Ieee Transactions on Information Technology in Biomedicine

Venous anastomotic intimal hyperplasia (IH) observed in the arteriovenous shunt (AVS) has been associated with disturbed hemodynamics. This study aims to correlate hemodynamics with wall histology and wall mechanics by examining the flow field in AVS with computational fluid dynamics using experimental data taken from in vivo experiments. Input data to the computational model was obtained in vivo one month later; adjacent vessels were submitted to histological and mechanical examination. The 3D shunt geometry was determined using biplane angiography. Ultrasound measurements of flow rates were performed with perivascular flow probes and pressures were recorded through intravascular catheters. This data was considered as boundary conditions for calculation of the unsteady flow field. Numerical findings are suggestive of strong Dean vortices towards both vein flow exits, verified by color Doppler. Manuscript is a modified and enhanced version of the paper presented in IEEE BIBE 2008 in Athens, Greece. This paper is part of the 03ED 262 research project, implemented within the framework of the “Reinforcement of Human Research Manpower” (PENED) and co-financed by National and Community Funds (20% from Greek Ministry of Development – General Secretariat of Research and Technology and 80% from E.U. – European Social Fund). T. A. Manos is with the Laboratory of Biofluid-Mechanics and Biomedical Engineering, National Technical University of Athens, Athens, Greece (e-mail: [email protected]). D. P. Sokolis is with the Center of Experimental Surgery, Foundation of Biomedical Research, Academy of Athens, Athens, Greece (e-mail: [email protected]). A. T. Giagini is with the Center of Experimental Surgery, Foundation of Biomedical Research, Academy of Athens, Athens, Greece (e-mail: [email protected]). C. H. Davos is with the Clinical Research Center, Foundation of Biomedical Research, Academy of Athens, Athens, Greece (e-mail: [email protected]). J. D. Kakisis is with the Vascular Unit, 3rd Department of Surgery, University of Athens School of Medicine, Attikon University Hospital, Athens, Greece (e-mail: [email protected]). E. P. Kritharis is with the Laboratory of Biofluid-Mechanics and Biomedical Engineering, National Technical University of Athens, Athens, Greece (e-mail: [email protected]). P. E. Karayannacos is with the Center of Experimental Surgery, Foundation of Biomedical Research, Academy of Athens, Athens, Greece (e-mail: [email protected]). N. Stergiopulos is with the Laboratory of Hemodynamics and Cardiovascular Technology, Swiss Federal Institute of Technology, Lausanne, Switzerland (e-mail: [email protected]). S. Tsangaris is with the Laboratory of Biofluid-Mechanics and Biomedical Engineering, National Technical University of Athens, Athens, Greece (corresponding author, e-mail: [email protected], 0030-210-7721043; fax: 0030-210-7721057). The high wall shear stresses and their gradients appear to be related to areas of IH and vessel wall stiffening, as evidenced in preliminary histological and mechanical studies of the venous wall. Additionally, suture line hyperplasia seems to be aggravated by the high wall shear stress gradients noted at the transition line from graft to vein.