Trial Comparing the Incidence of Steal Syndrome in the Two Types of anTEcubitaL Fossa Arteriovenous fistuLa AVF
Condition: Arteriovenous Fistulas; Renal Failure, End-Stage; Steal Syndrome
MeSH terms: Kidney Failure, Chronic; Arteriovenous Fistula; Syndrome; Fistula
Study type: Interventional

Summary: 
      Background:

      Arteriovenous fistula (AVF) is a form of vascular access for haemodialysis. An AVF is
      normally created at the level of the wrist, but occasionally it is created in the elbow when
      there is no suitable vessel in the forearm. The most common type of elbow (antecubital)
      fistula (AFF) is a brachiocephalic fistula, which carries significantly higher risk of steal
      syndrome (AVF-associated hand ischaemia) than wrist fistulas. More recently, AFF using
      proximal radial or ulnar artery as inflow has been described and shown to have a lower rate
      of Steal syndrome than brachiocephalic fistula. This study aims to investigate the incidence
      of steal syndrome between AFF using brachial artery and that using the proximal radial/ulnar
      artery as inflow.
    

Detailed description: 
      Arteriovenous fistulas (AVF) are the safest form of vascular access for long-term
      haemodialysis in patients with end-stage renal failure. The strategy in creating an AVF in
      the upper limbs is to start at a distal site and if that fails, to attempt an AVF on a more
      proximal site i.e. from wrist, forearm to elbow. The most common type of AVF is the
      radiocephalic AVF at the wrist. A more proximal AVF is often created as a primary procedure
      when there is poor vasculature in the distal forearm or as a secondary procedure when a wrist
      fistula has failed. Traditionally, brachiocephalic fistulas (BCF), which involves
      anastomosing the cephalic vein to the brachial artery, have been the most common type of AVF
      created in the antecubital fossa at the elbow level. Other common types of antecubital fossa
      arteriovenous fistula (AFF) are the brachiobasilic (BBF) and brachio-median cubital AVF.

      Steal syndrome relates to hand ischaemia associated with AVF creation, and is a major risk of
      AVF formation. The symptoms of steal syndrome ranges from cold extremities, numbness, hand
      claudication (pain after exercise), to rest pain and tissue loss. Steal syndrome can also be
      measured by Digital Brachial Pressure Index. Severe steal syndrome is debilitating, and
      limb-threatening, and requires surgical revision or ligation of the AVF. This leads to
      additional surgical risks and loss of dialysis vascular access.

      Diabetes and the types of AVF have been found to be independent risk factors for developing
      steal syndrome following AVF creation1. The highest risk is seen in patients with a proximal
      AVF i.e. BCF/BBF; up to 50% of patients in some studies, compared to 5-8% in all upper limb
      AVFs.

      An alternative technique that may reduce risk of steal in this group of patients is to
      anastomose the vein to the radial artery or ulnar artery, distal to the brachial artery
      bifurcation. This technique, theoretically, will only 'steal' blood from one artery e.g.
      radial artery if the anastomosis is created on the proximal radial artery so blood flow can
      therefore be maintained by the ulnar arterial system.

      Recent studies have suggested that using the proximal radial or ulnar artery reduced the risk
      of steal to as low as 0% to 3%. The type of arterial inflow to an AFF is therefore a
      potentially significant factor in causing steal syndrome. There is, however, no current
      randomised controlled trial to prove this hypothesis.

      The definition of steal syndrome varies greatly in the literature. Some studies have defined
      steal syndrome as the presence of mild symptoms such as cold hand, while the others reported
      steal syndrome when it was severe enough to require surgical intervention. This has led to
      the huge variations in the incidence of steal syndrome being reported and has made comparison
      difficult between studies. A few scoring systems to describe the severity of steal syndrome
      have been suggested in previous studies, but none of them has been widely used.

      In this study, the difference in the severity of steal between the two intervention groups
      will be investigated. This will be done using the Hoek score, which was originally used by
      Hoek et al in 2006 to report steal syndrome associated with the AVFs created in their centre.
      There was, however, no comparison of scores among the different types of AVF.
    

Intervention name(s): Proximal radial/ulnar artery as inflow
Intervention type(s): Procedure
Intervention description(s): Proximal radial/ulnar artery used as inflow
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Participant)
Primary purpose: Prevention