Hemodynamic investigation of intraluminal thrombus effect on the wall stress in a stented three-layered aortic aneurysm model under pulsatile flow

• Wall stresses were determined by two-dimensional axisymmetric finite element analysis.
• Calculations were performed as thrombus elastic modulus increased from 0.1 MPa to 2 MPa.
• Calculations were performed as thrombus depth increased from 10% to 100% of entire cavity.
• The maximum stress reduction of 46% occurred at the time of peak flow and 28% at the time of peak pressure.
• The wall stress at the time of peak flow and peak pressure decreased almost 25% and 20%.

PurposeAortic aneurysms occurs when the wall stress exceeds the strength of the vascular tissue. Intraluminal Thrombus (ILT) may absorb tension and reduce the aortic aneurysm wall stress. The purpose of this study is to test the hypothesis that the presence and growth of ILT alters the wall stress in a stented aneurysm.MethodA virtual stented aneurysm model with ILT is created to study the flow and wall dynamics by means of Fluid-Structure Interaction (FSI) analysis. Wall stresses are determined by two-dimensional axisymmetric finite element analysis. Calculations are performed as thrombus elastic modulus increased from 0.1 to 2 MPa and calculations are repeated as thrombus depth is increased in 10% increment until thrombus fills the entire aneurysm cavity.ResultsThe blood flow velocity, pressure, and maximum wall stresses are compared to the aforementioned models. The maximum stress reduction of 46% occurs at the time of peak flow and 28% at the time of peak pressure when thrombus elastic modulus increases from 0.1 to 2 MPa. In addition, as the thrombus depth increased from 10% to 100 %, the wall stress at the time of peak flow and peak pressure decreased almost 25% and 20%.ConclusionsThe findings of this study may have implications not only for understanding the wall stress in ILT but also for providing more detailed information about aortic aneurysm with intraluminal thrombus.