• Journal of Chest Surgery
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• v.40 no.3 s.272
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• pp.193-199
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• 2007

Background: Reoperation is usually required for a right ventricle to pulmonary artery conduit obstruction caused by valve degeneration, conduit peel formation or somatic growth of the patient. An autologous tissue reconstruction (peel operation), where a prosthetic roof is placed over the fibrotic tissue bed of the explanted conduit, has been used to manage conduit obstructions at our institute since May 2002. Herein, the early and midterm results are evaluated. Material and Method: Between May 2002 and July 2006, 9 patients underwent obstructed extracardiac conduit replacement with an autologous tissue reconstruction, at a mean of 5.1 years after a Rastelli operation. The mean age at reoperation was $7.5{\pm}2.4$ years, ranging from 2.9 to 10.1 years. The diagnoses included 6 pulmonary atresia with VSD, 2 truncus arteriosus and 1 transposition of the great arteries. The preoperative mean systolic gradient was $88.3{\pm}22.2mmHg$, ranging from 58 to 125 mmHg. The explanted conduits were all Polystan valved pulmonary conduit (Polystan, Denmark). A bioprosthetic valve was inserted in 8 patients, and a monocusp ventricular outflow patch (MVOP) was used in 1 patient. The anterior wall was constructed with a Gore-Tex patch (n=7), MVOP (n=1) and bovine pericardium (n=1). Pulmonary artery angioplasty was required in 5 patients and anterior aortopexy in 2. The mean cardiopulmonary bypass time . was 154 minutes, ranging from 133 to 181 minutes; an aortic crossclamp was not performed in all patients. The mean follow-up duration was 20 months, ranging from 1 to 51 months. All patients were evaluated for their right ventricular outflow pathway using a 3-D CT scan. Resuit: There was no operative mortality or late death. The mean pressure gradient, assessed by echocardiography through the right ventricular outflow tract, was 20.4 mmHg, ranging from 0 to 29.6 mmMg, at discharge and 26 mmHg, ranging from 13 to 36 mmHg, at the latest follow-up (n=7, follow-up duration >1 year). There were no pseudoaneurysms, strictures or thrombotic occlusions. Conclusion: A peel operation was concluded to be a safe and effective re-operative option for an obstructed extracardiac conduit following a Rastelli operation.

• Journal of Chest Surgery
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• v.40 no.3 s.272
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• pp.168-179
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• 2007

Background: The recent trend of an increasing number of patients with acute cardiogenic shock or chronic congestive heart failure following myocardial infarction, as well as the considerable number who can not be weaned from cardiopulmonary bypass after open heart surgery, call for immediate efforts to develop affordable ventricular assist devices that are suitable for the Korean physique. Recently, a pneumatic pulsatile ventricular assist device (VAD), named DKUH-75, has been developed by the Department of Biomedical Engineering, in collaboration with the Department of Thoracic and Cardiovascular Surgery of Dankook University College of Medicine. The feasibility of the DKUH-75 VAD was evaluated on the bases of common hemodynamic variables and echocardiographic measurements in pigs, which are subjected to an acute cardiogenic shock state following myocardial infarction, using a novel coronary artery ligation method employing the ischemic preconditioning concept. Material and Method: Acute cardiogenic shock was induced in 10 Yorkshire Landrace Duroc strain pigs by ligating the left anterior descending coronary artery via an ischemic preconditioning process. The hemodynamic variables were monitored, with epicardial echocardiographic measurements performed before and one hour after the ligation. The DKUH-75 VAD was implanted into 5 pigs one hour after the onset of the shock. The hemodynamic variables and echocardiographic measurements were taken one hour after installation of the VAD. Result: The systolic, diastolic and mean systemic arterial pressures were significantly decreased in all the experimental animals one hour after the ligation. The systolic, diastolic and mean pulmonary arterial pressures were increased (Eds note: this completely contradicts the preceding statement? However, if you mean the non-experimental animals this should be stated?). The left ventricular end diastolic pressure (LVEDP) was increased, but the cardiac index decreased, An increase in the left ventricular end systolic dimension and decreases in the fractional shortening and ejection fraction were observed all animals one hour after the coronary artery ligation. In all 5 of the VAD implanted pigs, the systolic and mean systemic arterial pressures were increased, and the pulmonary arterial pressures decreased one hour after the implantation; the LVEDP decreased, but the cardiac index was significantly increased, In the echocardiographic measurements, the left ventricular end systolic dimension decreased after the implantation of the VAD, but the fractional shortening and ejection fraction significantly increased. Conclusion: Significant improvements in the hemodynamic variables and echocardiographic measurements were observed in the 5 VAD implanted animals one hour after installation, which had been subjected to an acute cardiogenic shock state by ligation of the coronary artery, indicating that the DKUH-75 VAD could help in the recovery of the myocardial function. This suggests that the DKUH-75 VAD is feasible in the short term in relation to an acute cardiogenic shock state due to myocardial infarction.

• Journal of Biomedical Engineering Research
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• v.19 no.3
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• pp.279-284
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• 1998

Deep hypothermic circulatory arrest(DHCA), in which systemic temperatures of 2$0^{\circ}C$ or less are used to allow temporary cessation of the circulation, is an useful adjunct in cardiac surgery. Because man in natural circumstances is never exposed to the extreme hypothermic condition, however, one of the controversial aspects is appropriate blood gas management($\alpha$STAT versus PH-STAT) during DHCA. This study aims to compare $\alpha$STAT with PH-STAT management for control of blood gases in experimental cardiopulmonary bypass(CPB) circuits with a membrane oxygenator. Fourteen young pigs were assigned to one of two strategies of gas manipulation. After a median sternotomy, CPB was established. Core cooling was initiated and continued until nasopharyngeal temperature fell below 2$0^{\circ}C$. The flow rate was set at 2,500 ml/min. Once their temperatures were below 2$0^{\circ}C$, the animals were subjected to circulatory arrest for 40mins. During cooling, blood gas was maintained according to either $\alpha$$\alpha$STAT or pH-STAT strategies. After DHCA, the body was rewarmed to normal body temperature. Arterial blood gases were measured before the onset of CPB, before cooling, before DHCA, at the point of 27$^{\circ}C$ during re-warming, on completion of re-warming. Cooling time was significantly shorter in $\alpha$-STAT than PH-STAT strategy, while there was no significant differences in rewarming time between two groups. Carbon dioxide was added between 5.5 and 3.0% in PH-STAT, while no carbon dioxide was added in $\alpha$STAT management. Amounts of oxygen administration were gradually lowered as temperature decreased. In this way, criteria of PH, PaCO, and PaO adjustments were satisfied in both $\alpha$STAT and PH-STAT management groups.

• Journal of Chest Surgery
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• v.36 no.11
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• pp.812-819
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• 2003

Background: Left ventricular dysfunction is one of the important prognostic factors of early mortality and long-term survival after valve operation. We studied the intermediate term results of mitral valve reconstruction in patients with moderate to severe left ventricular dysfunction. Material and Method: Forty four patients who underwent mitral valve reconstruction with a left ventricular ejection fraction (EF) of <45% or less (20∼45%) from April 1995 through July 2001 were reviewed retrospectively. Ages ranged from 10 to 67 years (46∼14 years) and 32 patients were in NYHA class III-IV. The mitral valve diseases were regurgitation (MR) in 28 patients, stenosis(MS) in 10, and mixed lesion in 5. The etiologies of mitral valve disease were rheumatic in 20 patients, degenerative in 14, ischemic in 5, annular dilatation in 2, congenital in 2, and endocarditis in 1. Operatively, all patients had annuloplasty and/or various valvuloplasty techniques, and a total of 52 procedures were concomitantly performed. Total cardiopulmonary bypass and aortic crossclamp time were 160$\pm$57 minutes and 112$\pm$45 minutes respectively. Result: Two operative deaths occurred as a result of left ventricular failure (4.5%). After the mean follow-up of 39 months (range, 10∼83 months), there was no late death. Transthoracic echocardiography revealed no or grade I of MR in 29 patients (72.5%) and no or mild MS in 35 patients (87.5%). The actuarial survival at 5 years was 100%. Four patients required mitral valve replacement due to progressive mitral valvular disease. The actuarial freedom from valve-related reoperation at 5 years was 84$\pm$9%. Conclusion: This study suggests that mitral valve reconstruction in patients with moderate to severe left ventricular dysfunction offers good early and intermediate survival and acceptable freedom from valve-related reoperation, and it is the strategy for effective management for these patients.

• Journal of Chest Surgery
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• v.31 no.5
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• pp.466-471
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• 1998

Purpose: The safety and efficacy of minimally invasive techniques in congenital heart surgery were tested in this study. Materal and method: Between July 1997 and November 1997, a total of 46 children were underwent minimally invasive cardiac operations at Seoul National University Children's Hospital. Age and body weight of the patients averaged 34.6${\pm}$41.8 (Range: 1∼148) months and 14.5${\pm}$9.9(Range: 3.0∼40.0) kg, respectively. Twenty eight patients were male. Preoperative surgical indications included 15 atrial septal defects, 25 ventricular septal defects, 1 foreign body in aorta, 3 partial atrioventricular septal defects, 1 total anomalous pulmonary venous connection(cardiac type), and 1 tetralogy of Fallot. After creating a small lower midline skin incision starting as down as possible from the sternal notch, a vertical midline sternotomy extended from xyphoid process to the level of the second intercostal space, where one of the T-, J-, I- or inverted C-shaped lower lying mini-sternotomy was completed with a creation of unilateral right or bilateral trap door sternal opening. A conventional direct aortic and bicaval cannulation was routine. Result: A mean length of skin incision was 6.1${\pm}$1.0(range: 4.0∼9.0) cm. A mean distance between the suprasternal notch and the upper most point of the skin incision was 4.0${\pm}$1.1 (range: 2.0∼7.0) cm. Mean cardiopulmonary bypass time, aortic cross-clamp time, and the operation time were 62.9${\pm}$20.0(range: 28∼147), 29.8${\pm}$12.8(range: 11∼79), and 161.1${\pm}$34.5 (range: 100-250) minutes. A mean total amount of postoperative blood transfusion was 71.0${\pm}$68.1 (range: 0∼267) cc. All patients were extubated mean 11.3${\pm}$13.8(range: 1∼73) hours after operation. A mean total amount of analgesics used was 0.8${\pm}$1.8(range: 0∼9) mg of morphine. The mean duration of stay in intensive care unit and hospital stay were 35.0${\pm}$32.2 (range: 10∼194) hours and 6.2${\pm}$2.0(range: 3∼11) days. There were no wound complications and hospital deaths. Conclusion: This short-term experience disclosed that the minimally invasive technique can be feasibly applied in a selected group of congenital heart disease as well as is cosmetically more attractive approach.

• Journal of Chest Surgery
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• v.34 no.10
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• pp.787-791
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• 2001

Coronary artery aneurysm is a rare disorder. It is defined as abnormal dilatation of coronary artery with diameter exceeding 1.5 times the adjacent normal segments. The incidence of coronary aneurysm is 2.6% in Caucasians and 0.25% in Asians. Over half of the former were associated with atherosclerotic coronary artery disease. However, 70 percents of the latter were nonobstructive coronary artery aneurysms. Coronary artery fistula is a rare disorder. It has been identified in only 0.2% of routine cardiac angiographic studies conducted over a 10-year period. The clinical spectrums are various, asymtomatic, asymptomatic murmur, dyspnea on exertion, fatigue, and congestive heart failure. The right coronary artery (56%) and left coronary artery(36%) are mainly involved in the origin site of congenital coronary artery fistula. The draining site of fistula are right ventricle(39%), right atrium(33%), and pulmonary artery(20%) and so on. This 54 years-old woman had intermittent chest tightness and an abnormal mediastinal shadow on chest roentgenogram and chest C-T examination, which was diagnosed as a mediastinal mass such as teratoma. We performed the operation under left anterolateral thoracotomy for mass excision. However, we knew the mass had the pulsating arterial blood flow through a fine needle puncture of the mass and that it was attached to the left ventricle. We believed the excision of mass on beating heart would be very dangerous. Therefore, we closed the wound without excising the mass. After several days, we performed an echocardiography and coronary angiography, We knew it was cardiac tumor. Incidentally, the patient had a tortuous coronary fistula from the right coronary artery to pulmonary trunk. Using cardiopulmonary bypass with moderate systemic hypothermia, the mass was resected and the fistula was clipped with surgical clips. Pathology of the specimen was a giant coronary arterial aneurysm.

• Journal of Chest Surgery
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• v.29 no.12
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• pp.1316-1322
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• 1996

From May 1977 to December 1994, 1.060 cases of open heart surge y for congenital heart disease were performed under cardiopulmonary bypass in Chonnam University Hospital They were divided into two groups; group A(677 cases, from May 1977 lo December 1989), group B(38B cases, from January 1990 to December 1994), to be compared and analized. Of the 1, 060 cases, there were 889 acyanotic (83.9%) and 171 cyanotic(16.1%). The operative mortality was 7.8% in group A and 5.7% in group B (total : 6.6%). The operative mortality for group A was 25% in cyanotic disease and 3.7% in acyanotic disease, respectively in group B, it was 23.8%, 3.2%. There were 19 patients (3.8%) and 78 patients(20.4%) with body weight under 10kg in group A and group B respectively. The operative mortality for these patients were 31.6% in A group and 16.1% in B group. In result, increasing trend in congenital heart disease in patients under 10 kg of body weight has been noted, whereas mortality has decreased. The operative mortality of tetralogy of Fallot has decreased in group B t an group A. These results suggest that the operative result have improved in recent years.

• Journal of Chest Surgery
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• v.35 no.6
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• pp.430-438
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• 2002

It is known that low birth weight is a risk factor for poor outcome in cardiac surgery for many cardiac defects. We reviewed our recent surgical experiences on congenital heart defect (other than patent ductus arteriosus) in low birth weight babies. Material and Method: From September 1994 to February 2001, 31 consecutive infants weighing 2500 g or less underwent cardiac surgery with (OHS group n=12) or without cardiopulmonary bypass (CHS group n=19). A retrospective study was carried out to evaluate short-and intermediate-term outcome. Mean gestational age and age at operation were 36.9 weeks(range, 32.3-42weeks) and 32.1days (range, 0-87days) respectively. Mean body weight at birth and operation were 1972g (range, 1100-2500g) and 2105g (range, 1450-2500 g) respectively. There was no difference between the two groups in age and body weight. Defects included ventricular septal defect (VSD) (n=3), VSD with arch anomaly (n=2), total anomalous pulmonary venous return (n=2), transposition of the great arteries (TGA) (n=2), truncus arteriosus (n=2), and univentricular heart with cor triatriatum (n=1) in OHS group, and coarctation of aorta (n=7), tetralogy of Fallot (TOF) (n=3), TOF with pulmonary atresia (n=3), multiple muscular VSDs (n=1), double outlet right ventricle (n=1), pulmonary atresia with intact ventricular septum (n=2), tricuspid atresia (n=1), and TGA with multiple VSD (n=1) in CHS group. 13 patients (41.9%) were intubated pre-operatively. Result: There were 4 early deaths(＜30 days); 1 (8.3%) in OHS group and 3 (15.8%) in non-OHS group. All these early deaths were related to the pulmonary artery banding(PAB). There was no operative mortality in infants undergoing complete repair and palliative operations other than PAB. Delayed sternal closure was required in 3 patients. Prolonged postoperative mechanical ventilation (>7 days) was required in 7 patients(58.3%) in OHS and 7(38.8%) in CHS group. Late mortality occurred in 3 patients, two of which were non-cardiac. A patient in OHS group was documented to have neurologic sequelae. All the survivors except two are in NYHA class 1. Conclusion: Complete repair and palliative operations other than PAB can be performed in low birth weight infants with low operative mortality and an acceptable intermediate-term result. However, about a half of the patients required long-term postoperative mechanical ventilation.

• Journal of Chest Surgery
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• v.42 no.6
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• pp.710-718
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• 2009

Background: The Cox maze procedure has been used as a standard surgical treatment for atrial fibrillation for about 20 years. Recently, the creators have used a bipolar radiofrequency electrode (Cox maze IV procedure) instead of the incision and suture (cut-sew) technique to make atrial ablation lesions for persistent atrial fibrillation. We investigated clinical outcomes for the Cox maze procedure with a bipolar radiofrequency electrode and cryoablator in patients with persistent atrial fibrillation, and compared results with clinical outcomes of the cut-sew procedure. Material and Method: Between April 2005 and July 2007, 40 patients with persistent atrial fibrillation underwent Cox maze IV procedure with a bipolar radiofrequency electrode and cryoablator (bipolar radiofrequency group). Surgical outcomes were compared with those of 35 patients who had the cut-sew technique for the Cox maze III procedure. All patients had concomitant cardiac surgery. Postoperatively, the patients were followed up every 1 to 2 months. Result: At 6 months postoperatively, the conversion rate to regular sinus rhythm was not significantly different between the two groups: 95.0% for the bipolar radiofrequency ablation group; 97.1% for the cut-sew technique (p=1.0). At the end of the follow-up period, the conversion rate to regular sinus rhythm was also not significantly different (92.5% vs. 91.6%, p=1.0). In multivariate analysis using a Cox-regression model, the postoperative atrial dimension was an independent determinant of sinus conversion in the bipolar radiofrequency ablation group (hazard ratio 31, p=0.005). In the Cox-regression model for both groups, atrial fibrillation at 6 months postoperatively (hazard ratio 92.24, p=0.003) and the postoperative left atrial dimension (hazard ratio 16.05, p=0.019) were independent risk factors of continuance or recurrence of atrial fibrillation after Cox maze procedures. Aortic cross-clamp time and cardiopulmonary bypass time were significantly shorter in the radiofrequency group than in the cut-sew group. Conclusion: In the Cox maze procedure for patients with persistent atrial fibrillation, the use of bipolar radiofrequency ablation and a cryoablator is as good as the cut-sew technique for conversion to sinus rhythm. The postoperative left atrial dimension is an independent determinant of postoperative continuance and recurrence of atrial fibrillation.

• Journal of Chest Surgery
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• v.36 no.7
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• pp.463-471
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• 2003

The long-term results of combined mitral valve repair and aortic valve replacement (AVR) have not been well evaluated. This study was performed to investigate the early and long-term results of mitral valve repair with AVR. Material and Method: We retrospectively reviewed 45 patients who underwent mitral valve repair and AVR between September 1990 and April 2002. The average age was 47 years: 28 were men and 17 women. Twelve patients had atrial fibrillation and three had a previous cardiac operation. The mitral valve disease consisted of pure insufficiency (MR) in 34 patients, mitral stenosis (MS) in 3, and mixed lesion in 8. Mitral valve disease was due to rheumatic origin in 24 patients, degenerative in 11, annular dilatation in 8, and ischemia or endocarditis in 2. The functional anatomy of mitral valve was annular dilatation in 31 patients, chordal elongation in 19, leaflet thickening in 19, commissural fusion in 13, chordal fusion in 10, chordal rupture in 6, and so on. Aortic prostheses used included mechanical valve in 32 patients, tissue valve in 12, and pulmonary autograft in one. The techniques of mitral valve repair included annuloplasty in 32 patients and various valvuloplasty of 54 techniques in 29 patients. Total cardiopulmonary bypass and aortic cross clamp time were 204$\pm$62 minute and 153$\pm$57 minutes, respectively. Result: Early death was in one patient due to low output syndrome (2.2%). After follow up of 57$\pm$37 months, late death was in one patient and the actuarial survival at 10 years was 96$\pm$4%. Recurrent MR developed grade II or III in 11 patients and moderate MS in 3. Three patients required reoperation for valve-related complications. The actuarial freedom from recurrent MR, MS, and reoperation were 64$\pm$11%, 86$\pm$8%, and 89$\pm$7% respectively. Conclusion: Combined mitral valve repair with AVR offers good early and long-term survival, and adequate techniques and selection of indication of mitral valve repair, especially in rheumatic disease, are prerequisites for better long-term results.