Clinical Trial: Criteria for Accessory Vein Obliteration Trial.

Study Status: Recruiting
Recruit Status: Recruiting
Study Type: Interventional

Official Title: Assessing Clinical Utility of the Criteria for Accessory Vein Obliteration for Failing Arteriovenous Fistula.

Brief Summary: Hemodialysis (HD) vascular access dysfunction is a huge clinical problem which results in significant morbidity amongst patients with End Stage Renal Disease (ESRD), causing a severe economic burden on any health care system. Native arteriovenous fistula (AVF) is the preferred form of permanent dialysis access since it is associated with the best long term outcome as compared to other forms of dialysis access. Despite the clinical benefits, many patients on HD do not have AVF as there dialysis access. One of the reasons for low AVF rates is early fistula failure (EFF). The two most important causes for EFF amenable to intervention are stenosis anywhere in the circuit and/or presence of accessory vein (av). Although management of stenosis is well established with relatively clear guidelines, the management of av lacks clear scientific approach. In a recent study researchers recommended a hemodialysis arteriovenous flow quantification-diameter (HAQ) criteria for accessory vein obliteration. The purpose of this controlled, blinded, prospective trial is to assess the clinical utility of the HAQ criteria as compared to current recommendations for av obliteration.

Detailed Summary:

Hemodialysis (HD) vascular access dysfunction is a huge clinical problem which results in significant morbidity amongst patients with End Stage Renal Disease (ESRD), causing a severe economic burden on any health care system. Native arteriovenous fistula (AVF) is the preferred form of permanent dialysis access since it is associated with the best long term outcome as compared to other forms of dialysis access. Despite the clinical benefits, many patients on HD do not have AVF as there dialysis access. One of the reasons for low AVF rates is early fistula failure (EFF). EFF is defined as an AVF that never develops adequately for dialysis (failure to mature) or which fails within 3 months of starting dialysis. An adequate AVF for dialysis according to Dialysis Outcome Quality Initiative (DOQI) guidelines is the one which a) Has a flow of greater than 600ml/min, b) Has a diameter of 0.6cm or greater and c) Is approximately not deeper than 0.6cm from the skin surface. Between 23%-46% of newly constructed AVF have problems with early failure resulting in a dismal one year patency of 60-65%.

In order to devise a strategy to prevent EFF, one needs to understand the physiology of fistula maturation. Creation of an AVF leads to an immediate increase in flow through the vein due to the pressure gradient created. This increase in flow leads to increase wall shear stress which is defined mathematically by the formula 4ηQ/πr3, where η is blood viscosity, Q is blood flow and r is vessel radius. Shear stress thus is directly proportional to blood flow while inversely proportional to vessel diameter. After the creation of the AVF, the flow mediated increase in shear stress is mitigated by vessel dilatation through biological mediators. Consequently the shear stress is brought back to pre-anastomosis levels leading to vessel dilation. It seems that this positive remodeling
Sponsor: King Faisal Specialist Hospital & Research Center

Current Primary Outcome: Maturation of AVF [ Time Frame: 3 months ]

Maturation of AVF defined as an AVF which is used for hemodialysis with a pump speed of at least 300ml/min for 3 consecutive treatments


Original Primary Outcome: Same as current

Current Secondary Outcome:

  • Primary Patency [ Time Frame: 6 months ]
    AVF which is still being used for hemodialysis with a pump speed of at least 300 ml/min without any additional procedures.
  • Secondary Patency [ Time Frame: 6 months ]
    AVF which is still being used for hemodialysis with a pump speed of at least 300 ml/min with help of additional procedures.


Original Secondary Outcome: Same as current

Information By: King Faisal Specialist Hospital & Research Center

Dates:
Date Received: December 15, 2015
Date Started: September 2015
Date Completion: December 2018
Last Updated: October 3, 2016
Last Verified: October 2016