Showing 6 results for Coronary Artery
Volume 4, Issue 3 (8-2016)
Abstract
Aim: Continuous physical activity is required after coronary artery bypass graft (CABG) surgery to prevent recurrence of the disease; however, its amount is not suitable in many patients. The present study aimed to investigate the stages of physical activity in patients after CABG using the Trans-Theoretical Model (TTM).
Methods: In this cross-sectional research, 120 cardiac patients participated; they had CABG surgery and referred to Ekbatan Hospital of Hamadan. Sampling was conducted using a purpose-based approach. Data were collected using a researcher-made questionnaire based on the TTM and analyzed using the SPSS18 software. Descriptive statistics and statistical processes of one-way ANOVA, Tukey's post-hoc, and Chi-square tests were also conducted at a significant level of p<0.05.
Findings: The mean age of the participants was 57.87±9.89 years. From the 120 patients under study, 4.2% were in the pre-contemplation phase, 14.2% in the contemplation stage, 58.3% in the preparation stage, 10.8% in the action stage, and 12.5% in the maintenance phase of the physical activity. The results of ANOVA test showed a significant difference between the stages of change in behavior with perceived advantages, perceived disadvantages, perceived self-efficacy, and processes of change (p <0.001).
Conclusion: The results showed that many patients did not have regular physical activity after surgery. This makes clear the need for educational interventions based on theoretical models by health educators.
Volume 7, Issue 1 (3-2019)
Abstract
Aims: Coronary artery bypass graft (CABG) with social isolation, treatment rejection, and negative perception of the health status of patients. One of the methods to detect these problems is evaluating the quality of life. This study aimed at determining the effect of self-care behavior education on quality of life of patients after CABG based on Pender’s health promotion model.
Materials & Methods: This semi-experimental was conducted on cardiac surgery candidates, who underwent CABG in the cardiac center hospital of Mazandaran, Iran in 2017. Subjects were selected and divided into two intervention and control groups, using block randomization. at 220 individuals (110 cases per group), and data were collected, using interviews with subjects, the self-care questionnaire based on Pender’s health promotion model in cardiac surgery candidates, and SF-36 quality of life questionnaire. Moreover, the patients were followed-up and trained for 3 and 6 months after the intervention.
Findings: In this research, ANOVA results demonstrated that the different structures of quality of life significantly changed at 3 periods, including before, 3, and 6 months after the intervention (p<0.001). Furthermore, the mean total score of quality of life was higher in the intervention group (56.244±1.474), compared to the control group (48.120±1.508) in all 3 periods.
Conclusion: According to the results of the study, it is recommended that the model designed and used in the current research be applied to perform healthcare behaviors, so that the quality of life of patients can be improved after cardiac surgery.
Mehdi Kazemiyan, Hamed Afrasiab, Mohammad Hadi Pashaei,
Volume 16, Issue 2 (4-2016)
Abstract
Recent observations have shown that artery stenosis occurs as multiple-stenosis in 70% of patients with atherosclerosis plaques. Accordingly, the frequent occurrence of double-stenosis in blood arteries has inspired this paper to investigate and compare the plaque rupture risk in different arrangements of common plaque shapes in a double-stenosis. The plaque von-Mises stress in plaque fibrous cap is calculated by finite element modeling of the fluid-structure interaction (FSI) between the blood flow, artery and plaque components. Arbitrary Lagrangian-Eulerian approach is employed for FSI simulations and a benchmark problem dealing with wave propagation in a fluid-filled elastic tube is used for model verification. Transient velocity and pressure conditions of actual pulsatile blood flow through coronary artery are prescribed. The blood is assumed to be a Newtonian fluid and hyper-elastic material model is employed for describing nonlinear behavior of the human tissue composed of the arterial wall, lipid core and fibrous cap. It was observed that the arrangement composed of two diffused plaques is subjected to the maximum von-Mises stress, while the arrangement of ascending-descending plaques experiences the minimum von-Mises stress. The effect of different parameters such as the stenosis degree, the space length between the plaques, and the plaque length is studied and discussed.
Hamed Afrasiab, Bahereh Kordrostami,
Volume 16, Issue 5 (7-2016)
Abstract
Stenting is considered to be the favoured tool for therapy of coronary stenosis disease. However, despite the many advantages of this treatment strategy, its outcome may be undermined by the restenosis occurrence in the stent deployment site. Observations have shown that stent deployment in the artery alters the hemodynamic parameters such as wall shear stress and vortices size and prepares the conditions for in-stent restenosis development. Considering this fact, in this paper, the effect of some geometrical parameters such as the shape and the size of the stent strut on the wall shear stress distribution and vortices size is investigated. Furthermore, employment of a stent with partial flexible strut is suggested to decrease the restenosis risk, and the effect of the flexible part stiffness is explored. For this purpose, the interaction between the blood flow and the flexible part is simulated by arbitrary Lagrangian-Eulerian approach in the framework of the finite element method. The results indicate that in stents with circular strut, the partial flexibility of the cross-section can be effective in reducing the restenosis risk by lowering the maximum value of the wall shear stress and considerably decreasing the vortices size. On the other hand, in stents with rectangular struts, it not only does not decrease the shear stress maximum value but also significantly increases the vortices size and may lead to increase of the restenosis risk.
Ghassem Heidarinejad, Hamidreza Babakhani, Alireza Rostami,
Volume 16, Issue 12 (2-2017)
Abstract
Stenosis in coronary artery and the other cardiac diseases such as Atherosclerosis is major cause of death in the world. Numerical simulation of blood flow can help medical evaluation to curve arteries have been stenosis. The purpose of this paper is to find the effect of arteries stenosis on the hemodynamic parameters by simulation of blood flow in LAD branch of coronary artery. The computational domain has been determined from CT images of human heart. In this study, blood is assumed to be homogeneous, Newtonian and the blood flow assumed to be pulsatile. In order to more realistic modeling of flow and pressure, Seven–element lumped model has been used in coronary artery outlet, in order words the 0D and 3D models are coupled together. The results indicate that the calculated flow wave is the minimum in systolic phase and maximum in diastolic phase in coronary artery, in contrast with Aorta. On the other hand, by increasing the stenosis percent from 30 to 60 percent, no significant drop of flow has been observed in the state of rest, and it has been validated with experimental results. The results indicate that with increasing stenosis, time average wall shear stress in the stenosis region increases, while it decreases before and after the stenosis, also the investigation of oscillating shear index indicates that in the state of 60% of stenosis and in the main downstream branch, it has the maximum value, that is indicative of the presence of turbulent flow in this region.
F. Niknejad , N. Fatouraee , M. Nabaei ,
Volume 19, Issue 3 (3-2019)
Abstract
Coronary arteries play a vital role in heart nutrition, and if they get stenosis, they will be at risk of developing a heart attack. Coronary artery disease is a progressive disease that is caused by the accumulation of fat particles on the wall of the arteries, leading to thickening of the wall and the formation of layers of plaque on the wall of the arteries and ultimately causing stenosis. In the present study, in order to obtain the effect of percentage and position of stenosis on the pattern of flow and WALL SHEAR STRESS distribution, followed by the progression of atherosclerotic plaques, left coronary artery and its main branches, the anterior and anterior artery, in different conditions according to Medina classification, 50 and 75%, and three different positions of lesion locations based on their distance from carina relative to the center of the branching were modeled. According to the results, WALL SHEAR STRESS and flow ratio and the percentage of inflow into the lateral branch decreased with increasing percentage of stenosis. For example, in Medina type (1.1.1), in 50% diameter stenosis, the flow ratio was 41% of the main branch and it was 37% in 75% diameter stenosis. WALL SHEAR STRESS values are less than 1, even 0.5 Pascal and in critical range in 75% diameter stenosis. Increasing the spacing of the plaque from the center of the branch, the WALL SHEAR STRESS and lateral branch flow ratio increase, and the likelihood of the expansion of the plaque decreases. Based on the development of stenosis severity, modal type (1.0.1) has the highest probability of developing atherosclerotic plaques and total vein occlusion compared to other types of medina.
