• Journal of Chest Surgery
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• v.31 no.8
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• pp.739-748
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• 1998

Background: It has been well documented that transient occlusion of the coronary artery causes myocardial ischemia and finally cell death when ischemia is sustained for more than 20 minutes. Extensive studies have revealed that ischemic myocardium cannot recover without reperfusion by adequate restoration of blood flow, however, reperfusion can cause long-lasting cardiac dysfunction and aggravation of structural damage. The author therefore attempted to examine the effect of postischemic reperfusion on myocardial ultrastructure and to determine the rationales for recanalization therapy to salvage ischemic myocardium. Materials and methods: Young Holstein-Friesian cows(130∼140 Kg body weight; n=40) of both sexes, maintained with nutritionally balanced diet and under constant conditions, were used. The left anterior descending coronary artery(LAD) was occluded by ligation with 4-0 silk snare for 20 minutes and recanalized by release of the ligation under continuous intravenous drip anesthesia with sodium pentobarbital(0.15 mg/Kg/min). Drill biopsies of the risk area (antero-lateral wall) were performed at just on reperfusion(5 minutes), 1-, 2-, 3-, 6-, 12-hours after recanalization, and at 1-hour assist(only with mechanical respiration and fluid replacement) after 12-hour recanalization. The materials were subdivided into subepicardial and subendocardial tissues. Tissue samples were examined with a transmission electron microscope (Philips EM 300) at the accelerating voltage of 60 KeV. Results: After a 20-minute ligation of the LAD, myocytes showed slight to moderate degree of ultrastructural changes including subsarcolemmal bleb formation, loss of nuclear matrix, clumping of chromatin and margination, mitochondrial destruction, and contracture of sarcomeres. However, microvascular structures were relatively well preserved. After 1-hour reperfusion, nuclear and mitochondrial matrices reappeared and intravascular plugging by polymorphonuclear leukocytes or platelets was observed. However, nucleoli and intramitochondrial granules reappeared within 3 hours of reperfusion and a large number of myocytes were recovered progressively within 6 hours of reperfusion. Recovery was apparent in the subepicardial myocytes and there were no distinct changes in the ultrastructure except narrowed lumen of the microvessels in the later period of reperfusion. Conclusions: It is likely that the ischemic myocardium could not be salvaged without adequate restoration of coronary flow and that the microvasculature is more resistant to reversible period of ischemia than subendocardium and subepicardium. Therefore, thrombolysis and/or angioplasty may be a rational method of therapy for coronarogenic myocardial ischemia. However, it may take a relatively longer period of time to recover from ischemic insult and reperfusion injury should be considered.

• Journal of Chest Surgery
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• v.30 no.10
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• pp.966-972
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• 1997

Between June 1994 to August 1996, 13 patients underwent emergency coronary artery bypass operations. There were 3 males and 10 females and ages ranged from 56 to 80 years with the mean of 65.5 years. The indications for emergency operations were cardiogenic shock in 12 cases and intractable polymorphic VT(ve'ntricular tachycardia) in 1 case. The causes of cardiogenic shock were acute evolving infarction in 6 cases, PTCA failure in 4 cases, acute myocardial infarction in 1 case, and post-AMI VSR(ventricular septal rupture) in 1 case. Pive out of 13 patients could go to operating room within 2 hours. However, the operations were delayed from 3 to 10 hours in 8 patients due to non-medical causes. In 12 patients, 37 distal anastomoses were constructed with only 3 LITA's(left internal thoracic arteries) and 34 saphenous veins. In a patient with post-AMI VSR, VSR repair was added. In a patient with intractable VT and critical sten sis limited to left main coronary artery, left main coronary angioplasty was performed. Pive patients died after operation with the operative mortality of 38.5%. Three patients died in the operating room due to LV pump failure, one patient died due to intractable ventricular tachycardia on postoperative second day, and one patient died on postoperative 7th day due to multi-organ failure with complications of mediastinal bleeding, low cardiac output syndrome, ARF, and lower extremity ischemia due to IABP. In 8 survived patients, 3 major complications (mediastinitis, PMI, UGI bleeding) developed but eventually recovered. We think that the aggressive approach to critically ill patients will salvage some of such patients and the most important factor for patient salvage is early surgical intervention before irreversible damage occurs.

• Journal of Chest Surgery
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• v.44 no.6
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• pp.392-398
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• 2011

Background: The tetralogy of Fallot (TOF) with pulmonary atresia (PA) and a ductus-dependent pulmonary circulation (no major aorto-pulmonary collateral arteries (MAPCAs)) has been treated with staged repair or primary repair depending on the preference of surgeons or institutions. We evaluated the 19-year outcome of staged repair for this anomaly to find out whether our surgical strategy should be changed. Materials and Methods: Forty-four patients with TOF/PA with patent ductus arteriosus (PDA) who underwent staged repair from June 1991 to October 2010 were included in this retrospective study. The patients with MAPCAs were excluded. The average age at the first palliative shunt surgery was $40.8{\pm}67.5$ days (range: 0~332 days). Thirty-one patients (31/44, 70%) were neonates. The average weight was $3.5{\pm}1.6$ kg (range: 1.6~8.7 kg). A modified Blalock-Taussig (BT) shunt was performed in 38 patients, classic BT shunt in 4 patients, and central shunt in 2 patients. Six patients required concomitant procedures: pulmonary artery angioplasty was performed in 4 patients, pulmonary artery reconstruction in one patient, and re-implantation of the left pulmonary artery to the main pulmonary artery in one patient. Four patients required a second shunt operation before the definitive repair was performed. Thirty-three patients underwent definitive repair at $24.2{\pm}13.3$ months (range: 7.3~68 months) after the first palliative operation. The average age at the time of definitive repair was $25.4{\pm}13.5$ months (range: 7.6~68.6 months) and their average weight was $11.0{\pm}2.1$ kg. For definitive repair, 3 types of right ventricular outflow procedures were used: extra-cardiac conduit was performed in 30 patients, trans-annular patch in 2 patients, and REV operation in 1 patient. One patient was lost to follow-up after hospital discharge. The mean follow-up duration for the rest of the patients was $72{\pm}37$ months (range: 4~160 months). Results: Ten patients (10/44, 22.7%) died before the definitive repair was performed. Four of them died during hospitalization after the shunt operation. Six deaths were thought to be shunt-related. The average time of shunt-related deaths after shunt procedures was 8.7 months (range: 2 days~25.3 months). There was no operative mortality after the definitive repair, but one patient died from dilated cardiomyopathy caused by myocarditis 8 years and 3 months after the definitive repair. Five-year and 10-year survival rates after the first palliative operation were 76.8% and 69.1%, respectively. Conclusion: There was a high overall mortality rate in staged repair for the patients with TOF/PA with PDA. Majority of deaths occurred before the definitive repair was performed. Therefore, primary repair or early second stage definitive repair should be considered to enhance the survival rate for patients with TOF/PA with PDA.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.2
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• pp.112-119
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• 2009

Purpose: This study was performed to investigate the clinical significance of reverse redistribution(RR) phenomenon detected on delayed Tc-99m tetrofosmin myocardial single photon emission computed tomography(SPEG) in patients with acute myocardial infarction after revascularization. Materials and Methods: A Tc-99m tetrofrosmin myocardial SPECT was performed in 67 consecutive patients after revascularization for acute myocardial infarction. Myocardial SPECT imaging was performed for early imaging at 40 min and for delayed imaging at 180 min after reinjection at myocardial stress. Regional myocardial uptakes were scored by 4-point scoring in the left ventricular wall divided into 17 segments. Reverse redistribution was defined as an increase of more than 2 point in the activity score on the delayed image. Follow-up myocardial SPECT and coronary angiography(CAG) were performed 9 months later. Results: On myocardial SPECT performed following revascularization, RR was observed in 100 of all 319 segments(31%) and in 43 patients(64%). The abnormalities of perfusion and regional wall motion were more severe in the patients with RR compared to those without RR(p<0.05). On follow-up myocardial SPECT, the myocardial perfusion, regional wall motion, and myocardial thickness were significantly improved in the patients with RR(p<0.05) however, these changes were not significant in those without RR. There was no significant difference between the patients with RR and those without RR in the occurrence of restenosis on CAG. Conclusions: In patients with acute myocardial infarction, the regions showing the RR phenomenon on delayed Tc-99m tetrofosmin SPECT may reflect viable myocardium and indicate recovery of salvaged myocardium.

• 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.

• Childhood Kidney Diseases
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• v.1 no.2
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• pp.101-108
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• 1997

Purpose : The clinical characteristics of renovascular hypertension (RVHT) in children were analyzed. Methods : Medical records of 16 children diagnosed as RVHT on the basis of angiography during Jan. '86 to Jun. 94 in our hospital were reviewed retrospectively. Results : The mean age at the onset was 8.5 yrs and the sex ratio(M:F) was 7:9. The causes of RVHT were Takayasu arteritis in 6, Moyamoya disease in 5, and fibromuscular dysplasia in 3 patients. Abdominal bruit was noted in 6 patients (38%). Peripheral renin activity was raised in all tested patients. Bilateral renal arterial involvemnent was found in 9 patients (56%). Captopril renal scans showed good correlation with angiographic findings. Five patients were treated with antihypertensives only, and blood pressure was controlled completely in 2 and incompletely in 3. Percutaneous transluminal angioplasty was performed in 10 patients with 50% of success rate. However, hypertension was recurred due to restenosis or accompaning aortic stenosis in 3 patients. Surgical treatment was performed in 4 patients, and the blood pressure was controlled partially in 1 and poorly in the remaining 3. Conclusions : Takayasu arteritis, Moyamoya disease and fibromuscular dysplasia are the major causes of childhood RVHT in our country. The diagnosis of RVHT in children should be based on a set of tests individually selected for case by case. For the low curability of the current treatment modalities available, RVHT in children should not be regarded as 'curable' so far. We expect, however, that the outcome will be improved by more extensive application of the newly developed surgical technique.

• Journal of radiological science and technology
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• v.37 no.2
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• pp.109-116
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• 2014

Many studies have suggested that in the era of Drug-Eluting Stents(DES) are one of the causes of In-Stent Restenosis(ISR) of Stent Fracture(SF). The present study sought to evaluate clinical characteristics of patients with stent fracture after successful DES implantation. The 4,701 patients were selected for analysis who underwent a follow-up coronary angiography irrespective of ischemic symptoms. The overall incidence of SF was 32 patients(male:female=19:13, Av. age $62.44{\pm}9.8$year, 0.68%). Fractures of Sirolimus-Eluting Stents(SES), Paclitaxel-Eluting Stents(PES), Biolimus A9-Eluting Stents(BES), Everolimus-Eluting Etents(EES), Endothelial Progenitor Cell Capture Stent(EPC) and Zotarolimus-Eluting Stents(ZES) are accounted for 19(59.4%), 9(28.1%), 2(6.3%), 1(3.1%), 1(3.1%) and 0(0%) respectively. SF developed in the left Anterior Dscending(LAD) artery in 16 patients(50%) and in complex(type B2, C) lesions in 25 patients(69.4%). Ten patients were treated with heterogenous DES, the rest being treated with either homogenous DES(3 patients), plain old balloon angioplasty(3 patients), or conservative medical treatment(17 patients). None of the patients with SF suffered from cardiac death during a follow-up period of $32.9{\pm}12.4$ months. The overall rate of DES fracture over up to 3.7 years of follow-up was 0.68% with higher incidence in SES than in PES. SF frequently occurred in the LAD artery and in complex lesions. Of the patients with SF, coronary intervention was performed only when the binary restenosis lesion was significant. During the follow-up, patients with SF have continued on combination antiplatelet therapy. There is a very low rate of major adverse cardiac events(post-detection of SF), especially cardiac death associated with SF.

• Journal of Chest Surgery
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• v.36 no.8
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• pp.566-575
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• 2003

We reviewed our 18-year surgical experience of biventricular repair for double-outlet right ventricle. Material and Method: One hundred twelve consecutive patients (80 males and 32 females) who underwent biventricular repair for double-outlet right ventricle between May 1986 and September 2002 were included. We assessed risk factors for early mortality and reoperation. Reoperation-free survival rate and actual survival rate were analysed. Result: Most common type of ventricular septal defect was subaortic (n=58, 52%) and non-committed type was second most common (n=32, 29%). Four different surgical methods were used: intraventricular baffle repair (n=71 , 63%): right ventricle to pulmonary ariery conduit interposition or REV with left ventricle to aorta baffle repair (n=24, 21 .4%): arierial switch operation with left ventricle to pulmonary artery baffle (n=14, 12.5%): Senning atrial switch operation with left ventricle to pulmonary artery baffle (n=3, 2.7%). Thirty four patients(30%) underwent palliative procedures before definite repair. Twenty three patients (21%) required reoperations. There were 12 (10.7%) early deaths and 4 late deaths. Age younger than 3 months at repair (p=0.003), cardiopulmonary bypass and aortic cross clamp time (p=0.015, p=0.067), type of operation (arterial switch operation) (p <0.001) and type of ventricular septal defect (subpulmonic type) (p=0.002) were revealed as risk factors for early death in univariate analysis, while age under 3 months was the only significant risk factor in multivariate analysis. Patients younger than 1 year of age (p=0.02), pulmonary artery angioplasty at definitive repair (p=0.024), type of ventricular septal defect (non-committed) (p=0.001), type of operation (right ventricle to pulmonary artery conduit interposition and REV operation) (p=0.028, p=0.017) were risk factors for reoperation in univariate analysis but there was no significant risk factor in multivariate analysis. Follow-up was available on 91 survivals with a mean duration of 110.8$\pm$56.4 (2~201) months. 5, 10 and 15 year survival rates were 86.5%, 85% and 85% and reoperation free survival were 85%, 71.5%, 70%. Conclusion: Age under 3 months at repair, subpulmonic ventricular septal defect and arterial switch operation were significant risk factors for early mortality. Patients with non-committed ventricular septal defect and who underwent conduit interposition or REV operation were risk factors for reoperation. With careful attention to chose best timing and surgical approach depending on morphologic characteristics, biventricular repair for double outlet right ventricle can be achieved with good long-term outcome.

• The Korean Journal of Nuclear Medicine
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• v.32 no.3
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• pp.259-265
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• 1998

Purpose: We studied early rest/24 hour delay T1-201 perfusion SPECT for prediction of wall motion improvement after reperfusion in patients with acute myocardial infarction. Materials and Methods: Among 17 patients (male/female= 11/6, age: $59{\pm}13$) with acute myocardial infarction, 15 patients were treated with percutaneous transcoronary angioplasty (direct:2, delay: 11) and intravenous urokinase (2). Spontaneous resolution occurred in infarct-related arteries of 2 patients. We confirmed TIMI 3 flow of infarct-related artery after reperfusion in all patients with coronary angiography. We performed rest T1-201 perfusion SPECT less then 6 hours after reperfusion and delay T1-201 perfusion SPECT next day. T1-201 uptake was visually graded as 4 point score from normal (0) to severe defect (3). Rest T1-201 uptake ${\le}2$ or combination of rest T1-201 uptake ${\le}2$ or late reversibility were considered to be viable. Myocardial wall motion was graded as 5 point score from normal (1) to dyskinesia (5). Myocardial wall motion was considered to be improved when a segment showed an improvement ${\ge} 1$ grade in follow up echo compared with the baseline values. Results: Among 98 segments with wall motion abnormality, the severity of myocardial wall motion decrease was as follow: mild hypokinesia: 18/98 (18%), severe hypokinesia: 28/98 (29%), akinesia: 51/98 (52%), dyskinesia: 1/98 (1%). The wall motion improved in 85%. Redistribution (13%), and reverse redistribution (4%) were observed in 24 hour delay SPECT. Positive predictive value (PPV) and negative predictive value (NPV) of combination of late reversibility and rest T1-201 uptake were 99%, and 54%. PPV and NPV of rest T1-201 uptake were 100% and 52% respectively. Predictive values of combination of rest T1-201 uptake and late reversibility were not significantly different compared with predictive values of rest T1-201 uptake only. Conclusion: We conclude that early T1-201 perfusion SPECT predict myocardial wall motion improvement with excellent positive but relatively low negative predictive values in patients with acute myocardial infarction after reperfusion.

• Journal of Chest Surgery
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• v.39 no.11 s.268
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• pp.815-821
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• 2006

Background: Carotid endarterectomy is an effective treatment modality in patients with severe carotid artery stenosis, but it may result in serious postoperative complications, We analyzed the results of the carotid endarterectomy performed in our institution to reduce the complications related to the card endarterectomy. Material and Method: We analyzed retrospectively the medical records of 74 patients(76 cases) who underwent carotid endarterectomy for carotid artery stenosis by a single surgeon from February 1996 to July 2004. Result: There were 64 men and 10 women. The mean age of the patients was 63.6 years old. Carotid endarterectomy only was performed in 63 cases, carotid endarterectomy with patch angioplasty in 8 cases, and carotid endarterectomy with segmental resection of internal carotid artery and end to end anastomosis in 5 cases. Intra-arterial shunt was used in 29 cases. The mean back pressures of internal carotid arteries checked after clamping common carotid arteries and external carotid arteries were $23.48{\pm}10.04$ mmHg in 25 cases with changes in electroencephalography(group A) and $47.16{\pm}16.04$ mmHg in 51 cases without changes in electroencephalography(group B). There was no statistical difference in the mean back pressure of internal carotid arteries between two groups(p=0.095), but the back pressures of internal carotid arteries of all patients with changes in electroencephalography were under 40 mmHg. When there was no ischemic change of electroencephalography after clamping common carotid artery and external carotid artery, we did not make use of intra-arterial shunt regardless of the back pressure of internal carotid artery. Operative complications were transient hypoglossal nerve palsy in four cases, cerebral hemorrhage occurred at previous cerebral infarction site in two cases, mild cerebral infarction in one case, hematoma due to anastomosis site bleeding in one case, and upper airway obstruction due to laryngeal edema probably caused by excessive retraction during operation in two cases. One patient expired due to cerebral hemorrhage occurring at previous cerebral infarction site. Conclusion: Carotid endarterectomy is a safe operative procedure showing low operative mortality. We suggest that intra-arterial shunt usage should be decided according to the ischemic change of electroercephalography regardless of the back pressure of internal carotid artery. Excessive retraction during operation should be avoided to prevent upper alway obstruction due to laryngeal edema and if upper airway obstruction is suspected, prompt management is essential.