• Proceedings of the Korea Society for Simulation Conference
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• 2005.11a
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• pp.130-137
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• 2005

본 논문은 심장이 수축$\cdot$이완함에 따라 그 형태와 위치가 변하는 관상동맥의 구조와 그 움직임을 사실적으로 표현하기 위한 매개변수적 모델링 기법을 제안한다. 완성된 모델은 관상동맥의 움직임을 관찰함으로써 심장질환 판단에 도움을 주고, 심장시술 시뮬레이션 및 시술계획수립에 사용될 수 있다. 매개변수적 기법으로 생성된 모델은 메쉬 정점의 인덱스만으로 모델간 매칭을 위한 대응점을 찾을 수 있으므로, 시간대별로 달라지는 정점의 위치를 쉽게 추적함으로써 모델의 움직임을 표현할 수 있다. 그러나 이러한 기법으로 생성된 모델은 분리, 접합 등의 변형조작이 어렵고, 트리형태 객체에 적용하기 힘든 단점이 있다. 본 논문에서는 이를 극복하기 위해 분할된 혈관영역의 골격데이타에서 찾아낸 분기점을 중심으로 Generalized Cylinder를 이용하여 실린더 형태의 각 혈관세그먼트를 모델링 한 후, 분기영역을 3개의 하프파이프(half pipe)와 2개의 삼각형 패치로 연결하여 모델링하였다. 완성된 모델은 다시점 관상동맥데이터에 적용하였고, 각 시점에서 구해진 정점의 위치를 선형보간함으로써 부드러운 혈관의 움직임을 나타내었다.

• Journal of Chest Surgery
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• v.39 no.10 s.267
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• pp.754-758
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• 2006

Background: Surgical role for acute coronary syndrome has been reduced in recent years due to development of drug eluting stent. We evaluated the surgical results of acute coronary syndrome in our hospital. Material and Method: Between January 2001 and August 2005, 416 patients underwent coronary artery bypass grafting (CABG) under diagnosis of non-ST-elevation acute coronary syndrome (NSTE ACS). Mean age was $61.8{\pm}9.0$ years and 276 (66.3%) patients were male. 324 (77.9%) patients had triple vessel disease and 92 (22.1%) had left main disease at angiographic study. 236 (56.7%) patients had hypertension and 174 (41.8%) had diabetes mellitus. Conventional on-pump CABG was performed in 194 patients (46.6%) and off-pump CABG in 222 (53.4%). Total arterial revascularization with no touch technique was done in 97 patients (23.3%). The number of total distal anastomosis was 1,306 and the number per patient was $3.21{\pm}1.71$. Result: Surgical mortality rate was 1.0% (4 patients) and postoperative complication rate was 15.6% (65 patients). Graft patency was checked at mean $3.7{\pm}7.6$ months (from 1 to 37 months) postoperatively with multi-directional computed tomography in 152 patients. Left internal mammary artery was patent in 95.3%, right internal mammary artery in 98.1%, radial artery in 92.2% and saphenous vein in 89.0%. Conclusion: The surgical treatment of NSTE ACS showed relatively low mortality rate and good graft patency rate. Further study is needed to compare the long term results with drug eluting stent.

• Journal of Chest Surgery
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• v.36 no.5
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• pp.363-366
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• 2003

Background: Left ventricular rupture after acute myocardial infarction is a serious complication with high mortality. Emergency operation is usually the only available treatment. A 76-year-old female with persistent chest pain and syncopal attacks was admitted. Transthoracic echocardiography showed the pericardial effusion and generalized hypokinesia of the inferolateral wall of left ventricle. Coronary angiography revealed a total occlusion of the first diagonal branch. After percutaneous transluminal coronary angioplasty with coronary stent and insertion of intraaortic balloon pump, emergency operation was performed. Under cardiopulmonary bypass and cardiac arrest with cold blood cardioplegia, coronary artery bypass graft with saphenous vein, pericardial patch covering on the rupture area with 6-0 polypropylene running sutures, and fibrin glue compression under the patch were performed. We present a case of left ventricular (free wall) rupture after acute myocardial infarction.

• Journal of Chest Surgery
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• v.39 no.1 s.258
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• pp.28-34
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• 2006

Background: There has been an increase in the number of elderly patients considered for coronary artery bypass grafting (CABG). Recently, there were many satisfactory reports of coronary artery bypass grafting (CABG) in old age due to the development in operative technique and postoperative management. We evaluated operative and follow-up results of patients 70 years of age and older compared to 60 years old. Material and Method: We retrospectively studied the cases of 74 consecutive patients 70 years or older (group A) who underwent a elective CABG from January 2000 to December 2003 and compared that of relatively young age group (group B, 60-69 years old). We compared preoperative characteristics, operation technique, postoperative results that effect outcome, also we investigated late mortality and cardiac events at follow-up periods. Result: Preoperative demographic and clinical characteristics of two groups were not different, except preoperative renal dysfunction(serum creatinine: $\geq$1.4 mg/dl) (group A 17, 23$\%$ vs group B 14, 9$\%$) (p=0.024). There was no difference of the mean number of distal anastomosis and the left ventricular ejection fraction in group A decreased significantly from 53.7$\pm$13$\%$ preoperatively to 49.9$\pm$ 12$\%$ postoperatively (p=0.02), but not changed in group B. There was no difference at operative mortality rate and postoperative major morbidity rate, but wound problem of saphenous vein harvest site was significantly higher in group A than group B (6.8$\%$ vs 0.7$\%$, p=0.02). The mean follow up duration was 24.3$\pm$13 months and the cumulative survival were 95.4$\%$ at 2 year and 79.9$\%$ at 4 year in group A and 95.4$\%$ at 2 year and 90.1$\%$ at 4 year in group B (p=ns). Conclusion: We conclude that age is not a factor of determination when we decide about operation because coronary artery bypass grafting in elderly more than 70 years old can be performed with a low mortality rate and acceptable morbidity rate.

• Journal of Chest Surgery
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• v.31 no.12
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• pp.1159-1164
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• 1998

Background: Although operative outcome is progressing due to the development of operative techniques and myocardial protection, some patients face an increased morbidity and mortality. Therefore, it has become increasingly important to predict the operative morbidity and mortality. Material and Method: This retrospective study reports the results of risk factor analysis of morbidity and mortality of 137 consecutive patients who were underwent coronary artery bypass graft surgery(CABG). Preoperative variables were age, sex, preoperative myocardial infarction, operative priority, left ventricular ejection fraction, obesity and triple vessel disease. Postoperative morbidities were arrhythmia, wound infection, cerebral infarction, prolonged postoperative hospitalization, pneumonia, acute renal failure, prolonged use of ventilator and operative death. Result: The mean age of total patients was 56.7 years, from 27 to 74. The overall mortality was 6.6%(9 of 137) with the mortality of 3.9%(5 of 128) for elective operation, and 44.4%(4 of 9) for emergent or urgent cases. The morbidity of patients over 65 years was stastistically higher than that of under 65 years. Sex distribution showed no difference in morbidity, however operative mortality rate was slightly higher in women (5/41, 12.19%) than in men(4/96, 4.17%). Morbidity of emergent or urgent operation was 100%, much higher than that of the elective operation. Mortality of the patients whose left ventricular ejection fraction was under 50% was higher than that of those over 50%. Conclusion: We concluded that the risk factors of morbidity after CABG were old age above 65 years and emergent or urgent operation, and that risk factors of mortality were low left venticular ejection fraction under 50% and emergent or urgent operation.

• Journal of Chest Surgery
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• v.48 no.1
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• pp.33-39
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• 2015

Background: This study aimed to investigate sternal healing over time and the incidence of poor sternal healing in patients undergoing coronary artery bypass graft (CABG) surgery using bilateral internal thoracic arteries. Methods: This study enrolled 197 patients who underwent isolated CABG using skeletonized bilateral internal thoracic arteries (sBITA) from 2006 through 2009. Postoperative computed tomography (CT) angiography was performed on all patients at monthly intervals for three to six months after surgery. In 108 patients, an additional CT study was performed 24 to 48 months after surgery. The axial CT images were used to score sternal fusion at the manubrium, the upper sternum, and the lower sternum. These scores were added to evaluate overall healing: a score of 0 to 1 reflected poor healing, a score of 2 to 4 was defined as fair healing, and a score of 5 to 6 indicated complete healing. Medical records were also retrospectively reviewed to identify perioperative variables associated with poor early sternal healing. Results: Three to six months after surgery, the average total score of sternal healing was $2.07{\pm}1.52$ and 68 patients (34.5%) showed poor healing. Poor healing was most frequently found in the manubrium, which was scored as zero in 72.6% of patients. In multivariate analysis, the factors associated with poor early healing were shorter post-surgery time, older age, diabetes mellitus, and postoperative renal dysfunction. In later CT images, the average sternal healing score improved to $5.88{\pm}0.38$ and complete healing was observed in 98.2% of patients. Conclusion: Complete sternal healing takes more than three months after a median sternotomy for CABG using sBITA. Healing is most delayed in the manubrium.

• Journal of Chest Surgery
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• v.23 no.3
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• pp.482-487
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• 1990

The leading cause of death in patients with chronic renal failure is cardiovascular diseases. The problems relevant to cardiac surgery in these patients are occurring more frequently with a growing number of patients at risk. Among these, important risk factors related to uremic patients undergone open heart surgery are fluid and electrolytes imbalance, coagulopathy, increased susceptibility to infection. Since 1968 when Lansing and colleagues reported the first successful aortic valve replacement in patients with chronic renal failure and infective endocarditis, there have been increasing reports of the cardiopulmonary bypass surgery in chronic renal failure patients with acceptable perioperative morbidity and mortality From Jan. 1988 to Nov. 1989 we have experienced four uremic patients necessitating open heart surgery ; one needing a coronary artery bypass graft and the other 3 needed cardiac valve replacement. Based on our observations we would like to suggest followings 1]Intraoperative ultrahemofiltration during C-P bypass thought to be an excellent means for the control of hyperkalemia and fluid balance. 2] The immediate postoperative application of peritoneal dialysis instead of hemodialysis is beneficial in controlling fluid and electrolyte imbalance. 3]The cause of one early postoperative death was not associated to renal failure, rather it was the result of an accidental rupture in the right ventricular wall.

• Journal of Preventive Medicine and Public Health
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• v.34 no.1
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• pp.21-27
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• 2001

Objectives : To develop a model that will predict the mortality of patients undergoing Coronary Artery Bypass Graft (CABG) and evaluate the perfermance of hospitals. Methods : Data from 564 CABGs peformed in six general hospitals were collected through medical record abstraction by registered nurses. Variables studied involved risk factors determined by severity measures. Risk modeling was performed through logistic repression and validated with cross-validation. The statistical performance of the developed model was evaluated using c-statistic, $R^2$, and Hosmer-Lemeshow statistic. Hospital performance was assessed by severity-adjusted mortalities. Results : The developed model included age, sex, BUN, EKG rhythm, Congestive Heart Failure at admission. acute mental change within 24 hours, and previous angina pectoris history. The c-statistic and $R^2$ were 0.791 and 0.001, respectively. Hosmer-Lemeshow statistic was 10.3(p value=0.2415). One hospital had a significantly higher mortality rate than the average mortality rate, while others were net significantly different. Conclusion : Comparing the quality of service by severity adjusted mortality rates, there were significant differences in hospital performance. The severity adjusted mortality rate of CABG surgery may He an indicator for evaluating hospital performance in Korea.

• Journal of Chest Surgery
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• v.38 no.11 s.256
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• pp.733-738
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• 2005

Background: The possibility of incomplete revascularization and development of flow competition after revascularization of the borderline lesion made the hybrid strategy as an option for complete revascularization. Material and Method: From January f998 to July 2004, 25 $(3.2\%)$ patients underwent hybrid revascularization among 782 total OPCAB procedures. Clinical results and angiographic patencies were evalulated. Percutaneous coronary intervention (PCI) was peformed before CABG in 8 patients and after CABG in 47 patients. Result: The causes of PCIs before CABG were to achieve complete revascularization with minimally invasive surgery (n=7) and emergent PCI for culprit lesion (n=1). The indications of PCIs after CABG were high possibility of flow competition in the borderline lesion of right coronary artery territory (n=8), diffuse atheromatous lesion preventing anastomosis of graft (n=5), severe calcified ascending aorta with no more arterial grafi available (n=3), and intramyocardial coronary lesion (n=1). Mean number of distal anastomoses was $2.3\pm1.0$. Mean number of lesions treated by PCI was $1.2\pm0.4$. There was no operative or procedure-related mortality. PCI-related complication was periprocedural myocardial infarction in one patient, and complications related to CABG were transient atrial fibrillation (n=5), perioperative myocardial infarction (n=1), and transient renal dysfunction (n=1). Early postoperative coronary angiography $(1.8{pm}1.6days)$ revealed $100\%$ patency rate of grafts (57/57). The stenosis occurred in one patient performed PCI before CABG, which was successfully treated with re-ballooning. During midterm follow-up (mean; $25{\pm}26$ months), 1 patient died of congestive heart failure. All survivors (n=24) accomplished follow-up coronary angiographics, which showed .all grafts (56/57) were patent except one string sign. In-stent restenosis was developed in 2 patients who received bare metal stents. Conclusion: In selected patients, complete revascularization was achieved with low risk by taking the hybrid strategy.

• Journal of Chest Surgery
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• v.42 no.1
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• pp.22-27
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• 2009

Background: Coronary artery bypass grafting (CABG) is the standard surgical treatment for coronary artery disease. Although there are many clinical reviews of the long term results after CABG in the Western countries, not many such studies have been done for Korea. Therefore, we reviewed the long term clinical results for the patients who underwent CABG at our hospital. Material and Method: We retrospectively reviewed the medical records of 342 patients who underwent CABG at our hospital from February 1984 to December 2006, which is when CABG was first performed in our institution. A total of 286 patients (83.6%) were able to be followed-up, and the mean follow-up period was $75.7{\pm}46.1$ months. Result: The early mortality rate was 5.6%, and late mortality rate was 23.1%. The one-year survival rate, the five-year survival rate, the ten-year survival rate and the fifteen-year survival rate were 91.5%, 82.1%, 60.7% and 50.0%, respectively. The survival rate was significantly lower for the patients over the age of 60 (p=0.002) and for those with diabetes mellitus (p=0.000), hypertension (p=0.002), multivessel disease (p=0.006) and left ventricular dysfunction (p=0.015). No significant difference was observed between the genders. Multivariate analysis showed that the statistically significant risk factors were diabetes mellitus (p=0.001), age (p=0.005) and those cases for which the left internal thoracic artery was not used (p=0.037). Conclusion: CABG is the effective method of treatment for coronary artery disease. Therefore, active usage of the internal thoracic artery and appropriate medical treatment after surgery, and especially for diabetes mellitus patients, are mandatory for achieving good long-term survival.