 Purpose of proposed investigation The IMPROVA study will utilise novel non-invasive methods of arterial health assessment and correlate these measurements with the early outcomes of AVF formation. The development of new techniques to inform the clinician pre-operatively will aid in a more tailored approach to fistula planning, predict inevitable failures and consequently improve success rate. The ultimate aim is to identify novel methods of predicting fistula failure to prevent patients from developing into a cycle of consecutive failure, catheter dependence and therefore worse overall outcomes. 