Preoperative procedures Informed consent Eligibility screening Baseline clinical data collection Demographics Comorbidities Medications Dialysis history Vascular access history Vascular-mapping ultrasound Vascular function studies Brachial artery FMD/NMD Arterial pulse wave velocity measurement Venous occlusion plethysmography Blood collection for DNA, plasma and serum

Intraoperative procedures Surgical practices data collection Vein tissue collection End-of-surgery fistula status

Postoperative procedures Day-1 ultrasound 2-wk ultrasound and blood collection for plasma and serum 6-wk ultrasound a Precannulation ultrasound b Preprocedure ultrasound c26-wk ultrasound Fistula cannulation data collection Clinical maturation assessment Vascular access complications and fistula procedures data collection Fistula use and abandonment data collection

Abbreviations: FMD, flow-mediated dilation; NMD, nitroglycerin-mediated dilation

^aPre-cannulation ultrasound is not performed if the first cannulation attempt occurs before 10 weeks.

^bPre-procedure ultrasound is performed only if the angioplasty or surgical procedure occurs before the pre-cannulation ultrasound.

^c26-week ultrasound is performed only if the pre-cannulation ultrasound has not yet been performed.