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Dr John Swinnen
Vascular Surgeon
Dialysis Access Specialist
MSF Trauma Surgeon University Of SydneyWestmead Hospital
Too Much or Too Little flow:
Steal Syndrome and the Giant Fistula
Advanced Course in Vascular Access 2019
Convenor: Professor Kittipan Rerkasem
2 – 3 May 2019, Chiang Mai, Thailand
The Native Fistula
• A PATHOLOGY, a disease!
• A disease useful for Hemodialysis
AVF of Interest to 3 Parties
• The DIALYSIS PUMP:
Adequate Dialysis / RRT
• The FISTULA LIMB:
Adequate Perfusion
• The HEART:
Adequate Cardiac Function
AVF Acted on by 2 Forces
• Fistula Stenosis:
Driven by the body’s healing response
• Fistula Growth:
Driven by the inflow artery
Common Clinical Assumption
“Once a fistula becomes big enough for
adequate dialysis, all is well”
Not True!
• It may be too big !
• It may become too big !
• It may stenose and become too small !
• It may deprive the hand of adequate perfusion
Fistula Surveillance
• The Pathology that is the native AVF is unstable, and changes over time.
• Surveillance & possible revision is essential throughout the patient’s life to maintain good & uncomplicated function.
Role of the Access Specialist
Ensure that all fistulas are:
• Big enough for adequate hemodialysis
• Not too big and a burden to the heart
• The donor limb is adequately perfused
Qa: Fistula Flow
Fistula Flows
• Blood Flow Required by AVF: > 500mls/min
• Blood Flow Needed by forearm: > 200mls/min
therefore
• Blood Flow in Brachial artery: > 700mls/min
Measuring Qa
• On dialysis: eg Transonic
• With Ultrasound
• During angiography
Fistula Flows
Qa < 500ml/min - Too Small
Qa > 2000ml/min - Too Big
Qa 500 – 2000ml/min - Just Right!
• A common problem
• Poorly understood:
“The proximal fistula long a mystery to me!!”
• Better understanding from:
Fistulography, endovascular treatment,
Fistula duplex ultrasound & IVUS
Pressure & flow studies during intervention
THE GIANT FISTULA
NOTA BENE !
Giant Fistula ≠ Fistula vein aneurysm
THE GIANT FISTULA
VENOUS ANEURYSM/S
Venous aneurysm 32 mm
Feeding Radial artery 5 mm
Fistula flow Qa: 900 mls/min
THE GIANT FISTULA
Fistula vein 28 mm
Inflow brachial artery 11 mm
Fistula flow Qa: 3,500 mls/min
• Most AVF grow throughout their life
• The entire circuit, from L ventricle to R atrium
• Growth is artery driven
• Fistulas do not stop growing just because they have become adequate for dialysis !!!!
PATHOPHYSIOLOGY
GIANT FISTULA
Large fistula vein
Large inflow artery 9mm
Normal outflow artery 5mm
• Functional AVF: RC radial artery 3-5 mm
BC brachial artery 4-7mm
• Functional AVF: RC flow Qa : 500mls/min
BC flow Qa : 1000mls/min
• Giant AVF: Brachial artery ♂ > 8mm ♀ > 7mm
BC flow > 1500mls/min
DEFINITIONS
• Proximal fistulas (Brachiocephalic)
• Male sex
• Large patient / Large donor artery
• Large anastomosis (>5mm)
• Genetic factors
ETIOLOGY
• Asymptomatic
• Covert high-output cardiac failure
• Overt high-output cardiac failure
PRESENTATION
• Hypertensive fistula
• “Outflow” Problem:
High Venous Return Pressures
Prolonged Venous Bleeding
PRESENTATION
BRACHIAL ARTERY 1.82 CM
GIANT FISTULA
• Synthetic “choke” to swing vein
• Sacrifice fistula
• Giant Fistula must be treated:
BEFORE it becomes a problem!
TREATMENT
GIANT FISTULA: INFLOW CHOKE
“CHOKE” PROCEDURE: PRINCIPLE
• Synthetic patch stitched around swing vein
• Close to anastomosis without mobilisation
• Patch stitched over endovascular balloon
• Balloon size 3 – 5 mm pending indications
“CHOKE” PROCEDURE: TECHNICAL
• Straighten swing vein to avoid kinks
• Use long balloon (60-80mm): Melon seeding
• Anchor patch to vein proximally & distally
• Rifampicin soaking & systemic Vancomycin
“CHOKE” PROCEDURE
BC anastomosis
“CHOKE” PROCEDURE
“CHOKE” PROCEDURE
“CHOKE” PROCEDURE
“CHOKE” PROCEDURE
“CHOKE” PROCEDURE
CHOKE
DUPLEX U/S FOLLOW UP
DUPLEX U/S FOLLOW UP
DUPLEX U/S FOLLOW UP
COMPLICATIONS
• Not tight enough
• Too tight
• Occluded fistula
• Thrombo-embolism from poor flow
• (Infection)
CHOKE TOO TIGHT
Large RC AVF, anginaChoke too tight, 0,9mmInadequate dialysis
CHOKE TOO TIGHT
Angioplasty on 014” system with 3 x20 coronary balloon
CHOKE TOO TIGHT
Final run; choke lumen 2,8 mm
• Mrs PL, 74 yrs old
• BC AVF Queensland 2000, now in Sydney
• Qb: 300, -100, +160
• Duplex ultrasound assessment:
Flow 2387 mls/min
Brachial artery 8.8mm
Anastomosis 7.7mm
Elective Choke Procedure
GIANT AVF: CASE 1
GIANT AVF: CASE 1
CHOKE DOWN
TO 4mmm
POST-OP VISIT
• No more SOB !
• I can do the shopping again!
• So much more energy !
• Sleep better at nite !
• Qb: 300, -100, +120
GIANT AVF: CASE 1
+ 0.30cm
GIANT AVF: CASE 1
GIANT AVF: CASE 1
Giant fistula ligated at St Elsewhere
Brachial artery 14 mm with laminated thrombus
GIANT AVF: CASE 2
Brachial artery 14 mm
Excision & LSV bypassof brachial artery
• Generally MISUNDERSTOOD
• A lot of Access done by NON – Vascular Surgeons
Take Home Message:
“ Steal is an INFLOW problem ie Brachial a problem”
Steal Syndrome
Subclavian Steal Syndrome
Arm at Rest
Brain: Low Resistance
Arm:High Resistance
Very Limited Flow thru SCA Stenosis
Subclavian Steal Syndrome
Arm:Very Low Resistance
Brain: Low Resistance
Arm Exercising
Very Limited Flow thru SCA Stenosis
• Present in most fistulas
• Arm “claudication” – common
• Critical ischemia - uncommon with native AVF
• Seen mainly in diabetics
• ?Commoner with proximal anastomoses
Steal Syndrome in AVF
• Less common in the native fistula
• Native fistula growth gradual, allowing for collateralisation, inflow artery growth.
• AVG is sudden diversion of blood supply –
Steal more common
Steal Syndrome in AVF
Patho-Physiology
At rest: Brachial arteryblood flow 100-200 mls/min
Exercise: Brachial arteryblood flow 1000 mls/min
A - Brachial artery inflow
B - Fistula flow (LOW resistance)
C - Forearm / hand (HIGH resistance)
BRACHIO-CEPHALIC FISTULANORMAL
NORMAL
BRACHIO-CEPHALIC FISTULA
Increase in size / flow
inflow brachial artery ++++
Increased flow in
fistula vein +++
Small / modest decrease
in forearm flow +
NO significant increase in
size/flow brachial a due to disease
Increased flow in
fistula vein +++
Severe decrease
in forearm flow +++
CLINICAL STEAL SYNDROME
DUE TO
FAILURE OF BRACHIAL A GROWTH
Physiology of Steal
1. Blood flow to BC fistula
(Minimum 500ml/min)
2. Blood flow hand/forearm
(Minimum 200ml/min)
3. Blood flow R upper limb
(Minimum 700ml/min)
1
2
3
1. 1600mls/min
Normal BC AVF 2. 1400mls/min
3. 200mls/min
1. 1100mls/min
BC AVF & STEAL 2. 1080mls/min
3. 20mls/min
Diseased runoff vessels
with high resistance
Diseased bra a +++
limiting inflow
1
2
3
Physiology of Steal
Severely diseased, calcified brachial artery
Algorithm
• Diagnosis (Accurate diagnosis!!)
• Is steal limb threatening?
• NO: Conservative Management
• YES: Duplex scan & Volume flow Brachial a
(Not fistulography!)
Diagnosis
• All patients have a “steal”
• Diagnosis of clinically significant steal
• Steal largely a problem of Diabetics
• Accurate dx on Clinical Grounds DIFFICULT !
Diagnosis
Ischemic rest pain vs other symptoms
• Diabetic Neuropathy
• Carpal Tunnel syndrome
• “Median Nerve Neuropathy”
• Other neuropathy: cervical
• Peripheral Nerve damage
• History
• Physical Examination: Berger’s sign
• Finger Plethysmography
• Nerve conduction studies
DIAGNOSIS
BERGER’S SIGN
HANDS UP
R HAND WHITE
BERGER’S SIGN
HANDS DOWN
R HAND RED
ISCHEMIA
Severe Ischemia: Westmead, Sydney
Severe Ischemia: SIUT, Karachi, Pakistan
50 year old DMLost his fistula
& His hand!
Finger Plethysmography
Finger Plethysmograpy
• Absolute Pressures, not ratios to the Brachial a
• Both hands
Pressures < 30mm Hg
Pressures >> lower Fistula hand
• Significant Steal Pressures lower on Radial side
Flattened wave forms
Unrecordable pressure / wave
Nerve Conduction Study
Two scenarios:
• “High Flow Steal” (Qa > 1000mls/min)
“Choke” procedure
• “Low Flow Steal” (Qa < 800mls/ min)
Ligate fistula
Other? (Low life expectancy!)
STEAL: Treatment
Flow in fistula vein
limited by choke (3mm)
Small increase
in forearm flow eliminating
critical ischemia
TREATMENT OF CLINICAL STEAL
WITH INFLOW CHOKE
“High Flow Steal” : CHOKE
1. 1200mls/min
BC AVF & STEAL 2. 1180mls/min
3. 20mls/min
1. 1200mls/min
BC AVF & CHOKE 2. 600mls/min
3. 600mls/min
11
2 2
33
CHOKE FOR STEAL
• Choke needs to be tight: 3mm balloon
• Risk of occlusion / inadequate dialysis
• Creating new fistula high risk ischemia
• Patients with limited life: Vascath
TREATMENT OF STEAL: ANGIOPLASTY
LOCALISED INFLOW STENOSIS
Angioplasty +/- stent
OUTFLOW STENOSIS
Angioplasty +/- stent
“Low Flow Steal” : LIGATE FISTULA
1. 400mls/min
BC AVF & STEAL 2. 300mls/min Inadequate inflow to upper limb
3. 100mls/min
1
2
3
PERSONAL EXPERIENCE
46 “CHOKE” Procedures
30 Giant Fistula 16 Critical Ischemia
26/30 Fistula Saved 9/16 Fistula Saved
PERSONAL EXPERIENCE
16 Critical Ischemia
4 Ligated 2 Brach a Angioplasty 10 Choked
2/2 Saved 7/10 Fistula Saved
Conclusions
• Steal is a problem of the inflow Brachial a
• Almost always in the Diabetic
• Accurate diagnosis CRITICAL
• Finger Plethysmography essential
Conclusions
• High Flow steal treated with Choke
• Accurate Choke a difficult operation!
• Low Flow steal treated with Ligation
OR
• ? Improving INFLOW to upper limb
Dr Ruth Carter, GP
Aboriginal Health
Tennant Creek
Sydney
Tennent Creek
3,600 km
Sally Swinnen
English, Bahasa Indonesia
Official Bahasa Translator
Australian National University
2018 Strategic Studies Tour
Kalimantan, Indonesia
Tui Swinnen
English, Spanish
Emergency Nutrition Network,
Project Manager,
Niamey, Niger, Africa
Lucy Swinnen
Turkish, Arabic
Journalist,
Currently in London