• Journal of Chest Surgery
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• v.30 no.5
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• pp.479-485
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• 1997

We investigated changes of the size of neoaortic annulus, root, and aortic anastomosis after arterial switch operation for complete transposition of the great arteries performed in infancy. A total of 23 patients were included in this study. Age ranged from 6 to 153 days. Body weight averaged 3.9$\pm$0.8kg and 17 patients were male. The preoperative angiocardiographic dimensions of the pulmonary annulus, the pulmonary root, and the sinotubular junction, standardized to the diameter of descending aorta at the level of diaphragm, were compared to the size of postoperative measurements of the neoaortic annulus, the neoaortic root, and the aortic an stomosis at a mean interval of 17.2$\pm$ 9.4 months. Mean dimensions of the neoaortic annulus and the neoaortic root were significantly increased postoperatively(n=23, annulus; p<0.01, root; p<0.01), however, those of the aortic anastomosis did not reveal significant change(n=23, p=0.06). There were no significant differences in changes of diameters of the neoaortic annulus, the root, and the aortic anastomosis between patients with(n=8) and without(n=15) postoperative neoaortic regurgitation(annulus; p=0.32, root; p=0.29, anastomosis; p=0.86). Postoperative dimensions of the neoaortic root and annulus between patients with ventricular septal defect(n: 10) and without ventricular septal defect(ni 13) were not significantly changed compared to the preoperative measurements(annulus; p=0.09, root; p=0.07) but mean diameters of the aortic anastomosis decreased significantly after operation in patients with ventricular septal defect(p=0.04). This study revealed that the site of the aortic an stomosis grows in proportion to patient's somatic growth after arterial switch operation. Although we could not demonstrate the relation between the aortic root dilatation and the postoperative neoaortic regurgitation in this study, a continuous close follow-up might be necessary to detect a possible progression of the aortic root dilatation and the resulting significant aortic valve regurgitation.

• Clinical and Experimental Pediatrics
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• v.46 no.2
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• pp.154-161
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• 2003

Purpose : The prognosis of patients with corrected transposition of the great arteries(C-TGA) is variably affected by associated intracardiac defects, systemic right ventricular function, tricuspid valve competence, and conduction disturbances. This study aims to evaluate the importance of those factors at mid-term follow-up. Methods : Medical records of 94 patients(males 58, females 36; mean age at last follow-up, $12{\pm}9$ years; mean follow-up duration, $9{\pm}6.4$ years) diagnosed between January 1980 and May 2002 at Seoul National University Children's Hospital were studied retrospectively. Results : Among 94 patients, operations were performed in 72 patients(classic operations in 55; double switch operations in 17). Among prognostic factors including associated intracardiac anomalies(at least moderately severe tricuspid insufficiency(TI), ventricular septal defect, pulmonary stenosis and pulmonary atresia), intracardiac operation and complete atrioventricular block, TI was the only significant factor for death(P=0.001), and in turn, Ebstein anomaly and high grade atrioventricular block predicted TI. 20-year survival without TI was 77%, but only 35% with TI(P=0.0002); excluding perioperative death, the 20-year survival rates with and without TI were 48% and 87% respectively(P=0.008). There was no statistical difference in 20-year survival rate or association with TI between classic and double switch operation. Conclusion : TI was the major prognostic factor for C-TGA and was associated with Ebstein anomaly and high grade atrioventricular block at mid-term follow-up. Long-term follow-up is required to evaluate other factors, including double switch operations and associated intracardiac defects more exactly.

• Journal of Chest Surgery
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• v.40 no.12
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• pp.825-830
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• 2007

Background: Minimally invasive cardiac surgery appears to offer certain advantages such as earlier postoperative recovery and a greater cosmetic effect than that achieved through conventional sternotomy. However, this approach has not yet been widely adopted in Korea to replace complex open heart surgery such as mitral valve reconstruction. This study compared the results of robot assisted minimally invasive mitral valve repair with those results of conventional sternotomy. Material and Method: From December 1993 to December 2005, 520 consecutive patients underwent mitral valve reconstruction for mitral regurgitation in our institution. These patients were subdivided according to those whose surgery used the conventional sternotomy approach (Group S, n=432) and those who underwent minimally invasive right anterior thoracotomy (Group M, n=88); we then compared the clinical results of both groups. When we performed minimally invasive right thoracotomy, we used a robot (AESOP 3000) and made an incision less than 5 cm. Result: Our study patients in both groups were similar for their age, gender and preoperative ejection fraction. There were two hospital mortalities in group S. but there was no mortality in the group M patients. Significant reductions in the ICU stay and the postoperative hospital stay were observed in the group M patients compared with the group S patients. However, both the bypass time and the aortic cross-clamp time were significantly longer in the group M patients. In spite of the confined incision in the group M patients, there were no limitations on the mitral valve repair techniques. There was a similar frequency of postoperative significant residual mitral regurgitation in both groups. Conclusion: In this study, the minimally invasive mitral valve repair showed comparable early results with the conventional sternotomy patients. We will now need long-term follow-up of these patients who underwent minimally invasive mitral valve repair, but we anticipate that based on the results of this study, we will begin to routinely perform minimally invasive cardiac surgery as out primary approach for mitral valve reconstruction.

• Journal of Chest Surgery
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• v.42 no.1
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• pp.28-33
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• 2009

Background: Functional tricuspid regurgitation (TR) greater than or equal to a mild grade requires tricuspid valvuloplasty, and tricuspid valvuloplasty with ring annuloplasty has shown good outcomes. We report here on our early experience with the Edwards $MC^3$ annuloplasty system (Edwards LifeSciences, Irvine, CA). Material and Method: From November 2004 to July 2006, 72 patients with tricuspid annular dilatation and TR underwent tricuspid valvuloplasty with using the Edwards $MC^3$ annuloplasty ring. Sixty-eight patients were operated on via median sternotomy and four patients were operated on using robotic assisted minimal invasive thoracotomy. The patient population included 21 males and 51 females and their mean age was $53.9{\pm}12.3$. The mean grade of TR, as assessed by the preoperative echocardiography, was $2.2{\pm}1.0$. The mean NYHA functional class was $3.1{\pm}0.8$. The mean left ventricular ejection fraction was $57.0{\pm}9.9$%. Result: The TR and NYHA functional class, as assessed by postoperative echocardiography, was significantly reduced (mean=$0.4{\pm}0.6$ and $2.0{\pm}0.7$, respectively p<0.001). There was one case of hospital mortality. One patient required permanent pacemaker insertion for third degree atrioventricular block. Conclusion: Our study shows that the Edwards $MC^3$ remodeling ring is easy to implant and it effectively corrects functional TR with excellent clinical and echocardiographic outcomes. Further follow-up and a larger clinical series are required to establish the long-term stability of this repair technique.

• Journal of Chest Surgery
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• v.43 no.4
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• pp.364-374
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• 2010

Background: We assessed the early and mid-term results of the modified Norwood procedure for first-stage palliation of hypoplastic left heart syndrome (HLHS) and its variants to identify the risk factors for hospital mortality. Material and Method: Between March, 2003, and December, 2009, 23 patients (18 males and 5 females) with HLHS or variants underwent the modified Norwood procedure. The age at operation ranged from 3 to 60 days (mean, $11.7{\pm}13.2days$) and weight at operation ranged from 2.2 to 4.8 kg (mean, $3.17{\pm}0.52kg$). We used a modified technique that spared the anterior wall of the main pulmonary artery in 20 patients. The sources of pulmonary blood flow were RV-PA conduit in 15 patients (group I) and RMBTS in 8 (group II). Follow-up was completed in 19 patients (19/20, 95%) in our hospital (mean $26.0{\pm}22.8months$). Result: Early death occurred in 3 patients (3/23, 13%), of whom 2 had TAPVC. Fourteen patients underwent subsequent bidirectional cavopulmonary connection (BCPC, stage 2) and seven underwent the Fontan operation (stage 3). Three patients died between stages, 2 before stage 2 and one before stage 3. The estimated 1-year and 5-year survival rates were 78% and 69%, respectively. On multivariate regression analysis, aberrant right subclavian artery (RSCA) and associated total anomalous pulmonary venous connection (TAPVC) were risk factors for hospital mortality after stage 1 Norwood procedure. Conclusion: HLHS and its variants can be palliated by the modified Norwood procedure with low operative mortality. Total anomalous pulmonary venous connection adversely affects the survival after a stage 1 Norwood procedure, and interstage mortality rates need to be improved.

• Journal of Chest Surgery
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• v.37 no.1
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• pp.56-63
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• 2004

Background: Patch angioplasty is an alternative surgical procedure to coronary artery bypass grafting (CABG) for left main coronary ostial stenosis. The purpose of this study is to evaluate the outcome of patch angioplasty by analyzing the short-term and long-term results. Material and Method: Twenty nine patients who had undergone patch angioplasty due to left main coronary ostial stenosis between July 1991 and May 2003 were enrolled in the study. The mean age of the patients was 53.1 $\pm$12.5 years. There were 8 males and 21 females, and there were 12 female patients who had no risk factor for atherosclerosis. Twenty six (89.7%) patients showed isolated coronary ostial stenosis without any distal coronary lesion. Result: Anterior approach was used in 28 patients and superior approach was used in one patient. Transsection of the main pulmonary artery was used in one patient. Concomitant CABG was performed in 4 patients because of left anterior descending artery lesions in 3 patients and unstable postoperative hemodynamic status in one patient. Hospital mortality had occurred in one patient (3.4%) and late mortality also in one patient, therefore the overall 5 year survival rate was 91.2$\pm$6.1%. Seventeen coronary angiographies were done in 13 patients (44.8%) postoperatively. Two distal patch stenoses, 1 proximal patch stenosis, and 1 new right coronary ostial lesion were identified and 3 percutaneous interventions and 1 CABG were performed during the follow-up period. The overall 5 year freedom from reintervention rate was 82.4 $\pm$ 8.5%. Aortic regurgitation less than grade 1 had developed postoperatively in 4 patients and one patient showed progression of preexisting aortic regurgitation from grade II to III. Conclusion: Patch angioplasty in left main coronary ostial lesion showed acceptable short-term and long-term results in this study. However, restenosis at the patch anastomosis site and aortic regurgitation should be carefully investigated during the follow-up period.

• Tuberculosis and Respiratory Diseases
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• v.46 no.4
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• pp.500-511
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• 1999

Background: Noninvasive positive pressure ventilation (NPPV) using facial or nasal mask have been widely used for several years in stable patients with chronic neuromuscular disease or central alveolar hypoventilation, and recently have been tried in patients with acute respiratory failure. In a few studies, NPPV was also used to rescue the patients with post-extubation respiratory failure. However, yet it has not been adopted as a weaning method in patients on long-term mechanical ventilation. So we performed this prospective clinical study to evaluate the usefulness of NPPV as a weaning method after removing endotracheal tube intentionally in patients on long-term mechanical ventilation. Method: Twelve patients who had been on invasive mechanical ventilation over 10 days were enrolled and 14 trials of NPPV were done. All had failed at least one weaning trial and showed ventilator dependence(pressure support requirement between 8-15cm $H_2O$, and PEEP requirement between 5-10cm $H_2O$), so tracheostomy was being considered. After removing the endotracheal tube, NPPV was applied using facial mask. Respiratory rate, arterial blood gas, pressure support level, and PEEP level were monitored just before intended extubation, at 30 minutes, 1 to 6, 6 to 12, 12 to 24 hours, 2nd day, and 3rd day following initiation of NPPV, and just before weaning from NPPV. The successful weaning was defined as spontaneous breathing off the ventilator for 48 hours or longer without respiratory distress. Results: The weaning through NPPV after intended extubation was successful in 7(50%) of 14 trials, and tracheostomy could be avoided in them. There were no differences in age, sex, APACHE III score, duration of invasive mechanical ventilation, baseline respiratory rate, $PaCO_2$ $PaO_2/FiO_2$, and ventilatory requirement(PS and PEEP) between the success and failure groups. In the success group, respiratory rate, pH, $PaCO_2$, and $PaO_2/FiO_2$ were not different between invasive MV and NPPV period. But in the failure group, pH decreased after 30 minutes of NPPV initiation compared with that of invasive MV($7.40\pm0.08$ vs. $7.34\pm0.06$, p<0.05). The causes of failure were worsening of ABG(n=3), retained tracheal secretion(n=2), mask intolerance(n=1), and flail chest(n=1). Conclusion: NPPV may be worth trying as a bridge method in weaning patients on long-term invasive mechanical ventilation.

• Journal of Chest Surgery
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• v.34 no.9
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• pp.680-685
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• 2001

Background: Tricuspid valve replacement is very rarely performed procedure and its long-term result is not yet satisfactory. Moreover, it is not well known whether bioprosthesis or mechanical prosthesis is the best selection for artificial valve. We reviewed 72 cases of tricuspid valve replacements in 71 patients between January 1989 and December 1998, trying to analyze the overall results and risk factors for mortality and morbidity. Material and Method: Average age of the patients at the time of operation was 42$\pm$13 years(range 16 to 65 years) and the sex ratio of male versus female was 32/39. Primary diagnosis consisted of 50 cases of aquired valvular heart disease and 18 cases of congenital heart disease, such as Ebstein’s anomaly. 4 cases had isolated tricuspid valve regurgitation. Implanted valves were 69 mechanical prosthesis and 3 bioprosthesis. Concomitant mitral or aortic valve replacements were performed in 50 cases. One patient received concomittant pulmonary valve replacement. Result: There were 7(9.72%) operative deaths and 7(13.0%) late deaths. Actuarial survival at 10 years was 59.2$\pm$7.2%. Prosthetic tricuspid valve thrombosis occurred 11 times in 5 patients. Reoperation for prosthetic tricuspid valve failure was performed in 1 patient. In this case, examination of the explanted prostheses showed that the tricuspid stenosis was the result of valve thrombosis. Among the 47 survivors, 46 patients(98%) were in functional class I or II. Conclusion: In our ten-year experience of tricuspid valve replacement, mortality and morbidity were satisfactory. Mechanical prosthesis in tricuspid position showed comparable clinical results as bioprosthesis.

• Journal of Chest Surgery
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• v.34 no.9
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• pp.698-703
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• 2001

Background: Endovascular stent-graft insertion in aortic diseases is now generally accepted as an attractive alternative treatment modality. We reviewed our clinical experiences of endovascular stent-graft insertion in thoracic aorta. Material and Method: Since 1995, we performed 8 cases of endovasclar stent-graft insertion. Preoperative diagnoses were aortic aneurysms in 4, traumatic aortic ruptures in 3, and ruptured aortic pseudoaneurysm in 1. All procedures were performed in angiography room with the guidance of fluoroscopy. The stent-graft device is a custom-made 0.35mm thickness Z-shaped stainless steel wires, intertwined with each other using polypropylene suture ligation. It is covered with expanded Dacron vascular graft. Result: All procedures were performed successfully. Follow-up studies revealed 2 minimal perigraft leakages. There was no significant leakage or graft migration. 2 patients expired due to multiple organ failure and fungal sepsis. Other survivors(6) are doing well. Conclusion: Endovascular stent-graft insertion is relatively saft and effective treatment modality in the managment of various types of aortic diseases. In may be an effective alternative in aortic diseases of great surgical risk.

• Journal of Chest Surgery
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• v.32 no.4
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• pp.347-352
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• 1999

Background: The atrial fibrillation in patients with mitral valvular heart disease is frequently converted to sinus rhythm after the mitral valve surgery. This sinus restoration implies an important meaning in that it not only helps postoperative convalescence in patients with unstable hemodynamics but also reduces the rate of postoperative thromboembolism. Material and Method: We retrospectively analyzed 184 patients who received mitral valve surgery from June 1986 to December 1996 to investigate the trend of rhythm change following mitral valve surgery and thus to clarify the predisposing factors of postoperative sinus rhythm conversion and its maintenance. Result: The sinus rhythm was restored after the operation in 54 out of 139 patients with atrial fibrillation preoperatively(38.8%). However, the atrial fibrillation recurred in 41 patients at the time of discharge showing a recurrence rate of 75.9 percent. The mean duration of sinus rhythm in patients with eventual atrial fibrillation recurrence was 8.2${\pm}$5.9 days. Only 15 patients were in sinus rhythm at the time of late follow-up with the mean follow-up period of 84.4${\pm}$34.7 months. While the age, duration of symptoms, duration of atrial fibrillation, left atral size, and pulmonary artery pressure were thought to be the predisposing factors for sinus conversion after the operation, only the duration of atrial fibrillation and ejection fraction were considered risk factors for the recurrence of the atrial fibrillation following sinus conversion. Conclusion: This study suggests that the early operation is mandatory for the satisfactory result regarding postoperative rhythm. Moreover, additional operative measure in adjunct to the intervention of mitral valve should be considered for the maintenance of restored sinus rhythm as reflected by high postoperative recurrence rate of atrial fibrillation.