• Journal of Chest Surgery
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• v.32 no.9
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• pp.790-798
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• 1999

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 atherosclerotic lesions of the arterial system followed by adequate alteration of operative strategy is needed.

• Journal of Yeungnam Medical Science
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• v.23 no.1
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• pp.113-117
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• 2006

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease that may affect many organ systems including the nervous system. The immune response in patients with SLE can cause inflammation and other damage that can cause significant injury to the arteries and tissues. A 48-year-old woman was admitted to the hospital because of transient monocular blindness. Magnetic resonance imaging and conventional angiography showed severe stenosis of the distal intracranial internal carotid artery. The patient was diagnosed as having SLE but the antiphospholipid antibodies were negative. Amaurosis fugax has not been previously reported as an initial manifestation of SLE in Korea. We report a patient with a retinal transient ischemic attack as the first manifestation of SLE.

• Proceedings of the KSMRM Conference
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• 2003.10a
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• pp.97-97
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• 2003

Contrast-enhanced MR angiography (CE-MRA) gradually occupies its position as a primary evaluation tool forsteno-occlusive disease of supra-aortic cervical arteries. It has several advantages over time-of-flight (TOF) technique such as shorter imaging time, less saturation effect, and less flow- and motion-related artifacts. Diverse methods of k-space sampling, imaging sequences, and strategies for image acquisitiontiming have been introduced since its early clinical application. Especially, methods of k-space sampling and image acquisition timing are very important to achieve maximal arterial enhancement and suppress venous signal while maintaining large scan coverage and high spatial resolution. In addition, regardless of several advantages over TOF technique, it still has a tendency to overestimate the degree of stenosis in patients with carotid or vertebralartery disease. In this exhibit, we will overview the current techniques of CE-MRA with special attention to methods of k-space sampling and image acquisition timing. We will also discuss diagnostic accuracy of CE-MRA in patients with supra-aortic cervical artery stenosis and artifacts frequently misinterpreted as steno-occlusive lesion on CE-MRA.

• Bulletin of the Korean Chemical Society
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• v.29 no.2
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• pp.422-426
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• 2008

Hemodialysis graft coated with paclitaxel prevents stenosis; however, large initial burst release of paclitaxel causes many negative effects such as drug toxicity and inefficient drug loss. Therefore we developed and tested a novel coating method, double dipping, to provide controlled and sustained release of paclitaxel locally. Expanded polytetrafluoroethylene (ePTFE) grafts were dipped twice into a solution of several different paclitaxel concentrations. In vitro release tests of the double dipping method showed that early burst release could be somewhat retarded and followed by sustained release for a long time. We observed the effect of paclitaxel coating by double dipping in porcine model of arterio-venous (AV) grafts between the common carotid artery and the external jugular vein. 12 weeks after constructing AV grafts, cross sections of the graft venous anastomosis were obtained and analyzed. Paclitaxel coated ePTFE grafts by double dipping were observed to prevent neointimal hyperplasia and therefore reduced stenosis of the arteriovenous hemodialysis grafts, especially at the graft venous anastomosis sites. Our results demonstrate that second dipping of ePTFE graft, which was already coated once with paclitaxel, washes off the drug on a surface of the graft and affects the ratio of paclitaxel on the surface to that of the inner space, possibly by diffusion: thus the early burst of drug can be somewhat reduced.

• Journal of the Korean Society of Radiology
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• v.81 no.4
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• pp.899-911
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• 2020

Purpose To evaluate the safety and efficacy of the newly designed open-cell type self-expandable nitinol stent (NiTi-stent) for peripheral arteries. Materials and Methods Twenty-eight limbs of 14 minipigs were randomly assigned to the NiTistent group or conventional nitinol stent group. Stents were symmetrically implanted into the iliac arteries of each animal using carotid artery approach and were observed for 1 month (n = 5) and 6 months (n = 9). The angiographic lumen diameter (ALD), late lumen loss, angiographic stenosis, histomorphometric lumen area, neointimal area, and area stenosis were analyzed and compared between the groups. Results Stent migration, stent fracture, or thrombus formation were not observed in either group. At the 1-month follow-up, the neointimal area (p = 0.008) and area stenosis (p = 0.016) were significantly smaller in the NiTi-stent group than in the control group. At the 6-months followup, the NiTi-stent group showed significantly larger ALD (p = 0.014), less late lumen loss (p = 0.019), less angiographic stenosis (p = 0.014), larger lumen area (p = 0.040), and smaller neointimal area and area stenosis (p = 0.004 and p = 0.014, respectively) compared with the control group. Conclusion The NiTi-stent is as safe and effective as the conventional nitinol stent and induces less neointimal hyperplasia in a minipig iliac artery model.

• Journal of radiological science and technology
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• v.33 no.3
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• pp.223-230
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• 2010

The purpose of this study was to utilize Magnetic Resonance Imaging (MRI) and Magnetic Resonance Angiography (MRA) to analyze intracerebral regional distributions (hot spot) of ischemic cerebrovascular diseases which were characterized by stenosis and occlusion cerebral vasculature, except for cerebrovascular diseases induced by rupture of cerebral vasculature in terms of Korean people's cerebrovascular diseases, so that it could apply the findings of analysis to clinical practices. This study focused only on analyzing intracerebral regional distributions of ischemic cerebrovascular diseases that are characterized by stenosis and occlusion cerebral vasculature, because there are different etiologic mechanisms of ischemic cerebrovascular diseases like hemorrhagic cerebrovascular diseases (caused by rupture of cerebral vasculature) and cerebral infarction (induced by atheromatous arteriosclerosis). As a result, this study could come to the following findings of analysis: 1. According to sex ratio analysis, it was found that male group comprised larger portion of total 626 subjects in this study than female one (55.0% > 45.0%). 2. According to analysis on actual intracerebral regional distributions of ischemic cerebrovascular diseases, it was found that most subjects (37.5 %) were attacked by such diseases on the right side of cerebral vasculature, which was followed by left side of cerebral vasculature (35.1%) and bilateral cerebral vasculature (27.3%) respectively. 3. According to analysis on actual intracerebral regional distributions of ischemic cerebrovascular diseases, it was found that internal carotid artery (ICA) comprised the largest portion (38.9%) of those distributions, which was followed by middle cerebral artery (MCA, 35.7%), posterior cerebral artery (PCA, 13.4%), anterior cerebral artery (ACA, 6.0%) and vertebral artery (VA, 3.3%) respectively. 4. It was found that there was no subject attacked by any disease on A-com region, and there was only one male subject attacked by cerebrovascular diseases on P-com region. 5. It was found that female group was more susceptible to the attack of cerebrovascular diseases on MCA region than male one (54.6% > 42.2%), which means significant differences depending upon sex on statistical basis ($x^2$ = 9.64, p < .01). 6. It was found that male group was more susceptible to the attack of cerebrovascular diseases on ICA region (56.4% > 46.8%), which means significant differences depending upon sex on statistical basis ($x^2$ = 5.71, p < .05). 7. Moreover, it was also found that male group was more susceptible to the attack of cerebrovascular diseases on BA region (2.3% > 0.4%), which means significant differences depending upon sex on statistical basis ($x^2$ = 4.25, p < .05). 8. However, it was found that there was not any significant difference in intracerebral vasculature-specific distributions of cerebrovascular diseases depending on age of subjects, and stenosis comprised larger portion of cerebrovascular diseases than occlusion.

• Journal of Korean Neurosurgical Society
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• v.63 no.1
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• pp.69-79
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• 2020

Objective : To analyze trends in the incidence and treatment of diseases associated with ischemic stroke, namely, cerebral infarction (CI), cerebral arterial stenosis (CASTN), and moyamoya disease (MMD), based on Korean National Health Insurance Service (NHIS) data from 2008 to 2016. Methods : Data was extracted from the national health-claim database provided by the NHIS for 2008-2016 using International Classification of Diseases codes. The crude and age-standardized incidences of each disease (CI, CASTN without a history of CI, and MMD) were calculated; additional analyses were conducted according to age and sex. Trends in the number of patients undergoing treatment according to treatment method were analyzed for each disease using the Korean Classification of Diseases procedure codes. Results : In 2016, the total number of adults with newly diagnosed CI was 83939, reflecting a 9.4% decrease from that in 2008. The age-standardized incidence of CI in adults was 153.2 per 100000 person-years in 2016, reflecting a 37.2% decrease from that in 2008, while that of CASTN was 167.3 per 100000 person-years in 2016, reflecting a 73.3% increase from that in 2008. Among treated cases, the number of patients who underwent intra-arterial (IA) treatment, including IA fibrinolysis and mechanical thrombectomy, showed the most prominent increase, increasing at an annual rate of 25.8%. For CASTN, the number of cases treated with carotid artery stenting or balloon angioplasty (CAS) showed the most prominent increase, increasing at a rate of 69.8% over the 9-year period. For MMD, the total number of patients with newly diagnosed MMD and that with adult MMD demonstrated significantly increasing trends, while the number of pediatric patients with newly diagnosed MMD declined by 18.0% over the 9-year period. The age-standardized incidences of pediatric and adult MMD in 2016 were 2.4 and 3.4 per 100000 person-years, respectively. Conclusion : Although the incidence of CI showed a declining trend over a 9-year period, the number and proportion of patients treated for CI increased. Meanwhile, the incidence of CASTN and the number of patients treated for CASTN have demonstrated increasing trends since 2008. On the other hand, the number of patients diagnosed with pediatric MMD decreased, despite no significant change in the incidence. In contrast, the number of patients and the incidence of adult MMD increased. These trends reflect changes in the population structure, gains in the accessibility of imaging examinations, and the development of endovascular techniques.

• Bulletin of the Korean Chemical Society
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• v.34 no.6
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• pp.1663-1667
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• 2013

Neointimal hyperplasia causes vascular access dysfunction in hemodialysis patients with synthetic arteriovenous (AV) grafts. Several studies have reported that paclitaxel- or sirolimus-eluting AV grafts inhibit neointimal hyperplasia and display lower rates of stenosis compared with control grafts. However, there have been few comparative studies of the efficacy of paclitaxel- and sirolimus-eluting grafts. We compared the neointimal hyperplasia of paclitaxel- and sirolimus-eluting grafts. AV grafts were implanted laterally between the common carotid artery and the external jugular vein in 12 female Landrace pigs. The animals were sacrificed six weeks after surgery. The neointimal hyperplasia at the anastomosis sites of the grafts was quantified using the ratio of the intragraft hyperplasia to the graft area (H/G ratio) at the graft-vessel interface. The area of intimal hyperplasia at the venous (paclitaxel 1.06 [0.72-1.56] vs sirolimus 2.40 [1.72-3.0] $mm^2$, P = 0.04) and arterial anastomosis sites (paclitaxel 0.93 [0.57-1.48] vs sirolimus 2.40 [1.72-3.0] $mm^2$, P = 0.04) was significantly different between the two groups. However, the H/G ratios for the venous anastomosis site (paclitaxel 0.25 (0.17-0.38) vs sirolimus 0.38 (0.2-0.66), P = 0.4) and the arterial anastomosis site (paclitaxel 0.19 (0.08-0.39) vs sirolimus 0.41 (0.34-0.50), P = 0.1) did not differ significantly between the groups. In conclusion, there was no significant difference in the inhibition of neointimal hyperplasia by sirolimus- and paclitaxel-eluting AV grafts.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.3
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• pp.545-550
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• 2017

When the systolic blood pressure is high, intermittent turbulence in blood flow appears in the aorta and carotid artery with stenosis during the systolic period. The turbulent blood flow is difficult to analyze using the Newtonian turbulence model due to the viscous characteristics of blood flow. As the shear rate is increased, the blood viscosity decreases by the viscoelastic properties of blood and a drag reduction phenomenon occurs in turbulent blood flow. Therefore, a new non-Newtonian turbulent model is required for viscoelastic fluid and hemodynamics. The main aims of this study were to develop a non-Newtonian turbulence model using the drag reduction phenomenon based on the standard $k-{\varepsilon}$ turbulent model for a general non-Newtonian fluid. This was validated with the experimental data and has a good tendency for non-Newtonian turbulent flow. In addition, the computation time and resources were lower than those of the low Reynolds number turbulent model. A modified turbulent model was used to analyze various turbulent blood flows.

• Tuberculosis and Respiratory Diseases
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• v.57 no.2
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• pp.188-192
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• 2004

Takayasu's arteritis is a chronic inflammatory disease, involving mainly the aorta and its main branches, which can cause stenosis or occlusion. It involves the bracheocephalic, carotid, subclavian, vertebral, and renal, as well as the coronary and pulmonary arteries. The clinical manifestations range from asymptomatic to catastrophic, with dizziness, hypertension, claudication, cerebral infarction, chest pain and dyspnea. Takayasu's arteritis involving the pulmonary arteries, but not the aorta and its main branches, is very rare. Herein, a case of isolated pulmonary Takayasu's arteritis combined with pulmonary thromboembolism, and hyperthyroidism is reported, with a review of the literature.