• 대한핵의학회:학술대회논문집
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• 1999.05a
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• pp.228-241
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• 1999

Percutaneous coronary angioplasty is well established therapeutic modality in the management of coronary artery disease. However, the high restenosis rate of 30 to 50% limits its usefulness. The principal mechanism of restenosis, intimal hyperplasia, is the proliferative response of vessel wall to injury, which consists largely of smooth muscle cells. A large body of animal investigations and a limited number of clinical studies have established the ability of ionizing radiation to reduce neointimal proliferation and restenosis rate significantly. Human studies have been reported that intravascular radiation after first restenosis inhibits a second restenosis. Encouraged by these reports, we are also conducting a double blind, placebo-controlled, randomized trial to evaluate this new therapeutic modality in patients with coronary artery stenosis. The objective of our trial is to determine the safety and efficacy of catheter-based solutional beta emitting radioisotope system in preventing restenosis after angioplasty. This review describes the vascular brachytherapy systems and isotopes that have been utilized in the initial clinical trials performed in this area of post PTCA coronary restenosis. The results of many worldwide ongoing clinical trials will determine whether this new technology will change the future practice of vascular intervention.

• Journal of Chest Surgery
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• v.33 no.7
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• pp.576-580
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• 2000

Transmycardial laser revascularization has made its position as a sole therapy for patients with chronic angina nonamenable to maximal medical therapy, percutaneous transluminal coronary angioplasty, and coronary artery bypass grafting. We report three cases of transmyocardial laser revascularization as a sole therapy for patients with recurrent angina after CABG.

• Journal of Chest Surgery
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• v.30 no.11
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• pp.1132-1135
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• 1997

We have experienced two cases of coronary revascularization without extracorporeal circulation in a 63 year old female patient and a 75 year old male patient. The first patient had the lesion which was the nearly total occulusion of mid-LAD, about 90% luminal narrowing of second diagonal branch and less than 50% stenosis of proximal RCA. The other male patient had a single vessel disease involving about 95% stenosis of proximal LAD and 1st diagonal branch. PTCA failed in the irst patient because of relatively long sinus pause during procedure In both of the patients, the coronary revascularizations were done at distal LAD and diagonal branch using left internal mammary artery and saphenous vein graft under the beating state, respectively. The postoperative courses were uneventful and the patients were discharged without any complications.

• Health Policy and Management
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• v.13 no.4
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• pp.115-130
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• 2003

Reperfusion delay in patients with acute myocardial infarction leads to increased morbidity and mortality. We sought to measure the rates of reperfusion delay and to identify factors associated with reperfusion delay after arrival to hospitals. We included 360 patients who had acute myocardial infarction with ST-elevation or left bundle branch block on electrocardiogram and received reperfusion therapy from the three participating academic medical centers from 1997 to 2000. Through retrospective chart review, we collected data about time to reperfusion therapy, patient and hospital factors potentially associated with reperfusion delay. Factors independently associated with reperfusion delay were determined by logistic regression analysis. Median door­to­needle time was 60.0 minutes, and median door­to­balloon time was 102.5 minutes. According to recommendation of the American College of Cardiology/American Heart Association Guidelines, 226 out of 264(85.6％) of thrombolytic patients and 43 out of 96(44.8％) percutaneous transluminal coronary angioplasty(PTCA) patients experienced reperfusion delay. The significant factors associated with delay were type of reperfusion therapy, patient factors including hypertension and delayed symptom onset to presentation(>4 hours), and hospital factors including nocturnal presentation(6pm∼8am), weekend, and an individual hospital. A significant proportion of patients experienced reperfusion delay. The identified predictors of reperfusion delay may help design a hospital system to reduce the delay in reperfusion therapy

• Journal of Chest Surgery
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• v.29 no.11
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• pp.1263-1266
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• 1996

We have experienced a case of coronary artery bypass surgery without extracorporeal circulation through limited anterior thoracotomy. The lesion was a single vessel disease involving the take off of the left anterior descending artery(LAD) which showed tubular lesion with irregular contour and eccentric stenosis of more than 95% luminal narrowing. Percutaneous transluminal coronary angioplasty(PTCA) seemed to have moderate success rate and moderate complication rate. A segment of left internal mammary artery(LIMA) from the second rib down to the sixth rib was harvested through the bed of resected fourth costal cartilage. Anastomosis between LIMA and LAD was performed under beating condition. The patient was extubated in the operation room and showed excellent postoperative course without complications. The coronary angiography on the postoperative 7th day revealed good patency at the anastomosis site.

• The Korean Journal of Nuclear Medicine
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• v.37 no.4
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• pp.219-228
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• 2003

Purpose: The amount of salvaged myocardium is an important prognostic factor in patients with acute myocardial infarction (MI). We investigated if early Tl-201 SPECT imaging could be used to predict the salvaged myocardium and functional recovery in acute MI after primary PTCA. Materials and Methods: In 36 patients with first acute MI treated with primary PTCA, serial echocardiography and Tl-201 SPECT imaging ($5.8{\pm}2.1$ days after PTDA) were performed. Regional wall motion and perfusion were quantified with on 16-segment myocardial model with 5-point and 4-point scaling system, respectively. Results: Wall motion was improved in 78 of the 212 dyssynergic segments on 1 month follow-up echocardiography and 97 on 7 months follow-up echocardiography, which were proved to be salvaged myocardium. The areas under receiver operating characteristic curves of Tl-201 perfusion score for detecting salvaged myocardial segments were 0.79 for 1 month follow-up and 0.83 for 7 months follow-up. The sensitivity and specificity of Tl-201 redistribution images with optimum cutoff of 40% of peak thallium activity for detecting salvaged myocardium were 84.6% and 55.2% for 1 month follow-up, and 87.6% and 64.3% for 7 months follow-up, respectively. There was a linear relationship between the percentage of peak thallium activity on early redistribution imaging and the likelihood of segmental functional improvement 7 months after reperfusion. Conclusion: Tl-201 myocardial perfusion SPECT imaging performed early within 10 days after reperfusion can be used to predict the salvaged myocardium and functional recovery with high sensitivity during the 7 months following primary PTCA in patients with acute MI.

• Journal of Chest Surgery
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• v.32 no.11
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• pp.1009-1016
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• 1999

Background: Minimally invasive direct coronary artery bypass surgery(MIDCAB) has been increasing in interest along with the new techniques in myocardial immobilization for easier and safer procedures. Until the opening of the era of new techniques, adequate accuracy and good patency of grafts were debatable. Our experiences of MIDCAB were studied according to the stages of technical developments. Material and Methods: Since March 1996, 55 patients have undergone MIDCAB procedures. The patients of off-pump CABG(no cardiopulmonary bypass under full sternotomy) were excluded from the study. In the early experience(Stage I), a left anterior small thoracotomy through the left parasternal incision was performed(n=6); then an approach through the lower partial sternotomy was used(Stage II, n=33); and recently, a chest wall elevator for harvesting the internal thoracic artery and the foot plate for myocardial immobilization have been used(USSC, Norwalk, CT)(Stage III, n=16). Result: The surgical procedures of four patients in the Stage II group have been converted to conventional bypass because of the deeply seated left anterior descending coronary artery in two patients, fracture of the calcific lesion in the right coronary artery in one patient, and a cardiogenic shock during hypothermia in the other patient with ventricular dysfunction. Two patients in stage II experienced symptomatic recurrences after surgery and restenosis was verified on angiocardiography. They were managed by interventional procedures. All the other patients were doing well without symptoms, except one patients in Stage II who underwent PTCA procedure for a lesion in the circumflex artery during the follow up period. Conclusion: The new and specialized devices are essential to the development of MIDCAB surgery. MIDCAB and the hybrid procedures in multi-vessel disease are on the way to further development. So far, our experience is limited only to a single device among the many new devices for the purpose.

• Journal of Chest Surgery
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• v.28 no.5
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• pp.453-463
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• 1995

During 42 month period 91 consecutive patient underwent coronary artery bypass surgery. The mean age of these patient was 57 years [range from 28 to 78 years . There were 57 men and 34 women. The preoperative risk factors that include beyond the 50 % of total patients were male sex, obesity, hypo-high-density lipoproteinemia, smoking, hypercholesterolemia, hyper-low-density lipoproteinemia, hypertriglyceridemia and hypertension. Preoperatively 27 patients had stable angina pectoris and 39 patients of unstable angina pectoris. Twenty five patients had previous myocardial infarction history. The patterns of disease were 8 patients of single vessel involvement, 18 patients of double vessel involvement, 54 patients of triple vessel involvement and 11 patients of left main coronary artery disease. Fifty five patients were in Canadian Cardiovascular Society functional class III. Myocardial revascularization was performed under emergency conditions in 5 patients. Nine percent of patients had previous PTCA history. We performed 16 cases of sequential anastomosis, internal mammary artery harvest in 86 percent of total patients and total 284 distal anastomoses[mean 3.1 anastomosis per patient . The mean ACC time was 60.5 minutes and ECC time was mean 110 minutes. The combined surgeries were 16 cases of endarterectomy, 2 cases of LV aneurysmectomy, 1 case of Bentall operation, 1 case of repair of sinus of Valsalva, 1 case of ligation of coronary AV fistula and 1 case of excision of breast mass. The most common complication was wound infection[12 cases, 13 % . There was one hospital death due to postoperative respiratory failure and low output syndrome in patient with postinfarction VSD, LV aneurysm. Postoperative 88 patients were in Functional class I or II. The 99mTc-MIBI myocardial perfusion scan that used as evaluation of postoperative state was well correlated with patient`s symptoms instead of some disadvantages.

• 대한핵의학회:학술대회논문집
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• 1999.05a
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• pp.205-208
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• 1999

Percutaneous Transluminal Coronary Angioplasty (PTCA) remains limited by restenosis that occurs in 30 to 50% of patients with coronary artery disease. During the last decade, numerous agents have been used to prevent restenosis. Despite positive results in animal models, no pharmacological therapy has been found to significantly decrease the risk of restenosis in humans. These discrepancies between animal models and clinical situation were probably related to an incomplete understanding of the mechanism of restenosis. Neointimal thickening occurs in response to experimental arterial injury with a balloon catheter. Neointimal formation involves different steps: smooth muscle cell activation, proliferation and migration, and the production of extracellular matrix. The factors that control neointimal hyperplasia include growth factors, humoral factors and mechanical factors. Arterial remodeling also plays a major role in the restenosis process. Studies performed in animal and human subjects have established the potentials for "constrictive remodeling" to reduce the post-angioplasty vessel area, thereby indirectly narrowing the vessel lumen and thus contributing to restenosis. The reduction of restenosis rate in patients with intracoronary stent implantation has been attributed to the preventive effect of stent itself for this negative remodeling. In addition to these mochanisms for restenosis, intraluminal or intra-plaque thrombus formation, reendothelialization and apoptosis theories have been introduced and confirmed at least in part.

• Journal of Chest Surgery
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• v.31 no.11
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• pp.1049-1055
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• 1998

Background: Coronary artery bypass surgery is an important treatment for ischemic heart disease. Recently operative mortality and morbidity has decreased, however further improvement is necessary. Materials and methods: This study was designed to evaluate the risk of operative mortality and morbidity by retrospective method. From 1992 to 1997, eighty six patients underwent coronary artery bypass surgery. There were 61 males and 25 females aged 36~74 years(mean, 58.6). Fourteen patients(16%) had previous PTCA or stent insertion, 41 patients(48%) had unstable angina, and 45 patients(52%) had three vessel disease. Patients with low LV ejection fraction(<35%) were 7 cases and urgent or emergent operation were 10 cases. There were 6 cases of combined surgery which were mitral valve replacement(2 cases), aortic valve replacement(2 cases), ASD repair(1 case), and VSD repair(1 case). Average number of distal anastomosis was 3.5 per patient and average aortic cross clamp time was 115±38.3min. Preoperative risk factors were defined as follows: female, old age(>70 years), low body surface area(<1.5M2), PTCA or stent insertion history, hypercholesterolemia, smoking, hypertension, DM, COPD, urgent or emergent operation, left main disease, low LV ejection fraction(<35%), and combined surgery. Results: Operative mortality was 7cases(8%). As a postoperative morbidity, perioperative myocardial infarction was 6 cases, cerebrovascular accident 6 cases, reoperation for bleeding 5 cases, acute renal failure 4 cases, gastrointestinal complication 3 cases, and mediastinitis 3 cases. In the evaluation of operative risk factors, low body surface area, DM and low LV ejection fraction were found to be predictive risk factors of postoperative morbidity(p<0.05), and low ejection fraction was especially a risk factor of hospital mortality(p<0.05). Conclusions: In this study, low body surface area, DM and low LV ejection fraction were risk factors of postoperative morbidity and low ejection fraction was a risk factor of hospital mortality.