Chapter 30: Hemodialysis Access Grafts and Fistulae Flashcards
(118 cards)
1
Q
The location where the artery and vein are connected or where the graft is connected to the artery or vein
A
anastamosis
2
Q
A balloon-like dilation of the blood vessel of the artery or vein
A
aneurysm
3
Q
a deliberate connection between a native artery and vein constructed with an end-to-end anastamosis, created to allow for hemodialysis acccess
A
arteriovenous fistula
4
Q
a type of hemodialysis access that uses an interposing bicompatible synthetic tube connecting an artery to a vein to allow for hemodialysis access
A
arteriovenous graft
5
Q
the audible sound caused by the high pressure pressure arterial flow of blood passing through a low-resistance venous structure such as an arteriovenous fistula or graft
A
bruit
6
Q
a means to artificially cleanse the blood by removing by-products, waste, and fluid in patients with end-stage renal disease via a dialyzer machine
A
hemodialysis
7
Q
also known as vascular access, is a surgically created connection between an artery and a vein to allow for the removal of toxic by-products from the blood via hemodialysis
A
hemodialysis access
8
Q
a minimally invasive method for arteriovenous fistula created by means of readiofrequency energy that combines heat and pressure
A
percuteaneous fistula
9
Q
a balloon-like outpuching of the access, often associated with repeated needle puncture, leading to loss of structural integrity
A
pseudoaneurysm
10
Q
the palpable sensation of an arteriovenous fistula or graft caused by the high pressure arterial flow of blood passing through a low-resistance venous structure
A
thrill
11
Q
posterior radial artery to cephalic vein
A
snuff box fistula
12
Q
radial artery to cephalic vein
A
Brescia-Cimino fistula
13
Q
Normal AVF characteristics
A
anechoic flow lumen free of intraluminal echoes
lumen fills wall to wall with color flow
low-resistive pulsatile flow without focal velocity elevation
14
Q
Stenotic AVF characteristics
A
intraluminal echos
thickened walls
reduced flow lumen
disturbed color-flow patterns
elevated velocities in region of stenosis
15
Q
occluded AVF characteristics
A
intraluminal echogenicity
loss of flow lumen
no flow
absent Doppler signal
16
Q
The National Kidney Foundation Kidney Dialysis Outcomes Quality initiative recommends ____% of future hemodialysis access be constructuted with autogenous AV access
A
50
17
Q
Goal of AVF or AV graft creation
A
provide repeared hemodialysis access while maintaining a low frequency of reinterventions and complication rates
18
Q
An autogenous fistula should be created as _____ as possble in ______ arm.
A
distal
nondominant
19
Q
Why is autogenous AVF creation the preferred finrst line therapy?
A
superior patency rates
lower rate of complication
20
Q
surgically created anastamosis between any artery and vein
A
native AVF
21
Q
Thr room should be kept comfortably warm to prevent _____
A
vasospasms
22
Q
Acceptable diameter of an artery for fistula
A
> 25 mm
23
Q
Why are arteries interrogated before AV procedure?
A
calcifications
intimal thickness
stenosis
compliance
24
Q
The quality of the arterial wall determines the ____ of the artery to dilate and accomodate increased flow
A
capacity
25
Where is atherosclerosis most often observed in the upper extremities?
subclavian artery
26
In the diabetic patient where can you find atherosclerosis?
radial and ulnar arteries
27
Focal narrowing of vein at any level may prevent ______
fistula maturation
28
The basicilic vein needs to be greater than ___ cm in legtnth with adequate diameters for transposition
10
29
central venous occlusion doppler characteristics
loss of phasic flow, presence of a continuous wavefore
30
Routine unilateral upper extremity mapping should take __-__ minutes
30
40
31
Contraindications to upper extremity mapping
local infections
obtrustive dressing
open wounds
restricting patient positioning
32
The radial, ulnar, and brachial arteries need to have an arterial diameter greater than ___ mm.
20
33
bright white echoes along or within vessel walls
calcifications
34
Normal arterial Doppler spectral waveform
high resistive with a rapid upstroke, sharp peak, and low diastolic flow
35
Favorable diameter for AV creation
2.5 cm
36
Venous Doppler criteria from central veins
respiratory phasicity
cardiac pulsatility
augmentation
37
The goal of hemodialysis access evaluation
provide a durable means for vessul cannulation that is located distally in the limb; allows the option for creating of a more proximal access should distal AVF fail
38
frequently performed fistula; involves mobilizing distal cephalic vein at wrist and anastamosing it to distal radial artery in an end-to-side configuration
Brescia-Cimino fistula
39
connecting posterior branch of radial artert to cephalic vein
snuffbox fistula
40
requires vein to be transposed and juxtaposed to a distal artery (radial or ulnar) in order to creat AVF
medial location of forearm basilic vein
41
Most common upper arm access
brachial artery to cephalic vein fistula; created at or just distal to the antecubital fossa
42
Possible sites for arterial infolow of basilic transposition
brachial, radial, ulnar
43
Lower extremeity hemodialysis access sites
common femoral artery
superficial femoral artery
transposed great saphenous of femoral veinFi
44
Fistula maturation takes place __-__ weeks after creation of fistula
10-12
45
defined by a dilated cein, ,palpable thrill, audible bruit
Matured fistula
46
Flow rates are greater than ___ mL/min for fistulas that failed to mature
500
47
You should change system presets to ____ flow setting for hemodialysis access examination
high flow
48
Inflow artery supplying dialysis access waveform
low-resistance waveform with constant antegrade flow throughout cardiac cycle
49
volumetric flow calculation
time average velocity x area x 60
50
Hemodilaysis access examiantion takes about __-__ minutes
30
45
51
hypoechoic to anechoic depending on age
thrombosisb
52
bright white relfectirs within vessel walls
calcifications
53
54
valve protruding into vessel lumen; potentially a site for initmal hyperplasia formation
incompetent valve
55
Well function fulsta demonstrate PSV between ____-___ cm/s
150
300
56
EWll functioning fistulas demonstrate an EDV of ____-____ cm/s
60
200
57
Stenosis may be present if PSV is less than ___ cm/s
50
58
inflow artery blood flow characteristics
low resistance flow
increased PSC (30-100 mL/min)
pulsatile flow in outflorw vein
59
Expected flow through fistula
marked spectral broadening, continuous forward diastolic flow; high velocity
60
Account for ___% access-related complications
anastomotic and vein or graft stenosis
61
echogenic intraluminal lesions; luminal flow reduction on B-mode
outflow vein stenosis
62
high resistance signal, absent flow lumen, intraluminal echogenic thrombus
fistula or graft occlusion
63
Normal flow volume in a fistula
greater than 800 mL/min
64
mild-to-moderate stenosis in fistula
500-800 mL/min
65
severe stenosis in fistula
less than 500 mL/min
66
retrograde flow in artery distal to fistula or graft anastamosis
steal phenomenon
67
Occurs in 75-90% of patients after access creation
steal phenomenon
68
based on fluid dynamics, low resistance outflow vein draws antegrade flow from inflow artery and in addition "steals" retrograde flow from distal artery
steal phenomenon
69
symptoms of steal phenomenon
pain during hemodialysis
rest pain
weakness
paresthesias
tissue loss if advanced
70
cause of steal phenomenon
problem with high flow through fistula, insufficient distal collateral circulation, inflow arterial occlusive disease
71
Significant steal syndrome if digital pressure is less than ___ mm Hg
40
72
Significant steal syndrome if digital brachial pressure index is less than ___
0.6
73
novel minimally invasive percuteaneous AVF creation devices
EndoAVF
74
use magnetic catheters and radiofrequency energy to create in vivo anastomosis
EndoAVF
75
For an endoAVF an adequate perforating vein is needed at the ______
antecubital fossa
76
The WavelinQ EndoAVF system requires two access sites, the _______ and the ______ in the distal forearm
brachial artery
radial or ulnar vein
77
The Ellipsys Vascular Access System requires one single point of access, through a perforating vein into the ______
radial artery
78
The goal of the Kidney Dialysis Outcomes Quality Initiative was to increase and expand the creation of which of the following?
a. prosthetic hemodialysis access grafts
b. autogenous hemodialysis access fistulae
c. lower extremity hemodialysis access
d. central venous port access
b
79
What is the most common cause of maturation failure of dialysis access fistulae?
small or suboptimal veins
80
Which of the following should be included during the physical examination for preoperative artery mapping for dialysis fistula creation?
a. bilateral arm blood pressure measurements
b. pulse examination of brachial, radial, and ulnar arteries
c. Allen's test for palmar arch assessment
d. all of the above
d
81
Which of the following is NOT a finding suggestive of a central venous stenosis or occlusion?
a. are edema
b. prominent chest wall veins
c. painful, cool, pale hand
d. presence of arm collaterals
c
82
Which of the following describes the proper patient positioning for upper extremity venous evaluation before fistula creation?
a. supine with arm elevated
b. supine or sitting with arm dependent
c. standing with weight held in arm to be examined
d. Trendelenburg with feet elevated
b
83
With what does standard protocol for evaluation of the upper extremity arteries and veins for fistula creation begin?
arteries of nondominant arm
84
85
All Doppler studies should be performed at an angle of ____ or less, even if actual velocities are not recorded to achieve adequate Doppler signals.
60 degrees
85
What is the acceptable minimum vein diameter for favorable fistula creation?
2.5 mm
86
Which of the following should venous Doppler signals from central veins NOT display?
a. respiratory phasicity
b. cardiac pulsatility
c. augmentation
d. continuous flow
d
87
The most common upper arm access is made between the cephalic vein and which artery?
brachial artery
87
What is a type of fistula created by connecting the posterior branch of the radial artery to the cephalic vein?
snuffbox fistula
88
Approximately how long should it take an autogenous fistula to mature?
8-12 weeks
89
During evaluation of the upper extremity either before or after fistula creation, the examination room should be kept warm to avoid what?
vasospasm
90
Which of the following is NOT included in a physical examination of a patient with a current AV fistula?
a. assessment of thrill
b. assessment for edema or redness
c. bilateral radial blood pressures
d. visual inspection for focal dilations and collateral veins
c
91
During duplex assessment of the hemodialysis fistula, what should Doppler settings be adjusted to detect?
high flow
92
Which of the following describes how volumetric flow is calculated?
a. time average velocity/PSV
b. time average velocity x area x 60
c. time average velocity x vessel diameter
d. PSV-EDV/PSV
b
93
What can remaining valve leaflets that project into the lumen of a fistula become a source for?
pseudoaneurysm development
94
A patient presents to the vascular lab for follow up evaluation of a dialysis fistula. Velocities within the fistula are 40 cm/s. What are these findings consistent with?
inflow artery stenosis
95
What should be the approximate normal volume flow in a fistula?
800 mL/min
96
The goal of arteriovenous access is to provide long-term hemodialysis access with a ____ frequency of reintervention and a low _____ rate.
low
complication
97
______ access has been the preferred first-line therapy because is has superior patency rates and lower complication rates compared to ________
autogenous AVF
prosthetic grafts and tunneled catheters
98
AV fistulas have higher long-term patency rates; however, they suffer from lower _______ rates and higher early _____ rates.
maturation
AVF thrombosis
99
Placement of central venous catheters, pacemakers, defibrillators, or prior mastectomy with lymph node dissection may _____ the creation of an arteriovenous hemodialysis fistula.
preclude
100
AV fistula creation is usually first attempted in the ______ upper extremity as far _____ as possible
non-dominant
distal
101
Atherosclerosis is uncommon in the upper extremities, but when it occurs, it most commonly affects the _____ artery.
subclavian
102
To maximally dilate the veins, a(n) ______ may be used either just below the antecubital fossa for forearm veins or at the axillary level for upper arm veins
tourniquet
103
Patency of veins should be confirmed both with transducer _____ and spectral Doppler waveforms.
pressure
104
A dilated, easily palpable, usable fistula with a flow rate of greater than 350 cc/min defines a fistula that has _____
matured
105
A partially or noncompressible vein suggests the presence of an occluding ______ within the vein lumen, making it ______ as an autogenous conduit.
thrombus
unusable
106
A Brescia-Cimino fistula is the most frequently created fistula and involves the ______ vein and the _____ artery at the wrist.
cephalic
radial
107
Because of its deep location, the ______ vein requires that is be transposed and juxtaposed to a distal artery to create an AV fistula.
basilic
108
While performing duplex assessment either preoperatively or after hemodialysis fistula placement, the examination room should be kept warm to avoid ______
vasospasm
108
To assess for edema, redness, presence of collateral veins, rotation of access sites, and focal dilations, the arm should be _______ by the technologist before duplex assessment.
physically inspected
109
Presence of perigraft masses, pseudoaneurysms, stenotic valves, and intimal flaps should be assessed during _____ imaging evaluation of a dialysis fistula.
B-mode
110
When stenosis is found, spectral Doppler velocities should be measured ____, _____, and _____ the area of interest.
proximal
distal
within
111
When measuring volume flow rates of a hemodialysis fistula, the ______ is used and is best measured over ____ cardiac cycles to obtain an accurate calculation.
time average velocity
3-4
112
As fistulas mature, they typically become tortuous and can become aneurysmal, thus requiring larger amounts of ___ to maintain proper skin contact over these surface irregularities
gel
113
If a hemodialysis fistula has a volume flow measurement less than 500 mL/min, this would indicate ____ in the fistula.
stenosis
114
When performing preoperative duplex evaluation for endovascular AVF creation, closer attention is paid to the ______ between the superficial and deep venous systems
tributaries
115
