title: The efficacy and durability of the Venous Window Needle Guide implanted on uncannulatable arteriovenous fistulas.
abstract: BACKGROUND
  The Venous Window Needle Guide (VWING; Vital Access Corp, Salt Lake City, Utah) is a surgically implanted titanium device designed to facilitate cannulation of uncannulatable dialysis access arteriovenous fistulas (AVFs) because of excessive depth, aneurysm formation, or tortuosity but that exhibit sufficient flow volume to support hemodialysis. We report the 18-month fistula patency, functionality, and complications of the use of the VWING device.
  
  
  METHODS
  This retrospective study examined AVF patency, VWING functionality, interventions, and device infections at 18 months after VWING implantation. The study population comprised the eligible patients enrolled in the VWING Salvage of AV Fistula (SAVE) trial.
  
  
  RESULTS
  Fifty-four patients were originally enrolled in the SAVE trial, and 35 were enrolled in the follow-up study. At 18 months, when considering surgical or percutaneous interventions at the VWING site(s) only, the primary AVF patency rate was 78%. Interventions elsewhere on the AVF, outside the boundaries of the VWING, resulted in a primary patency rate of 38%. The VWING accounted for 13% loss of AVF primary patency compared with 53% loss from the remaining AVFs. The overall AVF assisted primary patency rate was 91%, and the primary patency rate was 21%. VWING secondary functionality, the continued ability to access the fistula through the VWING using a constant site cannulation technique, was 65%. During the 12 months after the SAVE Study 80% of patients did not require the use of a central venous catheter. Eleven VWING devices were removed from eight patients, all but one for cannulation difficulties. One device was removed during the SAVE trial because of infection. No device or systemic infection was identified in the ensuing 12 months, for an overall systemic infection rate of 0.014 per device-year. An intervention rate of 0.32 per device-year was required to maintain device functionality during the 18-month follow-up period.
  
  
  CONCLUSIONS
  Implantation of the VWING device is a safe and effective means of establishing hemodialysis access in an otherwise functional but uncannulatable AVF. The device infection rate is acceptably low.
authors.affiliation: Mountain Medical Physician Specialists, Murray, Utah; Vital Access Corporation, Salt Lake City, Utah. Electronic address: sgalt@mtnmedical.com.
authors.forename: Spencer
authors.initials: S
authors.lastname: Galt
authors.affiliation: Vital Access Corporation, Salt Lake City, Utah.
authors.forename: Mark
authors.initials: M
authors.lastname: Crawford
authors.affiliation: Vascular Surgery, University of Oklahoma, Tulsa, Okla.
authors.forename: John
authors.initials: J
authors.lastname: Blebea
authors.affiliation: Ladenheim Dialysis Access Centers, Fresno, Calif.
authors.forename: Eric
authors.initials: E
authors.lastname: Ladenheim
authors.affiliation: Sharp HealthCare, San Diego, Calif.
authors.forename: Barry
authors.initials: B
authors.lastname: Browne
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001166:Arteriovenous Shunt, Surgical / Q000009:adverse effects / Q000295:instrumentation*; D001783:Blood Flow Velocity; D002406:Catheterization, Peripheral / Q000009:adverse effects / Q000295:instrumentation*; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009339:Needles; D011677:Punctures; D006435:Renal Dialysis; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome; D014481:United States; D014654:Vascular Patency