1. What I gained from my time in ReDVA
Nicolas Aristokleous
UoD, ER, Jan 2015 – Jan 2017
August, 30, 2017

2. Introduction The Need The Aim
To develop hemodynamic solutions to improve the performance and longevity of AVF.
It is estimated that over 2 million patients worldwide have end stage renal disease (ESRD) and this number continues to grow at a constant rate of ~7% per annum [1] .
The cost for treatment is estimated to exceed €750 billion in the next decade [2].
Therapy Methods
Renal Transplantation (Tx)
Peritoneal Dialysis (PD)
Haemodialysis (HD) Most common treatment method but still the failure rates are high (~50%)
AVFs suffer from thrombosis (44%) and from the fail of mature (23-46%).
The Aim
To develop haemodynamic solutions to improve the performance and longevity of AVF for ESRD patients.
Follow-up study on a Brachial-Cephalic AVF to monitor the maturation process and to estimate the haemodynamic and mechanical conditions that endothelial cells experience (WSS metrics).
[1] A. Grassmann, S. Gioberge, S. Moeller, and G. Brown, “ESRD patients in 2004: Global overview of patient numbers, treatment modalities and associated trends,” Nephrol. Dial. Transplant., vol. 20, no. 12, pp. 2587–2593, 2005.
[2] “

3. Methodology: 1. Imaging Non-Contrast MR Imaging Segmentation
MR Images in DICOM format
Slice-by-slice manual and
semi-automated segmentation
3D geometry reconstruction
2D PC MR Imaging

4. Methodology: 2. Morphology
Surface Modelling
Geometric Changes L D
L/D-1
Tortuosity
Curvature
1/r
Bifurcation Angle: notably increased on the II scan, decreased to 50deg on the IV scan.
Curvature and Tortuosity: decreased on the IV scan compared with the I scan.

5. Methodology: 3. CFD Mesh Construction CFD simulations Ansys ICEM-CFD
Hexahedral Elements ~1.2m
CFD simulations
Ansys Fluent
Blood: ρ = 1.05 gr/cm3, μ = 3.5x10-3 Pa s
High WSS distribution after the AVF creation
Gradually degreased to IV scan

6. Conclusions
The methodology followed from MRI to CFD is well established
Morphological and Haemodynamical alterations May influence and contribute in maturation
failure (Neo-Intimal Hyperplasia and Thrombosis)
Need more follow-up studies to find possible correlations between Geometric & Haemodynamic Parameters and their impact on AVF maturation
Improvement in some steps for more accurate results and save time:
Imaging (better resolution)
Automate segmentation (reduce time)
Optimization of the haemodynamic performance and functionality of medical devices
(stents; grafts; endografts; catheters)  Bio-inspired design by the spiral flow.

7. Career Development ReDVA project contributed to:
Gain more in-depth knowledge in biomedical area
Acquire more experience and a stronger background in this area
Improve communication skills
Engaged with experimental setups and industry
Improve my scientific track record
Provided me space and conditions to
move on and continue my researh and find a new position

8. Publications Selected Publications in Conference Proceedings
E.A. Murphy, S.P. Broderick, N. Aristokleous, L.D. Browne, E. Kokkalis, C.V. Cunnane, C. Macdonald, R. Ross, S.Z. Matthew and J.G. Houston, “Oxygen Transport in Patient-Specific Arteriovenous Fistulas”, The 23rd Congress of the European Society of Biomechanics, Sevilla, Spain, 2017.
N. Aristokleous, L.D. Browne, E. Kokkalis, S.P. Broderick, M.T. Walsh, and J.G. Houston, “Monitor Morphology Alterations using MRI. A Follow-Up Study on Two Different Arterio-Venous Fistula Types”,ESMRMB 2016, 33rd Annual Scientific Meeting, Vienna, Austria, 2016.
N. Aristokleous, S. Matthew, S. Gandy, and J.G. Houston, “Morphological and haemodynamical changes on arteriovenous fistula image-based models. An MRI Follow-Up Study”, SINAPSE Annual Scientific Meeting, Stirling, UK, 2016.
N. Aristokleous, S. Matthew, S. Gandy, E. Kokkalis, L.D. Browne, S.P. Broderick, M.T. Walsh, and J.G. Houston, “The influence of arm position on the geometric features of the Brachial Artery and Basilic Vein”, VASBi, Manchester, UK, 2015.
C. MacDonald, N. Aristokleous, S. Matthew, S. Gandy, M. Dunn, and J. G. Houston, “Arm position alters the geometry of Brachial artery and Basilic vein”. 27th MRWG Annual International Conference. Cincinnati, Ohio, USA, 2015.
N. Aristokleous, and J.G. Houston, “International Aneurysm CFD Challenge 2015”. SB3C2015, Summer Biomechanics, Bioengineering and Biotransport Conference. Snowbird, Utah, USA, 2015.
Journal Papers
E.A. Murphy, R.A. Ross, R.G. Jones, S.J. Gandy, N. Aristokleous, M. Salsano, J.R. Weir-McCall, S.Z. Matthew, and J.G. Houston, “Imaging in Vascular Access”, Cardiovasc Eng Technol, Jul 13, (Epub ahead of print)
E. Kokkalis, N. Aristokleous and J. G. Houston, “Haemodynamics and Flow Modification Stents for Peripheral Arterial Disease: A Review”, Ann Biomed Eng., Oct 2016
Book Chapter
J.G. Houston, N. Aristokleous, E. Kokkalis, “Chapter 33: Haemodynamics and their Relation to Stent design for the
Treatment of Peripheral Arterial Disease”, European Symposium on Vascular Biomaterials (ESVB 2015) Conference Book, 2015

9. Thank you For your Attention Many Thanks: Shona Matthew
I’d like to start
Many Thanks: Shona Matthew
J. Graeme Houston
Michael Walsh