Byung Won Yoo

Yonsei University Hospital, Sŏul, Seoul, South Korea

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Publications (11)15.69 Total impact

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    ABSTRACT: Objective Congestive hepatopathy after Fontan operation has a major impact on long-term morbidity. We evaluated congestive hepatopathy in patients with Fontan circulation using transient elastography (TE), and aimed to determine which risk factors of hepatopathy are related to liver stiffness (LS). Methods We evaluated 46 patients with Fontan circulation comparing with 26 patients with RHF and hepatic congestion using laboratory tests, AST-to-platelet ratio index (APRI), ultrasound, and TE. Results The LS value was significantly higher in the Fontan group (21.1±8.0 kPa) than in the RHF group (10.0±9.0 kPa). Serum levels of total bilirubin and albumin, WBC count, and APRI were significantly correlated with LS in the Fontan group. Among risk factors, age at evaluation (r=0.42, P=0.004), age at completion of Fontan procedure (r=0.51, P<0.001), inferior vena cava (IVC) diameter (r=0.35, P=0.02) and spleen size ((r=0.53, P=0.002) were significantly correlated with LS. Nineteen patients of the Fontan group (41.3%) showed abnormal ultrasound findings, and the frequency of abnormal findings increased with LS (P=0.002). In the subgroup with the highest LS value (≥30 kPa), 88.9% showed abnormal ultrasound findings and 44.4% showed liver cirrhosis. Multivariate analysis revealed that age at completion of Fontan procedure and total bilirubin were independent risk factors for hepatopathy. Conclusions This study revealed that congestive hepatopathy developed in a significant fraction of patients with long-term Fontan circulation, and that TE might be an easy and useful method to assess congestive hepatopathy in these patients.
    The Journal of thoracic and cardiovascular surgery 01/2014; · 3.41 Impact Factor
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    Byung Won Yoo, Han Ki Park
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    ABSTRACT: Repair of tetralogy of Fallot (TOF) has shown excellent outcomes. However it leaves varying degrees of residual hemodynamic impairment, with severe pulmonary stenosis (PS) and free pulmonary regurgitation (PR) at both ends of the spectrum. Since the 1980s, studies evaluating late outcomes after TOF repair revealed the adverse impacts of residual chronic PR on RV volume and function; thus, a turnaround of operational strategies has occurred from aggressive RV outflow tract (RVOT) reconstruction for complete relief of RVOT obstruction to conservative RVOT reconstruction for limiting PR. This transformation has raised the question of how much residual PS after conservative RVOT reconstruction is acceptable. Besides, as pulmonary valve replacement (PVR) increases in patients with RV deterioration from residual PR, there is concern regarding when it should be performed. Regarding residual PS, several studies revealed that PS in addition to PR was associated with less PR and a small RV volume. This suggests that PS combined with PR makes RV diastolic property to protect against dilatation through RV hypertrophy and supports conservative RVOT enlargement despite residual PS. Also, several studies have revealed the pre-PVR threshold of RV parameters for the normalization of RV volume and function after PVR, and based on these results, the indications for PVR have been revised. Although there is no established strategy, better understanding of RV mechanics, development of new surgical and interventional techniques, and evidence for the effect of PVR on RV reverse remodeling and its late outcome will aid us to optimize the management of TOF.
    Korean Journal of Pediatrics 06/2013; 56(6):235-241.
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    ABSTRACT: In correction of tetralogy of Fallot (TOF), surgical strategies to minimize right ventricular outflow tract (RVOT) enlargement have recently been preferred. However, we may be confronted with residual pulmonary stenosis (PS) combined with pulmonary regurgitation (PR), and how the pressure load affects these patients is not evident. We compared 51 patients with PR and significant PS (PR with PS group) with 87 patients with PR without significant PS (PR group) using echocardiography and cardiac magnetic imaging. We evaluated the differences in parameters derived by magnetic resonance imaging between the 2 groups and the influence of the pressure load on right ventricular (RV) volume and function. Although the PR fraction was similar between the 2 groups, the PR with PS group showed significantly smaller RV end-diastolic volume (136.7 ± 26.5 mL/m(2) vs 151.2 ± 34.7 mL/m(2); P = .01), RV end-systolic volume (68.1 ± 23.7 mL/m(2) vs 80.2 ± 27.5 mL/m(2); P = .01), and slightly better RV ejection fraction (51.1% ± 9.8% vs 47.6% ± 8.9%; P = .03) than the PR group. For influence of the pressure load, PR fraction (r = -0.18, P = .03), RV end-diastolic volume (r = -0.25, P = .003), and RV end-systolic volume (r = -0.24, P = .005) were decreased as peak pressure gradient of PS was higher. Linear regression analysis revealed that both PR fraction and peak pressure gradient of PS were independent predictors for RV volume. Our study demonstrated that the RV pressure load prevented RV dilatation from chronic PR without systolic dysfunction. It is suggested that a proper relief of RVOT obstruction with acceptable residual stenosis is more advantageous than aggressive RVOT enlargement in the long-term outcome of repaired TOF.
    The Journal of thoracic and cardiovascular surgery 01/2012; 143(6):1299-304. · 3.41 Impact Factor
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    ABSTRACT: Traumatic ventricular septal defect (VSD) resulting from blunt chest injury is a very rare event. The mechanisms of traumatic VSD have been of little concern to dateuntil now, but two dominant theories have been described. In one, the rupture occurs due to acute compression of the heart; in the other, it is due to myocardial infarction of the septum. The clinical symptoms and timing of presentation are variable, so appropriate diagnosis can be difficult or delayed. Closure of traumatic VSD has been based on a combination of heart failure symptoms, hemodynamics, and defect size. Here, we present a case of a 4-year-old boy who presented with a traumatic VSD following a car accident. He showed normal cardiac structure at the time of injury, but after 8 days, his repeated echocardiography revealed a VSD. He was successfully treated by surgical closure of the VSD, and has been doing well up to the present. This report suggests that the clinician should pay great close attention to the patients injured by blunt chest trauma, keeping in mind the possibility of cardiac injury.
    Korean Journal of Pediatrics 02/2011; 54(2):86-9.
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    ABSTRACT: The rigid coupling between the delivery wire and the right atrial disk has been occasionally encountered during transcatheter closure of atrial septal defect (ASD). Therefore the device frequently makes a perpendicular angle, and the leading edge of left atrial disk slips through the defect and prolapses into right atrium (RA) before it is properly placed in the septum. The purpose of this study is to investigate relating factors to the need of technical modification in transcatheter closure of large ASD and to evaluate relevant morphologic characteristics of atrial septal rim in this situation. From July, 2003 to May, 2007, 312 patients underwent transcatheter occlusion of ASD with Amplatzer Septal Occluder(R) (ASO, AGA medical corporation, Golden Valley, MN, USA) at Yonsei Cardiovascular Center and among them 109 patients had large ASD (>/=25 mm) and these patients were enrolled in our study. Patients were divided into two groups according to the deploying methods of the device (Group I: standard method, Group II: modified methods). Assessments of the defects and its surrounding rims were made by echocardiography. There were no differences between 2 groups in age, body weight and height except for balloon-stretched diameter (stop-flow technique) and device size. Group II patients with modified methods showed larger balloon-stretched diameter and device size than group I patients with standard method. The mean length of anterosuperior (AS) rim in group II was significantly shorter than group I (p<0.05). As the size of the device used in procedure increased, there was a trend towards increase in the need of modified methods. This study shows that AS rim deficiency and the size of ASD may be the relating factors to the need of technical modification in transcatheter closure of ASD. Therefore, when the initial try with standard method is not successful in large ASD with deficient AS rim, we suggest that changing strategy of implantation may save time and efforts and possibly reduce the risk of complications associated with prolonged procedure.
    Korean Circulation Journal 01/2010; 40(4).
  • Korean Journal of Pediatrics 01/2010; 53(2).
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    ABSTRACT: The purpose of this study is to investigate the association of programmed death-1 gene (PD-1) polymorphisms with genetic predispositions to Kawasaki disease (KD). A total of 73 patients with KD and 100 healthy controls were enrolled from 2007 to 2008. Two single nucleotide polymorphisms of the PD-1 gene, rs41386349 and rs2227981, were analyzed. Higher T allele frequency of rs41386349 was found in the patient group than the control group (p = 0.007, odds ratio (OR) = 1.9, 95% CI = 1.2–2.9). PD-1 rs2227981 polymorphism was not significant in patients with KD comparing with the control group (p = 0.4, OR = 1.2 (0.8–1.9)). Furthermore, no difference of PD-1 polymorphisms between patients with coronary artery dilatation (CAD) and those without CAD was found. Our data support the possibility that PD-1 gene polymorphism may be related with the genetic susceptibility of KD in Korean population.
    European Journal of Pediatrics 01/2010; 169(2):181-185. · 1.98 Impact Factor
  • Anadolu kardiyoloji dergisi: AKD = the Anatolian journal of cardiology 06/2008; 8(3):234; author reply 234-5. · 0.72 Impact Factor
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    ABSTRACT: Long-term outcomes of patients with repaired tetralogy of Fallot (TOF) are known to be related with right ventricular (RV) volume overload, severity of pulmonary insufficiency (PI) and the type of outflow repair. Right ventricular restrictive physiology (RVRP) has also been reported to interfere with several factors influencing the late result in repaired TOF patients. However, the mechanism and physiology of this unique myocardial property in the chronically overloaded right ventricle are not yet clearly understood. We investigated 43 patients after repair of TOF to assess the relationships among biventricular diastolic function, volume characteristics, and influence of respiratory effort. The patients were classified into 3 groups; 15 patients with RVRP and significant PI (RP group, 35%), 19 without RVRP in the presence of significant PI (NR+PI group, 44%), and 9 without RP or significant PI (NR-PI group, 21%). Doppler spectrals obtained by echocardiography from systemic and pulmonary veins, main pulmonary artery (MPA), and both ventricular inlets, and biventricular diastolic function were compared according to the respiratory cycle. The RP group revealed higher pulmonary venous systolic/diastolic flow ratio (S/D ratio) and the NR+PI group showed larger velocity-time integral (VTI) ratio of total regurgitant/antegrade flow at the MPA and more respiratory variability in the systemic vein. RP is associated with less volume overload of the RV and smaller respiratory variability is also associated with the restrictive RV. The diastolic function and volume status of the RV may influence the diastolic properties of the left heart.
    International journal of cardiology 04/2008; 125(1):28-35. · 6.18 Impact Factor
  • Korean Journal of Pediatrics 01/2007; 50(10).
  • Korean Journal of Pediatrics 01/2007; 50(10).