• Journal of Chest Surgery
• /
• v.56 no.6
• /
• pp.394-402
• /
• 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.

• Clinical and Experimental Pediatrics
• /
• v.49 no.9
• /
• pp.917-929
• /
• 2006

Over the last several decades there has been a remarkable change in the therapeutic strategy of congenital heart disease. Development of new tools and devices, accumulations of experience, technical refinement have positively affected the outcome of interventional treatment. Many procedures including atrial septostomy, balloon valvuloplasty, balloon dilation of stenotic vessel with or without stent implantation, transcatheter occlusion of abnormal vascular structure, transcatheter closure of patent arterial duct and atrial septal defect, are now performed as routine interventional procedures in many institutes. In diverse conditions, transcatheter techniques also provide complementary and additive role in combination with surgery. Intraoperative stent implantation on stenotic vessels, perventricular device insertion, and hybrid stage 1 palliative procedure for hypoplastic left heart syndrome have been employed in high risk patients for cardiac surgery with encouraging results. Transcatheter closure of ventricular septal defect has been performed safely showing comparable result with surgery. Investigational procedures such as percutaneous valve insertion and valve repair are expected to replace the role of surgery in certain group of patients in the near future. Continuous evolvement in this field will contribute to reduce the risk and suffering from congenital heart disease, while surgery will be still remained as a gold standard for significant portion of congenital heart disease.

• Journal of Chest Surgery
• /
• v.29 no.9
• /
• pp.951-958
• /
• 1996

Bet een November 1991 and December 1993, twelve patients (Male: 2, Female: 10) who had mitral valve disease without primary pulmonary disease underwent mitral valve replacement. The pulmonary function test (PFT) was performed preoperatively and postoperatively (mean, 9 months after operation). Mitral valve replacement was indicated for mitral stenosis in 9 patients and for mitral insufficiency in 3 patients. Preoperative WHh functional class were 111 in 11 patients and class rV in 1 patient. Postoperatively, ten patients (83 %) were classified into NYHA functional class 1. There was a significant decrease in cardiothoracic ratio (CTR) postoperatively (p< 0.05). The pulmonary function before operation was low compared with predicted values in vital capacity (VC) and forced mid-expiratory flow (FEF 25∼75 %). The FEF 25%-75% and maximal voluntary ventilation (MW) were low compared with predicted values postoperatively. There was no significant difference in the pulmonary function before an after op- eration. Twelve patients were divided into 2 groups according to the early postoperative NYHA functional class. In class I group, the postoperative pulmonary function was significantly improved in 6 parameters (RV, FRC, TLC, FEVI , FEVI /FVC, and FEF 25∼75%), but in class ll group, there was no significant change in the pulmonary function after operation.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.56 no.8
• /
• pp.1424-1429
• /
• 2007

This paper presents a simple and reliable one-touch type multi-immunosensing lab-on-a-chip (LOC) detecting antibodies as multi-disease markers using electrochemical method suitable for a portable point-of-care system (POCS). The multi-stacked LOC consists of a PDMS space layer for liquids loading, a PDMS valve layer with 50 im in height for the membrane, a PDMS channel layer for the fluid paths, and a glass layer for multi electrodes. For the disposable immunoassay which needs sequential flow control of sample and buffer liquids according to the designed strategies, reliable and easy-controlled on-chip operation mechanisms without any electric power are necessary. The driving forces of sequential liquids transfer are the capillary attraction force and the pneumatic pressure generated by air bladder push. These passive fluid transport mechanisms are suitable for single-use LOC module. Prior to the application of detection of the antibody as a disease marker, the model experiments were performed with anti-DNP antibody and anti-biotin antibody as target analytes. The flow test results demonstrate that we can control the fluid flow easily by using the capillary stop valve and the PDMS check valves. By the model tests, we confirmed that the proposed LOC is easily applicable to the bioanalytic immunosensors using bioelectrocatalysis.

• Journal of Chest Surgery
• /
• v.17 no.2
• /
• pp.223-230
• /
• 1984

Since January 1977 to the end of September 1982, total 60 Ionescu-Shiley pericardial xenograft heart valves were implanted for valve replacement in 50 patients at the Han Yang University Hospital. The operative procedures were as follow: Mitral valve replacement [MVR] in 25 patients, Mitral valve replacement [MVR] and Tricuspid valve [TV] annuloplasty in 7 patients, Aortic valve replacement [AVR] in 8 patients, Aortic valve replacement [AVR] and Mitral valve replacement [MVR] in 8 patients. Aortic valve replacement [AVR] and Mitral valve replacement [MVR] and Tricuspid valve [TV] annuloplasty in 2 patients. To evaluate the immediate hemodynamic changes after valve replacements, the pressures of each cardiac chamber and ulmonary artery were checked before and after valve replacement on the operation table. Right ventricle [RV] pressure was decreased from 52.09\ulcorner6.71 to 45.57\ulcorner5.03 mmHg, Pulmonary artery [PA] pressure was decreased from 45.97\ulcorner2.69 to 41.00\ulcorner3.99 mmHg, and Left atrium [LA] pressure was decreased from 30.33\ulcorner13.02 to 22.76\ulcorner.97 mmHg before and after valve replacement. In MVR group, RV pressure was decreased from 49.17\ulcorner7.89 to 43.14\ulcorner4.14 mmHg, PA pressure was decreased from 44.67\ulcorner3.18 to 38.67\ulcorner2.85 mmHg, and LA pressure was decreased from 31.46\ulcorner13.47 to 21.91\ulcorner.17 mmHg. In AVR group, RV pressure was decreased from 53.0\ulcorner7.44 to 44.71 \ulcorner3.24 mmHg, PA pressure was decreased from 34.83\ulcorner0.73 to 31.86\ulcorner.36 mmHg, and LA pressure was not changed. In double valve replacement [MVR and AVR] group, RV pressure was decreased from 57.50\ulcorner3.82 to 42.50\ulcorner.80 mmHg, PA pressure was decreased from 51.17\ulcorner1.42 to 43.33\ulcorner4.53mmHig, and LA pressure was decreased from 34.33\ulcorner2.09 to 25.50\ulcorner0.21 mmHg. But in the group where MVR and TV annuloplasty were performed, preoperative RV and PA pressure were markedly increased and no pressure decrease in RV and PA noticed after valve replacement. This study shows good immediate postoperative hemodynamic results after valve replacement using Ionescu-Shiley xenograft valve except in the cases of MVR and TV annuloplasty and advanced disease with pulmonary hypertension.

• Journal of Chest Surgery
• /
• v.22 no.6
• /
• pp.1025-1035
• /
• 1989

Since we first performed open heart surgery on December 30, 1986, 126 cases were operated on up to August 31, 1989. Among the 126 cases, 65 cases were congenital heart disease of which 63 were acyanotic disease, and 61 cases were acquired heart disease, most of which were valvular heart disease. The age distribution of congenital heart disease was from 1 years 2 months to 48 years, and males had a slightly higher incidence. The age of acquired heart disease was from a minimum of 15 years to a maximum of 68 years, and the male to female ratio was 1;1.5. Midsternotomy was performed in all cases, and the aortic cannula was inserted through ascending aorta and the venous cannula inserted into the SVC and IVC through the right atrium. Vent was inserted through the right superior pulmonary vein. Cardioplegia solution was used in all cases; it was composed of sodium bicarbonate 3.5 ampule, KCL 14 mEq, 2% lidocaine 2.5 ml, 20 % albumin 50 ml and heparin 1000 units mixed to 950 ml with Hartman solution, and was made to 4oC and infused 10 ml per Kg every 20 minutes. The congenital heart disease had a variety of VSD in 32 cases, ASD 23 cases, PS 6 cases, PDA 2 cases, and one case each of Ebsteins anomaly and tricuspid atresia. The operations performed for acquired heart disease were 4 cases of OMC, 33 cases of MVR, and 5 cases of AVR, and 1 case of AVR with CABG. DVR was perfomed in 13 cases, and triple valve replacement was done in 1 case. Other than these, excision of LA myxoma was 2 cases, and repair of traumatic VSD and removal of a pulmonary embolism were one case each. The surgical mortality was 5 cases[4%], all of which occurred in valve replacement cases. Follow-up study revealed 2 late deaths. One died after a traffic accident and one died due to sepsis after he had received a gastrectomy for ulcer bleeding. The remaining patients were in good condition.

• Journal of Chest Surgery
• /
• v.55 no.6
• /
• pp.435-441
• /
• 2022

Background: This study aimed to evaluate the impact of the treatment modality on post-procedural acute kidney injury (AKI) and other clinical outcomes in patients with advanced chronic kidney disease who underwent surgical or transcatheter aortic valve replacement (AVR). Methods: A total of 147 patients with advanced chronic kidney disease (stage 3 to 5) who underwent isolated surgical AVR (SAVR group; n=70) or transcatheter AVR (TAVR group; n=77) were retrospectively studied. Postprocedural AKI was defined according to the RIFLE definition (an acronym corresponding to the risk of renal dysfunction, injury to the kidney, failure of kidney function, loss of kidney function, and end-stage kidney disease). Factors associated with postoperative complications and mortality were analyzed using multivariable logistic regression models and Cox proportional hazard models. Results: Postprocedural AKI occurred in 17 (24.3%) and 6 (7.8%) patients in the SAVR and TAVR groups, respectively (p=0.006). Multivariable analyses demonstrated that the SAVR group had higher risks of AKI (odds ratio [OR], 5.63; 95% confidence interval [CI], 1.85-17.73; p=0.002) and atrial fibrillation (OR, 16.65; 95% CI, 4.44-62.50; p<0.001), whereas the TAVR group had a higher risk of permanent pacemaker insertion (OR, 5.67; 95% CI, 1.21-26.55; p=0.028). The Cox proportional hazard models showed that the occurrence of AKI, contrary to the treatment modality, was associated with overall survival. Conclusion: In patients with chronic kidney disease, the risk of postprocedural AKI might be higher after SAVR than after TAVR.

• Journal of Chest Surgery
• /
• v.50 no.4
• /
• pp.255-262
• /
• 2017

Background: Transcatheter aortic valve replacement (TAVR) has been suggested as a less invasive treatment for high-risk patients with aortic valve disease. I n this study, we compared the outcomes of conventional surgical aortic valve replacement (AVR) and TAVR in elderly patients aged over 80. Methods: A total of 108 patients aged 80 years or older who underwent isolated AVR (n=35) or TAVR (n=73) from 2010 through 2015 at Asan Medical Center were identified. Early and late clinical outcomes, including echocardiographic findings, were evaluated in both groups. The mean follow-up duration was $766.4{\pm}528.7days$ in the AVR group and $755.2{\pm}546.6days$ in the TAVR group, and the average timing of the last follow-up echocardiography was at $492.6{\pm}512.5days$ in the AVR group and $515.7{\pm}526.8days$ in the TAVR group. Results: The overall early mortality was 2.8% (0 of 35, 0% in the AVR group vs. 3 of 73, 4.1% in the TAVR group). Permanent pacemaker insertion was significantly more common in the TAVR group (p=0.010). Renal failure requiring dialysis and new-onset atrial fibrillation was more frequent and the length of hospital stay was longer in the AVR group; however, this difference did not reach statistical significance. In the TAVR group, 14 patients (19.2%) were rehospitalized due to cardiac problems, and 13 patients (17.8%) had developed significant paravalvular leakage by the time of the last follow-up echocardiography. Conclusion: TAVR could be a good alternative to conventional surgical AVR in elderly patients. However, TAVR has several shortcomings, such as frequent significant paravalvular leakage or readmission, which should be considered in decision-making.

• Clinical and Experimental Pediatrics
• /
• v.59 no.11
• /
• pp.446-450
• /
• 2016

Purpose: Generally, aspirin is used as a protective agent against thrombogenic phenomenon after pulmonary valve replacement (PVR) using a bioprosthetic valve. However, the appropriate duration of aspirin use is unclear. We analyzed the impact of postoperative duration of aspirin use on the longevity of bioprosthetic pulmonary valves in patients who underwent repair for congenital heart diseases. Methods: We retrospectively reviewed the clinical data of 137 patients who underwent PVR using a bioprosthetic valve between January 2000 and December 2003. Among these patients, 89 were included in our study and divided into groups I (${\leq}12$ months) and II (>12 months) according to duration of aspirin use. We analyzed echocardiographic data from 9 to 11 years after PVR. Pulmonary vale stenosis and regurgitation were classified as mild, moderate, or severe. Results: The 89 patients consisted of 53 males and 36 females. Their mean age was $14.3{\pm}8.9$ years (range, 2.6-48 years) and body weight was $37.6{\pm}14.7kg$ (range, 14-72 kg). The postoperative duration of aspirin use was $7.3{\pm}2.9$ months in group I and $32.8{\pm}28.4$ months in group II. However, no significant difference in sex ratio, age, body weight, type of bioprosthetic valve, and number of early redo-PVRs. In the comparison of echocardiographic data about 10 years later, no significant difference in pulmonary valve function was found. The overall freedom rate from redo-PVR at 10 years showed no significant difference (P=0.498). Conclusion: Our results indicated no benefit from long-term aspirin medication (>6 months) in patients who underwent PVR with a bioprosthetic valve.

• Journal of Chest Surgery
• /
• v.23 no.4
• /
• pp.617-621
• /
• 1990

A heart supplies blood of about 15, 000 liters to each human organ in a day. A normal function of heart valves is necessary to accomplish these enormous work of heart. The disease of heart valve develops to a narrowness of a closure, resulting in an abnormal circulation of blood. In an attempt to eliminate the affliction of heart valves, the operative method to replace with artificial heart valves has developed and saved numerous patients over past 30 years. This replacement operation has been performed since early 1960`s in Korea, but all the artificial heart valves used are imported from abroad with very high costs until recent years. New artificial heart valves have been developed in Korea Advanced Institute of Science and Technology since early 1980`s. The first developed valve was designed with a free-floating pyrolytic carbon disk that is suspended in a titanium cage. The design of the valve was tested in vitro, and in animals in 1987. The results from this study was that the eccentrically placed struts creates a major and minor orifice when the disc opens and stagnation of flow in the area of the minor orifice has led to valve thrombosis. In this work, the design of the valve was changed from a single - leaflet valve to double - leaflet one in order to resolve the problems observed in the first - year tests. Morphological and hemodynamic studies were made for the newly designed valves through the in vitro and in vivo tests. The design and partial materials of the artificial heart valve was improved comparing with first - year`s model. The disc in the valve was modified from single - leaflet to bi - leaflet, and the material of the cage was changed from titanium metal to silicon - alloyed pyrolytic carbon. A test was made for the valve in order to examine its mechanical performance and stability. Morphological and hemodynamic studies were made for the valve that had been implanted in tricuspid position of mongrel dogs. All the test animals were observed just before the deaths. A new artificial heart valve was designed and fabricated in order to resolve the problems observed in the old model. The new valve was verified to have good stability and high resistance to wear through the performance tests. The hemodynamic properties of the valve after implantation were also estimated to be good in animal tests. Therefore, the results suggest that the newly designed valve in this work has a good quality in view of the biocompatibility. However, valve thrombosis on valve leaflets and annulus were found. This morphological findings were in accordance with results of surface polishing status studies, indicating that a technique of fine polishing of the surface is necessary to develop a valve with higher quality and performance.