• 대한의용생체공학회:의공학회지
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• 제13권2호
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• pp.87-96
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• 1992

In thIns paper, a numerical simulation of steady laminar and turbulent flow in a two dimensional model for the total artificial heart is'presented. A trlleaflet polyurethane valve was simulated at the outflow orifice while the Inflow orifice had a trileaflet or a flap valve. The finite analytic numerical method was employed to obtain solutions to the governing equations in the Cartesian coordinates. The closure for turbulence model was achieved by employing the k-$\varepsilon$-E model. The SIMPLER algo rithm was used to solve the problem in primitive variables. The numerical solutions of the slulated model show that regions of relative stasis and trapped vortices were smaller within the ventricular chamber with the flap valve at the Inflow orifice than that with the trileaflet valve. The predicted Reynolds stresses distal to the inflow valve within the ventricular chamber were also found to be smaller wlth the flap valve than with the trlleaflet valve. These resu1ts also suggest a correlation be- tween high turbulent stresses and the presence of thrombus In the vicinity of the valves in the total artificial hearts. The computed velocity vectors and trubulent stresses were comparable with previ ously reported in vitro measurements in artificial heart chambers. Analysis of the numerical solo talons suggests that geometries similar to the flap valve(or a tilting disc valve) results in a better flow dynamics within the total artificial heart chamber compared to a trileaflet valve.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1993년도 추계학술대회
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• pp.81-84
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• 1993

Artificial Heart Valve is the one of the most important artificial organ which has been implanted to many patients. The most important problems related to the artificial heart valve prosthesis are thrombosis and hemolysis. Usual method to test against this problem in vivo experiment, which is complex and hard work. Nowadays the request for In vitro Artificial Heart Valve testing system is increasing. Several papers has announced us flow pattern of Artificial Heart Valve is highly correlated with thrombosis and hemolysis. They usually gel flow pattern by LDA, it is also hard work and has narrow measuring region. In this reason we have determined to develop PTV(Particle Tracking Velocimetry). By using High-speed camera and image processing technique, flow pattern could be relatively easily obtained. Parachute and Bileaflet Artificial Heart Valve designed by SNU were testified.

• Journal of Chest Surgery
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• 제49권1호
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• pp.35-38
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• 2016

The management of recurrent tricuspid regurgitation after tricuspid valve repair in patients with Ebstein anomaly is difficult, and tricuspid valve replacement is most commonly performed in such patients. We report two cases of recurrent tricuspid regurgitation in patients with Ebstein anomaly that were successfully re-repaired using the cone technique. The cone repair technique is a useful surgical method for reconstructing a competent tricuspid valve, and can be applied in patients who have undergone previous tricuspid valve repair.

• 한국가시화정보학회지
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• 제4권1호
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• pp.47-55
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• 2006

The left ventricular filling flow is now considered as an indicator which can be used for early diagnosing of cardiovascular diseases. Because the understanding of left ventricular flow physics is critical for this purpose, the downstream flow characteristics of the artificial heart valve are investigated using particle image velocimetry (PIV) method. In this study, we investigated the wake characteristics of flows passing through three different artificial valves (St.Jude medical bileaflet mechanical valve. Bjork-Shiley monostrut mechanical valve and St.Jude medical Biocor bio valve). The downstream flow field has remarkably altered according to the different valves. SJM MHV has the flow field similar to the pulsating circular jet and BS MHV has oblique pulsating jet. SJM BHV shows the similar flow field of clinical data of normal heart.

• Journal of Chest Surgery
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• 제29권2호
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• pp.164-170
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• 1996

From January 1986 to June 1993, 12 patients Aad required reoperation: 9 had undergone mitral and 3 aortic valve replacement. Five were male and 7 female, and ages ranged from 29 to 61 years. Replacement of the prosthetic heart valve was performed at a mean interval of 98 $\pm$ 1 months after the Hrst operation. In aortic valve replacement patients the mean interval was 115 $\pm$ 2 months and in mitral valve replacement patients 98 $\pm$ 4 months. Primary tissue failure was the most frequent reason of replacement (10 patients) followed by valve thrombosis (1 patient) and prophylactic replacement (1 patient) in order. The most pronounced pathology of the failed prosthetic heart valves seen in the primary tissue failure group was calcification, perforation, shrinkage and tearing of the cusps. There was one early operative death (8.3%) due to intractable low cardiac output and acute renal failure. Eleven early survivors had successful operative results and there was no late death.

• 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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• 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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• 제19권4호
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• pp.644-662
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• 1986

Seventy cases of open heart surgery were performed in the department of Thoracic and Cardiovascular Surgery, Pusan Paik Hospital, Inje College, from Oct. 1985 to Oct. 1986. And the results were summarized as follows. 1. Among the 70 cases, there were 48 cases of congenital heart anomalies and 22 cases of acquired rheumatic valvular heart diseases. Age range of the congenital patients was 7 months to 31 years with the mean age of 10 years, and the acquired patients was 18 to 62 years with the mean age of 40 years. 2. The heart-lung machine used for cardiopulmonary bypass was Sarns 7000, 5-head roller pump, and the number and type of oxygenators were 5 of membrane type and 65 of bubble type. For all cases GIK [glucose-insulin-potassium] solution was used as cardioplegic solution for myocardial protection during operation. 3. Among the 48 congenital anomalies, there were 12 cases of ASD group, 29 of VSD group, 3 of ECD, 3 of TOF and one of PDA + MR, and to all of which the appropriate radical operations were applied. 4. Among the 22 acquired valvular diseases, there were 11 cases of mitral valve diseases [MS; 4, MSr; 3, MRs; 4], 3 cases of aortic valve diseases [AR:1, ARs;1, ASr;1], 4 cases of double valve diseases [MRs+TR; 3, MRs+ARs; 1] and 4 cases of triple valve diseases [MSr+ASr+TR; 3, MSr+Ar+TR; 1]. To all the diseased mitral and aortic valves, artificial valve replacement was applied except one [As], in which valve plication was applied. And to all the diseased tricuspid valve, DeVega annuloplasty was applied. 5. The number of replaced artificial valves were 29 in 25 patients [congenital; 3, acquire; 22]. In MVR, 6 of mechanical valves [St. Jude Medical valve; 6] and 15 of tissue valves [Carpentier-Edward valve; 11, lonescu-Shiley valve; 4] were used. In AVR, 6 of mechanical valves [St. Jude Medical valve; 6] and 2 of tissue valves [Carpentier-Edward valve; 2] were used. 6. Postoperative complications were occurred in 12 cases. Among them 11 cases were recovered with intensive cares, but one patient [VSD + Fistula of Valsalva sinus] was expired with low cardiac out put syndrome.

• Journal of Chest Surgery
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• 제18권3호
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• pp.383-390
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• 1985

108 cases of open heart surgery were done at our department in 1984. There were 58 male and 50 female patients ranging in age from 20 months to 52 years. 75 cases were congenital heart disease, and 33 cases were acquired heart disease. There were 75 congenital heart anomalies with 5 operative deaths [6.7%], consisting of 62 acyanotic cases with 2 deaths [3.2%] and 13 cases of cyanotic cases with 3 deaths [23.1]. In 33 patients of acquired valvular disease, 29 valves were implanted; 20 mitral valve replacement with 2 death [10%], 2 aortic valve replacement with 1 death [50%], 2 double valve replacement [MVR+AVR] and 2 open mitral commissurotomy plus aortic valve replacement with no death. Postoperative, Warfarin sodium was medicated with checking prothrombin time. Finally, the operative mortality was 9.2% in congenital anomaly, and 9.1% in acquired heart disease, overall mortality rate was 9.3%.

• Journal of Chest Surgery
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• 제22권6호
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• pp.996-1000
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• 1989

Open heart surgery begun at 1959 in Korea. From that time to 1979, the surgery was performed below 100 cases in a year. However,that was performed above, 1,000 cases in a year from 1981. During the recent three years, i.e., 1985, 1986, and 1987, the annual operative cases were 3614,4503, and 4906, and then the mortality rates were progressively decreased to 6.2%, 5.3 %, and 5.0 %. In these time, overall mortality rate above 1 year old was 5.0 % versus that below 1 year old 17.9 9o in congenital heart diseases. These results are statistically different between two groups. Of the valvular heart disease cases, which occupied 97 % of total acquired heart disease, individual incidence was in mitral 68 %, and aortic 28%. The operative method was mainly valve replacement. Operative mortality for valve surgery in total was 4.4 %. Until 1985, bioprosthetic valve was frequently implanted but mechanical valve has been done more frequently in these days. Coronary artery bypass graft was large portion [67 * 75 %] of open heart surgery in western, but was below 1 % in Korea. However our diet patterns have been changed. Therefore we think the incidence of coronary artery disease will be increased. So we will be familiar to this field.