• International Journal of Vascular Biomedical Engineering
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• v.1 no.2
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• pp.36-41
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• 2003

Both flow visualizations and computational fluid dynamics were performed to determine hemodynamics in a total cavopulmonary connection (TCPC) model for surgically correcting congenital heart defects. From magnetic resonance images, an anatomically correct glass model was fabricated to visualize steady flow. The total flow rates were 4, 6 and 8L/min and flow rates from SVC and IVC were 40:60. The flow split ratio between LPA and RPA was varied by 70:30, 60:40 and 50:50. A pressure-based finite-volume software was used to solve steady flow dynamics in TCPC models. Results showed that superior vena cava(SVC) and inferior vena cava(IVC) flow merged directly to the intra-atrial conduit, creating two large vortices. Significant swirl motions were observed in the intra-atrial conduit and pulmonary arteries. Flow collision or swirling flow resulted in energy loss in TCPC models. In addition, a large intra-atrial channel or a sharp bend in TCPC geometries could influence on energy losses. Energy conservation was efficient when flow rates in pulmonary branches were balanced. In order to increase energy efficiency in Fontan operations, it is necessary to remove a flow collision in the intra-atrial channel and a sharp bend in the pulmonary bifurcation.

• International Journal of Vascular Biomedical Engineering
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• v.2 no.1
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• pp.11-16
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• 2004

Both flow visualizations and computational fluid dynamics were performed to determine hemodynamics in a total cavopulmonary connection (TCPC) model for surgically correcting congenital heart defects. From magnetic resonance images, an anatomically correct glass model was fabricated to visualize steady flow. The total flow rates were 4, 6 and 8L/min and flow rates from SVC and IVC were 40:60. The flow split ratio between LPA and RPA was varied by 70:30, 60:40 and 50:50. A pressure-based finite-volume software was used to solve steady flow dynamics in TCPC models. Results showed that superior vena cava(SVC) and inferior vena cava(IVC) flow merged directly to the intra-atrial conduit, creating two large vortices. Significant swirl motions were observed in the intra-atrial conduit and pulmonary arteries. Flow collision or swirling flow resulted in energy loss in TCPC models. In addition, a large intra-atrial channel or a sharp bend in TCPC geometries could influence on energy losses. Energy conservation was efficient when flow rates in pulmonary branches were balanced. In order to increase energy efficiency in Fontan operations, it is necessary to remove a flow collision in the intra-atrial channel and a sharp bend in the pulmonary bifurcation.

• 한국전산유체공학회:학술대회논문집
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• 2003.10a
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• pp.146-146
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• 2003

• Journal of Chest Surgery
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• v.36 no.8
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• pp.559-565
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• 2003

By improving the flow pattern in Fontan circuit, total cavopulmonary connection (TCPC) could result in a better outcome than atriopulmonary connection Fontan operation. For the patients with impaired hemodynamics after atriopulmonary Fontan connection, conversion to TCPC can be expected to bring hemodynamic and functional improvement. We studied the results of the revision of the previous Fontan connection to TCPC in patients with failed Fontan circulation. Material and method: From October1979 to June 2002, eight patients who had failed Fontan circulation, underwent revision of previous Fontan operation to TCPC at Yonsei University Hospital. Intracardiac anomalies of the patients were tricuspid atresia (n=4) and other functional single ventricles (n=4). Mean age at TCPC conversion was 14.0$\pm$7.0 years (range, 4.6~26.2 years) and median interval between initial Fontan operation and TCPC was 7.5 years (range, 2.4~14.3 years). All patients had various degree of symptoms and signs of right heart failure. NYHA functional class was 111 or IV in six patients. Paroxysmal atrial fibrillation (n:f), cyanosis (n=2), intraatrial thrombi (n=2), and protein losing enteropathy (PLE) (n=3) were also combined. The previous Fontan operation was revised to extracardiac conduit placement (n=7) and intraatrial lateral tunnel (n=1). Result: There was no operative death. Major morbidities included deep sternal infection (n=1), prolonged pleural effusion over two weeks (n=1), and temporary junctional lachyarrhythrnia (n=1). Postoperative central venous Pressure was lower than the preoperative value (17.9$\pm$3.5 vs. 14.9$\pm$1.0, p=0.049). Follow-up was complete in all patients and extended to 50,1 months (mean, 30.3$\pm$ 12.8 months). There was no late death. All patients were in NYHA class 1 or 11. Paroxysmal supraventricular tachycardia developed in a patient who underwent conversion to intraatrial lateral tunnel procedure, PLE was recurred in two patients among three patients who had had PLE before the convertsion. There was no newly developed PLE. Conclusion: Hemodynamic and functional improvement could be expected for the patients with Fontan circulatory failure after atriopulmonary connection by revision of their previous circulation to TCPC. The conversion could be performed with low risk of morbidity and mortality.

• Journal of Chest Surgery
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• v.35 no.1
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• pp.48-51
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• 2002

The conversion of failing Fontan circuit to total cavopulmonary connection(TCPC) is recommended as a therapeutic option in patients with late Fontan complications such as atrial arrhythmia, atrial enlargement, pulmonary venous obstruction, and ventricular dysfunction. Combined TCPC with extracardiac conduit and cryoablation of arrhythmia circuit is preferred for treatment of failing Fontan coulection with atrial lachyarrhythrnia. We report a case of conversion of atriopulmonary connection to extracardiac conduit Fontan and cryoablation of atrial arrhythmia circuit in a patient with tricuspid atresia, who also had ectopic atrial tachycardia, right atrial thrombi, pulmonary venous obstruction, and ventricular dysfunction. This patient and the parents were Jehovah's Witnesses; therefore, the patient underwent the procedure without blood transfusion.

• Clinical and Experimental Pediatrics
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• v.46 no.3
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• pp.250-258
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• 2003

Purpose : The actual clinical examples of co-appliance of catheter intervention with surgical procedures in the treatment of pulmonary atresia with an intact ventricular septum(PA/IVS) which we have experienced in our institution are here shown, and the anatomical and hemodynamical profiles between each method is compared. Methods : Medical records of 33 patients with PA/IVS who underwent various treatment from January, 1995 to December, 2000 were reviewed for a retrograde study. Results : In three out of 10 patients who underwent percutaneous balloon pulmonary valvotomy (PPV), residual pulmonary stenosis were observed in their out patient department(OPD) follow-ups, eventually necessitatig balloon pulmonary valvuloplasty(BPV). One out of three patients exhibited deterioration of tricuspid regurgitation after BPV, requiring surgical tricuspid annuloplasty(TAP). Two out of the seven patients who received primarily surgical right ventricle outlet tract(RVOT) repair without any systemic-pulmonary shunt or intervention needed additional intervention employing cardiac catheterization after operation. Two patients received interventional catheterization before surgical RVOT repair. In five out of 11 cases of Fontan type operation, coil embolization of collateral circulation was done before total cavo-pulmonary connection(TCPC), and in three cases, interventional catheterization was needed after TCPC. Conclusion : Both medical and surgical treatment modalities are widely used in management of PA/IVS patients, and recent results prove that medico-surgical cooperative treatment is essential.