The present disclosure relates to devices, systems, and methods for evaluating and preserving arteriovenous access sites. More particularly, the present disclosure relates to a sensor wire that is sized, shaped, and configured to pass through a delivery instrument to measure pressure and flow within and around an AV access site, thereby indicating the impact of the arteriovenous access site on the blood flow to the surrounding vasculature and tissues in real time. Also, the present disclosure relates to a therapeutic system comprising a combination pressure-flow sensor wire, a balloon catheter with imaging capabilities, and a computer system to allow the user to evaluate the blood flow and blood pressure within and around an AV access site in real time, diagnose the presence of complications associated with arteriovenous access sites, treat such complications, and assess the effectiveness of treatment both during and after treatment.