AV Access in the Hemodialysis Patient

1
AV Access in the Hemodialysis Patient

• Robert D.H. Lee, M.D.
• Vascular Surgery
• Mid-Atlantic Renal Coalition

2
Objectives

• Describe means of acute vs chronic dialysis
• Review anatomy of AVG AVF
• Describe catheter complications
• Describe AVG disadvantages
• Present DOQI guidelines
• Understand chronic AV access algorithm
• Understand chronic AV access monitoring for
  salvage

3
Magnitude of Renal Failure

• gt180,000 dialysis patients
• Dialysis pop inc 10/yr
• Dialysis access as most common vascular surgical
  procedure

4
Patient Assessment

• Urgency of dialysis?
• Prior central venous catheter insertion?
• Inspection of superficial arm veins with
  tourniquet
• Venous collateralization?
• Pulse assessment (neg Allens test)

5
Acute Dialysis Options

• Percutaneous catheter
• Firmer plastic
• Bedside insertion
• In-hospital use
• Cuffed catheter
• Softer silicone
• Operative insertion
• Potentially long-term use

6
Cuffed Hemodialysis Catheter
7
Chronic Dialysis Options

• AV Graft
• Subcutaneously placed conduit between donor
  artery recipient vein
• Usually PTFE
• 10-14day delay before use
• AV Fistula
• Direct connection between artery vein
• 6-8wk maturation time

8
Forearm Loop AVG
Radial Artery
Basilic Vein
9
Brachio-Axillary AVG
Axillary Vein
Brachial Artery
10
Femoral Loop AVG
Femoral Artery
Femoral Vein
11
Radio-Cephalic AVF
Radial Artery
Cephalic Vein
12
Radio-Cephalic AVF
Cephalic Vein
Proximal
Distal
13
Brachio-Cephalic AVF
Cephalic Vein
Brachial Artery
14
Basilic Vein Transposition
Basilic Vein
15
The Case Against Catheters

• Insertion Complications
• Mechanical Complications
• Infectious Complications

16
Catheter Insertion Complications

• Hematomas
• Catheter malposition
• Pneumo or hemothorax, hemomediastinum
• Air embolism
• Arterial or venous injury
• Brachial plexus or phrenic injury
• Arrhythmia, cardiac tamponade

17
Mechanical Catheter Complications

• Kinking, migration, breaking, embolism
• Dislodgement, removal
• Catheter thrombosis
• Central venous thrombosis

18
Infectious Catheter Complications

• Local infection
• Septic thrombophlebitis
• Sepsis, bacteria, fungemia

19
AVG Disadvantages in Chronic AV Access

• Inferior patency rate
• Higher infection risk
• Shorter overall lifespan

20
AVG vs AVF Patencies

• Gibson, Univ Washington, JVS 10/01
• 2247 dialysis pts between 96-97
• AVG 25 primary patency/2yr
• AVF 40
• AVF use will inc patencies dec revisions

21
DOQI Guidelines

• National Kidney Foundation sponsored Dialysis
  Outcomes Quality Initiative, 1997
• lt10 long-term (gt90day) catheter usage
• gt40 functioning AVF/dialysis unit
• gt50 AVF of new access procedures

22
Chronic AV Access Principles

• AVF preferable to AVG
• Distal approach first
• Nondominant extremity if veins are equivalent
• Lower extremity less preferable

23
Chronic AV Access Algorithm

• Radio-cephalic AVF
• Brachio-cephalic AVF
• Basilic vein transposition
• Brachio-axillary AVG
• Femoral loop AVG

24
Preop Planning

• Duplex US vein mapping
• No contrast
• Reliable vein diameters
• Assess for central vein stenosis
• Venogram
• Locate vein branching
• Noninvasive arterial testing if pulses are
  abnormal

25
AVF Nonmaturation

• Inability to cannulate AVF 3-4mo after creation
• Higher incidence in women diabetics
• Fistulogram
• Anastomotic stenosis
• Inadequate vein
• Multiple branching

26
Monitoring AV Access Function

• Venous pressure lt200mmHg
• Duplex US velocities
• PSV lt400cm/s
• PSV ratio lt2.5
• EDV lt250cm/s
• Residual lumen gt2mm
• Fistulogram

27
AVF Salvage

• Balloon vs open angioplasty for short segment
  vein stenosis
• Graft interposition for long segment vein
  stenosis
• Revision for anastomotic stenosis
• Ligation of vein branches
• Balloon angioplasty/stenting for central venous
  stenosis

28
Conclusions

• Catheter for acute dialysis
• AVG AVF for chronic dialysis
• Catheter complications
• AVF superiority over AVG
• DOQI guidelines
• lt10 long-term catheter usage
• gt40 functioning AVF/dialysis unit
• gt50 AVF of new access procedures

29
Conclusions

• Algorithm for AV access
• Preop vein mapping or venogram
• Monitoring AV access
• Venous pressure
• Duplex US velocities
• AVF salvage