• Korean Journal of Radiology
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• v.22 no.9
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• pp.1547-1554
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• 2021

Objective: We aimed to investigate whether repeated intravascular administration of iodinated contrast media (ICM) or gadolinium-based contrast agents (GBCAs) within a short interval was associated with an increased risk of post-contrast acute kidney injury (PC-AKI). Materials and Methods: This retrospective study included 300 patients (mean age ± standard deviation, 68.5 ± 8.1 years; 131 male and 169 female) who had undergone at least one ICM-enhanced perfusion brain CT scan, had their baseline and follow-up serum creatinine levels available, and had not undergone additional contrast-enhanced examinations 72 hours before and after a time window of interest were included. The study population was divided into three groups: single-dose group and groups of patients who had received multiple contrast administrations in the time window of interest with the minimum contrast repeat interval either within 4 hours (0-4-hour group) or between 4 to 48 hours (4-48-hour group). Multivariable logistic regression analysis was conducted to evaluate the association between AKI and repeated ICM administrations. A similar supplementary analysis was performed including both ICM and GBCA. Results: When ICM was only considered ignoring GBCA, among 300 patients, 207 patients received a single dose of ICM, 58 had repeated doses within 4 hours (0-4-hour group), and 35 patients had repeated doses between 4 to 48 hours (4-48-hour group). Most patients (> 95%) had a baseline estimated glomerular filtration rate (eGFR) of ≥ 30 mL/min/1.73 m². AKI occurred in 7.2%, 13.8%, and 8.6% of patients in the single-dose, 0-4-hour, and 4-48-hour groups, respectively. In the 0-4-hour and 4-48-hour groups, additional exposure to ICM was not associated with AKI after adjusting for comorbidities and nephrotoxic drugs (all p values > 0.05). Conclusion: Repeated intravascular administrations of ICM within a short interval did not increase the risk of AKI in our study patients suspected of acute stroke with a baseline eGFR of ≥ 30 mL/min/1.73 m².

• Korean Journal of Radiology
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• v.23 no.10
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• pp.939-948
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• 2022

Objective: Evidence supports the efficacy of coronary computed tomography angiography (CCTA)-based risk scores in cardiovascular risk stratification of patients with suspected coronary artery disease (CAD). We aimed to compare two CCTA-based risk score algorithms, Leiden and Confirm scores, in patients with diabetes mellitus (DM) and suspected CAD. Materials and Methods: This single-center prospective cohort study consecutively included 1241 DM patients (54.1% male, 60.2 ± 10.4 years) referred for CCTA for suspected CAD in 2015-2017. Leiden and Confirm scores were calculated and stratified as < 5 (reference), 5-20, and > 20 for Leiden and < 14.3 (reference), 14.3-19.5, and > 19.5 for Confirm. Major adverse cardiovascular events (MACE) were defined as the composite outcomes of cardiovascular death, nonfatal myocardial infarction (MI), stroke, and unstable angina requiring hospitalization. The Cox model and Kaplan-Meier method were used to evaluate the effect size of the risk scores on MACE. The area under the curve (AUC) at the median follow-up time was also compared between score algorithms. Results: During a median follow-up of 31 months (interquartile range, 27.6-37.3 months), 131 of MACE were recorded, including 17 cardiovascular deaths, 28 nonfatal MIs, 64 unstable anginas requiring hospitalization, and 22 strokes. An incremental incidence of MACE was observed in both Leiden and Confirm scores, with an increase in the scores (log-rank p < 0.001). In the multivariable analysis, compared with Leiden score < 5, the hazard ratios for Leiden scores of 5-20 and > 20 were 2.37 (95% confidence interval [CI]: 1.53-3.69; p < 0.001) and 4.39 (95% CI: 2.40-8.01; p < 0.001), respectively, while the Confirm score did not demonstrate a statistically significant association with the risk of MACE. The Leiden score showed a greater AUC of 0.840 compared to 0.777 for the Confirm score (p < 0.001). Conclusion: CCTA-based risk score algorithms could be used as reliable cardiovascular risk predictors in patients with DM and suspected CAD, among which the Leiden score outperformed the Confirm score in predicting MACE.

• Korean Journal of Radiology
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• v.23 no.3
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• pp.333-342
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• 2022

Objective: Intracranial atherosclerotic stroke occurs through various mechanisms, mainly by artery-to-artery embolism (AA) or branch occlusive disease (BOD). This study evaluated the spatial relationship between middle cerebral artery (MCA) plaques and perforating arteries among different MCA territory infarction types using vessel wall magnetic resonance imaging (VW-MRI). Materials and Methods: We retrospectively enrolled patients with acute MCA infarction who underwent VW-MRI. Thirty-four patients were divided into three groups according to infarction pattern: 1) BOD, 2) both BOD and AA (BOD-AA), and 3) AA. To determine the factors related to BOD, the BOD and BOD-AA groups were combined into one group (with striatocapsular infarction [BOD+]) and compared with the AA group. To determine the factors related to AA, the BOD-AA and AA groups were combined into another group (with cortical infarction [AA+]) and compared with the BOD group. Plaque morphology and the spatial relationship between the perforating artery orifice and plaque were evaluated both quantitatively and qualitatively. Results: The plaque margin in the BOD+ group was closer to the perforating artery orifice than that in the AA group (p = 0.011), with less enhancing plaque (p = 0.030). In the BOD group, plaques were mainly located on the dorsal (41.2%) and superior (41.2%) sides where the perforating arteries mainly arose. No patient in the AA group had overlapping plaques with perforating arteries at the cross-section where the perforator arose. Perforating arteries associated with culprit plaques were most frequently located in the middle two-thirds of the M1 segment (41.4%). The AA+ group had more stenosis (%) than the BOD group (39.73 ± 24.52 vs. 14.42 ± 20.96; p = 0.003). Conclusion: The spatial relationship between the perforating artery orifice and plaque varied among different types of MCA territory infarctions. In patients with BOD, the plaque margin was closer and blocked the perforating artery orifice, and stenosis degree and enhancement were less than those in patients with AA.

• Korean Circulation Journal
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• v.52 no.4
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• pp.304-319
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• 2022

Background and Objectives: De-escalation of dual-antiplatelet therapy through dose reduction of prasugrel improved net adverse clinical events (NACEs) after acute coronary syndrome (ACS), mainly through the reduction of bleeding without an increase in ischemic outcomes. Whether the benefits of de-escalation are sustained in highly thrombotic conditions such as ST-elevation myocardial infarction (STEMI) is unknown. We aimed to assess the efficacy and safety of de-escalation therapy in patients with STEMI or non-ST-segment elevation ACS (NSTE-ACS). Methods: This is a pre-specified subgroup analysis of the HOST-REDUCE-POLYTECH-ACS trial. ACS patients were randomized to prasugrel de-escalation (5 mg daily) or conventional dose (10 mg daily) at 1-month post-percutaneous coronary intervention. The primary endpoint was a NACE, defined as a composite of all-cause death, non-fatal myocardial infarction, stent thrombosis, clinically driven revascularization, stroke, and bleeding events of grade ≥2 Bleeding Academic Research Consortium (BARC) criteria at 1 year. Results: Among 2,338 patients included in the randomization, 326 patients were diagnosed with STEMI. In patients with NSTE-ACS, the risk of the primary endpoint was significantly reduced with de-escalation (hazard ratio [HR], 0.65; 95% confidence interval [CI], 0.48-0.89; p=0.006 for de-escalation vs. conventional), mainly driven by a reduced bleeding. However, in those with STEMI, there was no difference in the occurrence of the primary outcome (HR, 1.04; 95% CI, 0.48-2.26; p=0.915; p for interaction=0.271). Conclusions: Prasugrel dose de-escalation reduced the rate of NACE and bleeding, without increasing the rate of ischemic events in NSTE-ACS patients but not in STEMI patients.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.2
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• pp.188-193
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• 2015

It has been generally recognized that $N_2O$(Nitrous Oxide) emission from marine diesel engines has a close correlation with $SO_2$(Sulfur Dioxide) emission, and diversity of fuel elements using ships affects characteristics of the $N_2O$ emission. According to recent reports, in case of existence of an enough large NO(Nitric Oxide) generated as fuel combustion, effect of the $SO_2$ emission in exhaust gas on the $N_2O$ formation is more vast than effect of the NO. Therefore, $N_2O$ formation due to the $SO_2$ element operates on a important factor in EGR(Exhaust Gas Recirculation) systems for NOx reduction. An aim of this experimental study is to investigate that intake gas of the diesel engine with increasing of $SO_2$ flow rate affects $N_2O$ emission in exhaust gas. A test engine using this experiment was a 4-stroke direct injection diesel engine with maximum output of 12 kW at 2600rpm, and operating condition was set up at a 75% load. A standard $SO_2$ gas with 0.499%($m^3/m^3$) was used for changing of $SO_2$ concentration in intake gas. In conclusion, the diesel fuel included out sulfur elements did mot emit the $SO_2$ emission, and the $SO_2$ emission in exhaust gas according as increment of the $SO_2$ standard gas had almost the same ratio compared with $SO_2$ rate in mixture inlet gas. Furthermore, the $N_2O$ element in exhaust gas was formed as $SO_2$ mixture in intake gas because increment of $SO_2$ flow rate in intake gas increased $N_2O$ emission. Hence, diesel fuels included sulfur compounds were combined into $SO_2$ in combustion, and $N_2O$ in exhaust gas should be generated to react with NO and $SO_2$ which exist in a combustion chamber.

• The Korea Journal of Herbology
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• v.23 no.2
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• pp.159-168
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• 2008

Objectives : The present study has been undertaken to investigate the effects of Dipsaci Radix on Muscle Fiber Atrophy and MyoD Expression in Gastrocnemius of MCAO Rats Methods : In order to investigate effects of Dipsaci radix on the skeletal muscle atrophy following stroke, cerebral infarct was induced by the middle cerebral artery occlusion (MCAO) in the rats. Water extract of Dipsaci radix (184.4 mg/100 g) was treated for 4 weeks, once a day orally, after the MCAO. Effects were evaluated with muscle fiber type composition and cross-sectioned area of muscle fibers in gastrocnemius of the unaffected & affected hind limbs. And MyoD protein expression in gastrocnemius was demonstrated with immunohistochemistry and western blotting. Results : Obtained results were as follows; 1. Infarct volume was not attenuated by Dipsaci radix treatment in the MCAO rats. 2. At the affected-side hind limb of the MCAO rats, the increase of type-I fibers and the decrease of type-II fibers were induced by Dipsaci radix treatment. 3. At the affected-side hind limb of the MCAO rats, decreases of cross-sectioned areas of type-I and type-II fibers were attenuated by Dipsaci radix treatment. 4. At the affected-side hind limb of the MCAO rats, MyoD positive cells were increased by Dipsaci radix treatment. 5. At the affected-side hind limb of the MCAO rats, MyoD expressions were increased by Dipsaci radix treatment. Conclusions : These results suggest that Dipsaci radix has a protective effect against muscle atrophy, through the inhibition of the muscle cell apoptosis, following the central nervous system demage.

• Journal of Nutrition and Health
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• v.44 no.6
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• pp.498-506
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• 2011

This study examined the relationship among plasma homocysteine, folate, and vitamin $B_{12}$ levels and neurocognitive function in 118 community-dwelling elderly subjects (mean age, $75.1{\pm}6.7$ years). The Mini-Mental State Examination (MMSE-KC) was used to screen and assess neurocognitive function in the participants. Dietary intake data including the use of dietary supplements were obtained using the 24-hour recall method by well-trained interviewers. Plasma folate and vitamin $B_{12}$ concentrations were analyzed by radioimmunoassay, and homocysteine was assessed by a high performance liquid chromatography-fluorescence method. The proportions of participants with suboptimal levels of plasma folate (< 3 ng/mL), vitamin $B_{12}$ (< 221 pmol/mL), and homocysteine (> $15{\mu}mol/L$) were 16.1%, 5.9%, and 21.2%, respectively. A multiple regression analysis showed that plasma homocysteine was negatively associated with plasma folate and vitamin $B_{12}$ levels. The MMSE-KC test scores were significantly associated with plasma homocysteine and folate, but not with vitamin $B_{12}$, after adjusting for age, gender, body mass index, living with spouse, education, current smoking, energy intake, and chronic diseases such as hypertension, diabetes, thyroid disease, dyslipidemia, stroke, and cardiovascular disease. A general linear model adjusted for covariates revealed that MMSE-KC test scores increased from the lowest to the highest quartiles of vitamin $B_1$, vitamin $B_2$, vitamin $B_6$, vitamin $B_{12}$, and vitamin C intake (p for trend = 0.012, 0.039, 0.014, 0.046, 0.026, respectively). These results indicate that the problem of folate inadequacy and hyperhomocysteinemia are highly prevalent among community-dwelling elderly people and that dietary intake of the B vitamins and vitamin C is positively associated with cognitive function scores.

• Journal of Chest Surgery
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• v.46 no.6
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• pp.426-432
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• 2013

Background: Heart transplantation has become a widely accepted surgical option for end-stage heart failure in Korea since its first success in 1992. We reviewed early postoperative complications and mortality in 239 patients who underwent heart transplantation using bicaval technique in Asan Medical Center. Methods: Between January 1999 and December 2011, a total of 247 patients aged over 17 received heart transplantation using bicaval technique in Asan Medical Center. After excluding four patients with concomitant kidney transplantation and four with heart-lung transplantation, 239 patients were enrolled in this study. We evaluated their early postoperative complications and mortality. Postoperative complications included primary graft failure, cerebrovascular accident, mediastinal bleeding, renal failure, low cardiac output syndrome requiring intra-aortic balloon pump or extracorporeal membrane oxygenation insertion, pericardial effusion, and inguinal lymphocele. Follow-up was 100% complete with a mean follow-up duration of $58.4{\pm}43.6$ months. Results: Early death occurred in three patients (1.3%). The most common complications were pericardial effusion (61.5%) followed by arrhythmia (41.8%) and mediastinal bleeding (8.4%). Among the patients complicated with pericardial effusion, only 13 (5.4%) required window operation. The incidence of other significant complications was less than 5%: stroke (1.3%), low cardiac output syndrome (2.5%), renal failure requiring renal replacement (3.8%), sternal wound infection (2.0%), and inguinal lymphocele (4.6%). Most of complications did not result in the extended length of hospital stay except mediastinal bleeding (p=0.034). Conclusion: Heart transplantation is a widely accepted option of surgical treatment for end-stage heart failure with good early outcomes and relatively low catastrophic complications.

• The Journal of Korea Assosiation for Disability and Oral Health
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• v.13 no.2
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• pp.108-113
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• 2017

Moyamoya disease is a disorder in which certain arteries in the brain are constricted. Blood flow can be blocked by the constriction and blood clots. The patients frequently experience transient ischemic attacks (TIA), cerebral hemorrhage, or may not experience any symptoms at all. It is reported that they have a higher risk of recurrent stroke and a distinct underlying pathophysiology. A 3-year-8-month old boy with moyamoya disease experienced cerebral infarctions five times, and he underwent a cerebrovascular anastomosis surgery four years ago. He showed swallow disturbance, general delayed development, hemiplegia, and strabismus. Also he had hypocalcified teeth with or without multiple caries lesions in all dentitions. Dental treatment under general anesthesia using sevoflurane was performed due to his lack of cooperation. Moyamoya disease is associated with various medical conditions requiring a thoughtful deliberation and a careful examination before and during dental treatment. Pain and anxiety control during dental treatment is important because hyperventilation induced by crying has been seen to trigger TIA. Both isoflurane and sevoflurane are commonly used in patients with MMD, but dynamic autoregulation is better preserved during sevoflurane than isoflurane anesthesia. So sevoflurance general anesthesia may be recommendable to manage dental patients having multiple caries with moyamoya disease.

• Journal of Chest Surgery
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• v.51 no.2
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• pp.100-108
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• 2018

Background: The question of which type of prosthetic aortic valve leads to the best outcomes in patients in their 60s remains controversial. We examined the hemodynamic and clinical outcomes of aortic valve replacement in sexagenarians according to the type of prosthesis. Methods: We retrospectively reviewed 270 patients in their 60s who underwent first-time aortic valve replacement from 1995 to 2011. Early and late mortality, major adverse valve-related events, anticoagulation-related events, and hemodynamic outcomes were assessed. The mean follow-up duration was $58.7{\pm}44.0$ months. Results: Of the 270 patients, 93 had a mechanical prosthesis (mechanical group), and 177 had a bioprosthesis (tissue group). The tissue group had a higher mean age and prevalence of preoperative stroke than the mechanical group. The groups had no differences in the aortic valve mean pressure gradient (AVMPG) or the left ventricular mass index (LVMI) at 5 years after surgery. In a sub-analysis limited to prostheses in the supra-annular position, the AVMPG was higher in the tissue group, but the LVMI was still not significantly different. There was no early mortality. The 10-year survival rate was 83% in the mechanical group and 90% in the tissue group. The type of aortic prosthesis did not influence overall mortality, cardiac mortality, or major adverse valve-related events. Anticoagulation-related events were more common in the mechanical group than in the tissue group (p=0.034; hazard ratio, 4.100; 95% confidence interval, 1.111-15.132). Conclusion: The type of aortic prosthesis was not associated with hemodynamic or clinical outcomes, except for anticoagulation-related events.