• Journal of Korean Neurosurgical Society
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• v.54 no.4
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• pp.280-288
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• 2013

Objective : Perfusion computed tomography (PCT) has the ability to measure quantitative value and produce maps of mean transit time (MTT), cerebral blood flow (CBF), and cerebral blood volume (CBV). We assessed cerebral hemodynamics by using these parameters and acetazolamide (ACZ) challenge for pre- and post-procedural evaluation in patients with unilateral cerebrovascular stenotic disease. Methods : Thirty patients underwent pre-procedural PCT with ACZ challenge, and 24 patients (80%) was conducted follow up PCT after angioplasty with same protocol. The mean MTT, CBF, and CBV were measured and compared in both middle cerebral arterial (MCA) territories before and after ACZ challenge. Hemispheric ratio and percent change after ACZ challenge were calculated before and after angioplasty. Results : The mean stenosis rate was 76.6%. Significant increases in MTT (32.6%, p=0.000) and significant decreases in CBF (-14.2%, p=0.000) were found in stenotic side MCA territories. After ACZ challenge, there were significant changes in MTT (37.4%, p=0.000), CBF (-13.1%, p=0.000), and CBV (-10.5%, p=0.001) in pre-procedural perfusion study. However, no significant increases were found in MTT, or decreases in CBF and CBV in post-procedural study. There were no significant changes after ACZ challenge also. In addition, the degrees of these changes (before and after ACZ challenge) were highly correlated with the stenotic degrees in pre-procedural perfusion study. Conclusion : PCT with ACZ challenge appears to be a useful tool to assess the cerebral perfusion status especially in patients with unilateral symptomatic stenotic disease.

• Journal of Mechanical Science and Technology
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• v.19 no.5
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• pp.1158-1168
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• 2005

A shunt from the left ventricle to the left anterior descending artery is being developed for coronary artery occlusive disease, in which the shunt or conduit connects the the left ventricle (LV) with the diseased artery directly at a point distal to the obstruction. To aid in assessing and optimizing its benefit, a computational model of the cardiovascular system was developed and used to explore various design conditions. Computational fluid dynamic analysis for the shunt hemodynamics was also done using a commercial finite element package. Simulation results indicate that in complete left anterior descending artery (LAD) occlusion, flow can be returned to approximately 65% of normal, if the conduit resistance is equal for forward and reverse flow. The net coronary flow can increase to 80% when the backflow resistance is infinite. The increases in flow rate produced by asymmetric flow resistance are enhanced considerably for a partial LAD obstruction, since the primary effect of resistance asymmetry is to prevent leakage back into the ventricle during diastole. Increased arterial compliance has little effect on net flow with a symmetric shunt, but considerably augments it when the resistance is asymmetric. The computational results suggest that an LV-LAD conduit will be beneficial when the resistance due to artery stenosis exceeds 27 PRU, if the resistance is symmetric. Fluid dynamic simulations for the shunt flow show that a recirculating region generated near the junction of the coronary artery with the bypass shunt. The secondary flow is induced at the cutting plane perpendicular to the axis direction and it is in the attenuated of coronary artery.

• Clinical and Experimental Pediatrics
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• v.55 no.10
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• pp.377-382
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• 2012

Purpose: This single-center study aimed to assess the clinical features and surgical approaches and outcomes of complete transposition of the great arteries (TGA). Methods: TGA patients who had undergone surgical correction at the Kyungpook National University Hospital from January 2000 to December 2010, were retrospectively evaluated for patient characteristics, clinical manifestation, preoperative management, intraoperative findings, postoperative progress, and follow-up status. Results: Twenty-eight patients (17 boys and 11 girls, mean age=$10.6{\pm}21.5$ days) were included and were categorized as follows: group I, TGA with intact ventricular septum (n=13); group II, TGA with ventricular septal defect (VSD, n=12); and group III, TGA/VSD with pulmonary stenosis (n=3). Group I underwent the most intensive preoperative management (balloon atrial septostomy and prostaglandin E1 medication). Group II showed the highest incidence of heart failure (P<0.05). Usual and unusual coronary anatomy patterns were observed in 20 (71%) and 8 patients, respectively. Arterial and half-turned truncal switch operations were performed in 25 and 3 patients (Group III), respectively. Postoperative complications included cardiac arrhythmias (8 patients), central nervous system complications (3 patients), acute renal failure (1 patient), infections (3 patients), and cardiac tamponade (1 patient), and no statistically significant difference was observed between the groups. Group II showed the mildest aortic regurgitation on follow-up echocardiograms (P<0.05). One patient underwent reoperation, and 1 died. The overall mortality rate was 4%. Conclusion: Our study showed favorable results in all the groups and no significant difference in postoperative complication, reoperation, and mortality among the groups. However, our results were inadequate to evaluate the risk factors for reoperation and mortality owing to the small number of patients and short follow-up duration.

• Tuberculosis and Respiratory Diseases
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• v.43 no.2
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• pp.267-273
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• 1996

Takayasu's arteritis(aortoarteritis) is a chronic inflammatory disease involving the aorta, the arteries arising from the aorta, and the pulmonary arteries also may be involved. The inflammation leads to either stenosis and occlusion of the involved artery or formation of aneurysm or both. The arterial lesions can lead to secondary hypertension, retinopathy, cardiac involvement, cerebrovascular events, and premature death. The course and prognosis of patients with aortoarteritis show wide variation, and few authors have published systematic studies documenting the natural history of this disease. While the etiology of Takayasu's arteritis remains unknown, various modes of treatment including steroids, vascular surgery, and balloon angioplasty have been used for management of these patients. We experienced a case of Takayasu's arteritis with multiple occlusion of pulmonary arteries, which was confirmed by angiography and perfusion scan, so reported it with a review of literature.

• Journal of Korean Neurosurgical Society
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• v.64 no.6
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• pp.853-863
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• 2021

Objective : Biodegradable poly-L-lactic acid (PLLA) with a highly biocompatible surface via tantalum (Ta) ion implantation can be an innovative solution for the problems associated with current biodegradable stents. The purpose of this study is to develop a Taimplanted PLLA stent for clinical use and to investigate its biological performance capabilities. Methods : A series of in vitro and in vivo tests were used to assess the biological performance of bare and Ta-implanted PLLA stents. The re-endothelialization ability and thrombogenicity were examined through in vitro endothelial cell and platelet adhesion tests. An in vivo swine model was used to evaluate the effects of Ta ion implantation on subacute restenosis and thrombosis. Angiographic and histologic evaluations were conducted at one, two and three months post-treatment. Results : The Ta-implanted PLLA stent was successfully fabricated, exhibiting a smooth surface morphology and modified layer integration. After Ta ion implantation, the surface properties were more favorable for rapid endothelialization and for less platelet attachment compared to the bare PLLA stent. In an in vivo animal test, follow-up angiography showed no evidence of in-stent stenosis in either group. In a microscopic histologic examination, luminal thrombus formation was significantly suppressed in the Ta-implanted PLLA stent group according to the 2-month follow-up assessment (21.2% vs. 63.9%, p=0.005). Cells positive for CD 68, a marker for the monocyte lineage, were less frequently identified around the Ta-implanted PLLA stent in the 1-month follow-up assessments. Conclusion : The use of a Ta-implanted PLLA stent appears to promote re-endothelialization and anti-thrombogenicity.

• Sleep Medicine and Psychophysiology
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• v.27 no.2
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• pp.77-81
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• 2020

Obstructive sleep apnea (OSA) is a sleep-related breathing disorder in which narrowing and obstruction of the upper airway lead to frequent arousal and decreased arterial oxygenation during sleep. OSA is more common in children with genetic disorders like achondroplasia compared to children without genetic disorders. Achondroplasia is genetic disorder characterized by hypoplasia of the facial bone and skull base with foramen magnum stenosis, resulting in exceedingly high frequency of OSA. The authors present a case of a patient with achondroplasia diagnosed with severe OSA through polysomnography after adenectomy showed little therapeutic effect and who was treated with continuous positive airway pressure.

• Journal of Genetic Medicine
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• v.18 no.2
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• pp.142-146
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• 2021

Alagille syndrome (AGS) is a rare autosomal dominant inherited disorder, with major clinical manifestations of bile duct paucity, cholestasis, cardiovascular anomaly, ophthalmic abnormalities, butterfly vertebrae, and dysmorphic facial appearance. It is caused by heterozygous mutations in JAG1 or NOTCH of the Notch signaling pathway presenting with variable phenotypic penetrance and involving multiple organ systems. The following case report describes a unique case of a 16-year-old female with AGS who presented with the primary complaint of renovascular hypertension. She had a medical history of ventricular septal defect and polycystic ovary syndrome. The patient had a dysmorphic facial appearance including frontal bossing, bulbous tip of the nose, a pointed chin with prognathism, and deeply set eyes with mild hypertelorism. Stenoocclusive changes of both renal arteries, celiac artery, lower part of the abdominal aorta, and left intracranial artery, along with absence of the left internal carotid artery were found on examination. Whole exome sequencing was performed and revealed a pathologic mutation of JAG1, leading to the diagnosis of AGS. Reverse phenotyping detected butterfly vertebrae and normal structure and function of the liver and gallbladder. While the representative symptom of AGS in most scenarios is a hepatic problem, in this case, the presenting clinical features were the vascular anomalies. Clinical manifestations of AGS are diverse, and this case demonstrates that renovascular hypertension might be in some cases a presenting symptom of AGS.

• Journal of the Korean Orthopaedic Association
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• v.55 no.1
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• pp.85-89
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• 2020

Bow hunter's syndrome is a rare disease that shows the symptoms of vertebrobasilar insufficiency resulting from a dynamic obstruction or stenosis of the vertebral arteries during neck movement. This paper reports a case of a 59-year-old male who visited the emergency room with diplopia, tinnitus, and gait disturbance. Magnetic resonance imaging and angiography revealed a multiple cerebellar infarct, total obstruction of the right vertebral artery, and dynamic obstruction of the left vertebral artery during neck extension. As the infarction worsened, a thrombectomy was done. Posterior decompression and fusion at C5-6 were performed for the left vertebral artery. The left vertebral arterial patency was confirmed by intraoperative and postoperative angiography. No recurrence of the symptoms was observed for six months after surgery. Physicians need to pay attention to the diagnosis of vertebrobasilar insufficiency caused by an obstruction of the vertebral arteries during neck extension in cervical instability patients.

• Korean Journal of Radiology
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• v.2 no.3
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• pp.145-150
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• 2001

Objective: To investigate the effectiveness of the newly designed Niti-S stent in the management of iliac arterial stenoses and occlusions. Materials and Methods: Stenoses (n=25) or occlusions (n=5) in the iliac arteries of 25 patients (30 limbs) were treated. The site of the lesions was the common (n=15) or external (n=11) iliac artery, or both (n=4). Eight limbs were treated for diffuse disease, six for highly eccentric lesion, five for occlusive lesion, and 11 for failed angioplasty. Results: In all patients, technical success was achieved without major complications. One death, not procedure-related, occurred within 30 days. Ankle-brachial indexes improved from 0.63 0.30 to 0.99 0.21, and ischemic symptoms showed improvement in 22 patients (88%). Fontaine classifications before stenting, namely IIa(n=3), IIb(n=16), III(n=2), and IV(n=4) improved to I(n=17), IIa(n=5), and IV(n=3). Follow-up over a 27 (mean, 19.8 8)-month period showed that cumulative patency rates were 95.8% at 1 year and 86.2% at 2 and 3 years. No significant decrease in the mean ankle-brachial index was observed. Conclusion: The Niti-S stent appears to be a safe and effective device for the treatment of iliac stenoses and occlusions. These preliminary results require confirmation with a larger series.

• 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.