Numerical simulation of pulsatile blood flow characteristics in multi stenosed coronary artery

BACKGROUND: Coronary artery disease (CAD) is reported as one of the most common sources of death all over the world. The presence of stenosis (plaque) in the coronary arteries results in the restriction of blood supply, which leads to myocardial infarction. OBJECTIVE: The aim of this study was to investigate the effect of multi stenosis on hemodynamics parameters in idealized coronary artery models with varying degrees of stenosis and interspace distance between the stenosis. METHODS: A finite volume-based software package (ANSYS CFX 17.2) was employed to model the blood flow. The hemodynamic stenosis parameters of blood, such as the pressure, velocity, and wall shear stress were obtained. RESULTS: The computed results showed that the pressure drop is maximum across the 90% area stenosis (AS). The pressure drop is increased as the distance between the proximal and distal stenosis is decreased across the proximal stenosis for the model P70_D70 durign the systolic period of the cardiac cycle. A recirculation zone is formed behind the stenosis and is restricted by the occurrence of distal stenosis as the interspacing distance decreases, which could lead to further progression of stenosis in the flow-disturbed area. The wall shear stress was found to increase as the distance between the proximal and distal stenosis is increased across the distal stenosis. The maximum wall shear stress was found at the 90% AS. CONCLUSIONS: In the clinical diagnosis an overestimation of distal stenosis severity could be possible. Furthermore, the low wall shear stress zone in between the proximal and distal stenosis may help atherosclerotic growth or merging of adjacent stenosis.

Numerical and experimental investigations of Fractional Flow Reserve (FFR) in a stenosed coronary artery

The coronary artery is numerically investigated based on CFD techniques for measuring the severity of stenosis. In mild cases, medication is often preferred whereas for severe cases surgical intervention is `required but most of the cases fall in between. Thus, it poses a problem for clinicians in choosing an appropriate action. The Fractional Flow Reserve (FFR) is a number which helps to predict the functional significance of stenosis in this scenario. In this study, various cases of occlusion percentranging between 40 to 70 are considered using different models for predicting FFR in the stenosed coronary artery. The lesion length is also varied between 1 cm and 5 cm based on patient–specific data. The experimental investigation of FFR in the coronary stenosis using silicon model is also carried out in this study and compared with numerical results. The effect of occlusion percentage and lesionlengthon the FFR value are quantified.

A NUMERICAL STUDY OF THE BLOOD FLOW BEHAVIOR IN CORONARY ARTERY ANOMALIES FOR NORMAL AND DIABETIC PERSONS

This work is developed to facilitate studying the flow of blood through a stenosed coronary artery of a diabetic person. It is Important in the diagnosis, risk assessment, and management of patients with known or suspected coronary artery disease where the major cause of death worldwide is the cardiovascular diseases. Two different cases of coronary artery were investigated to demonstrate the difference between blood flow in a normal and stenosed artery for both normal and diabetic persons. A 3D model was designed and meshed using ANSYS Program, the outputs of the computational fluid dynamics analysis were observed. This paper shows full and non-invasive visualization of the blood flow with high degree of precision that can be applied to the heart diseases. The results show that the disturbed flow patterns and oscillating velocity indicate that the vulnerability of plaque formation is high in case of diabetes. The increasing in blood viscosity causes a deviation in the wall shear stress especially in the presence of stenosis.