Dr John Swinnen Vascular Surgeon Dialysis Access Specialist MSF Trauma Surgeon University Of Sydney Westmead 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
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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”