RPVI-Lower arterial duplex Flashcards by Christine Herman

what are pitfall in LED?

edema
obese
low outflow

calcified
imaging pop at trifurcation
tandem lesions

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what is normal waveform?

fast upstroke
reversal in early diastole
forward in late diastole
high resistance flow which is normal
PSV gradually decrease distally

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What does a biphasic waveform look like

reversal in early diastole but no forward flow in late diastole

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what does mono phasic look like

slow upstroke and no early diastole reversal

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What are stenotic effects to the waveform at the site os stenosis

early D flow reversal decreases and disappears with severity
S acceleration time slowed
S peak is rounded and reduced (tarsus and parvus)
decreased PSV
turbulent flow
dampened

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What are average velocities for the LE vessels?

CFA 114
SFA P 90
SFA D 90
POP A 70
PTA 40-50

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How to we define stenosis

compare one set to another
if is doubles then 50% stenosis or greater
2-4 cm prox to stenosis then at stenosis

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What features represent normal LE flow?

PSV 70-100 cm/s

triphasic

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What features represent 20-49% LE flow?

> 30% increase in psv

triphasic

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> 50%

> 100% increase in psv

monophasic/turbulent beyond stenosisl

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> 75%?h

> 400cm/s or quadruple

monophasic/high velocity

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What is a hemodyn signif stenosis? what does is cause?

50%
vasod and collateral formation
not necessarily cause symptoms

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What is different about flow in stents?

may have increased velocities b/c smaller diameters and lack of normal arterial elasticity

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what is appropriate bypass surveillance?

within 7 d
1month
3-6 months x 1 year
then 1-2 year

do this to increase patency. primary assisted patency

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where do you sample the bypass

sample every 2-3 cm of the graft

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what is the bypass graft stenosis criteria?

PSV sten/ PSV 2-4 cm prox

ratio >2 >50% stenosis
ratio >3 >75%
ratio >4 surgical intervention
EDV >100-120c,/sec severe stenosis

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What are normal velocities in bypass?

70-100cm/s

<45 should be monitored this is better predictor in ptfe then vein

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What are signs that graft is at increased risk?

triphasic-monophasic
PSV400 cm/sec
ratio >3.5

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what defines an aneurysm in LE?

50% increase in size from normal segment

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What is plethysmography?

indirect measurement of volume changes in the extremities. ABI is air. PVR
photo is for digits ppg

what is a normal PVR or ppg?

sharp upstroke with dicrotic notch

what happens to pvr or ppg with disease

loss of dicrotic notch
delayed upstroke
rounded waveforms

what are limitations to CW

can't determine depth
less sensitive then PW
can't determine direction
calcification can effect
room temp can effect

what size should BP cuff be

> 20% then limb diameter
narrow is falsely elevated
wide falsely low pressures

what are abi criteria?

>0.9 normal 0.4-0.9 mil to mod disease (0.70) <0.4 severe

what is the margin of error for ABI?

0.15

what is a normal high thigh /brachial index?

>1.2 0.8-1.2 inflow/prox dz <0.8 inflow occlusion/severe stenosis

what is normal changes between segmental pressure?

<20mmhg

what are some abi artifacts?

cuff mismatch non-compressible vessels patient movement improper angle

post exercise testing?

pressures after exercise every 2-3 minutes

post exercise changes, how long until return to normal for single level dz? multilevel

2-6 min | 10 min

what are normal post exercise changes? abnormal

increase in pressures | decreas in pressures

what if patient not able to exercise? what does single level, multilevel look like?

do reactive hyperemia. occlude vessels for 3-5 mins with cuff normal limb may also have a drop single 50%

when do we do toe pressure?

if non compressible ankle abnormal ankle level waveforms non-healing ulcers diabetic

what is a ppg that will still likely heal ulcer

>50 hhmg more

what is normal TBI?

>0.7 normal 0.4-0.69 mil-mod 0.2-0.39 severe <0.2 critical

what is tcpO2? | what abnormal

measure amount of o2 diffusing from the skin >35-40 good 10-35 intermediate <10 poor

what is normal worst brachial index? finger brachial index?

<0.9 | <0.7 abnormal

what stress manoeuvres can you perform in UE testing for TOS?

rest--90 degree arms-overhead raise military position-then turn head right and left any position that the have symptoms

how do you perform an allens test

ppg on 2 and 5th digits | asses rest, compression, after release

how do you test for raynauds?

baseline | ppg after ice water for 2-5 minutes

what are normal AVF hemodynamics?

low resistance, high flow, can be monophasic

how to measure AVF

``` native artery prox to AVF native artery distal to AVF anastomosis evaluate outflow superficial vein first 10cm of draining vein for branches ```

what is the ideal fistula

>4mm vein mean volume >500ml.min >600 for grafts depth less then 5mm

what are criteria for avf stenosis for artery

PSV at stenosis, then 2cm prox | 3:1 ratio = >50%

what are criteria for avf stenosis for draining vein/graft narrowing?

2:1 velocity ratio = >50%

what is criteria at venous anastomoso

2: 1 > 50% 3: 1 > 75% stenosis

What is arterial steal in an avf?

retrograde flow in the native artery distal to anastomosis because blood flow to area of least resistance gentle compression of avf shows a return of ante grade flow