The purpose of this study is to determine if the creation of a fistula or a graft plays a role in the development of heart disease for patients undergoing hemodialysis

Patients with end stage renal disease are at 18-20 times greater risk of dying from cardiovascular disease as the general population. Both traditional and non-traditional cardiovascular risk factors are thought to be important. Of the non-tradtional cardiovascular risk factors, creation of an arteriovenous fistula or graft for the purposes of a blood access for hemodialysis may contribute to an elevation in BNP and left ventricular hypertrophy - both factors that have been associated with an increased risk of mortality Prior to access creation and at one month and one year post access creation - samples for BNP will be collected Prior to access creation and at one year post access creation - echocardiography will be performed

Inclusion Criteria: 1)Hemodialysis 2)high risk for heart failure (DM, age>50, and/or systolic dysfunction) 3) first arteriovenous fistula/graft 4) informed consent 5) technically adequate echocardiogram 6) stable hgb(>100) 7) stable mineral metabolism (normal calcium, phosphate <2.1mmol/L, PTH>50pmol/L)

Exclusion Criteria: 1)Expected survival <1 year 2) Expected to get a living donor transplant in one year 3)primary access failure 4) ARF