Coronary Angiography after Coronary artery Bypass Grafting / 대한흉부외과학회지

BACKGROUND: There have been many reports of coronary angiographic findings aft er coronay bypass grafting,most of which are focused on the graft patency rate of the bypass conduits. However,postoperative angiography can provide numerous informations other than patency rates that are useful for establishing operative strategy. MATERIAL AND METHOD: We studied 73 patients in whom coronary angiography was done after more than 1 month of CABG.Mean interval from the operation to coronary angiography was 10.6 months and the reasons for coronary angiography follow up were residual or recurrent angina in 54 patients, abnormalities on myocardial perfusion scan or echocardiography in 13 patients,and for simple follow up in 6 patients. RESULT: Overall graft patency rate was 80.9% (internal thoracic artery 100%,saphenous vein 75.0%) in patients of simple follow up and 61.6% (internal thoracic artery 81.1%,saphenous vein 55.3%) in patients with ischemia. Progression of native coronary arterial disease proximal to the grafting site was found in 50 patients(68.5%). Among 201 coronary arterial branches that had not been completely occluded preoperatively, ninty five branches(47.3%)revealed progression of diameter stenosis by more than 20%on the follow up study. Among them,64 branches(31.8%)progressed to total occlusion.The incidence of disease progression was highter in the coronary arteries with patent grafts (57.5%)than in those with occluded grafts(36.3%)(p < 0.05). Comparing internal thoracic artery graft with saphenous vein graft, internal thoracic artery was superior to saphenous vein,not only in terms of patency(83.3% vs 56.6%), but also in terms of result of later percutaneous intervention success rate(100% vs 62%,p < 0.05). CONCLUSION: Due to the considerable incidence of progression of native coronary artery stenosis in the early postoperative periods, bypass grafting of a vessel with borderline stenosis,especially with vein graft,must be done prudently. And it was confirmed again that revascularization of left anterior descending artery is most important and that internal thoracic artery was superior to saphenous vein.

Complicatons and Residual Defects After Correction of Noncomplicated Ventricular Septal Defect / 대한흉부외과학회지

BACKGROUND: The purpose of this study is to review the clinical course after the correction of noncomplicated ventricular septal defect and to analyze the morbidity and risk factors of postoperative complications and evaluate residual defect during the follow-up period. MATERIAL AND METHOD: From September 1994 to June 1998 24 patients(median age 10 months) underwent surgery under the diagnosis of ventricular septal defect. We made a retrospective review of the clinical records including the operation notes critical care unit records echocardiography results and the follow-up records. RESULT: There was no early mortality nd late mortality. There was no postoperative complete conduction block. Respiratory complication was the most common complication. The body weight age type of ventricular septal defect associated anomalies and operative procedure were not related to the incidence of complications. residual ventricular septal defects aortic valve regurgitation and tricuspid valve regurgitation were insignificant in postoperative hemodynamics, CONCLUSIONS: Correction of the noncomplicated ventricular septal defect was done without mortality and complete heart block. Aggressive preoperative medical treatment and early surgical treatment may decrease postoperative complications. Postoperative residual shunt and tricuspid regurgitation were not problematic during the follow-up.

transprosthetic Pressure Gradient after aortic Valve Replacement with Small Sized Prostheses / 대한흉부외과학회지

BACKGROUND: The prognosis after an aortic valve replacment can be affected significantly by the transprosthetic pressure gradient which is determined mainly by the size of the patients body and the prosthesis used. We analyzed the hemodynamic feature of two relatively new prosthese the ATS and the evensized Medtronic-Hall(M-H) valves by measuring the transprosthetic pressure gradient in the cases where small sizes (23mm or smaller) were used. MATERIAL AND METHOD: There were 94 patients who received whom aortic valve replacement with prosthesis smaller than 23 mm from October 1994 to June 1998. In these patients the transprosthetic pressure gradient clalculated from the pressure half time during postoperative Dopper echocardiographic examination was compared between the prostheses of different sizes. The body surface area of each patient was also taken into consideration. RESULT: The mean pressure gradient and body surface area in each group were 21.7+/-10.2 mmHg and 1.52+/-0.14m2 in ATS 19mm 11.4+/-6.5 mmHg and 1,57+/-0.20m2 in M-H 20mm 15.2+/-6.3 mmHg and 1.54+/-0.13m2 in ATS 21mm 9.3+/-2.5 mmHg and 1.63 +/-0.14m2 in M-H 22 mm and 12.9+/-5.3 mmHg and 1.69+/-0.13m2 in ATS 23mm. CONCLUSIONS: The 19mm ATS prosthesis showed significant trasprosthetic pressure gradient which is similar to the values previously reported with other bileaflet prosthesesm Close follow-up was needed in terms of exercise capacity and change in left ventiricular geometry. In patients with small aortic valve annulus the 20mm M-H valve is recomendable as an alternative to 19mm bileaflet valves because it has less pressure gradient with similar outer diameter.

Transmyocardial Laser Revascularzation for Patients with Recurrent Angina after CABG: Report of 3 cases / 대한흉부외과학회지

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.

Clinical Analysis of 500 Cases of Coronary Artery Bypass Grafting / 대한흉부외과학회지

BACKGROUND: We analyzed five hundred patients who underwent either isolated or concomitant coronary artery bypass grafting(CABG) between November 1981 and June 1997. MATERIAL AND METHOD: There were 330 males and 170 females with a mean age of 57.4+/-8.9 years. To evaluate the preoperative status, we performed electrocardiograghy, echocardiography, MIBI scan, Duplex sonogram, common blood test including CK and LDH and coronary angiography. RESULT: Preoperative clinical diagnoses were unstable angina in 282 (56.4%), stable angina in 141 (28.2%), postinfarction angina in 58 (11.6%), acute myocardial infarction in 8 (1.6%), variant angina in 7 (1.4%) and failed percutaneous transluminal coronary angioplasty in 4 (0.8%) patients. Preoperative angiographic diagnoses were three-vessel disease in 263 (52.6%), two-vessel disease in 93 (18.6%), one-vessel disease in 71 (14.2%), left main disease in 68 (13.6%), and others in 5 (1.0%) patients. Patients had various risk factors for coronary disease, and the frequency of the risk factors such as hypertension, diabetes and smoking showed increasing tendency year by year. We used saphenous vein grafts in 1143, internal thoracic artery grafts in 442, radial artery graft in 17, and gastroepiploic artery graft in 1 anastomosis. The mean number of grafts was 3.2+/-1.2 per patient. Concomitant operations were prosthetic valve replacement or valvuloplasty in 31, coronary endarterectomy and angioplasty in 27, left main coronary angioplasty in 13, carotid endarterectomy in 5, and neurologic problems, bleeding, and perioperative myocardial infarction. The mean follow-up period was 25+/-23 months and there were 5 cases of reoperation. CONCLUSION: We hope that the surgical results would improve with the accumulation of experience, application of new myocardial protection technique, and timely intervention of mechanical assisted devices.

Minimal Skin Incision with Full Sternotomy for Congenital Heart Surgery / 대한흉부외과학회지

BACKGROUND: Although there have been few reports about minimal skin incision for the repair of congenital heart lesions, minimizing an unsightly scar is a particularly important factor in growing children. We have adopted a technique that permits standard full sternotomy, conventional open chest cardiopulmonary bypass, aortic cross-clamping, left atrial vent, and antegrade cardioplegia with minimal surgical scar. MATERIAL AND METHOD: With minimal skin incision and full sternotomy, 40 patients with congenital heart disease underwent open heart surgery from April 1997 through September 1997. Defects repaired included 30 ventricular septal defects, 4 atrial septal defects, and 1 sinus Valsalva aneurysm in 35 children(M:F=17: 18), and 3 Atrial septal defects, 1 ventricular septal defect, and 1 partial atrioventricular septal defect in 5 adults(M:F=1:4). Midline skin incision was performed from the second intercostal space to 1 or 2 cm above the xiphoid process. For full sternotomy, we used the ordinary sternal saw in sternal body, and a special saw in manubrium under the skin flap. During sternal retraction, surgical field was obtained by using two retractors in a crossed direction. RESULT: The proportion of the skin incision length to the sternal length was 63.1+/-3.9%(5.2~11cm, mean 7.3cm) in children, and 55.0+/-3.5%(10~13.5cm, mean 12cm) in adults. In every case, the aortic and venous cannulations could be done through the sternal incision without additional femoral cannulation. There was no hospital death, wound infection, skin necrosis, hematoma formation, or bleeding complication. CONCLUSION: We conclude that minimal skin incision with full sternotomy can be a safe and effective alternative method for the repair of congenital heart diseases in children and adults.

Risk Factors of Neurologic Complications After Coronary Artery Bypass Grafting / 대한흉부외과학회지

BACKGROUND: As the early outcome after coronary artery bypass grafting(CABG) has been stabilized, neurologic complication has now become one of the most important morbidity. The aim of this study was to find out the risk factors associated with the neurologic complications after CABG. MATERIAL AND METHOD: In 351 patients who underwent CABG, the incidence and features of neurologic complications, with associated perioperative risk factors, were retrospectively reviewed. Neurologic complication was defined as a new cerebral infarction confirmed by postoperative neurologic examination and radiologic studies, or delayed recovery of consciousness and orientation for more than 24 hours after the operation. RESULT: Neurologic complications occurred in 18 patients(5.1%), of these nine(2.6%) were diagnosed as having new cerebral infarctions(stroke). Stroke was manifested as motor paralysis in four patients, mental retardation or orientation abnormality in four, and brain death in one. Statistical analysis revealed the following variables as significant risk factors for neurologic complications by both univariate and multivariate analyses: cardiopulmonary bypass longer than 180 minutes, atheroma of the ascending aorta, carotid artery stenosis detected by Duplex sonography, and past history of cerebrovascular accident or transient ischemic attack. Age over 65 years, aortic calcification detected by simple X-ray, and intraoperative myocardial infarction were significant risk factors by univariate analysis only. Neither the severity of carotid artery stenosis nor technical modifications such as cannulation of the aortic arch or single clamp technique, which were expected to affect the inciden e of neurologic complications, had significant relationship with the incidence. CONCLUSION: This study confirmed the strong association between neurologic complications after CABG and atherosclerosis of the arterial system. Therefore, to minimize the incidence of neurologic complications, systematic evaluation focused on atheroscleroti.

Partial Left Ventriculectomy in the Pediatric Patient with Dilated Cardiomyopathy / 대한흉부외과학회지

Heart transplantation was planned for a 10-year old boy who had dilated cardiomyopathy with severe congestive heart failure and had been on dopamine for 1month. However, partial left ventriculectomy and mitral annuloplasty were performed instead, because there was no donor heart of the adequate size and the symptoms were aggravated. The clinical symptoms were markedly improved after the surgery. Comparing the postoperative echocardiographic results with the preoperative results, there were remarkable changes in the left ventricular ejection fraction(preoperative LV EF 17% to postoperative 3 months 29%, 6 months 35%, 1 year 36%) and the left ventricular end-diastolic dimension(preoperative 72 mm to postoperative 3 months 59 mm, 6 months 61 mm, 1 year 61 mm). Partial left ventriculectomy and mitral annuloplasty reduced the cardiac loading in the dilated cardiomyopathy. Partial left ventriculectomy and mitral annuloplasty may be considered as one of the alternative surgical metho s to carry over until a heart transplantation can be performed, especially for children.

A Clinical Study of Isolated Aortic Valve Replacement with CarboMedics and St. Jude Prosthesis / 대한흉부외과학회지

MATERIALS AND METHODS: Between 1984 to 1994, 136 patients underwent primary and isolated aortic valve replacement with 79 Carbomedics and 57 St. Jude prostheses. RESULTS: Age ranged from 16 to 67 year (mean : 44.5+/-12.7 years). Statistically significant differences in preoperative clinical characteristics between two groups were not found. There was one early death in the St. Jude group and none in the Carbomedics group. Early prosthetic valve-related complications including death were not significantly different between the two groups (p value= 0.572). One hundred thirty five early survivors were followed for a total of 354.2 patient-years (mean=31.5+/-16 months). In the CarboMedics group, actuarial survial rate at 5 years was 97.1+/-1.9%, and in the St. Jude group, it was 95.9+/-2.8%. In the CarboMedics group, actuarial free rate from all valve-related events at 5 years was 92.1+/-3.1%, and in St. Jude group, it was 89.8+/-5.0%. CONCLUSION: We conclude that early and late results after performing isolated aortic valve replacement with CarboMedics and St. Jude valve are not significantlly different.

The Role of Intra-Aortic Balloon Pump in Coronary Artery Bypass Surgery / 대한흉부외과학회지

In the era of coronary artery bypass grafting, the intraaortic balloon pump(IABP) is more widely used and its indication has been expanded. We performed retrospective clinical analysis on the patients who have received IABP pre and/or postoperatively during the course of CABG. From January 1981 to June 1995, total 322 patients have received CABG at the Seoul National University Hospital and among them 50 patients(15.5%) were supported by IABP during the course of the operation. The mean age at the time of the operation was 57.2 years(39-75 years) and the male to female ratio was 33:17. The preoperative diagnosis was unstable angina in 33(66%), stable angina in 7(14%) and postinfarct angina in 8 patients(16%). As for the indications of the IABP, there were 13 cases(26%) with left main disease, 13(26%) with class IV angina, 12(24%) with difficulty in CPB weaning, 6(12%) with postinfarct angina and 3(6%) with severe LV dysfunction. In the remaining 3 cases, one patient was operated on after PTCA failure in emergency basis, another was a patient with AMI, and the other was one who had postoperative low cardiac output syndrome. All IABPs were introduced via femoral artery and among them 45 cases(90%) percutaneously. The mean postoperative assist time was 22.3 hours(0.5-168 hours) and IABP could be removed within 48 hours in most of them(44/50). The operative mortality was 6.1%(3 cases) and postoperative morbidity was only one with lower extremity ischemia. The more general application of the IABP during the course of the CABG ,especially in patients with high preoperative risk factors or difficulty in CPB weaning is a good measure of protecting and recovering myocardial function with minimal risk.

Development of Animal Model for Orthotopic Non-Small Cell Lung Cancer in Nude Rat / 대한흉부외과학회지

A major obstacles to evaluation of newly-developed treatment strategy for human lung cancer has been the lack of appropriate experimental animal models. We describe a new experimental model of orthotopically-developed non-small cell lung cancer in nude rat, involving inoculation of tumor cell suspension by thoracotomy. Over 40 direct implantation to the periphery of the lung has been performed to date, each requiring less than 1 hour for completion. This model has been used to perform a series of experiments to investigate whether the rat lung and surrounding structures trapped tumor cells with 2 different non-small cell lung cancer cell lines(NCI-H460 and NCI-H1299). Every animal showed development of tumor masses, which were loculated at the periphery of the lung paren- chyma and identified also by radiography. After 3 weeks of the inoculation, tumor develop ment at the mediastinal strutures were identified. The life expectancies of the victims were different between the cell lines, but were approximately 5 weeks when NCI-H460 cell line was used. This new orthotopic lung cancer model may be facilitate future studies of the new therapeutics of localized non-small cell lung cancer .

Complete Myocardial Revascularization Utilizing Parallel Sequential Anastomoses / 대한흉부외과학회지

We evaluated the feasibility and safety of this method by reviewing the early outcome of the patients who underwent coronary artery bypass grafting(CABG) utilizing parallel sequential anastomoses with saphenous vein grafts, comparing with the outcome of the patients revascularized with grafts having only single distal anastomosis. During the one-year period of 1995, a total of 79 patients underwent isolated CABG, among whom 39 patients with sequential vein grafts(sequential group) and 40 patients without sequential grafts(non-sequential group). There was no difference between the two groups in terms of preoperative status, except in the extent of the coronary disease; 87.2% of the sequential group and 45.0% of the non-sequential group had left main and/or triple vessel involvement. 318 distal coronary anastomoses were done; 198 for the sequential group(5.1/patient) and 120 for the non-sequential group(3.0/patient). In the sequential group, the mean durations of cardiopulmonary bypass and aortic clamp per one distal anastomosis were 33.5 and 21.1 minutes, respectively. In the non-sequential group, these were 41.8 and 22.7 minutes. There were two operative deaths, both in the non-sequential group. There was no difference in the incidence of postoperative complications including myocardial infarction. During the follow-up period(2 to 15 months), 8 patients(3 in the sequential and 5 in the non- sequential group) complained of residual or recurrent angina. Comparison of preoperative and postoperative 201Thallium myocardial perfusion scans in 30 patients showed improved or normal perfusion reserve in 83.3% of segments bypassed with sequential grafts and 82.5% of segments bypassed with non-sequential graft(s). These results show that, utilizing parallel sequential anastomoses with saphenous vein grafts, we could achieve satisfactory short-term clinical results in patients with extensive coronary stenoses. So, we conclude that this technique is a safe, technically feasible strategy for CABG, which can achieve the aim of complete myocardial revascularization with a limited length of graft. These results show that, utilizing parallel sequential anastomoses with saphenous vein grafts, we could achieve satisfactory short-term clinical results in patients with extensive coronary stenoses. So, we conclude that this technique is a safe, technically feasible strategy for CABG, which can achieve the aim of complete myocardial revascularization with a limited length of graft.

Early Clinical Outcome and Doppler Echocardiographic Data after Cardiac Valve Replacement with the ATS prosthesis / 대한흉부외과학회지

This is a report on the clinical outcome and hemodynamic profile of the ATS(R) cardiac valve prosthesis, which is a recently introduced pyrolytic carbon bileaflet prosthesis. We retrospectively reviewed the early outcome of 100 consecutive patients who underwent isolated cardiac valve replacement with the ATS(R) prosthesis from October 1994 through June 1996 at our hospital. All patients were evaluated with Doppler echocardiography before discharge from the hospital. The mean age of the patients was 48.6 years(range: 2 to 74). A total of 124 prosthesis were implanted; 71 mitral, 46 aortic, and 7 tricuspid. The two most frequently used sizes were 27 mm(40.8%) and 29 mm(35.2%) in the mitral position, and 23 mm(30.4%) and 21 mm(28.3%) in the aortic position. There was no early or late death. The total follow-up period was 950 patient-months with 99% follow-up rate. Serious late morbidity occurred in three patients; reoperation in two patients for late rupture of Sinus of Valsava in one and for endocarditis with prosthetic dehiscence in the other, and intracranial hemorrhage due to hypertension in one patient. There has been no thromboembolic complication or structural valve deterioration. In the mitral position, the average values of peak and mean transprosthetic pressure gradients and valve area calculated from pressure half time were 6.9+/-2.8 mmHg, 2.6+/-1.5 mmHg, and 2.7+/-0.8 cm2 respectively. In the aortic position, the peak and mean pressure gradients were 26.4+/-15.9 mmHg and 14.2+/-7.9 mmHg. For the mitral prostheses larger than 25-mm size, there was no significant difference among prosthetic sizes in terms of transprosthetic gradients, whereas there was a significant negative correlation between the prosthesis size and the transprosthetic gradients for the aortic valves. The peak and mean pressure gradients were 52.2+/-17.6 mmHg and 26.9+/-7.4 mmHg across the 19-mm aortic prostheses, and 27.1+/-11.9 mmHg and 13.3+/-6.6 mmHg across the 21-mm size. Above results can lead to the conclusion that the early clinical outcome of the ATS valve prosthesis is quite satisfactory. And the hemodynamic characteristics are comparable, if not better, with other bileaflet prostheses.

Thromboelastographic Analysis of the Coagulation System During Cardiopulmonary Bypass: Analysis of the Effect of Low-Dose Aprotinin / 대한흉부외과학회지

Thromboelastography(TEG) is the unique measure that gives rapid information about the whole clotting process. Simplifying the diagnosis of coagulopathy during operations, TEG can provide an adequate therapy for postoperative bleeding. Remarkable improvement in hemostasis after cardiopulmonary bypass(CPB) has been achieved by the treatment with proteinase inhibitor aprotinin, but the hemostatic mechanism of aprotinin during CPB is still unclear. This study was designed to evaluate the effects of aprotinin on coagulation system during CPB by using TEG. Forty patients who underwent CPB were divided into two groups: aprotinin(2 X 10(6) kallikrein inhibition units, as a single dose into the cardiopulmonary bypass priming solution) treatment group(male 14, female 8, mean age=50.8years) and no aprotinin treatment(control) group(male 10, female 8, mean age=53.4 years). TEG, activated clotting time, prothrombin time, activated partial thromboplastin time, platelet counts, fibrinogen and fibrinogen degradation product(FDP) concentrations were checked before and after CPB(30 minutes after neutralization of heparin effect by protamine sulfate). There was no significant difference in other conventional coagulation tests of two groups except postcardiopulmonary bypass FDP concentration in control group, which was significantly increased compared to that in aprotinin group(p0.05). On the contrary, R was not changed markedly but MA was decreased significantly in control group after CPB(p<0.05). This result shows that the main change in coagulation system during CPB is not hyperfibrinolysis but decrease in clot strength by platelet dysfunction, and the main effect of aprotinin during cardiopulmonary bypass is the maintenance of clot strength to the pre-CPB level by the preservation of platelet function.

Telomerase Activity in Non-small Cell Lung Cancer / 대한흉부외과학회지

Although many reseraches have been persued to detect the molecular tumor marker to define the cancer, ideal tumor marker which speak for the characteristics of malignancy and has high sensitivity and specificity is not known. One of the characteristics of the malignant cells is indefinite proliferative potential, in other word, immortality. The expression of telomerase and stabilization of telomeres are concomitant with the attainment of immortality in tumor cells; thus the measurement of telomerase activity in clinically obtained tumor samples may provide important information which would be useful as a diagnostic marker to detect immortal cancer cells. Telomerase activity was analyzed in 12 non-small cell lung cancer cell lines and 41 primary non-small cell lung cancers with the use of a PCR-based assay. All the cell lines and the majority of tumors displayed telomerase activity, but telomerase was not detectable in most of the corresponding pathologically-normal tissues. Telomere length was not correlated with telomerase activity. The present study indicate that measurement of telomerase activity may be useful as a molecular tumor marker in non-small cell lung cancer.

Optimal Management of Patent Ductus Arterisus in Premature / 대한흉부외과학회지

Between December 1994 and October 1996, 57 premature infants with evidence of a hemodynamically significant PDA associated with cardiopulmonary compromise underwent indomethcin therapy(Group I, n=48) or surgical ligation(Group II, n=9) because of indomethacin failure. The gestational age(29.6+/-3.1weeks vs. 28.1+/-1.6weeks) and birth weight(1,413+/-580gm, 1,098+/-235gm) showed no significant differences between the two groups. Medical management included fluid restriction, diuretics, and indomethacin therapy(one or two cycles). Surgical ligation was done at the neonatal intensive care unit(NICU) without moving the patient to the operation room. There was no complication associated with the operation. There were 9 deaths in Group I(19%, 9/48) and 2 deaths in Group II(22%, 2/9). The main causes of deaths were persistent bronchopulmonary dysplasia with sepsis(n=8) and intrapulmonary hemorrhage(n=3). The rate of medical treatment failure including death and complication in premature infants whose body weights were less than 1500gm was higher(41%, 15/38) than in premature infants whose body weights were more than 1500gm(16%, 3/19). Early surgical ligation of PDA may be applicable in the premature infant with a large size, low birth weight(<1500 gm), or associated intracardiac anomalies. Perfoming the operation in the NICU may be safe in stead of moving the patient to the operating room.

Effects of Modified Ultrafiltration in Pediatric Open Heart Surgery / 대한흉부외과학회지

Cardiopulmonary bypass in children is associated with capillary leak, which results in an increase in total body water after open heart surgery. The purpose of these studies was to assess the cardiopulmonary effects of modified ultrafiltration after pediatric open heart surgery. Study A: Twenty-six consecutive children aged 0.1~10 years(median 7 months) underwent cardiac operation incorporating modified ultrafiltration. After completion of cardiopulmonary bypass, modified ultrafiltration was commenced at the flow rate of 100~150l/min for 3~14 min. After modified ultrafiltration, elevation of hematocrit(28.3%+/-3.6% vs. 33.8%+/-4.0%, p<0.001), increased systolic blood pressure(66.7+/-11.2mmHg vs. 76.2+/-11.8mmHg, p<0.02), and decreased central venous pressure(7.8+/-3.7mmHg vs. 6.9+/-2.9mmHg, p<0.001) were observed. Study B: Twenty-six children who underwent cardiac operation with the diagnosis of VSD under 2 years were assigned to control(n=14) or modified ultrafiltration(n=12). Peak inspiratory pressure checked immediately after operation was significantly lower in modified ultrafiltration group than in control group(20.0+/-2.4 cmH2O vs. 22.4+/-2.3cmH2O, p< 0.03). Modified ultrafiltration after cardiopulmonary bypass in children improves early hemo- dynamics and pulmonary mechanics, and represents an excellent option for perioperative management of accumulation of fluid in the tissues. We will continually employ the modified ultrafiltration technique in pediatric cardiac operations.

Surgical Treatment of Intramural Hematoma of the Aorta: Case Report / 대한흉부외과학회지

We experienced a female patient with intramural hematoma of the aorta. This patient had a severe anterior chest pain radiating to interscapular area with choking sensation. CT revealed a intramural hematoma of the thoracic aorta and a part of the abdominal aorta but there was no evidence of intimal tearing. We did the emergency operation under hypothermic circulatory arrest and retrograde cerebral perfusion. Ascending aorta was replaced and coronary artery bypass graft was done because of intimal tearing of the ostium of right coronary artery. She was discharged without any significant complication. We reported this case with consideration about necessity of emergency operation for intramural hematoma of the thoracic aorta.

Intraoperative Measurement and Analysis of Coronary Artery Bypass Graft Flow / 대한흉부외과학회지

This study aimed to determine factors that influence blood flow through coronary bypass grafts and to analyze relationship between the graft flow and postoperative outcome. Blood flow through 146 bypass grafts(GBF) was measured with transit-time ultrasound flowmeter during coronary artery bypass grafting operations in 50 patients. Single and multiple regression analyses were done for relationships between the GBF and four variables: internal diameter of recipient coronary artery, myocardial value of bypassed branch(es), type of graft, and finding of preoperative myocardial perfusion scan. The relationship between GBF and postoperative scan finding was also analyzed. 1. The mean GBF was significantly higher in sequential grafts than in single vein grafts or in internal thoracic artery grafts(61.5 vs. 46.9 and 42.5 ml/min). 2. Myocardial value and recipient artery diameter were found to be the factors determining GBF. There was no correlation between GBF and presence of perfusion defect in the preoperative scan. 3. Myocardial value was found to be more important than recipient artery diameter in determinintg GBF. 4. Reversible perfusion defects were more frequently found in the areas supplied by grafts with low GBF. But this fact had only mild statistical significance. These results suggest that blood flow through a bypass graft is more determined by the size of its supplying myocardium than by the size of recipient artery. So, we can expect effective improvement in myocardial flow reserve after grafting of small(1~1.5mm) coronary arteries, if they supply substantial area of myocardium.

Long-Term Results of the Cardiac Valve Replacement-Experiences in Seoul National University Hospital(1968-1994)

A total of 3,119 cardiac valves were replaced in 2,471 patients with acquired valvular heart diseases at Seoul National University Hospital during a period of 26 years from 1968 to 1994. Mechanical valves including St. Jude, Carbomedics, Bjork-Shiley and Duromedics were used in 1,609 cases(52%) and bioprosthetic valves including Lonescu-Shiley, Hancock and Angell Shiley were implanted for the rest of the patients(1,510 cases, 48%). A total of 308(12.5%) redo valve replacement was performed during the same period, and 10 of 308 patients underwent second redo valve replacements. The single valve replacement was done in 1,846 cases, double valve replacement in 602 cases and triple valve replacement in 23 cases. Among the single valve replacement, the mitral valve replacement was performed most frequently(1,377 cases). The male to female ratio was almost equal(1.223 : 1,248) and the mean age was 37.9+/-10.5 years old. But the mean age has been increasing year by year and it reached to 44.8 years old in the 1990's. The overall hospital mortality was 5.3%, and 6.8% in redo valve replacement. However, the hospital mortality for the recent 10 years dropped to 1 to 4%. The number of redo valve surgery has been increasing since the mid-1980's because of structural deterioration of bioprostheses that were replaced during the late-1970's and early 1980's. Redo valve surgery comprised 34% for all valve replacement in 1994. The causes of the redo valve operation were structural deterioration(81.5%), prosthetic valve endocarditis(11.7%), paravalvular leakage(5.6%), and valve thrombosis(0.9%). The actuarial freedom from overall valve failure in Ionescu-Shiley were 81.0+/-7.1%(5 year) in mitral position, 89.1+/-1.8%(7 year) in aortic position and 88.9+/-7.6% in double valve replacement. The 5 year actuarial freedom from all complications in Carbomedics were 90.1+/-3.1% in mitral position, 84.9+/-4.2% in aortic position and 81.7+/-5.1% in double valve replacement. The 10 year actuarial freedom from all complications in St. Jude were 80.9+/-3.8%, 81.4+/-6.1%, 72.4+/-10.7% in each positions. In conclusion, the mean age of patients was younger than that of western countries, but it showed increasing tendency year by year. Bioprosthetic valves were used during the initial period until mid-1980's when mechanical valves were used instead of bioprosthetic valves, mainly because of the structural deterioration of the bioprostheses. In terms of thromboembolism, both bioprostheses and mechanical valves seems to be almost comparable although the comparison of both valves was impossible because of the different period of operation, various surgeon and level of the prothrombin time and so on. Recently the number of valve replacement has been decreased since the 1990's and the number of redo valve surgery and valve repair has been increased.