Steady Flow in an Aneurysm Model: Correlation Between Fluid Dynamics and Blood Platelet Deposition

Abstract

Laminar and turbulent numerical simulations of steady flow in an aneurysm model were carried out over Reynolds numbers ranging from 300 to 3600. The numerical simulations are validated with Digital particle Image Velocimetry (DPIV) measurements, and used to study the fluid dynamic mechanisms that characterize aneurysm deterioration, by correlating them to in vitro blood platelet deposition results. It is shown that the recirculation zone formed inside the aneurysm cavity creates conditions that promote thrombus formation and the viability of rupture. Wall shear stress values in the recirculation zone are around one order of magnitude less than in the entrance zone. The point of reattachment at the distal end of the aneurysm is characterized by a pronounced wall shear stress peak. As the Reynolds number increases in laminar flow, the center of the recirculation region migrates toward the distal end of the aneurysm, increasing the pressure at the reattachment point. Under fully turbulent flow conditions (Re = 3600) the recirculation zone inside the aneurysm shrinks considerably. The wall shear stress values are almost one order of magnitude larger than those for the laminar cases. The fluid dynamics mechanisms inferred from the numerical simulation were correlated with measurements of blood platelet deposition, offering useful explanations for the different morphologies of the platelet deposition curves.

Assessment of inflammatory infiltration and angiogenesis in the thrombus and the wall of abdominal aortic aneurysms on the basis of histological parameters and computed tomography angiography study

“…Many cytokines and metaloproteinases (MMP-3 or MMP-9), secreted by inflammatory cells, are responsible for further structural proteins like elastin, collagen and laminin degradation of the vessel wall, resulting in a gradual weakening of the wall strength. Therefore, inflammation and angiogenesis may be important events associated with the AAA progression and its rupture [33][34][35] as was also demonstrated in our present study by showing correlation between CD34 expression and lymphocytic infiltration.…”

“…It has been proved that the course of AAA is connected with neovascularization, inflammatory processes activity, free oxygen radicals activity and also with the width of the mural thrombus [8]. Mayranpaa www.fhc.viamedica.pl bus, inflammation and neovascularization within aneurysmal wall, that may decrease integrity and stability of the aneurysm wall leading to its rupture [9,10].…”

A haemodynamic predictor of intraluminal thrombus formation in abdominal aortic aneurysms

“…For example, Bluestein et al [36] presented results many years ago for steady flow simulations within idealized axisymmetric lesions. They concluded that 'the recirculation zone formed inside the aneurysm cavity creates conditions that promote thrombus formation' [36, p. 280].…”

Pulmonary Thromboembolism Caused by Prolonged Compression at the Femoral Access Site and a Venous Aneurysm of the Ipsilateral Popliteal Vein

“…4) Under the turbulent flow in an aneurysm, platelets with elevated shear histories and higher incidence of activation were readily deposed to the wall in areas of low wall shear stress, which promote the formation of mural thrombi. 5) In the present case, because of enlarging hematoma formation in the ipsilateral groin corresponds to the three components of Virchow's triad. Moreover, in case with both venous and arterial puncture, the risk of developing proximal DVT is reported 3.5 times higher than arterial puncture alone.…”