2Medical Physics, NHS Tayside, Ninewells Hospital and Medical School, Dundeee ... Ninewells hospital, Dundee, has recently included Velocity Vector Imaging ...
Velocity Vector Imaging, Shear Wave Elastography and Flow Mediated Dilation as Potential Predictors of Arterio-Venous Fistula Outcome 1 3 2 C MacDonald , R Ross , JG Houston
1Department of Cardiovascular and Diabetes Medicine, School of Medicine, University of Dundee, Dundee, UK 2Medical Physics, NHS Tayside, Ninewells
Hospital and Medical School, Dundeee, UK 3Vascular laboratory, NHS Tayside, Ninewells Hospital and Medical School, Dundeee, UK
Overview & Aim Ninewells hospital, Dundee, has recently included Velocity Vector Imaging (VVI), Shear Wave Elastography (SWE) and Brachial Flow Mediated Dilation (FMD) as part of the Ultrasound (US) based preoperative assessment for patients undergoing arteriovenous fistula surgery for haemodialysis. VVI, by analysing wall motion, and SWE which maps the elasticity of tissue (fig.1) can act as measures of arterial stiffness (AS) [1]. AS is an important measure of vascular health and has recently been linked to a negative AVF outcome after surgery [2,3], but data exists showing no link [4]. Few studies have been conducted using VVI or SWE in this patient group [5], but it is believed that measures could provide simple and non-invasive measures of AS which could be added to existing US protocols.
Methods Patients who have been indicated for AVF creation and have undergone a pre-operative scan at Ninewells hospital & medical school will be identified through NHS databases. Ultrasound data of these patients will be accessed via Vascular Laboratory. We aim to determine if any link between the pre-operative ultrasound measurements of brachial artery SWE, brachial wall motion via VVI and brachial FMD and the outcome of the arterio-venous fistula exist. The results from SWE and VVI will be compared to an agematched healthy comparator group, and a young group, due to a lack of baseline data in the literature.
Discussion If a link between AS, as measured by SWE or VVI, and the outcome of the AVF were to be found, these methods could potentially be added to existing pre-surgical US protocols as a simple method of pre surgical assessment. This may help reduce failure to mature rates, which metaanalyses have suggested are as high as 40%. Comparison between two healthy groups of different ages (18-30 and 45-80) will allow us to determine if the tools can detect age related AS and are acceptable as a measures of AS in Fig 1. Shear wave velocity map of healthy volunteer the general population.
References [1] Ma, X. J., Duan, Y. Y., Yuan, L. J., Cao, T. S., Wang, Y., Yang, H. G., & Chen, S. (2012). Quantitative assessment of maternal common carotid artery mechanics using velocity vector imaging in pre-eclampsia. European Journal of Obstetrics, Gynecology, and Reproductive Biology, 160(1), 30–34. [2]M. Kheda, L. Brenner, M. Patel, J. Wynn, J. White, L. Prisant, S. Jones, W. Paulson, Influence of arterial elasticity and vessel dilatation on arteriovenous fistula maturation: a prospective cohort study, Nephrol Dial Transplant (2010) 25 (2): 525-31 [3]Arterial Stiffness and Arteriovenous Fistula Outcomes,D.G. McGrogan, G. McKevit, S. Stringer, P. Cockwell, M. Jesky, C. Ferro, A.P. Maxwell, N.G. Inston, Euro J Endovasc Surg(2016) 52, e73-78 [4]A. Masengu, J. B. Hanko, A. P. Maxwel, Arterial stiffness and arteriovenous fistula failure of maturation, J Vasc Access 2016; 17(6): 477 – 482 [5]A. G. Sorace, M. L. Robbin, H. Umphrey, C. A. Abts, J. L. Berry, M. E. Lockhart, M. Allon, K. Hoyt, Ultrasound measurement of Brachial Artery Elasticity Before Hemodialysis Access Placement: A Pilot Study, J Ultrasound Med . 2012 October ; 31(10): 1581–1588
Acknowledgements This work has received funding from the European Unions 7th Framework Program for research, technological development and demonstration under grant agreement no. 3244487 (ReDVA) The author of this study has received funding from SINAPSE Postdoctoral and Early Career Exchange.
