se prezinta rolul ultrasonografiei Doppler in evaluarea patului vascular arterio-venos la pacientii cu indicatie de dializa, monitorizarea fistulei arterio-venoase si a eventualelor complicatii

1. FISTULA A-V
Alexandru Andritoiu
ESC, Artery Research (Cambridge)
European Atherosclerosis Society

2. TIPURI DE FISTULA A-V
•
•
•
•
Congenitale
Post-traumatice
Leziuni vasculare prin impuscare
Chirurgicale (dializa)
(1) fistula nativa
(2) graft

3. The fistula is the “gold standard”
because:
• It has a lower risk of infection than grafts or catheters
• It has a lower tendency to clot than grafts or catheters
• It allows for greater blood flow, increasing the
flow
effectiveness of hemodialysis as well as reducing
treatment time
• It stays functional for longer than other access types; in
some cases a well-formed fistula can last for decades
• Fistulas are usually less expensive to maintain than
synthetic accesses

4. INDICATII
DIALIZA
• IRC – UREMIE
• Creatinina serica >4 mg/dL
• Cl Cr <25 mL/min
NKF-DOQI clinical practice guidelines for vascular access. Am J Kidney Dis 1997; 37 Suppl 1:
S150−S191.

5. ETAPE
• Montarea fistulei AV de catre echipa
chirurgicala
• Maturarea fistulei (2-4 luni)
• Canularea fistulei de catre personalul ce
deserveste serviciul de dializa
• Mentinerea fistulei patente pe termen lung

6. Diagrams of the three types of upper arm arteriovenous
fistulas used for hemodialysis
Fig. Diagrams of the three types
of upper arm arteriovenous
fistulas used for hemodialysis
A. Normal anatomy of the right
antecubital fossa, showing the
cephalic vein (CV), median
antecubital vein (MACV), basilic
vein (BV), brachial artery (BA),
radial artery (RA), and ulnar artery
(UA).
B. Brachiocephalic arteriovenous
fistula.
C. Brachiobasilic arteriovenous
fistula.
D. Brachial artery–to–median
antecubital vein arteriovenous
fistula.
Stepansky F et al. Radiographics 2008;28:e28-e28

7. Brachiobasilic
transposition
A-V fistula

8. Brachiocephalic
A-V fistula

9. Radiocephalic
A-V fistula
Brescia - Cimino

11. NKF-DOQI Clinical Practice Guidelines for Vascular Access
New York, National Kidney Foundation, 1997
Fistula versus graft survival in patients starting hemodialysis with a permanent
vascular access comparing DOPPS results from Europe and United States.

12. Hemodinamica
• Q in AB = 85 mL/min
• Fistula = Q se amplifica de aprox. 10 ori

13. Utilitatea US la initierea Fistului AV
• Masurarea Diametrului AB /AR –
predictibila ptr. evolutia fistulei
• Masurarea Q in AB
• Masurarea Diametrului V cefalice
• Compresibilitatea V cefalice

14. Fistula AV radio-cefalica
(A) B-mode sonogram showing a
longitudinal section of an
arteriovenous fistula created by
anastomosing the cephalic vein (V)
to the radial artery (A) at the wrist
in a side-to-end fashion.
(B) With the same sectional view,
Color Doppler sonography shows
turbulent flow at the a-v
anastomosis. The radial artery (A)
is feeding the shunt vein (V).

15. Doppler
The typical effect of an arterio-venous fistula on the Doppler tracings is shown on this
diagram. The inflow artery can show a low resistance pattern due to the low
resistance outflow into the vein. The bigger the effective fistula, the more diastolic
flow is seen. The arterial waveform distal to the fistula regains a more typical
appearance. The communicating channel and the vein close to the channel show an
arterialized signal and a broad frequency range of signals

16. Fistula AV - Doppler color

17. Semin Dial. 2001 Sep-Oct;14(5):314-7.
The clinical utility of Doppler ultrasound prior to arteriovenous fistula creation
Brimble KS, Rabbat CG, Schiff D, Ingram AJ.
Abstract
Arteriovenous fistula (AVF) is the preferred access for long-term hemodialysis, with
superior long-term patency rates; however, early failure rates are significant.
Recent evidence has brought into question the preferred site of AVF creation in many
patient groups.
A preoperative test that could reliably predict the outcome of a proposed AVF would be
of great benefit.
Doppler ultrasound has been the most extensively studied and widely used test to
guide access creation. Accurate and validated measurements of internal vessel
diameter, both arterial and venous, and blood flow in the upper extremity are
obtainable by Doppler ultrasound.
Studies evaluating the utility of Doppler ultrasound prior to AVF creation suggest that
vessel size and blood flow are predictive of AVF outcome.
An AVF created using a cephalic vein and/or radial artery smaller than 1.5-2.0 mm is
likely to fail; such preoperative data may indicate that an upper arm AVF should be the
primary access attempted.

18. Predictori ai evolutiei fistulei A-V
evaluare Doppler preoperator
• D arterial <1.5 mm
• D venos <2.5 mm
• IR > 0.8

19. COMPLICATII
•
•
•
•
Bacteriemie/infectie
Stenoza
Tromboza
Malfunctie

20. Rolul US in supravegherea
fistului AV
• Malfunctia fistulei = reducerea Q fistulei
<120 mL/min
• Stenoza
• Tromboza
• Anevrism/Pseudoanevrism

21. Stenoza fistulei
The typical blood flow velocity in a dialysis access is in the 200 cm/sec range.
This dialysis access fistula shows a decreased blood flow velocity (less than
100cm/sec). The waveform has a typical appearance, showing evidence of
turbulence as witnessed by the shaggy contour of the waveform. Turbulence is
manifest by a random fluctuation of the peaks seen in the spectral tracing from
millisecond to millisecond

22. Pseudoanevrism
There is evidence of a large hematoma (white arrows) surrounding the access graft
(color channel). This makes insertion of the needles needed to perform dialysis very
difficult.

23. Hemodynamic changes in the early phase of
artificially created arteriovenous fistula: color
Doppler ultrasonographic findings
K. Mahmutyazicioglu, et al.
Journal of Ultrasound in Medicine, 1997;16,12: 813-817
Color Doppler ultrasonography is a very effective method
in the evaluation of hemodynamics of arteriovenous
fistulas in hemodialysis patients. It will allow an
understanding of the pathology in nonfunctioning fistulas
or of the cause of complications that develop secondarily.

24. Pietura R et al. Eur J Radiol 2005;55:113-119
Colour Doppler ultrasound assessment of well-functioning mature
arteriovenous fistulas for haemodialysis access
The mean flow volume was 1204.1 ml/min (S.D. = 554).
It was significantly higher in the fistulas with aneurysms, calcifications and tortuous
vessels and lower in those with stenosis.
There was no correlation between the flow volume or presence of stenosis and
fistula age.
Stenosis was detected in 64% fistulas. Fifty-seven percent of stenoses were located
in the anastomotic region, 22% stenoses were in vein junction, 19% were at one or
both ends of aneurysm, and 2% in the remaining region of the efferent vein.
Perivascular colour artefacts were present at the 94% fistulas with stenosis. Chronic
venous occlusion with collateral veins was detected in 6% of fistulas.
The aneurysms were observed in 54% fistulas. The mean diameter of aneurysms
was 12.4 mm. Ninety-six percent of aneurysms were located at puncture sites.
Ten patients had a small thrombus in an aneurysm and at puncture sites.

25. Hemodialysis arterio-venous fistula
complications
Fig. Hemodialysis arteriovenous fistula
complications.
(a)
Time-resolved contrast-enhanced MR angiographic
images at 6 seconds per frame demonstrate a leftside brachiobasilic hemodialysis fistula with
multiple venous stenoses(arrows).
(b)
Coronal postcontrast 3D T1-weighted fatsuppressed spoiled gradient-echo images reveal
an additional significant finding: multiple
intraluminal venous thrombi (arrowheads).
(c)
Time-resolved contrast-enhanced MR angiograms
in two patients with arteriovenous hemodialysis
fistula complications; the patient in the left image
has two venous aneurysms (arrows), and the
patient in the right image has complete venous
occlusion with collateral vessels present
(arrowhead).
Stepansky F et al. Radiographics 2008;28:e28-e28

26. Hemodialysis arterio-venous fistula complications
Fig. Hemodialysis arteriovenous fistula complications.
(a)
Time-resolved contrast-enhanced MR angiographic images at 6 seconds per frame demonstrate a left-side
brachiobasilic hemodialysis fistula with multiple venous stenoses(arrows).
(b)
Coronal postcontrast 3D T1-weighted fat-suppressed spoiled gradient-echo images reveal an additional
significant finding: multiple intraluminal venous thrombi (arrowheads).
(c)
Time-resolved contrast-enhanced MR angiograms in two patients with arteriovenous hemodialysis fistula
complications; the patient in the left image has two venous aneurysms (arrows), and the patient in the right
image has complete venous occlusion with collateral vessels present (arrowhead).
Stepansky F et al. Radiographics 2008;28:e28-e28

27. Hemodialysis arterio-venous fistula complications
Time-resolved contrast-enhanced MR
angiograms in two patients with arteriovenous
hemodialysis fistula complications; the patient in
the left image has two venous aneurysms
(arrows), and the patient in the right image has
complete venous occlusion with collateral vessels
present (arrowhead).
Stepansky F et al. Radiographics 2008;28:e28-e28