• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.10
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• pp.893-899
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• 2010

A previous study showed that hemodynamics is correlated with stenosis in the coronary artery. The flow characteristics and the distributions of the hemodynamic wall parameters in the coronary artery are investigated under physiological flow condition. The present study also aims to establish the mechanism of the generation of atherosclerosis by analyzing the hemodynamic variables in the coronary artery where atherosclerosis frequently occurs. The stenosis phenomena due to atherosclerosis are related to not only the biochemical reaction between blood and blood vessels but also the hemodynamic factors sush as flow separation and oscillatory wall shear stress. As the bifurcated angle increases, the size of the recirculation area that appears in the cross section increases and disturbed flow is observed in this area. We speculate that this area is the starting point of atherosclerosis in the coronary artery.

• Journal of agricultural medicine and community health
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• v.39 no.1
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• pp.25-36
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• 2014

Objectives: The objective of this study was to investigate the relationship between coronary artery calcification and risk factors of cardiovascular disease with multidetector computed tomography. Methods: Data were collected from 5,899 males between 30 and 59 years old by interview, survey, physical examination, blood test, and multidetector computed tomography in the university hospital from January 2010 to December 2011. We confirmed the coronary artery calcium scores of subjects by multidetector computed tomography and identified risk factors of cardiovascular disorders. We investigated the relationship between coronary artery calcification and risk factors of cardiovascular disorders. Results: Mean calcium score of the coronary arteries in 5,899 participants was 8.20, and 773 participants (13.1%) exhibited coronary artery calcification. The presence of coronary artery calcification was correlated to risk factors of cardiovascular disease (age, blood pressure, triglyceride, HDL cholesterol, LDL cholesterol, glucose, Apolipoprotein A-1, Apolipoprotein B, body mass index, waist circumference) and risk assessment tools of cardiovascular disorders. Significant predicted factors of coronary artery calcification had different patterns in each age group (30-39, 40-49, 50-59 years old). Conclusions: We confirmed the relationship between coronary artery calcification and either typical risk factors of cardiovascular disease or risk assessment tools of cardiovascular disease. In addition, we also observed that the pattern of these factors varied according to age. Therefore, age-related variation needs to be considered in management strategies to prevent cardiovascular disease.

• Journal of Chest Surgery
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• v.37 no.5
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• pp.410-415
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• 2004

Background: In the operation for coronary artery stenosis, the procedures for mitral regurgitation are restricted to cases of more than moderate mitral regurgitation or for the lesions in leaflets. This is based on the belief that the less than mild regurgitation are a form of reversible change results from ischemia with coronary artery stenosis. We studied the changes and prognostic factors of mitral regurgitation in patients with coronary artery stenosis and mitral regurgitation who underwent coronary artery bypass surgery alone. Material and Method: We reviewed the medical records of 90 patients with coronary artery stenosis and mitral regurgitation who underwent coronary artery bypass surgery alone by a single surgeon from Jan. 1995 to Dec. 2002, We grouped the patients according to the postoperative changes of mitral regurgitation, and then we statistically compared the findings of echocardiogram between preoperative and last follow up. Result: There were 24 cases with progression of mitral regurgitation, 12 cases without changes, 54 cases with improvements of mitral regurgitation in total 90 patients. The bypass to LAD was proven as the significant prognostic factor of mitral regurgitation. The preoperative end diastolic left ventricular volume index were higher in aggravated group with 105.38$\pm$38.89 $m\ell$ compared to 71.75$\pm$28,45 $m\ell$ in improvement group, and 84.00$\pm$11.66 $m\ell$ in no change group. The grade of preoperative mitral regurgitation did not show significant differences among the groups. Conclusion: The mitral regurgitation in patient with coronary artery stenosis can be improved after the coronary artery bypass surgery alone. However, the expectation of improvements based on the degree of preparative mitral regurgitation can not be justified, therefore, the procedures for mitral regurgitation should be aggressively considered even in the cases of mild mitral regurgitation. Also, further study should be performed to identify the exact prognostic factors of mitral regurgitation including the left ventricular volume index, and whether the left anterior descending artery has been bypassed.

• Journal of Preventive Medicine and Public Health
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• v.34 no.3
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• pp.244-252
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• 2001

Objective : Health insurers and policy makers are increasingly examining the hospital mortality rate as an indicator of hospital quality and performance. To be meaningful, a risk-adjustment of the death rates must be implemented. This study reviewed 5 severity measurement methods and applied them to the same data set to determine whether judgments regarding the severity-adjusted hospital mortality rates were sensitive to the specific severity measure. Methods : The medical records of 584 patients who underwent coronary artery bypass graft surgery in 6 general hospitals during 1996 and 1997 were reviewed by trained nurses. The MedisGroups, Disease Staging, Computerized Severity Index, APACHE III and KDRG were used to quantify severity of the patients. The predictive probability of death was calculated for each patient in the sample from a multivariate logistic regression model including the severity score, age and sex to evaluate the hospitals' performance, the ratio of the observed number of deaths to the expected number for each hospital was calculated. Results : The overall in-hospital mortality rate was 7.0%, ranging from 2.7% to 15.7% depending on the particular hospital. After the severity adjustment, the mortality rates for each hospital showed little difference according to the severity measure. The 5 severity measurement methods varied in their statistical performance. All had a higher c statistic and $R^2$ than the model containing only age and sex. There was a little difference in the relative hospital performance evaluation by the severity measure. Conclusion : These results suggest that judgments regarding a hospital's performance based on severity adjusted mortality can be sensitive to the severity measurement method. Although the 5 severity measures regarding hospital performance concurred, more often than would be expected by chance, the assessment of an individual hospital mortality rates varied by the different severity measurement method used.

• Journal of Biomedical Engineering Research
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• v.40 no.2
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• pp.62-67
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• 2019

The purpose of this study was to evaluate the performance of deep neural network model in order to determine whether there is a risk factor for coronary artery disease based on the cardiac variation parameter. The study used unidentifiable 297 data to evaluate the performance of the model. Input data consists of heart rate parameters, which are SDNN (standard deviation of the N-N intervals), PSI (physical stress index), TP (total power), VLF (very low frequency), LF (low frequency), HF (high frequency), RMSSD (root mean square of successive difference) APEN (approximate entropy) and SRD (successive R-R interval difference), the age group and sex. Output data are divided into normal and patient groups, and the patient group consists of those diagnosed with diabetes, high blood pressure, and hyperlipidemia among the various risk factors that can cause coronary artery disease. Based on this, a binary classification model was applied using Deep Neural Network of deep learning techniques to classify normal and patient groups efficiently. To evaluate the effectiveness of the model used in this study, Kernel SVM (support vector machine), one of the classification models in machine learning, was compared and evaluated using same data. The results showed that the accuracy of the proposed deep neural network was train set 91.79% and test set 85.56% and the specificity was 87.04% and the sensitivity was 83.33% from the point of diagnosis. These results suggest that deep learning is more efficient when classifying these medical data because the train set accuracy in the deep neural network was 7.73% higher than the comparative model Kernel SVM.

• Yonsei Medical Journal
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• v.59 no.9
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• pp.1057-1063
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• 2018

Purpose: Coronary artery spasm (CAS) and diabetes mellitus (DM) are implicated in endothelial dysfunction, and insulin resistance (IR) is a major etiological cause of type 2 DM. However, the association between CAS and IR in non-diabetic individuals has not been elucidated. The aim of the present study was to evaluate the impact of IR on CAS in patients without DM. Materials and Methods: A total of 330 eligible patients without DM and coronary artery disease who underwent acetylcholine (Ach) provocation test were enrolled in this study. Inclusion criteria included both hemoglobin A1c <6.0% and fasting glucose level <110 mg/dL without type 2 DM. Patients were divided into quartile groups according the level of homeostasis model assessment of insulin resistance (HOMA-IR): 1Q (n=82; HOMA-IR<1.35), 2Q (n=82; $1.35{\leq}HOMA-IR<1.93$), 3Q (n=83; $1.93{\leq}HOMA-IR<2.73$), and 4Q (n=83; $HOMA-IR{\geq}2.73$). Results: In the present study, the higher HOMA-IR group (3Q and 4Q) was older and had higher body mass index, fasting blood glucose, serum insulin, hemoglobin A1c, total cholesterol, and triglyceride levels than the lower HOMA-IR group (1Q). Also, poor IR (3Q and 4Q) was considerably associated with frequent CAS. Compared with Q1, the hazard ratios for Q3 and Q4 were 3.55 (95% CI: 1.79-7.03, p<0.001) and 2.12 (95% CI: 1.07-4.21, p=0.031), respectively, after adjustment of baseline risk confounders. Also, diffuse spasm and accompanying chest pain during Ach test were more strongly associated with IR patients with CAS. Conclusion: HOMA-IR was significantly negatively correlated with reference diameter measured after nitroglycerin and significantly positively correlated with diffuse spasm and chest pain.

• Korean Journal of Adult Nursing
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• v.20 no.4
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• pp.537-547
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• 2008

Purpose: The study aimed to apply Tai Chi exercise to patients with coronary artery disease for 6 months, and to examine changes on body composition, physical strength, and cardiovascular risks. Methods: Applying a quasi experimental design with a nonequivalent control group, 90 subjects with cardiovascular disease were recruited at C university hospital. For 6 months, 44 subjects performed Tai Chi exercise once a week and daily home exercise, while 46 subjects did not. Body composition was assessed by body mass index, % body fat, and waist-hip ratio; physical strength by balance, mobility, flexibility, grip strength, and back muscle strength; and cardiovascular risk checklist for fixed and modifiable risk factors. Data were analyzed by SPSS/WIN program with ANCOVA to consider group differences at the pretest. Results: The subjects were 66 years old in average. In 6 months, Tai Chi group improved significantly in balance, mobility, and flexibility with decreased modifiable cardiovascular risks after adjusting for the pretest scores. Conclusion: Tai Chi exercise was safely applicable to individuals with coronary artery disease, and effective in some measures of physical strength and modifiable cardiovascular risks. It could be an alternative exercise for outpatient cardiac rehabilitation program in this population.

• Journal of Korean Critical Care Nursing
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• v.12 no.1
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• pp.82-93
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• 2019

Purpose : The purpose of this study was to investigate the degree of post-traumatic stress disorder (PTSD) symptoms and the effect of PTSD on quality of life (QoL) among coronary artery disease (CAD) patients. Methods: The participants were 135 CAD patients who visited outpatient clinics in a university hospital in B city of Korea. Their PTSD symptoms and QoL were measured by structured questionnaires and analyzed with multiple hierarchical regression analysis. Results: Among the 135 participants, 20.7% were classified as moderate risk, and 3.7% as high risk for PTSD. PTSD symptoms were significantly higher in participants who were diagnosed with CAD within 6 months (t=26.02, p<.001). The physical component of health-related QoL was influenced by gender (${\beta}=-.25$, p =.003), recurrence of CAD (${\beta}=.21$, p =.008), and PTSD symptoms (${\beta}=-.33$, p <.001). The mental component of health-related QoL was influenced by religion (${\beta}=-.17$, p =.044), body mass index (${\beta}=.17$, p =.033), and PTSD symptoms (${\beta}=-.37$, p <.001). Conclusion: Patients who had had a CAD diagnosis for less than 6 months were found to be vulnerable to PTSD, and PTSD was found to have a negative impact on the physical and mental components of their QoL. It is necessary to develop an intervention program for the effective prevention and management of PTSD symptoms in patients with CAD.

• Journal of Chest Surgery
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• v.55 no.3
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• pp.189-196
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• 2022

Background: This study investigated the predictive value of the frailty index calculated using laboratory data and vital signs (FI-L) in patients who underwent coronary artery bypass grafting (CABG). Methods: This study included 508 patients (age 67.3±9.7 years, male 78.0%) who underwent CABG between 2018 and 2021. The FI-L, which estimates patients' frailty based on laboratory data and vital signs, was calculated as the ratio of variables outside the normal range for 32 preoperative parameters. The primary endpoints were operative and medium-term all-cause mortality. The secondary endpoints were early postoperative complications and major adverse cardiac and cerebrovascular events (MACCEs). Results: The mean FI-L was 20.9%±10.9%. The early mortality rate was 1.6% (n=8). Postoperative complications were atrial fibrillation (n=148, 29.1%), respiratory complications (n=38, 7.5%), and acute kidney injury (n=15, 3.0%). The 1- and 3-year survival rates were 96.0% and 88.7%, and the 1- and 3-year cumulative incidence rates of MACCEs were 4.87% and 8.98%. In multivariable analyses, the FI-L showed statistically significant associations with medium-term all-cause mortality (hazard ratio [HR], 1.042; 95% confidence interval [CI], 1.010-1.076), MACCEs (subdistribution HR, 1.054; 95% CI, 1.030-1.078), atrial fibrillation (odds ratio [OR], 1.02; 95% CI, 1.002-1.039), acute kidney injury (OR, 1.06; 95% CI, 1.014-1.108), and re-operation for bleeding (OR, 1.09; 95% CI, 1.032-1.152). The minimal p-value approach showed that 32% was the best cutoff for the FI-L as a predictor of all-cause mortality post-CABG. Conclusion: The FI-L was a significant prognostic factor related to all-cause mortality and postoperative complications in patients who underwent CABG.

• Journal of Periodontal and Implant Science
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• v.34 no.3
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• pp.607-622
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• 2004

Recently epidemiologic studies have indicated that the patients with periodontitis may have increased risk of ischemic cardiovascular events, and have suggested the important roles of blood cytokines and acute reactant proteins in the systemic infection and inflammatory response. Periodontitis and coronary heart disease (CHD) may share the common risk factors and the genetic mechanism associated with interleukin(IL)-1A, B and RA genotype may be involved in the production of IL-1. This study was aimed to investigate the relationship between angiographically defined CHD and periodontitis as chronic Gram-negative bacterial infection and to determine whether the IL-1 gene polymorphism is associated in both diseases. Patients under the age of 60 who had undergone diagnostic coronary angiography were enrolled in this study. Subjects were classified as positive CHD (+CHD, n=37) with coronary artery stenosis more than 50% in at least one of major epicardial arteries, and negative CHD (-CHD, n=30) without significant stenosis. After recording the number of missing teeth, periodontal disease severity was measured by means of plaque index (PI), gingival index (GI), bleeding on probing (BOP), probing depth (PD), clinical attachment level (CAL), and radiographic bone loss around all remaining teeth. Gingival crevicular fluid (GCF) was collected from the 4 deepest periodontal pockets and assessed for cytokine ($IL-1{\beta}$, IL-6, IL-1ra, tumor necrosis $factor-{\alpha}$, and prostaglandin $E_2$). Additionally, blood CHD markers, lipid profile, and blood cytokines were analyzed. IL-1 gene cluster genotyping was performed by polymerase chain reaction and enzyme restriction using genomic DNA from buccal swab, and allele 2 frequencies of IL-1A(+4845), IL-1B(+3954), IL-B(-511), and IL-1RA(intron 2) were compared between groups. Even though there was no significant difference in the periodontal parameters between 2 groups, GCF level of $PGE_2$ was significantly higher in the +CHD group(p<0.05). Correlation analysis showed the positive relationship among PD, CAL and coronary artery stenosis(%) and blood $PGE_2$. There was also significant positive relationship between the periodontal parameters (PI, PD, CAL) and the blood CHD markers (leukocyte count, C-reactive protein, and lactic dehyrogenase). IL-1 gene genotyping showed that IL-1A(+3954) allele 2 frequency was significantly higher in the +CHD group compared with the -CHD group (15% vs. 3.3%, OR 5.118,p=0.043). These results suggested that periodontal inflammation is related to systemic blood cytokine and CHD markers, and contributes to cardiovascular disease via systemic inflammatory reaction. IL-1 gene polymorphism might have an influence on periodontal and coronary heart diseases in Korean patients.