• Journal of Chest Surgery
• /
• v.32 no.11
• /
• pp.998-1003
• /
• 1999

Background: Bovine pericardium treated with glutaraldehyde(GA) is one of the most popular prosthetic materials. However, its late calcific degeneration after implantation results in early failure of the prosthesis. Therefore, we investigated the effects of combined treatment with sodium dodecyl sulfate(SDS) and glutamate on calcific degeneration of GA treated bovine pericardium. Material and Method: Sixty square-shaped pieces of bovine pericardia were fixed in 0.625% GA solution with 4g/L MgCl2.6H2O as a control group (group 1). Sixty pieces pretreated with 1% SDS (group 2) and sixty pieces posttreated with 8% glutamate (group 3) were also fixed in the same GA solution. Sixty pieces pretreated with 1% SDS and posttrated with 8% glutamate were also fixed in the same GA solution (group 4). After 1 month of fixation, the pieces were implanted into the belly of sixty Sprague-Dawley rat subdermally and were extracted 1 month, 2 months and 3 months after the implantation. With an atomic absorption spectrophotometry, we measured the calcium amount deposited. Result: The calcium deposition in 1 month was 2.01$\pm$0.13 mg/g in group 1, 1.45$\pm$0.31 mg/g in group 2, 2.49$\pm$0.15 mg/g in group 3 and 0.75$\pm$0.27 mg/g in group 4. In 2 months, it was 3.57$\pm$0.15 mg/g in group 1, 0.98$\pm$0.30 mg/g in group 2, 3.46$\pm$0.12 mg/g in group 3, and 1.48$\pm$0.39 mg/g in group 4, and 5.45$\pm$0.42 mg/g in group 1, 2.43$\pm$0.53 mg/g in group 2, 4.20$\pm$0.55 mg/g in group 3, and 1.02$\pm$0.27 mg/g in group 4 in 3 months. The calcium depositions in group 2 and 4 were less than those of group 1 and 3 in 1 month 2, months, and 3 months(p<0.01). The calcium depositions in group 1, 2 and 3 increased with time. However, they remained unchanged in group 4, which was statistically significant(p<0.01). Conclusion: Pretreatment with SDS is effective in reducing calcification of GA treated bovine pericardium, and the combined method of pretreatment with SDS and posttreatment with glutamate was more effective than the other methods.

• Journal of Chest Surgery
• /
• v.50 no.4
• /
• pp.255-262
• /
• 2017

Background: Transcatheter aortic valve replacement (TAVR) has been suggested as a less invasive treatment for high-risk patients with aortic valve disease. I n this study, we compared the outcomes of conventional surgical aortic valve replacement (AVR) and TAVR in elderly patients aged over 80. Methods: A total of 108 patients aged 80 years or older who underwent isolated AVR (n=35) or TAVR (n=73) from 2010 through 2015 at Asan Medical Center were identified. Early and late clinical outcomes, including echocardiographic findings, were evaluated in both groups. The mean follow-up duration was $766.4{\pm}528.7days$ in the AVR group and $755.2{\pm}546.6days$ in the TAVR group, and the average timing of the last follow-up echocardiography was at $492.6{\pm}512.5days$ in the AVR group and $515.7{\pm}526.8days$ in the TAVR group. Results: The overall early mortality was 2.8% (0 of 35, 0% in the AVR group vs. 3 of 73, 4.1% in the TAVR group). Permanent pacemaker insertion was significantly more common in the TAVR group (p=0.010). Renal failure requiring dialysis and new-onset atrial fibrillation was more frequent and the length of hospital stay was longer in the AVR group; however, this difference did not reach statistical significance. In the TAVR group, 14 patients (19.2%) were rehospitalized due to cardiac problems, and 13 patients (17.8%) had developed significant paravalvular leakage by the time of the last follow-up echocardiography. Conclusion: TAVR could be a good alternative to conventional surgical AVR in elderly patients. However, TAVR has several shortcomings, such as frequent significant paravalvular leakage or readmission, which should be considered in decision-making.

• Korean Journal of Head & Neck Oncology
• /
• v.16 no.2
• /
• pp.172-176
• /
• 2000

Objectives: To improve local control and reduce toxicity, 3-D conformal radiotherapy was used as a boost the primary tumor site following fractionated radiotherapy in patients with nasopharyngeal carcinoma. Materials and Methods: Eight patients with previously untreated nasopharyngeal carcinomas were treated with 3-D conformal radiotherapy following fractionated radiotherapy from September 1998 to April 2000. All patients had biopsy confirmation of disease before radiation therapy. Stages were II in 1, III in 5, and IV in 2. Two patients received cisplatin based chemotherapy in addition to radiation therapy; induction chemotherapy in 1, concurrent chemoradiation in 1. 3-D conformal radiotherapy delivered using 6MV Linac as a boost(range 25.2-28.8Gy, median 25.7Gy) following conventionally fractionated radiotherapy(range 50.4Gy). Average total dose ranged from 75.6-79.2Gy(median 76Gy). Follow-up time was 4-21 months(median 9.6 months). Results: Seven of 8 patients were evaluated radiologically within 3 months after completion of radiation therapy. All 7 patients were seen complete remission. One of 7 patients had distant metastasis after 5 months and local failure after 7 months. The tree interval of local recurrence was ranged from 4 - 21 months(median 10.2 months). One patient without radiological evaluation got complete remission clinically. Treatment related toxicity was grade 1-3 xerostomia, dysphagia, and mucositis. During 3-D conformal radiotherapy, there was no aggravation of any toxicity. Conclusion: Although the number of patients was small and follow-up period was short, 3-D conformal radiotherapy following conventional radiotherapy improved tumor control and dose escalation without increased toxicity. Survival and late toxicity should be evaluated through long term follow-up. In addition, it is necessary to confirm the benefits of 3-D conformal radiotherapy in nasopharyngeal carcinoma with randomized trial.

• Journal of Chest Surgery
• /
• v.31 no.12
• /
• pp.1165-1171
• /
• 1998

Background: All currently available mechanical and bioprosthetic valves are associated with various types of deterioration leading to dysfunction and/or valvular complications. Reoperation on prosthetic heart valves is increasingly under consideration for both clinical and prophylactic indications. This review was conducted to determine the factors affecting the risk of reoperation for prosthetic valve replacement. Material and method: From January 1985 to July 1996, 124 patients underwent reoperation on prosthetic heart valves, and 3 patients had a second valve reoperation. The causes of reoperation were prosthetic valve failure(96 cases, 77.4%), prosthetic valve thrombosis(16 cases, 12.9%), prosthetic valve endocarditis(7 cases, 5.6%) and paravalvular leak(5 cases, 4.1%). This article is based on the analysis of the experience with particular emphasis on the preoperative risks affecting the outcome of the reoperation. Result: Overall hospital mortality rate was 8.9%(11/124). Low cardiac output was the most common cause of death(70.6%). Left ventricular systolic dimension(p=0.001), New York Heart Association functional class IV(p=0.003) and serum creatinine level(p=0.007) were the independent risk factors, but age, sex and cardiothoracic ratio did not have any influence on the operative mortality. Follow-up period was ranged from 3 to 141 months (mean, 50.6 months). A late mortality rate was 1.8%. Conclusion: The surgical risk of reoperation on heart valve prostheses in the advanced NYHA class patients is higher, therefore reoperation is recommended before the hemodynamic impairment become severe.

• Journal of Chest Surgery
• /
• v.37 no.7
• /
• pp.553-558
• /
• 2004

Avoiding cardiopulmonary bypass (CPB) in coronary artery bypass grafting (CAB G) has been known to reduce early mortality and morbidity. Diabetes Mellitus is a significant risk factor for adverse early and late outcomes after CABG. We compared the clinical results of off-pump CABG versus on-pump CABG in diabetes patients. Material and Method: 682 patients (424 off-pump CABG and 258 on-pump CABG) underwent isolated coronary artery bypass grafting between January 2001 and June 2003. Data were collected 242 patient who had diabetes. Among them, 154 patients underwent off-pump CABG and 90 patients underwent on-pump CABG. We analyzed the preoperative risk factors and postoperative results between 2 groups. Result: Two groups did not show statistical differences in age, sex, coronary and operative risk factors. Operative time was significantly shorter in off-pump CABG, however, number of grafts was fewer in off-pump CABG. Postoperative inotropic usage was lower in off-pump CABG. Postoperative CK-MB level was lower in off-pump CABG, and ICU stay and ventilation time was significantly shorter in off-pump CABG. However, there was no statistical difference between 2 groups in operative mortality, reoperation rate, perioperative myocardial infarction, wound infection, renal failure, neurological complications and hospital stay. Conclusion: Off-pump CABG group showed less myocardial damage and early recovery. We concluded that off-pump CABG is the more reasonable technique in diabetes patients although two techniques showed good results. The long-term follow up and prospective study may be warranted.

• Radiation Oncology Journal
• /
• v.29 no.3
• /
• pp.156-163
• /
• 2011

Purpose: To evaluate long-term local control rate and toxicity in patients treated with external beam radiotherapy (EBRT) for pituitary adenomas. Materials and Methods: We retrospectively reviewed the medical records of 60 patients treated with EBRT for pituitary adenoma at Korea University Medical Center from 1996 and 2006. Thirty-five patients had hormone secreting tumors, 25 patients had non-secreting tumors. Fifty-seven patients had received postoperative radiotherapy (RT), and 3 had received RT alone. Median total dose was 54 Gy (range, 36 to 61.2 Gy). The definition of tumor progression were as follows: evidence of tumor progression on computed tomography or magnetic resonance imaging, worsening of clinical sign requiring additional operation or others, rising serum hormone level against a previously stable or falling value, and failure of controlling serum hormone level so that the hormone level had been far from optimal range until last follow-up. Age, sex, hormone secretion, tumor extension, tumor size, and radiation dose were analyzed for prognostic significance in tumor control. Results: Median follow-up was 5.7 years (range, 2 to 14.4 years). The 10-year actuarial local control rates for non-secreting and secreting adenomas were 96% and 66%, respectively. In univariate analysis, hormone secretion was significant prognostic factor (p = 0.042) and cavernous sinus extension was marginally significant factor (p = 0.054) for adverse local control. All other factors were not significant. In multivariate analysis, hormone secretion and gender were significant. Fifty-three patients had mass-effect symptoms (headache, dizziness, visual disturbance, hypopituitarism, loss of consciousness, and cranial nerve palsy). A total of 17 of 23 patients with headache and 27 of 34 patients with visual impairment were improved. Twenty-seven patients experienced symptoms of endocrine hypersecretion (galactorrhea, amenorrhea, irregular menstruation, decreased libido, gynecomastia, acromegaly, and Cushing's disease). Amenorrhea was abated in 7 of 10 patients, galactorrhea in 8 of 8 patients, acromegaly in 7 of 11 patients, Cushing's disease in 4 of 4 patients. Long-term complication was observed in 4 patients; 3 patients with cerebrovascular accident, 1 patient developed dementia. Of these patients, 3 of 4 received more than 60 Gy of irradiation. Conclusion: EBRT is highly effective in preventing recurrence and reducing mass effect of non-secreting adenoma. Effort to improve tumor control of secreting adenoma is required. Careful long-term follow-up is required when relatively high dose is applied. Modern radiosurgery or proton RT may be options to decrease late complications.

• Nuclear Engineering and Technology
• /
• v.28 no.2
• /
• pp.129-136
• /
• 1996

Influence diagram method is applied to containment performance analysis of Young-Gwang 3&4 in an effort to overcome some drawbacks of current containment performance analysis method. Event tee methodology has been adopted as a containment performance analysis method. There are, however, some drawbacks on event tree methodology. This study is to overcome three major drawbacks of the current containment performance analysis method : 1) Event tree cannot express dependency between events explicitly. 2) Accident Progression Event Tree (APET) cannot represent entire containment system. 3) It is difficult to consider decision making problem. To resolve these problems, influence diagrams, is proposed. In the present ok, the applicability of the influence diagrams has been demonstrated for YGN 3&4 containment performance analysis and accident management strategy assessments of this study are in good agreement with those of YGN 3&4 IPE. Sensitivity analysis has been peformed to identify relative important variables for each early containment failure, late containment and basemat melt-though. In addition, influence diagrams are used to assess two accident management strategies : 1) RCS depressurization, 2) cavity flooding. It is shown that influence diagrams can be applied to the containment performance analysis.

• Korean Journal of Head & Neck Oncology
• /
• v.7 no.2
• /
• pp.120-128
• /
• 1991

Reconstruction of the pharynx and cervical esophagus presents a tremendous surgical challenge to the Head and Neck Surgeon. Because life expectancy of patients with advanced carcinoma of the hypopharynx, and cervical esophagus is limited, treatment must be aimed at palliation. A variety of techiques have been proposed over the years with none proving entirely satisfactory. These techiques include prosthesis; skin graft; cervical flaps; tubed cutaneous and myocutaneous chest flaps; visceral reconstruction with stomach, colon. and jejunum; and jejunal free autografts. Many factors dictate the best method of reconstruction in any given clinical situation. The goal of the surgery is a one-stage reconstruction of swallowing function with minimal morbidity to allow as short a hospital stay as posible. Nine patients underwent the free jejunal autograft reconstruction of the pharyngoesophagus after the ablative surgery for the advanced hypopharyngeal cancer. Postoperative complications included one perioperative death, two abdominal wound dehiscences, two neck hematomas, one carotid rupture, one funtional dysphagia, one late strictures. There were no graft failure, no immediate stenosis and no fistula. An oral diet was started between days 8 and 16, with an average of 9 days and median of 8 days. Patients left the hospital between days 9 and days 38, with an average of 23.4 days and median of 23 days. This method of reconstruction is advocated as reliable palliative procedure with short-term follow-up. In conclusion, we at Korea Cancer Center Hospital are of the opinion that the free jejunal autograft offers an excellent, safe and relative easy method of the pharyngeal and cervical esophageal reconstruction with significant advantages over other techiques.

• Journal of Chest Surgery
• /
• v.34 no.9
• /
• pp.680-685
• /
• 2001

Background: Tricuspid valve replacement is very rarely performed procedure and its long-term result is not yet satisfactory. Moreover, it is not well known whether bioprosthesis or mechanical prosthesis is the best selection for artificial valve. We reviewed 72 cases of tricuspid valve replacements in 71 patients between January 1989 and December 1998, trying to analyze the overall results and risk factors for mortality and morbidity. Material and Method: Average age of the patients at the time of operation was 42$\pm$13 years(range 16 to 65 years) and the sex ratio of male versus female was 32/39. Primary diagnosis consisted of 50 cases of aquired valvular heart disease and 18 cases of congenital heart disease, such as Ebstein’s anomaly. 4 cases had isolated tricuspid valve regurgitation. Implanted valves were 69 mechanical prosthesis and 3 bioprosthesis. Concomitant mitral or aortic valve replacements were performed in 50 cases. One patient received concomittant pulmonary valve replacement. Result: There were 7(9.72%) operative deaths and 7(13.0%) late deaths. Actuarial survival at 10 years was 59.2$\pm$7.2%. Prosthetic tricuspid valve thrombosis occurred 11 times in 5 patients. Reoperation for prosthetic tricuspid valve failure was performed in 1 patient. In this case, examination of the explanted prostheses showed that the tricuspid stenosis was the result of valve thrombosis. Among the 47 survivors, 46 patients(98%) were in functional class I or II. Conclusion: In our ten-year experience of tricuspid valve replacement, mortality and morbidity were satisfactory. Mechanical prosthesis in tricuspid position showed comparable clinical results as bioprosthesis.

• Radiation Oncology Journal
• /
• v.31 no.3
• /
• pp.118-124
• /
• 2013

Purpose: The optimal treatment of advanced maxillary sinus cancer has been challenging for several decades. Intra-arterial chemotherapy (IAC) for head and neck cancer has been controversial. We have analyzed the long-term outcome of neoadjuvant IAC followed by radiation therapy (RT) and surgery. Materials and Methods: Twenty-seven patients with advanced maxillary sinus cancer were treated between 1989 and 2002. Five-fluorouracil (5-FU, $500mg/m^2$) was infused intra-arterially, and followed by RT (total 50.4 Gy/28 fractions). A planned surgery was performed 3 to 4 weeks after completion of IAC and RT. Results: At a median follow-up of 77 months (range, 12 to 169 months), the 5-year rates of overall survival in all patients were 63%. The 5-year rates of overall survival of stage T3/T4 patients were 70.0% and 58.8%, respectively. Seven of fourteen patients with disease recurrence had a local recurrence alone. The 5-year actuarial local control rates in patients with stage T3/T4, and in all patients were 20.0%, 32.3%, and 27.4%, respectively. Overall response rate after the completion of IAC and RT was 70.3%. During the follow-up, seven patients (25.9%) showed mild to moderate late complications. The tumor extent (i.e., the involvement of either orbit and/or base of skull) appeared to be related with local recurrence. Conclusion: Neoadjuvant IAC with 5-FU followed by RT and surgery may be effective to improve local tumor control in the patients with advanced maxillary sinus cancer. However, local failure was still the major cause of death. Further investigations are required to determine the optimal treatment schedule, radiotherapy techniques and chemotherapy regimens.