Arterial Hemodynamics Flashcards
cuff size affects limbs pressures
too narrow - falsely high too wide - falsely low
ABI > 1.4
diabetes
chronic renal failure
medial calcification
significance of 15 mm difference PT and DP
proximal disease
ABI uses which pressures for brachial and DP/PT
highest brachial pressure
highest DP or PT
30 mm hg gradient btw segments
significant disease
pressures may not drop
due to compensation from collaterals
pressures reflect function
not anatomy
pressure difference arm and proximal thigh
20-30 mm
contraindications for exercise testing
recent coronary event
shortness of breath
arthritis
ABI < 0.5
key in exercise testing
drop in pressure 20% not ABI (may increase)
treadmill exercise
10-12 % incline - start 1 mph - increase to 2.5
significance of recovery from exercise < 5 min
good collateralization
PPG
photoelectric plesmothography
normal PVR

dicrotic notch
sharp systolic upstroke
narrow peak
dicrotic notch
reflected wave
PVR amplitude dependent on following
PVR measures cuff pressure changes due to cuff volume which reflects changes in limb volume
stroke volume
blood pressure
vasomotor tone
blood volume
limb size
limb position
PVR waveforms with obesity & edema
attenuate
pressures for PVR
65 mm limbs/ 40 mm digits
PVR (measure over 3-4 cycles)
measures global perfusion under cuff
abnormal PVR

dampened upstroke
peak round and delayed
no dicrotic notch
PPG
light sensitive diode detects RBC
toe brachial index
toe pressure over highest brachial pressure
severe disease toe index
0.11-0.34
mild moderate toe index
0.35-0.64
normal toe index
> 0.65
able to differentiate stenosis versus occlusion
NO
patients in which to measure toe index
diabetes
medial calcification
primary testing pitfalls
inflow stenosis
inability to distinguish stenosis and occlusion
noncritical stenosis
Normal ABI/waveforms but claudication
stress exam - if positive then duplex
common iliac aneurysm
2.0 cm 1.7 cm per Pellerito 1,5 cm upper normal
criteria for femoral or popliteal aneurysm
increase by 50%
AAA rupture risk
43 % if > 6 cm
10-20 % risk of rupture
characteristics of endoleak
spongy aneurysm sac areas of decreased echogenicity pulsations
meaning of 20-49% stenosis
plaque without velocity elevation
ratio for 50-75% stenosis
2:1 velocity ratio
velocity ratio for >75% stenosis
3:1
significance of tandem lesion on velocity
decreases velocity elevation
popliteal and tibial velocities
60’s
SFA velocity
CFA velocity
90 +/- 15 cm/sec
115 +/- 25 cm/sec
criteria for occlusion
pre occlusive thump
internal echoes
prominent collaterals
no flow
velocity criteria for bypass graft failure (lower extremity) (not for > 6 mm vein grafts) ****
45 cm/sec
ischemia of extremities involving upper extremities
5% of disease
wrist brachial index
0.9 - 1.1
digit brachial index
>= 0.9
significant brachial pressure difference
20 mm
Allen test
PPG on 3rd digit intact arch if waveform reverses incomplete arch if waveform stops
5% of UE disease is large vessel
90-95% UE disease is small vessel
nipple or peak of top of waveform

vasospasm
characteristics of arteritis
smooth circumferential
popliteal entrapment
hyperextension of knee
passive dorsiflexion
active plantar flexion
low thigh and calf pressures
fem pop disease
low toe pressure
vasospasm versus small vessel disease
difference between Doppler and PVR
direct versus global perfusion
low pressures in foot ankle
use CW
sonographic appearance of endoleaks

spongy
hypoechoic or anechoic area
endoleak type I
attachment site high pressure poor apposition hyperdense on precontrast type IA - proximal type IB - distal iliac artery
endoleak type II
most common retrograde from excluded aortic branch lumbar or IMA
type III endoleak
high pressure
structural failure of graft
holes in fabric
junctional separations
leak through body of stent graft
poor apportion or separation of graft or
graft rupture or tear of graft
may see high velocity jet
type IV endoleak
immediately after placement
ransient graft porosity
blush on angio at time of placement
diagnosis of exclusion
type V endoleak
endotension
persistent growth without visible cause
PPG waveform with double peak
(early anacrotic notch and high dicrotic notch)
means
Raynaud’s disease
PPG in incomplete arch
after release of either radial or ulnar no bouncing waveform
ratio for 76-99% stenosis
3:1
ratio for 50-75%
2:1
significance of pandiastolic flow
aortic insufficiency
popliteal entrapment - plantar flexion
velocity elevates to 327 cm/sec
CW
continuous wave Doppler
2 crystals
5-10 mHz
Doppler probe 45-60 degrees
what is this waveform demonstrating

hyperemia
exercise testing
recovery < 5 min
adequate collateralization
exercise testing
recovery > 10 min
poor collateralization
waveform finding

serrated margin
post stenotic turbulence
popliteal velocity
69 +/- 15 mm