Modeling human leg arteries: a comparison of conditions and diseases

Abstract

Peripheral artery disease is a condition that is prevalent among the American population. It is caused by plaque buildup in arteries, known as atherosclerosis, other than those arteries in the heart and brain. While peripheral artery disease is not generally life threatening, complications from this disease can lead to intense pain, amputation and severe loss of quality of life. Most of the studies focusing on the lower limb arteries have been finite element studies looking at the bending effects on stents. These models are useful for stent design; however do not encompass the effects that curvatures, bifurcations and bends have on the fluid mechanics of blood flow. This thesis creates several computational fluid dynamics models of the Superficial Femoral, Deep Femoral and the Popliteal Arteries in an attempt to evaluate diseases and conditions that may contribute to peripheral artery disease. This includes the varying positions that the artery many take on during ordinary leg movement, the effects of pulsating flow, the effects of stenosis and stents, as well as the effects of increased and decreased viscosity caused by variable hemotocrit count. The results of these models were examined using various graphs of the mass flow rates, velocity profiles, wall shearing stress and static pressures. It was shown that stead state simulations will underestimate wall shearing stress and that diabetic blood will nearly double the wall shearing stress experienced in the arteries. The curvatures in the arteries will create areas of increased and decreased wall shear stress, as well as generate recirculation zones. Higher hemotocrit count decreases the recirculation zones and lower hemotocrit count increases these zones. These areas of low wall shear stress have a greater chance of forming plaque buildup; whereas the increased areas of stress can cause aneurisms in the arteries and put additional strain on the stent implants, possibly contributing failure.