Devices, systems and methods are disclosed for the formation of an arteriovenous fistula in the limb of the patient. Embodiments include a device for the creation, modification and maintenance of a fistula that includes an integral fistula creation assembly near its distal end that passes through the skin of the patient, through a first vessel such as an artery, and into a second vessel such as a vein. The fistula creation assembly preferably includes an anastomotic implant that is placed within the fistula to maintain long-term blood flow therethrough. 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.