Devices, systems and methods are disclosed for the formation of an arteriovenous fistula in the limb of the patient. Embodiments include an apparatus for the creation, modification and maintenance of a fistula, including the modification of an existing dialysis fistula; and a method of supplying oxygenated blood to the venous circulation of a patient. A kit of anastomotic implants is described which supports a broad base of patient anatomies and fistula locations. The devices, systems and methods can be used to treat patients with one or more numerous ailments including chronic obstructive pulmonary disease, congestive heart failure, hypertension, hypotension, respiratory failure, pulmonary arterial hypertension, lung fibrosis and adult respiratory distress syndrome.