Oscillating LDL accumulation in normal human aortic arch - shear dependent endothelium.

OBJECTIVE

Abnormal mass transfer of blood components to the arterial walls initiates atherosclerosis. Understating the role of mass transfer within the arterial walls requires quantitative analysis. The oscillating lipid accumulation in the aortic wall is examined in the normal human aortic arch with shear dependent endothelium properties.

METHODS

A semi-permeable nature of the arterial wall computational model, applied in the normal human aortic arch under unsteady normal flow and mass conditions, is incorporated with hydraulic conductivity and permeability treated as wall shear stress dependent. The coupling of fluid dynamics and solute dynamics at the endothelium was achieved by the Kedem-Katchalsky equation. A typical aortic arch blood flow waveform at resting conditions and lasting 800 msec is applied.

RESULTS

With constant values of water infiltration and endothelial permeability the surface vertex average normalized luminal concentration is 4.25 % higher than that at the entrance. With shear dependent values the surface vertex average normalized luminal concentration is 7.3 % higher than at the entrance. The luminal surface concentration at the arterial wall is flow-dependent with local variations due to geometric features. Concave sides of the aortic arch exhibit, relatively to the convex ones, elevated low density lipoprotein at all time steps.

CONCLUSIONS

The degree of elevation in luminal surface LDL concentration is mostly affected from the water infiltration velocity at the vessel wall. Shear dependent endothelial values must be taken into account whenever fluid and mass flow within the arterial system is incorporated.