass time and smaller valve size were associated with adverse events. Thromboembolic or hemorrhagic complications might rarely occur.