AV Fistula

Artery and Venous Communication

1. Basement
membrane Yalye

Endothelium

Tunica intima
+— Basement
7 membrane

Tunica media

2. 3 major types
Arteries
Capillaries

Venules

100,000km of Red blood cell I
blood vessels Capillary 3

3. Arteries

Veins

Capillaries

Material exchange

Function Send blood from heart | Send blood to heart with tissues
Pressure High Low Low
. M Extremely narrow
Lumen Diameter Narrow Wide (one cell wide)
Wall Thickness Thick Thin Extremely in
(single cell thick)

Three Three One

Wall Layers . Tunica adventitia . Tunica adventitia + Tunica intima
+ Tunica media + Tunica media
+ Tunica intima + Tunica intima

Muscle & Elastic Fibres | Large amounts Small amounts None

Valves No Yes No

4. Vascular tumors

Vascular malformations

Infantile hemangiomas

Congenital hemangiomas
Tufted angioma
Kaposiform

Spindle cell
hemangioendothelioma

Other, rare hemangioendotheliomas
(epithelioid, composite, retiform,
polymorphous, etc.)

Dermatologic acquired vascular
tumors

Slow-flow vascular
malformations

Capillary malformation (CM)

Venous malformation (VM)

Lymphatic

malformation (LM)
Fast-flow vascular
malformations

Arterial malformation (AM)

Arteriovenous fistula (AWF)

Arteriovenous

malformation (AWM)
Complex-combined vascular
malformations

CVM, CLM, LVM, CLWM,

ANIM-LM

ISSVA: International society for the study of vascular anomalies, CVM: Capillary
venous malformation, CLM: Capillary lymphatic malformation, LVM: Lymphatic venous.

5. Vascular tumors Vascular malformations

+ Infantile hemangioma Slow-flow vascular malformations
+ Congenital hemangioma (RICH and -CM
NICH) i :
« Tufted angioma (with or without ech
Kasabach-Merritt syndrome) 2 itis

« Kaposiform hemangioendothelioma
(with or without Kasabach-Merritt
syndrome}

+ Spindle cell hemangioendothelioma

+ Other, rare hemangioendotheliomas

Common sporadic VM
GVM (glomangioma)
«LM

Fast-flow vascular malformations

(epithelioid, composite, retiform,

polymorphous, Dabska tumor, etc.) + AM
+ Dermatologic acquired vascular + AVF

tumors (pyogenic granuloma, targetoid * AVM

Oma. CS MOR REMENS! Complex-combined vascular malformations
+ CVM, CLM, LVM, CLVM, AVM-LM, CM-
AVM

6. Vein

Arteriovenous Fistula

Artery

7. Arteriovenous Fistula
Introduction & History.

+ Abnormal communication between an
artery and vein

William Hunter first recognised it being
different from traumatic aneurysm.

8. A-V fistula
First described in 19621
latrogenic (percutaneous procedure) —Trauma

Asymptomatic (80%)
Gross hematuria — High output cardiac failure
Thrombo-embolic episodes — RF — HTN

Evolution Most regress spontaneously in 6 months
Some progress to life-threatening complication

Rx Asymptomatic: follow-up by Doppler
Symptomatic: embolization

Routine post-biopsy Doppler US & 6 months later

! Fernstrom | et al. J Urol 1962 ; 88 : 709.
24 Clin Ultrasound 2008 ; 36 : 377 — 380.

9. Introduction

Definition

+ Abnormal connection between artery and vein which
bypasses capillary bed

Aetiology
+ congenital
+ acquired:
- surgically created for haemodialysis
- penetrating trauma
- iatrogenic eg following surgical dissection of artery,
cannulation of artery or vein

10. tiology:

> Causes of AV fistulas:

1 Congenital (arteriovenous malformations or
hemangiomas

2. Acquired which may be

Traumatic

p>

latragenic.
Neoplastic.
Spontaneous
Surgically created

cs A

11. SYSTEMIC A-V FISTL
- Types - A. Congenital
e.g. Osler-Weber-Rendu disease

Parks Weber syndrome
Klippel Trenauay syndrome

B. Acquired
‘Trauma
latrogenic — Dialysis
Spine surgery

+ Extent of increase in CO depends on Physical size and
Flow magnitude of the Fistula

12. AM Fistula For Dialysis

13. Artery

\

Blood to Dialysis

Blood from Dialysis Machine

Machine

14. AV Fistula - Locations

+ Usually created in the nondominant
arm == \
+ May be situated on the hand euch von artery
° 'Snuffbox' Fistula
+ The forearm a A
+ Radiocephalic fistula astuja
= Radial artery to the cephalic vein Fae
+ Also called Brescia-Cimino Fistula if sa
© The elbow = TO
)

+ Brachiocephalic Fistula

= brachial artery to the cephalic vein
116/200. Paul A. Peirce, EMT-B 1/C 36

15. Types of common arteriovenous fistula
according to its site in the upper limb

Forearm Radial artery to cephalic vein

ANCE Radial artery to basilic vein

Radial artery to any other transposition

Arm AVF Brachial artery to cephalic vein
Brachial artery to basilic vein

Brachial artery to any other

te a
trancnocitian

16. Arteriovenous Fistula

Pathology
+ Abnormal circuit —_
Ischemia distally ! peripheral resist.

Collaterals 1 | car rate

| size of swelling Cardiac failure

17. Post-Operative care of AVF or AVGs
Immediately following surgery (half-hourly at first),
the site of AVF should be checked for :
> Excessive bleeding, haematoma, swelling, pain and
later signs of infection such as raised temperature.
> Check radial pulse, colour, movement, warmth, and
sensitivity of affected limb to ensure blood flow

reaches extremities (peripheral circulation).

18. Arteriovenous Fistula Clinical
Features

* Inspection:

Soft, diffuse mass
Pulsatile swelling
Dilated veins

- Palpation:Auscultation:
Thrill
Machinary murmur

19. ANASTOMOSIS EXAMINATION

+ THRILL (indicator of flow)
Strong = Good flow
Weak = Poor Flow

¢ Thrill felt during Systole & Diastole (Biphasic) =
Good Flow

+ Thrill during Systole ONLY = downstream
(antegrade) stenosis = PULSE

20. AV Fistula

® Fistula
® Advantages
* Lower infection rates
2 Higher blood flow rates
* Lower thrombosis/stenosis rates
® Disadvantages
* Longer maturation time
® Potential for steal syndrome
* Aneurysm formation

www.radelinie.com

21. Arteriovenous fistulas: Complications

Failure to mature

Stenosis at the proximal venous limb (48%).
Thrombosis (9%)

Aneurysms (7%)

Heart failure

The arterial steal syndrome and its ensuing ischemia
occur in about 1.6%: pain, weakness, paresthesia,
muscle atrophy, and, if left untreated, gangrene
Venous hypertension distal to the fistula : distal tissue
swelling, hyperpigmentation, skin induration, and
eventual skin ulceration.

22. A fistula is created direct connecting of an artery toa
vein. Once the fistula is created it is a natural part of the
body.

Most preferred access -once the fistula properly
matures and gets bigger and stronger; it provides an
access with good blood flow that can last for decades

It can take weeks to months before the fistula matures
and is ready to be used for hemodialysis

Exercises including squeezing a rubber ball to
strengthen the fistula before use.

23. Artery : Vein