Education

• Masters in Chemical Engineering (MChE) – 2012 University of Delaware
• Diploma in Engineering – 2009 Aristotle University of Thessaloniki

Alex Apostolidis
Ph.D. candidate
115 Colburn Laboratory
alexapo@udel.edu
Tel: +1 302 831 6314

Cardiovascular diseases represent the leading cause of death in the US and contribute more than half a trillion dollars to the US health cost annually.  The most common cardiovascular diseases, myocardial infarction (heart attack) and stroke, relate to blood circulation and the inhibition of it, which is caused by atherosclerosis.  Atherogenesis, the initial step of atherosclerosis, has been found to occur in regions of low/oscillatory shear.  The aim of our work is to systematically develop low-dimensional blood flow models capable of predicting the pressure and flow at any point of the human arterial network.  A reliable blood flow model can improve our understanding of how the cardiovascular diseases develop and therefore it can contribute to the prevention or such pathological conditions.

In order to develop a complete blood flow model we are adopting a multiscale approach.  On one end, this involves the use of a low-dimensional, 1D network model which provides pressure/flow predictions across the entire vascular network ^[1].  This is where the non-Newtonian rheology is accounted for; blood is a complex fluid with a shear-thinning, viscoplastic and thixotropic behavior.  Our group has studied the complex rheology blood in simple shear flow under both steady state ^[2] and transient conditions ^[3].

The other end of my research regards more detailed, 3D simulations of specific vascular geometries of the human arterial network.  Our focus is on the left coronary artery (LCA) of the heart which bifurcates into the left circumflex (LCX) and the left anterior descending (LAD).  Using anatomically accurate dimensions we have created meshes of this geometry and use them for CFD simulations. We also consider hypothetical cases of (i) an occlusion developing in the LAD artery and (i) an implemented bypass that is used to restore the flow ^[4].

References

[1] Johnson, D.A.,J. R.  Spaeth, W. C.  Rose, U. P. Naik, A. N. Beris, “An Impedance model for blood flow in the human arterial system, Part I: Model Development and Matlab Implementation,” Computers in Chemical Engineering 35, 1304-1316 (2011)

[2] Apostolidis, A. J., and A. N. Beris, “Modeling of the blood rheology in steady-state shear flows,” Journal of Rheology 58, 607-633 (2014)

[3] Apostolidis, A. J., M. J. Armstrong, and A. N. Beris, “Modeling of human blood rheology in transient shear flows,” Submitted 07/2014, under revision

[4] Apostolidis, A. J., A. N. Beris, and P. S. Dhurjati, “Introducing CFD through a cardiovascular application in a Fluid Mechanics Course,” Chemical Engineering Education, In Press (2014)