Woo-Sung Yun

Sungkyunkwan University, Sŏul, Seoul, South Korea

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Publications (9)14.81 Total impact

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    ABSTRACT: To investigate the clinical course of patients with venous malformation (VM) treated conservatively. We reviewed retrospectively the database of our Congenital Vascular Malformation clinic and interviewed 207 patients with VM, who had been managed only conservatively. The questionnaires asked about changes in size (no change, increase in proportion to growth, increase greater than in proportion to growth, decrease) and changes in symptoms (markedly worse, moderately worse, no change, moderately improved, markedly much improved). Progression of VMs was defined as an increase greater than in proportion to growth or worsening symptoms. Fifty patients (24 %) reported an increase in size greater than in proportion to growth and 25 patients (12 %) reported symptoms worsening from their initial symptoms. Overall, sixty-six (32 %) of the patients reported evidence of progression of their VM. A binary logistic regression model identified VM combined with capillary malformation (CM) or lymphatic malformation (LM) as an independent predictor of VM progression (OR 2.67, 95 % CI 1.29-5.53). Based on responses to the questionnaire, the size and symptoms of VM progressed in 32 % of patients over the course of their life. VMs combined with CM or LM were the only independent predictor of progression of a VM after conservative management.
    Surgery Today 04/2012; 42(10):950-5. DOI:10.1007/s00595-012-0185-x · 1.21 Impact Factor
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    ABSTRACT: This study aimed to investigate prevalence of asymptomatic carotid artery stenosis (ACAS) in Korean patients with peripheral arterial disease (PAD) and identify predictive factors of ACAS in patients with PAD. Between 1994 and 2008, 546 patients who underwent bypass surgery due to PAD were identified in a single tertiary teaching hospital. Of those, 409 patients underwent preoperative screening carotid duplex ultrasonography (CDUS). Patients who had an episode of cerebrovascular event or previous carotid artery intervention were excluded and then a retrospective analysis was made of 340 patients. The degree of internal carotid artery (ICA) stenosis was determined by the criteria of Society of Radiologists in Ultrasound Consensus Conference. To determine the risk factors of ACAS, demographic, coexisting medical condition and lesion characteristics were tested with binary logistic regression model. The prevalence of > or = 70% ICA stenosis was 14%. ICA occlusion was detected in 7.1%. Multivariate analysis revealed age > 65 yr (OR: 2.610, 95% CI: 1.197-5.691) and coronary artery disease (CAD, OR: 2.333, 95% CI: 1.169-4.657) are predictive factors of > or = 70% stenosis. A PAD patient who needs revascularization, particularly, > 65 yr or has a concomitant CAD, can be a good candidate of screening CDUS.
    Journal of Korean medical science 08/2010; 25(8):1167-70. DOI:10.3346/jkms.2010.25.8.1167 · 1.25 Impact Factor
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    Journal of Vascular Surgery 06/2010; 51(6). DOI:10.1016/j.jvs.2010.02.241 · 2.98 Impact Factor
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    ABSTRACT: Purpose: The aim of this study was to compare the short and long-term outcomes following carotid endarterectomy (CEA) with either primary closure (PC) or patch angioplasty (PAT) performed by single center vascular surgeons. Methods: Between November 1994 and March 2008, a total of 366 patients underwent 401 consecutive primary CEA procedures at our institution. We retrospectively reviewed patients' medical records. Two vascular surgeons prefer routine PC and one vascular surgeon prefer routine patch closure using bovine pericardial patch. Postoperative neurologic complications were determined by clinical neurologists. Restenosis was defined as >50% stenosis on follow-up duplex scan. Data was analyzed to compare the early (<= 30 days) and late results of CEA between PC group and PAT group. Results: The mean follow-up duration was significantly longer in the PC group than that in the PAT group (61.7 months vs. 41.2 months, P<0.001). Coronary artery disease and combined CEA. with coronary artery bypass were more common in the PAT group (39% vs. 55%, P<0.002; 4% vs. 12%, P<0.004). Perioperative ipsilateral TIA/stroke rates in the PC and PAT groups were 1.5% and 0.7% (PC=4/270 vs. PAT=1/131, P=0.564). Regarding late outcomes, Kaplan-Meier analysis failed to show any difference between 2 groups on freedom from ipsilateral transient ischemic attack (TIA)/stroke, freedom from restenosis and TIA/stroke-free survival (P=0.851, P=0.232, P=0.103, log-rank test). Conclusion: Our results suggest that PC following CEA is not necessarily inferior to PAT for experienced surgeons. (J Korean Surg Soc 2010;78:314-319)
    Journal of the Korean Surgical Society 05/2010; 78(5). DOI:10.4174/jkss.2010.78.5.314 · 0.21 Impact Factor
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    ABSTRACT: This study used air plethysmographic parameters to evaluate the changes in venous hemodynamics after the surgical treatment of primary varicose veins. We retrospectively analyzed 1756 limbs of 1620 patients who had undergone surgery for great saphenous vein (GSV) reflux from January 1996 to June 2009 at Samsung Medical Center. Venous hemodynamic changes were evaluated by performing air plethysmography preoperatively and 1 month postoperatively and assessing the venous volume (VV), the venous filling index (VFI), the residual volume fraction (RVF), and the ejection fraction (EF). Preoperatively, median (interquartile range) values were VV, 121.6 (94.7-160.6) mL; VFI, 4.8 (2.9-7.6) mL/s; RVF, 40.6% (29.7%-50.0%); and EF, 53.5% (44.3%-64.1%). Postoperatively, the median (interquartile range) values were VV, 90.6 (69.1-116.8) mL; VFI, 1.4 (0.9-1.9) mL/s; RVF, 28.4% (17.5%-38.7%); and EF, 65.2% (54.5%-77.2%). VV, VFI, and RVF were reduced 25.2%, 71.5%, and 29.9%, respectively; EF was increased 20.3%. The results were significant for all four variables (P < .001). We compared the degree of hemodynamic changes according to the treatment modalities: the high ligation and stripping group , 1578 cases; the GSV valvuloplasty group, 124 cases; and the VNUS group (VNUS Medical Technologies Inc, San Jose, CA), 54 cases. The reduction of the VV, VFI, and RVF was greater in the GSV stripping group and in the VNUS group than in the valvuloplasty group (P < .001), yet no difference was noted in the EF increase among the surgical modalities (P = .157). Our results show that the venous hemodynamic parameters of primary varicose veins were improved after surgical treatment.
    Journal of vascular surgery: official publication, the Society for Vascular Surgery [and] International Society for Cardiovascular Surgery, North American Chapter 03/2010; 51(3):634-8. DOI:10.1016/j.jvs.2009.11.061 · 2.98 Impact Factor
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    ABSTRACT: Type III endoleak is one of the causes of secondary intervention after endovascular aortic aneurysm repair (EVAR). We report two cases of a late type III endoleak with a review of the literature. One case had a disconnected iliac limb and the other case was due to a defect of the main body fabric at the bifurcation level. Both cases were successfully treated by open conversion. Before open conversion, it should be determined how to get proximal aortic control (suprarenal vs. infrarenal and cross-clamping vs. balloon inflation). When the suprarenal aortic control is required, to reduce suprarenal clamping time, it is not necessary to remove the endograft completely. Partial endograft removal and a graft-to-graft anastomosis is an alternative, if it is well incorporated and not infected. Making a plan for delayed open conversion should be individualized according to the type and status of the endograft and the vascular anatomy.
    Journal of the Korean Surgical Society 01/2010; 78(4). DOI:10.4174/jkss.2010.78.4.262 · 0.21 Impact Factor
  • Ui-Jun Park · Young-Nam Rho · Woo-Sung Yun · Young-Wook Kim
    Journal of vascular surgery: official publication, the Society for Vascular Surgery [and] International Society for Cardiovascular Surgery, North American Chapter 10/2009; 52(1):222. DOI:10.1016/j.jvs.2009.08.041 · 2.98 Impact Factor
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    ABSTRACT: Percutaneous ethanol sclerotherapy (PES) is the primary tool in the treatment of venous malformations (VM). However, PES has known serious complications. This study is aimed at identifying predictors of good response to PES in patients with VM to improve patient selection. We performed a retrospective, cross-sectional study of 158 VM patients (mean age, 14.3 years, male 42%) who underwent ethanol sclerotherapy at a specialized vascular malformation center. For clinical result assessment, patients or parents in pediatric patients answered questions on symptomatic, functional, and cosmetic improvement after PES. In each category, the possible choices were markedly improved, moderately improved, no change, moderately worse, or markedly worse compared with pretreatment status. A "good response" was defined as one or more areas of marked improvement on the self-assessment in conjunction with marked improvement on post-treatment images (> or =30% decrease in maximal diameter of VM on magnetic resonance imaging [MRI] or > or =50% decrease in abnormal blood pool ratio on whole body blood pool scintigraphy [WBBPS] compared with pretreatment images). To determine predictors of a good response to PES, uni- and multivariate analysis were conducted on demographics (age, gender), clinical features of VM (location, size, depth of involved tissue, presence of associated lymphatic malformation, MRI findings; well-defined vs ill-defined margin, characteristics of venous drainage during PES) and treatment variables (number of PES sessions, maximal concentration and dosage of ethanol used in PES, adjuvant therapy). Symptomatic, functional, and cosmetic improvement was 28%, 27%, and 34%, respectively, based on patient questionnaires. Based on imaging studies, 42 patients (27%) had markedly improvement. Composite outcome combining questionnaire results and imaging study showed that 16% of patients had a "good response". On multivariate analysis, female gender (odds ratio [OR]: 4.49, 95% confidence interval [CI]: 1.24-16.28), no or delayed visualization of drainage vein (OR: 9.22, 95% CI: 1.79-47.51), and a well-defined margin on MRI (OR: 13.38, 95% CI: 2.84-63.12) were independent predictors of "good response" to PES. PES should be performed in selected patients in order to obtain the best outcomes and minimize complications. No or delayed visualization of drainage vein on initial direct puncture venogram, a well-defined margin on MRI, and female gender were statistically significant predictors of a "good response" to PES and may be useful in selecting patients.
    Journal of vascular surgery: official publication, the Society for Vascular Surgery [and] International Society for Cardiovascular Surgery, North American Chapter 06/2009; 50(3):581-9, 589.e1. DOI:10.1016/j.jvs.2009.03.058 · 2.98 Impact Factor
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    ABSTRACT: External banding valvuloplasty (EBV) of the great saphenous vein (GSV) in patients with varicose veins is still controversial. The present study evaluated the effectiveness of EBV in selected patients with an insufficiency of the GSV after a mean follow-up of 92.6 months. A total of 101 limbs underwent EBV for the treatment of a GSV insufficiency. Thirty-one limbs from 27 patients (three men, 24 women; mean age 44.2 years; range 19 to 58 years) were re-examined and followed for a mean of 92.6 months. The venous volume, venous filling index, ejection fraction and residual venous fraction were analyzed preoperatively and at the follow-up using air plethysmography. The diameter and reflux of the GSV were evaluated using duplex ultrasound. Overall, the mean (± SD) follow-up time was 92.6±22.3 months (range 46 to 138 months). At the follow-up, the preoperative venous hemodynamic states had improved significantly, to the following values: venous volume 96.0±32.3 mL to 83.4±32.6 mL; venous filling index 3.6±2.9 mL/min to 2.4±2.2 mL/min; and residual venous fraction 39.7%±18.6% to 26.1%±16.8% (P<0.05). The diameter of the GSV was 6.4±1.4 mm preoperatively and 4.8±1.7 mm postoperatively (P<0.01). Reflux in the proximal GSV was demonstrated preoperatively in 19 (61.3%) of 31 limbs. During the follow-up period, four limbs (12.9%) had high ligation and stripping of the GSV performed due to the recurrence of varicosity. EBV of the GSV provides good results in terms of the venous hemodynamics and decreasing the diameter of the GSV. EBV may be an alternative procedure to stripping or endovenous ablation therapy in selected patients.
    International Journal of Angiology 01/2009; 18(1):25-8. DOI:10.1055/s-0031-1278318