Please select the eligibility criteria that correspond to the clinical trial below.
Title: N/A
Brief Summary: The type of hemodialysis access and preservation of this access greatly influences the quality of life and survival of patients undergoing hemodialysis. The Kidney Disease Outcomes Quality Initiative (K/DOQI) guidelines for vascular access recommend the primary placement of native or autogenous hemodialysis fistulas in preference to polytetrafluoroethylene (PTFE) grafts and central venous catheters because the former form of access has fewer complications and a longer durability. However, autogenous hemodialysis fistulas, like polytetrafluoroethylene grafts, are also subject to dysfunction and eventual failure. Endovascular angioplasty has become an accepted alternative treatment to surgical revision for hemodialysis access-related venous stenoses and occlusions. However, the patency rates in the follow-up period are low because of the high frequency of restenosis due to intimal hyperplasia. Since 1988, noncovered stents have been used to improve fistula patency. In the central veins, bare stents demonstrate better patency rates than percutaneous transluminal angioplasty (PTA) alone. Neointimal hyperplasia is the major reason for restenosis following stent placement. The cephalic vein forms the outflow conduit for radiocephalic and brachiocephalic autogenous fistulas. It has recently been suggested that a focal area of the cephalic vein is prone to developing hemodynamically significant stenosis, in what is now termed the cephalic arch. This is the perpendicular portion of the cephalic vein in the region of the deltopectoral groove before its junction with the axillary vein. To overcome the problem of restenosis due to intimal hyperplasia in the cephalic arch the investigators used the insertion of a stent-graft as an alternative approach. In this study they investigated the use of a PTFE-covered nitinol stent-graft (Fluency, Bard) versus a Luminex (Bard) stent.


Options:
A: Inclusion Criteria:

* Angiographic and clinical diagnosis of dysfunctional dialysis access due to one or more stenotic lesions.
* Patients with AVF or AVG
* Fistula or graft or vessel diameter ranging from 3 mm up to 12 mm

Exclusion Criteria:

* Fistula or graft or vessel diameter \< 3 mm and \> 12 mm
* History of severe allergic reaction to contrast media
* Intolerance to aspirin and/or clopidogrel
* Systemic coagulopathy or hypercoagulation disorders
B: Inclusion Criteria:

* Patients included in this study would be presented for intervention after observation in the Vascular Access Unit for one of the following:

  * the recurrent cephalic arch stenosis identified on periodic duplex scanning, performed by one of the surgeons from the Vascular Access Unit;
  * reduction of flow rate of more than 20% from baseline access flow rate;
  * dynamic venous pressures exceeded threshold levels three consecutive times; or
  * clinical signs (arm swelling, pulsatile fistula, prolonged bleeding from puncture sites) suggesting fistula dysfunction in a patient with previously treated cephalic arch stenosis.
C: Inclusion criteria:

* Age 18-21 depending on state regulations
* Life expectancy of at least six months
* Chronic renal failure with anticipated start of hemodialysis within six months of enrollment, or current dialysis dependence
* A new or planned arteriovenous (AV) graft placed in any location for the purpose of hemodialysis. (Any type of graft material and any configuration of the access is acceptable).
* The patient is expected to stay at a participating dialysis facility for at least 6 months.
* The patient's physician(s) will allow the patient to participate.
* Ability to give informed consent.

Exclusion Criteria:

* Women must not be pregnant, breastfeeding, or plan to be pregnant during the course of the study.
* The presence of ongoing bleeding.
* The presence of a known bleeding disorder (e.g., hemophilia or von Willebrand's disease).
* Recent bleeding episode requiring transfusion within 12 weeks of entry.
* The presence of acute ulcer disease. Acute ulcer disease is defined as a new diagnosis of peptic disease including esophagitis, gastritis, or ulcer or the initiation of treatment with proton pump inhibitors, H2 blockers or therapy for Helicobacter pylori within three months prior to obtaining consent.
* Known allergy or adverse reaction to Aggrenox or any of its study components (dipyridamole and aspirin).
* Required use of warfarin, dipyridamole, non-steroidal antiinflammatory drugs or other antiplatelet agents other than aspirin.
* Current uncontrolled hypertension with systolic blood pressure in excess of 200 mm Hg or diastolic blood pressure in excess of 115 mm Hg.
* Baseline platelet count less than 75,000/mm3.
* Known advanced liver disease with decompensated cirrhosis, jaundice, ascites or bleeding varices.
* Current problem with substance abuse.
* Concurrent participation in another medical intervention trial.
* Anticipated non-compliance with medical care based on physician judgment.
* Patient refusal.
D: Inclusion Criteria:

* Male or female patients between 18 to 90 years of age whose hemodialysis access was a synthetic AV access graft located in an arm.
* Angiographic evidence of one or more stenoses, 7 cm or less in length and greater than or equal to 50%, at the graft-vein anastomosis of a synthetic AV access graft. The entire lesion must have been located within 7 cm of the anastomosis such that approximately 1 cm of the IMPRA/Bard Device must have extended into non-diseased vein and approximately 1 cm, but no more than 2 cm, of the IMPRA/Bard Device will be extended into non-diseased AV graft.
* Clinical evidence of a hemodynamically significant stenosis.
* Percutaneous endovascular therapy for the identified lesion was the best treatment choice in the opinion of the investigator.
* Patients must have been able to understand and provide informed consent.
* Patients whose synthetic AV access grafts had been implanted greater than 30 days and had undergone 1 or more successful hemodialysis sessions.
* During primary balloon angioplasty, full expansion of an appropriately sized angioplasty balloon, in the operator's judgment, must have been achieved.

Exclusion Criteria:

* Concomitant disease (e.g., terminal cancer) or other medical condition that was likely to result in death of the patient within 6 months of the time of implantation.
* Stenoses that had a corresponding thrombosis treated within 7 days.
* The presence of a second lesion in the access circuit less than or equal to 3 cm from the edges of the primary lesion that was treated within 30 days or that was greater than or equal to 30%. Access circuit was defined as the area from the AV access graft arterial anastomosis to the superior vena cava-right atrial junction.
* The presence of a second lesion in the access circuit greater than 3 cm from the edges of the primary lesion that was greater than or equal to 30%. Second lesions that were greater than or equal to 30% must have been treated prior to patient inclusion to reduce the percent stenosis to less than 30%.
* Patients who were unwilling or unable to return for follow-up visits or patients with whom follow-up visits may have been unreliable.
* Patients who had a stent placed at the target lesion site.
* Patients with a blood coagulative disorder or sepsis.
* Patients in which the IMPRA/Bard Device would have been required to cross an angle (between the inflow vein and synthetic AV access graft) that was greater than 90 degrees.
* Patients in which the IMPRA/Bard Device would have been required to be deployed fully across the elbow joint, which is identified radiographically by a combination of the humeroulnar joint and the humeroradial joint.
* Patients with a contraindication to the use of contrast media.
* Patients whose AV access graft was infected.
* Patients who were currently or were scheduled to enroll in other investigations that conflicted with follow-up testing or confounds data in this trial.
* Procedural use of another investigational device.
* Patients who were pregnant.

Answer: B