Vascular Remodeling of Arteriovenous Fistula

INTRODUCTION Arteriovenous (AV) fistula failure is a major clinical problem for the 350,000 patients currently on hemodialysis in the United States. The reasons for this failure are mainly attributed to venous stenosis due to neointimal hyperplasia together with a possible failure of vascular dilatation [1]. Despite the magnitude of the clinical problem, there are currently no effective therapies for AV fistula failure. We believe that this is due to a lack of knowledge about the mechanisms involved in both neointimal hyperplasia and vascular dilatation in the specific context of AV fistulae. Although it has been shown by several studies that the hemodynamic environment is primarily responsible for dilatation at early stages, the exact mechanism of flow mediated vascular dilatation in AV fistulae is still unclear [2]. In our preliminary studies we have documented the pattern of WSS in two different configurations at the time of surgery [3] and compared the results with the histology at 42 days when there was maximal stenosis [4]. In order to understand the factors responsible for vascular dilatation or constriction, it is important to study the progression of the remodeling phenomenon in the same animal in a temporal fashion. Thus, this study aims to describe the methodology of measurement techniques that can be used to establish a complete hemodynamic data at different time points in a pig model with two different configurations of AV fistulae. We believe that such approach will facilitate the correlation of hemodynamic data with histological findings and thus help in identifying the best possible fistula configuration that will result in favorable remodeling and potentially a reduction in clinical AV fistula failure.