• Journal of Chest Surgery
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• v.30 no.2
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• pp.152-157
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• 1997

From August 1986 until June 1995, single aortic valve replacement was performed in 65 patients at the Chonnam National University Hospital. worthy-eight were male and 17 were female patients, ranging from 19 to 68 years of age(median : 43 years). The causes of the valve lesions were rheumatic in 29 patients (44.6%), bicuspid aortic valve in 6 patients (6.2%), endocarditis in 6 patients(6.2%), unknown in others. Concomitant surgical procedures were performed in 10 patients : repair of congenital defect in 5, pericardiectomy in 1, coronary artery bypass grafting in 1, noncoronary sinus plication in 1, Valsalva sinus aneurysmectomy in 1, subaortic membrane resection in 1 Used valves were 51. Jude-Medical valve in 42, Duromedics valve in 22, Bjork-Shiley valve in 2, Carpentier-Edward valve in 1. There were 3 hospital deaths (4.6%), and 2 late deaths (3.2%). Follow-up was 95.2% complete. The 10-year acturlal survival rate was 85.3%. Postoperative complications were low cardiac utput in 8, arrythmia in 5, valve related hemolysis in 1, cerebral infarction in 1, and gastrointestinal bleeding in 2. Reoperation was performed in 4 for surgical bleeding, in 3 for paravalvular leak. The mean improvement in New York Heart Association functional class is from 2.79 $\pm$ 0.66 preoperatively to 1.25 $\pm$ 0.49 postoperatively(p < 0.001) The change of cardiothoracic ratio from preoperative to postoperative is 0.57 $\pm$ 0.06 to 0.54 $\pm$ 0.05 (p < 0.05). The left ventricular ejection fraction change is not significant perioperatively. There are no mechanical failures. This early and intermediate-term follow-up suggests that in adults in whom valve repair is not possible, the mechanical valve is a reliable and durable prosthesis with good hemodynamic function and a low rate of thromboembolic event.

• Journal of Chest Surgery
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• v.41 no.5
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• pp.591-597
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• 2008

Background: Pulmonary endarterectomy is widely accepted as a treatment for chronic thromboembolic pulmonary hypertension. Based on our experiences, we sought to find ways to reduce perioperative complications and to improve surgical outcomes in patients undergoing pulmonary endarterectomy. Material and Method: This study was designed as a retrospective analysis of 20 patients with pulmonary hypertension who underwent pulmonary endarterectomy between January 1998 and March 2008. All patients presented with chronic dyspnea. Deep vein thrombosis (DVT) was the major cause of chronic pulmonary thromboembolism (55%). Seventeen patients (85%) underwent inferior vena cava (IVC) filter placement. Thirteen patients underwent surgery under total circulatory arrest, while the others underwent surgery while on low flow cardiopulmonary bypass. Concomitant tricuspid annuloplasty was done in 6 patients (66%) whose tricuspid regurgitation was as severe as grade IV/IV. The mean follow-up duration was $45{\pm}32$ months. Result: Using of University of California, San Diego (UCSD), thromboembolism classification, 4 patients (20%) were type 1, 8 patients (40%) were type II, and 8 patients (40%) were type III. Right ventricular systolic pressure was reduced significantly from $77{\pm}29$ mmHg to $37{\pm}19$ mmHg after pulmonary endarterectomy (p<0.001). The degree of tricuspid regurgitation and the NYHA functional class were all improved postoperatively. Reperfusion edema occurred in 7 cases (35%). The incidence of reperfusion edema was higher in the UCSD type III group than in the other group (25% vs 50%, p=0.25) and the length of postoperative intensive care unit stay was longer in type III group ($5{\pm}2$ days vs $9{\pm}7$ days, p=0.07). The early mortality rate was 10%, and the late mortality rate was 15% (n=3); one death was due to progression of underlying non-Hodgkin's lymphoma, and the other deaths were related to recurrent thromboembolism and persistent pulmonary hypertension, respectively. Conclusion: Pulmonary endarterectomy, as a curative surgical method for treating chronic thromboernbolic pulmonary hypertension, should be performed aggressively in patients diagnosed with chronic thromboembolic pulmonary hypertension, and an effort should be made to reduce the frequency of perioperative complications and to improve surgical outcomes.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.16 no.4
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• pp.167-178
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• 2021

The purpose of this study is to analyze the direct investment decision factors in the Kaesong Industrial Complex and Vietnam, and to contribute to the creation of domestic jobs and the revitalization of the inter-Korean economy. According to the analysis, most of the Kaesong Industrial Complex and Vietnamese investment companies are entering the complex for the purpose of utilizing cheap labor, cheap factory locations, sales/development of local markets, and bypass export production bases in third countries. This can be divided into production-efficient investors using differences in production price such as labor costs and market-oriented investors to sell and expand the local market, which seems to be consistent with global direct investment patterns such as Nike, Apple, and Amazon. However, even if the North Korea-U.S. denuclearization talks ease or lift sanctions, Vietnamese investors' willingness to invest in the North Korea has been most burdened by the possibility of closing special economic zones due to political risks. Last but not least, it is important to note that those willing to invest in North Korea are mostly smaller enterprises in textiles, sewing, footwear and leather industries-those that benefit from low-cost labor. Since their size is small, they need policy support in financing, especially in the early stages of their business. Even after they grow past the early stages, those without collateral would still need state guarantee letters to get financing. Thus, it is worth considering to use the Inter-Korean Cooperation Fund to compensate commercial banks for bad loan loss or for low-interest loans for smaller SMEs. The interviews with SMEs found that red-tape is one of the biggest difficulties they face. Thus, it is recommended that a one-stop service agency should be established to cover all processes and issues related to inter-Korean economic cooperation to eliminate redundancy and expediate government support for SMEs.

• Journal of Chest Surgery
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• v.29 no.9
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• pp.983-988
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• 1996

Aneurysm of the sinus of Valsalva is fairly rare. Between 1987 and 1994, we operated on a total of 12 cases of aneurysm of the sinus of Valsalva at the Inje University Seoul Paik Hospital. This represents 0.7% of all cardiac operation under cardiopulmonary bypass. There were eight male and four female patients aged from 8 to 38 years(mean, 19.2 years). 8 of 12 patients had ruptured aneurysms. The origin of aneurysm of the sinus of Valsalva was the right coronary sinus in 10(83. 3%), and the noncoronary sinus in 2(16.6%). In ruptured aneurysm, the origin was the right oronary sinus in 6, and the noncoronary sinus in 2. The aneurysms originating from the right coronary sinus ruptured into the right ventricle in 5, and into both the right atrium and right ventricle in 1. The aneurysms originating from the noncoronary sinus ruptured into the right ventricle in 1, and into the right atrium in 1. Associated congenital cardiac defects included ventricular septal defect in 10(83.3%) patients 39 cases of these were associated with the aneurysms of the right coronary sinus), aortic regurgi- tation in 3 (all of these had an additional ventricular septal defect), mitral regurgitation in 1, and double chambered right ventricle in 1. No hospital deaths occurred, although one late death occurred as a result of endocarditis 15 months after the first operation. The mean follow-up period was 29 months, range from 4 to 60 months. Eleven patients except one late death were in New York Heart Association class 1. Due to the low mortality risk o( an operation for aneur sm of the sinus of Valsalva, a ruptured aneurysm of the sinus of Valsalva should be corrected surgically when the diagnosis is mane, and unruptured aneurysm of the sinus of Valsava with complication should also be operated. In most cases the aorta was opened to examine the morphology of the aneurysm and the aortic cusps, and an associated aortic valve defect should be corrected simultaneously.

• Journal of Chest Surgery
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• v.36 no.9
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• pp.646-650
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• 2003

Many surgical techniques for ischemic mitral regurgitation (IMR) have been used with their excellent results and advantages. Here, we report our simple posterior annuloplasty techniques using vascular graft strip with their early results. Material and Method: Twenty two patients (13 male) underwent the operations for IMR (excluding the papillary muscle rupture) from December 2001 to January 2003. Preoperative risk factors were low ejection fraction (<35％, n=9), hypertension (n=13), diabetes (n=9), and renal failure (Cr>2.5, n=4). The wide dissection beneath the both vena cavae and interatrial groove after bicaval cannulation enabled the easy exposure of mitral valve even in the small left atrium. After eight or nine interrupted sutures in posterior annulus for anchoring the 6 mm width vascular graft strip, symmetric (n=8) or asymmetric (n=14) annuloplasty were done. Combined surgeries were CABG (n=21), Dor procedures (n=3), tricuspid valve annuloplasty (n=1), Maze operation (n=1), and aorto-right subclavian artery bypass (n=1). Result: Except for one surgical mortality, all the patients were doing well and the mean grade of regurgitation was decreased from 2.95 to 0.88, however the ejection fraction had not changed significantly just before discharge. Post-operative valve function evaluated before discharge revealed no residual regurgitation in 8 (including 1 patient with mild stenosis due to over reduction), minimal in 11, mild in 2, and mild to moderate regurgitation in 1. One patient who had ischemic cardiomyopathy and renal failure died of the arrhythmia during the hemodialysis. Conclusion: These observations suggest that the annuloplasty with vascular graft strip could be a safe and cost effective techniques for ischemic mitral regurgitation. However, the long term evaluation for the mitral valve function should be defined for the final conclusion.

• Journal of Chest Surgery
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• v.30 no.2
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• pp.131-136
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• 1997

The hemodynamic effects of thyroid hormones which is well established, affect myocardial contractility, heart rate, and myocardial oxygen consumption. The alterations in thyroid function test are frequently seen in patients with nonthyroidal illness and often correlate with the severity of the illness and the prosnosis. In this study, thyroid hormone changes were investigated in 20 patients who received cardiopulmonary bypass(CPB). All patients showed a state of biochemical euthyroidism preoperatively: The results were as follows : 1. Serum triiodothyronine(73) reached to its nadir(30.05 $\pm$ 17.5ng/dl, p(0.001) at 10 minutes after the start of CPB and remained low(p(0.05) throughout the study period. 2. Serum thyroxine(74) concentr tion slightly decreased after CPB, but maintained within normal range. 3. Serum free thyroxine(W4) concentration slightly increased after CPB, but maintained within normal range. 4. Serum thyroid stimulating hormone(TSH) concentration increased 10 minute after CPB, reached to its nadir(3.37 $\pm$ 0.81u1U/m1, p(0.001) at 2 hours after CPB. After then, serum TSH concentration decreased and reached its normal levels at 24 hours after CPB. 5. The patients whose postoperative recovery was uneventful(Group 1) had higher serum 73 levels than those who had postoperative complications(Group 2)(p<0.05). Group 1 showed elevating patterns of serum 73 in the fourth day after operation, whereas group 2 did not show such an elevating pattern. These findings are similar to the euthyroid sick syndrome seen in severely ill patients and indicate that patients undergoing open heart surgery have suppression of the pituitary-thyroid axis.

• Journal of Chest Surgery
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• v.30 no.3
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• pp.287-292
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• 1997

.Itrial fibrillation is one of the most common cardiac arrhythmias requiring treatment. About 60% of patients with mitral valvular disease have atrial fibrillation and one third of patients with atrial fibrillation may have the past history of thromboembolic events. Between April 1994 and June 1995, 20 patients with organic heart diseases combined with atrial fibrillation underwent open heart surgery including Cox-maze 111 procedure. There were 6 men and 14 women with an average age of 48 years (range, 31 to 66 years). Nineteen patients had valvular heart diseases and 1 ventricular septal defEct (VSD). Mean duration of atrial fibrillation was 36 months (:42 months) (range, 1 to 132 months). T e past medical history of thromboembolic events was positive in 7 patients (35%) and left atrial thrombus was detected in 9 patients (45%). The concomitant procedures were mitral valve replacement (MVR) and aortic valve replacement (AVR) in 5 patients, MVR in 4, MVd and tricuspid annuloplasty(TAP) in 4, mitral valvuloplasty(Mln) in 3, Mln and Tln in 1, MIW and coronary artery bypass surgery in 1, AVR in 1, and patch closure of VSD in 1. Mean aortic cross-clamping time was 175 minutes (range, 116 to 270 minutes). Atrial fibrillation recurred in 16 patients (80%) during the early postoperative period, but, recurrent atrial fibrillation was converted to regular rhythm at postoperative forty-first day in average. There was no early or late death in this series of 20 patients and postoperative complications were inappropriate tachycardia in 5 patients (25%), low cardiac output syndrome in 3 (15%), aggravated hemiplegic in 1, and acute renal failure in 1. Mean follow-up interval of patient was 16.5 months (range, 10.5 to 24 months) and all patients are currently in regular rhythm. Seventeen patients (85%) are in sinus rhythm and 3 (15%) in junctional rhythm. Right atrial contraction was detected in 95% of patients and left atrial contraction in 63% on postoperative transthoracic echocardiogram. The surgical treatment of atrial fibrillation concomitant with open heart surgery is warranted in the recent clinical setting of improved myocardial protection technique, considering the untoward side-effects of atrial fibrillation.

• Journal of Chest Surgery
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• v.38 no.5 s.250
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• pp.335-348
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• 2005

Background: This retrospective review examines the preoperative condition, postoperative course, mortality and cause of death for the patients who underwent modified Blalock-Taussig shunt for complex congenital heart defects in early infancy. Material and Method: Fifty eight patients underwent modified Blalock-Taussig shunts from January 2000 to November 2003. The mean age at operation was $23.1\pm16.2$ days ($5\~81\;days$), and the mean body weight was $3.4\pm0.7\;kg\;(2.1\~4.3\;kg)$. Indications for surgery were pulmonary atresia with ventricular septal defect in 12 cases, pulmonary atresia with intact ventricular septum in 17, single ventricle (SV) in 18, and hypoplastic left heart syndrome (HLHS) in 11. Total anomalous pulmonary venous return (TAPVR) was associated with SV in 4 cases. Result: There were 11 ($19.0\%$) early, and 5 ($10.6\%$) late deaths. Causes of early death included low cardiac output in 9, arrhythmia in 1, and multiorgan failure in 1. Late deaths resulted from pneumonia in 2, hypoxia in 1, and sepsis in 1. Risk factors influencing mortality were preoperative pulmonary hypertension, metabolic acidosis, use of cardiopulmonary bypass, HLHS and TAPVR. Twenty four patients ($41.4\%$) had hemodynamic instability during the 48 postoperative-hours. Six patients underwent shunt revision for occlusion, and 1 shunt division for pulmonary overflow. Conclusion: Modified Blalock-Taussig shunt for complex congenital heart defects in early infancy had satisfactory results except in high risk groups. Many patients had early postoperative hemodynamic instability, which means that continuous close observation and management are mandatory in this period. Aggressive management may appear warranted based on understanding of hemodynamic changes for high risk groups.

• Journal of Chest Surgery
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• v.40 no.5 s.274
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• pp.351-355
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• 2007

Background: Postinfarction ventricular septal rupture is associated with mortality as high as $85\sim90%$, if it is treated medically. This report documents our experience with postinfarction ventricular septal rupture that was treated surgically, Material and Method: We retrospectively reviewed the medical records of 11 patients who were operated on due to postinfarction ventricular septal rupture between August 1996 and August 2006. There were 4 men and 7 women, with a mean age of $70{\pm}11$ years (age range: $50\sim84$ years). The location of the rupture was anterior in 7 cases and posterior in 4 cases. The interval between the onset of acute myocardial infarction and the occurrence of the ventricular septal rupture was $2.0{\pm}1.3$ days (range: $1\sim5$ days). Operation was performed at an average of $2.4{\pm}2.7$ days (range: $0\sim8$ days) after the diagnosis of septal rupture. Preoperative intraaortic balloon pump therapy was performed in 10 patients. Result: The infarct exclusion technique was used in all cases. Coronary artery bypass grafting was done in 8 cases, with the mean number of distal anastomosis being $1.0{\pm}0.8$. There was one operative death. In 2 patients, reoperation was performed due to a residual septal defect. The postoperative morbidities were transient atrial fibrillation (n=7), paroxysmal supraventricular tachycardia (n=1), low cardiac output syndrome (n=3), bleeding reoperation (n=2), delayed sternal closure (n=2), acute renal failure (n=2), pneumonia (n=1), intraaortic balloon pump-related thromboembolism (n=1), and transient delirium (n=2). Nine patients have been followed up for a mean of $38{\pm}40$ months except for one follow-up loss. There have been 3 late deaths. At the latest follow-up, all 6 survivors were in a good functional class. Conclusion: We demonstrated satisfactory operative and midterm results with our strategy of preoperative intraaortic balloon pump therapy, early repair of septal rupture by infarct exclusion and combined coronary revascularization.

• Journal of Chest Surgery
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• v.30 no.1
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• pp.27-33
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• 1997

Retrograde myocardial protection is widely accepted in CABG operation because of the limitations of the antegrade method in the coronary arterial stenosis lesions. We analyzed 76 c ses of retrograde myocardial protection among 96 cases of CABG operation performed between April 1994 and August 1995, There were 48 males and 25 females, and the mean age was 58.2 $\pm$ 8.3 years. 53 patients (70%) were operated for unstable angina, 14 (18%) for stable angina, 6 (8%) for post-infarct angina, 1 (1%) for acute myocardial infarction, and 2()%) for failed PTCA. Preoperative coronary angiography revealed 3-vessel disease in 42 cases, 2-vessel disease in 11, 1-vessel disease in 10, and left main disease in 13 cases. We used SVG(63 cases), LIMA(69 cases), RIMA(11 cases), radial artery(6 cases), and gastroepiploic artery(1 case) for the grafts. Mean anastomosis was 3.2 $\pm$ 1.1. We protected the myocardium with antegrade induction and retrograde maintenance in all the cases except a case of retrograde induction and maintenance. During the aortic cross-clamping, blood cardioplegia was administered intermittently in 19 cases, and continuously in 57 In 39 cases, we used retrograde ardioplegia and antegrade perfusion of RCA graft simultaneously. We had no operative motality. Perioperative complications were arrhythmia in 15 cases, perioperatve myocardial infarction in 10, low cardiac output syndrome In 8, transient neurologic problem in 7, transient psychiatric problem in 6, ARF in 3, bleeding in 2, pneumonia in 2, wound infection in 1, and duodenal ulcer perforation in 1 . In this report, we experienced 76 cases of CABG operation with retrograde myocardial protection under the acceptable operative risk without operative mortality.