Table 1: Methods of measuring vessel elasticity or distensibility that may help predict fistula maturation outcome.

Testing Method	References
Vein
Application of tourniquet (diameter by duplex ultrasound)	[42-45]
Warm water immersion (diameter by duplex ultrasound)	[46]
Strain-gauge plethysmography	[47]
Finite element analysis combined with duplex ultrasound	[48]
Artery
Lok Criteria (age, peripheral vascular disease, coronary artery disease, race)	[49]
Aortic pulse wave velocity	[41]
Cardio-ankle modification of pulse wave velocity	[50]
High resolution ultrasound speckle-tracking algorithms	[38, 52]
Elastic modulus by duplex ultrasound	[53]
Photoplethysmography	[54]
Flow mediated dilatation of brachial artery	[55]
Resistance index measured during fist relaxation after fist clenching	[36, 43, 45]
Small artery elasticity index by tonometer	[56-58]