3. Introduction
Arteriovenous graft or fistula
Direct communication between artery and vein without
an intervening capillary bed
Etiology
Congenital
Acquired
Surgically created dialysis graft/fistula
Traumatically created
Iatrogenically created during cannulation/treatment of
artery/vein
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5. What is KDOQI?
Kidney Disease Outcomes Quality Initiative
Evidence-based clinical practice guidelines developed
by volunteer physicians and health care providers for all
stages of chronic kidney disease and related
complications, from diagnosis to monitoring and
management
This presentation utilizes the National Kidney
Foundation (NKF) KDOQI Clinical Practice Guidelines
2006 update
www.kidney.org
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6. AV Access for Dialysis
Advent of hemodialysis in the early 60s has provided
significantly improved longevity for CKD patients
Initially used external AV shunt by Scribner and
Quinton
Currently provided by catheter, AV fistula, or AV
graft
Over 250k pts on permanent HD in US currently
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14. Catheter Access
Nontunneled (Mahurkar, etc.)
SHORT term access (up to 10 days)
Tunneled Cuffed
Short to medium term access (weeks to months)
Bridge to more durable access (AVF, AVG, PD)
If a patient with acute onset renal failure is likely to
require more than 7-10 days of access, primarily place
a tunneled HD catheter
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16. Catheter Complications
Treat when dialyzer blood flow of 300 cc/min not
being attained in a catheter previously able to deliver
greater than 350 at prepump pressure -250 torr
Dysfunctional catheter (<300) for 2 treatments should
be treated in HD unit w/ intraluminal interdialytic
thrombolytic lock protocol between 2 treatments
If the above fails, send for radiological evaluation
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17. IR Evaluation of HD Catheter
Catheter imaging w/ contrast can identify and treat
various issues
Residual lumen thrombus -> pharmacologic or
mechanical thrombolysis
Malpositioned catheter tip -> reposition or exchange
Fibrin sheath at tip -> angioplasty/exchange/stripping
SVC thrombosis/stenosis ->
thrombolysis/angioplasty/stent
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21. Catheter Infections
Treatment
Catheter exit-site, no tunnel infection
Treat w/ topical and/or oral Abx, not necessary to remove
catheter
If bacteremic pt is afebrile w/in 48 hrs and stable, catheter
salvage might be considered w/ interdialytic Abx lock
solution and 3wks of parenteral Abx, f/u Blood Cx in 1 wk
Abx lock when f/u cultures indicate reinfection w/ same
organism in pt w/ limited access
Short-term catheters should be removed when infected
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22. Save the veins!
CKD 3b or worse (eGFR < 45) pts are predialysis
Veins of dorsum of hand preferred IV site
Rotate sites if arm veins necessary
PICC lines are NOT benign!
Incidence of central vein stenosis and occlusion after
PICC/Port is 7%
Do NOT use PICC lines in predialysis patients (small bore
central catheter via IJV for medium term access instead)
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25. Surgical Access: AV Fistulas and
Grafts
Fistulas have a superior longevity compared to grafts
(85% vs 50% patency at 2 yrs) but take longer to
mature
Up to 1/3 of fistulas fail to mature
Fistulas can remain patient at flow rates of as low as
80 cc/min
Grafts require flow rates of > 450 cc/min to prevent
thrombosis
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26. AV Fistula Creation
Usually nondominant arm
Radiocephalic or Brescia-Cimino is anastamosis of
radial artery to cephalic vein
Braciocephalic fistula is brachial artery to cephalic
vein in the antecubital region
Average of 4-6 wks for maturation
Preferred sites radiocephalic > braciocephalic >
transposed brachial basilic
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29. AV Graft Creation
Artificial vessel (graft) made of synthetic material
such as PTFE or sterilized animal vessel connects the
native artery to vein
Preferred sites forearm loop > forearm straight >
upper arm > chest wall > lower extremity
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30. AV Graft
Advantage
Can be used much sooner
Disadvantages
Higher restenosis rates
usually at venous anastomosis
Higher thrombosis rates
Higher infection rates
Potential steal
Pseudoaneurysms
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33. Detection of Access Dysfunction
Prospective surveillance of fistulae/grafts for
hemodynamically significant stenosis, combined with
correction of anatomic stenosis, improves patency
rates and reduces incidence of thrombosis
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34. Physical Examination
Look (inspection)
Aneurysms
Fistula that does not collapse w/ arm elevation likely
has outflow stenosis
Palpable strictures
Downstream stenosis can produce venous dilatation
Arm edema
Prolonged bleeding after needle withdrawal
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36. Physical Examination
Touch (palpation) and listen (auscultate)
Strong pulse is NOT evidence of good flow!
Bruit over access system that is only systolic is
abnormal, should be continuous
Palpable thrill at the arterial, middle, and venous
segments of graft predicts flow > 450 cc/min
Palpable thrill at axilla predicts > 500 cc/min
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41. Recirculation
Return of dialyzed blood to dialyzer without
equilibration with systemic arterial circulation
Not a recommended technique for assessing grafts
Up to 1/3 of dysfunctional fistulae will show increased
recirculation, but often occurs late
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42. When to refer for evaluation
Do not respond to a single isolated abnormal value,
trend analysis is the key
Flow rate < 600 in grafts and < 400-500 in fistulae
Venous segment static pressure ratio greater than 0.5
in grafts or fistulae
Arterial segment static pressure ratio greater than
0.75 in grafts
Persistent abnormalities -> graftogram/fistulogram!
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43. Treatment of Fistulae
Complications
Intervene for
Inadequate flow
Significant venous stenosis
Aneurysm formation in primary fistula (also correct
postaneurysmal stenosis)
Ischemia
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45. Access Evaluation for Ischemia
Patients prone to develop ischemia
Elderly
Hypertensive
History of PAD
Diabetes
Not common (1-4%) but critical to recognize
Most occur early, but up to a quarter develop months
to years later
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46. Access Evaluation for Ischemia
Stage I, pale/blue and/or cold hand without pain
Stage II, pain during exercise and/or HD
Stage III, pain at rest
Stage IV, ulcers/necrosis/gangrene
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48. Ischemia -- Emergent Referral to
Vascular Access Surgeon
Treatments
Angioplasty of arterial stenosis proximal to anastomosis
Ligation of peripheral radial artery
DRIL (distal revascularization—interval ligation)
Pts w/ venous anastomosis to brachial artery, anastomosis is
bridged by venous bypass, after which the artery is ligated
closely peripheral to the anastomosis
Low flow rates and ischemia, proximal AV anastomosis
technique with ligation of the previous anastomosis and
placement of a new more proximal one with blood
brought to the vein by an interposed vein graft or small
caliber PTFE graft
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49. Surgical Steal Tx
DRIL – distal revascularization with interval ligation
RUDI – revision using distal inflow
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50. Infection
Rare, but potentially lethal
If at anastomosis, immediate surgery w/ resection
More often at cannulation sites, rest and treat w/ Abx
(treat like subacute bacterial endocarditis, 6 wks)
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51. Graft Complications
Extremity edema
Persisting > 2 wks require contrast imaging to evaluate
central veins with plasty as necessary
Stent placement if acute elastic recoil after plasty or if
stenosis recurs within 3 months
Indicators of risk for graft rupture (evaluate urgently)
Poor eschar formation
Spontaneous bleeding
Rapid expansion of pseudoaneurysm
Severe degeneration of graft material
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52. Graft Complications
Indications for revision/repair
AVGs w/ severe degeneration or pseudoaneurysm
(PSA) should be repaired if…
Number of cannulation sites limited by large or multiple
PSAs
PSA threatens viability of overlying skin
PSA is symptomatic
Possible infection
AVOID cannulation of PSA, especially if enlarging
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53. Graft Complications
Treat stenosis w/ angioplasty or surgery if > 50% in
diameter and…
Abnormal physical exam
Decreasing intragraft flow (< 600)
Elevated static pressure within graft
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54. Take Home Points
Save the veins!
PICC lines and subclavian catheters are NOT benign,
and should almost NEVER be used in dialysis or
predialysis patients
Surveillance of AV fistulae and grafts is crucial in
order to intervene early and prevent loss of a potential
access site
Open line of communication between dialysis center,
radiology, and surgical services is imperative
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