anatomy and physiology of vascular access...vascular access advanced course in vascular access 2019...

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Dr John Swinnen Vascular Surgeon Dialysis Access Specialist MSF Trauma Surgeon University Of Sydney Westmead Hospital Anatomy and Physiology of Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 3 May 2019, Chiang Mai, Thailand

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Page 1: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

Dr John Swinnen

Vascular Surgeon

Dialysis Access Specialist

MSF Trauma Surgeon University Of SydneyWestmead Hospital

Anatomy and Physiology

of

Vascular Access

Advanced Course in Vascular Access 2019

Convenor: Professor Kittipan Rerkasem

2 – 3 May 2019, Chiang Mai, Thailand

Page 2: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

• Native AVF 80% IN EUROPE

90% IN JAPAN

• Native AVF ≈ 60% IN THE USA !!

• Westmead Renal Unit >95% Native AVF*

Native Fistula First !First Only

* Fistulas created by our unit

Page 3: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

The Native Hemodialysis Access Fistula is

a Pathology,

a Disease,

Created surgically,

for therapeutic reasons!

Page 4: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

The Native Hemodialysis Fistula

• Changes throughout it’s lifetime

• Generally keeps growing

• It can be too big, too small or just right!

• There is no “normal”

Page 5: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

ANATOMY

Page 6: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

• Standardised to RC AVF

• Independently described by:

CLARK et al

SWINNEN et al

Nomenclature

Page 7: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

DIVISION OF

FISTULA CIRCUIT

INTO 6 ZONES

J SWINNEN 2000

NOTE:

3: Cephalic Vein Distal = “Swing vein”

5: Cephalic Vein Proximal = “Arch vein”

Page 8: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

DIVISION OF FISTULA CIRCUIT INTO 6 ZONES -

CLARK ET AL 2002

LOCATION OF 109 STENOSES WITHIN DYSFUNCTIONAL NATIVE RADIOCEPHALIC

FISTULAE.

1 = NATIVE ARTERY

2 = ANASTOMOSIS

3 = INITIAL 2cm OF FISTULA

4 = VENOUS OUTFLOW > 2cm FROM ANASTOMOSIS

5 = DISTAL OUTFLOW

6 = CENTRAL VEINS

Clark TWJ Vasc Interv Radiol2002; 13:51-59

Page 9: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

All Fistulas

have

3 Components

Page 10: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

OUTFLOW

INFLOW

USEABLE

LENGTH

Page 11: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

1.Inflow

• Subclavian A

• Brachial A

• Radial A

• Ulnar A / Palmar Arch

Page 12: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •
Page 13: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

Normal Radio-cephalic AVF

Page 14: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

AVF fed by

reverse flow thru

Palmar Arch

Ulnar

Inflow Artery

Page 15: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

ULNAR ARTERY FEED THRU PALM

Ulnar Inflow Artery

Page 16: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

Anatomical Vs Functional Inflow

Anatomical inflow (radial artery)

and the

Functional inflow (Radial a, Anastomosis Swing vein)

NB 30% of fistula stenoses occur in this area !

Page 17: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

Anatomical Vs Functional Inflow

Page 18: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

Distal Cephalic Vein:

“Swing Vein”

Page 19: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

OUTFLOW

INFLOW

USEABLE

LENGTH

Page 20: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

2. Useable Length

• Site of needling (Rule of 6’s)

• > 6 cm of “Useable Segment” for needling

• < 6 mm deep

• > 6 mm in diameter

• > 600 mls/min Fistula Flow (Qa)

• Straight & Accessible

Page 21: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

OUTFLOW

INFLOW

USEABLE

LENGTH

Page 22: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

3. Outflow

• Important variable between different fistulas

• Outflow stenoses the hardest to treat

• RC AVF has the best outflow configuration*

* The Radio-Cephalic Fistula is by far the best Native Fistula !!!

Page 23: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

OUTFLOW RC vs BC AVF

Page 24: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

VENOUS

“REAL ESTATE”

Page 25: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

Radio-Cephalic Brachio-Cephalic Brachio-Basilic

Loop Forearm RC Loop Forearm BC

Ulno-Basilic Native Fistula Configurations

Page 26: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

LSV Forearm Straight & Looped

LSV InSitu Thigh

Transposed DFV Brachio-Axillary

Thigh DFV

Transposed DFV Axillo-Jugular

Page 27: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

Distal Radio-Cephalic Fistula

The Gold Standard !

Page 28: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

• Best outflow configuration (Triple)

• Giant Fistula / High Output State rare

• Most convenient access

• Significant steal very uncommon

• Radial artery fully expendable

• Endovascular revision very safe!

Distal Radio-Cephalic Fistula

Page 29: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

“Triple Outflow” Radio-Cephalic Fistula

Page 30: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

Proximalised RC Fistula

Page 31: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

Other Native AVF:

Brachio-cephalic

AVF

Page 32: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

“Loop Forearm BC AVF”

Page 33: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

Loop Forearm BC AV Fistula

WOUNDS FROM CV

MOBILISATIONARTERIAL

ANASTOMOSIS

VENOUS OUTFLOW

Page 34: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

“Ulno Basilic AVF”

Page 35: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

Non-transposed Ulno-basilic

AVF

Page 36: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

ANATOMY OF THE BASILIC V

• Variable junction to brachial v

• Basilic vein preserved/protected

from damage by depth & position

• Usually good caliber vein

• Excellent outflow !

• One or Two Stage Surgery

• A good fistula !

“Brachio- Basilic AVF”

Page 37: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

Dr R Allen

“Brachio- Basilic AVF”

Page 38: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

• LSV may be only undamaged superficial v

• LSV prone to stenosis

• Primary patency rates ~ Synthetic grafts

• Can be matured & maintained with

aggressive endovascular techniques

Loop & Straight LSV Forearm AVF

Page 39: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

Loop & Straight LSV Forearm AVF

LOOP STRAIGHT

Page 40: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

“Loop LSV

Thigh AVF”

Page 41: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

Superficial Femoral Vein AVF

• Pioneered by Dr D Gawler in Darwin, Aus.

• Makes an excellent, early maturing fistula

BUT

• Patient must have NORMAL arterial circulation

• May require choke to prevent “Giant AVF”

Page 42: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

Superficial Femoral Vein AVF

Page 43: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

SIUT: Superficial Femoral Vein AVF

Page 44: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

In Situ SFV AVF in L Thigh

Page 45: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

Transposed SFV to R Arm

Page 46: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

PHYSIOLOGY

Page 47: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

Flow (Q) in Hemodialysis

Qa Fistula Flow

Qb Dialysis Circuit Flow

Page 48: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

Qa: Flow Thru the Fistula Circuit

Page 49: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

Qb: Flow Thru the Dialysis Circuit

Page 50: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

Qa:

Flow thru the Fistula Circuit

Page 51: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

1. For assessing fistula function

2. For assessing change in flow over time

3. For assessing significance of a stenosis

4. For assessing giant fistula formation

5. For fistula Surveillance

Qa: Fistula Volume Flow

Page 52: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

Measuring Qa

• On dialysis: eg Transonic

• With Ultrasound

Page 53: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

• Sample AVF where ALL the flow goes

• Good “arterial” signal – “Clean” Wave Form

• Heart rate / rhythm: Assumes Sinus Rhythm

• Correct angle

• Correct sample volume

• The effect of Radius: Errors magnified

Qa Measurement by Ultrasound

Poiseuille’s Law

Page 54: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

Qa Measurement by Ultrasound

Therefore:

• Qa is variably accurate – “Ballpark”

• Must be carefully done

• In a Standardised way at Standardised site

Page 55: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

Site of Qa Measurement

• Qa should ALWAYS be measured in

the INFOW BRACHIAL ARTERY

• Qa should ONLY be measured in

the INFOW BRACHIAL ARTERY

Page 56: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

• Brachial artery carries ALL the flow to AVF

• Good arterial signal

• Reproducible site of sampling

Site of Qa Measurement

Page 57: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

Effect of Radius on Flow

True Radius Brachial a

2mm

Measured Radius Brachial a

4mm

True Flow (Qa) Brachial a at 2mm

=

500 mls/min

Measured Flow (Qa) Brachial a at 4mm

=

8000 mls/min

Page 58: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

Qa is always measured in the

Inflow Brachial Artery

Arm Fistula

eg BC AVF Forearm Fistula

Page 59: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

2 Exceptions !!

High Bifurcation

Brachial artery

(~10% Patients)

&

Fistulas in the LEG

High Brachial a

bifurcation

Radial a

Ulnar Interosseous Trunk

(UIT)

Page 60: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

Fistula Flows

Qa < 500ml/min - Too Small

Qa > 2000ml/min - Too Big

Qa 500 – 2000ml/min - Just Right!

Page 61: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

Qb:

Flow thru the Dialysis Circuit

Page 62: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

Qb: Flow Thru the Dialysis Circuit

Page 63: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

• FLOW > 300 ml/min

• ARTERIAL PRESSURES - 100 mm Hg

• VENOUS PRESSURES + 100 mm Hg

• TREND OVER TIME ! OR

Qb: Flow Thru the Dialysis Circuit

Page 64: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

Inflow Stenosis

Page 65: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

Outflow Stenosis

Page 66: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

Fistula Flows: Qa and Qb

Qa

Fistula Flow

QbDialysis Flow

Page 67: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

AVF of Interest to 3 Parties

• The DIALYSIS PUMP:

Adequate Dialysis / RRT

• The FISTULA LIMB:

Adequate Perfusion

• The HEART:

Adequate Cardiac Function

Page 68: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

AVF Acted on by 2 Forces

• Fistula Stenosis:

Driven by the body’s healing response

• Fistula Growth:

Driven by the inflow artery

Page 69: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

The Native AVF

• It may be too big !

• It may betoo small !

• It may deprive the hand of adequate perfusion

• It may overburden the heart

Page 70: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

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

Page 71: Anatomy and Physiology of Vascular Access...Vascular Access Advanced Course in Vascular Access 2019 Convenor: Professor Kittipan Rerkasem 2 –3 May 2019, Chiang Mai, Thailand •

Thank You

For Your Attention