The effective delivery of dialysis requires repeated reliable access to the central circulation capable of providing rapid blood flow. This access to the circulation continues to be the 'weak link' in the provision of long-term renal replacement therapy. Dialysis access malfunction is a major cause of inadequate dialysis delivery and venous stenosis is the leading cause of access malfunction and thrombosis. Careful monitoring of venous dialysis pressures and recirculation along with urea kinetic modeling and physical examination of the graft can prospectively identify the malfunctioning vascular access. When these indicators are used for referral for fistulogram, venous stenosis can be identified and corrected before graft thrombosis. Not only can preemptive repair of the vascular access prevent thrombosis, it also allows for more efficient dialysis delivery to the patient.