URR Carotid Disease

Question 1

as area of vessel decreases what happens to velocity?

Answer 1

increases

Question 2

flow changes direction as it enters and leaves stenosed portion causing what?

Answer 2

turbulence and spectral broadening

Question 3

most common reason for underestimation is what?

Answer 3

improper sample volume location

Question 4

what happens in the pre stenotic zone?

Answer 4

-increase resistance and RI
-flow velocity may be dampened with loss of diastolic
-short acceleration time

Question 5

what happens in the stenotic zone?

Answer 5

-increase PSV
-increase diastolic
-decrease pressure
-spectral broadening
-highest velocity detected within stenosis or just distal

Question 6

what happens in the post stenotic zone?

Answer 6

-turbulence
-decreased resistance
-increase diastolic

Question 7

what happens distal to critical ICA stenosis?

Answer 7

-diastolic and systolic flow will be low velocity with blunted waveform
-slow acceleration time
-tardus parvus

Question 8

normal waveform of CCA?

Answer 8

low resistive
-more than 30 cm/s difference in PSV between rt and lt CCA can indicate issue

Question 9

CCA with reduced velocity, slow upstroke and holodiastolic flow means what?

Answer 9

stenosis prox

Question 10

CCA with reduced velocity, quick upstroke and minimal diastolic flow reversal means what?

Answer 10

occlusion distal

Question 11

CCA with elevated velocity means what?

Answer 11

tortuosity on that side or compensatory flow due to obstruction in other CCA

Question 12

increased velocity in bilat CCAs means what?

Answer 12

-overestimated carotid stenosis
-systemic HTN
-increased cardiac output
-decreased hematocrit
-mild to moderate AO stenosis

Question 13

decreased velocity in bilat CCAs means what?

Answer 13

-underestimated carotid stenosis
-CHF
-decreased cardiac ejection fraction\
-severe AO valve stenosis
-increased hematocrit
-polycythemia vera

Question 14

bilat CCA with increased diastolic flow reversal can indicate what?

Answer 14

significant Ao valv regurg

Question 15

intra AO balloon pump (IABP)

Answer 15

-have 2 systolic peaks
-1st peak = lt vent contraction
-2nd peak = balloon inflation
-EDV cannot be determined
-flow reversal commonly seen
-if possible, turn off for CCA eval

Question 16

lt vent assist device (LVAD)

Answer 16

-have decreased velocity flow
-CCA waveforms vary due to device
-waveform cant be evaled

Question 17

high resistance
-minimal to mild antegrade diastolic flow
-may have flow reversal at end of systole
-PSV normal <150 cm/sec

Answer 17

ECA

Question 18

ipsilat ICA occlusion can cause what to happen to ECA flow?

Answer 18

can become low resistive

Question 19

ipsilat CCA occlusion can cause what to ECA flow?

Answer 19

can cause ECA flow to reverse so it can supply flow to the ICA

Question 20

most accurate doppler predictor of the ICA stenosis is the what?

Answer 20

EDV

Question 21

nomal psv <125 cm/s and EDV < 40 cm/s
-as stenosis increases = PSV + EDV will increase

Answer 21

ICA

Question 22

highest ICA velocity is where in the vessel?

Answer 22

first 3 cm

Question 23

highest CCA velocity is where in the vessel?

Answer 23

first 3 cm

Question 24

compares the highest ICA to the distal CCA

Answer 24

systolic velocity ratio (SVR)
-higher ratios indicate stenosis
-when stenosis is present in the CCA, use highest normal CCA in the ratios

Question 25

compares highest end diastolic velocity to the end diastolic velocity in the distal CCA?

Answer 25

diastolic velocity ratio (DVR) -higher ratios indicate stenosis -when stenosis is present in the CCA, use highest normal CCA in the ratios

Question 26

indirect doppler criteria for significant ICA stenosis

Answer 26

-internalization of the ECA (becomes low resistive) w/ flow reversal in opthal A -collat flow noted in TCD exam such as cross filling in anterior or posterior communicating a -decreased blunted flow in one MCA

Question 27

critical stenosis

Answer 27

-near occlusion that should be treated -significant stenosis that demonstrates small amount of flow through narrowed segment -string flow sign -flow velocity very low with decreased pulsatility -bruit not usually present

Question 28

vertebral artery waveform

Answer 28

-low to medium velocity, low resistance -variations in flow velocity between left and right is normal, left usually dominant -stenosis usually occurs in prox A -loss of diastolic flow indicates a dist occlusion

Question 29

early systolic deceleration in the vert a is a sign of what?

Answer 29

subclavian a stenosis

Question 30

subclavian artery waveform?

Answer 30

-normal high resistive -right and left should be compared for expected similarity -biphasic or monophasic waveform are associated with stenosis or occlusion

Question 31

ulceration of plaque

Answer 31

-very difficult to identify -formation of a crevice within the atheroma deposit -leads to the formation of a protruding edge of the atheroma that could be sheared off by blood flow becoming an embolism

Question 32

soft plaque has the greatest risk of what?

Answer 32

embolization -complex and calcific plaque becomes increased in fibrous tissue and more easily adheres to vessel walls

Question 33

when an artery is occluded the risk of what drops?

Answer 33

risk of future stroke drops significantly when what?

Question 34

horizontal motion of vessel wall instead of wall pulsation and no flow indicates what?

Answer 34

carotid occlusion

Question 35

what happens to resistance prox to occlusion

Answer 35

increase -flow velocity decreases too (thump flow, stump flow, or thud flow)

Question 36

diagnostic criteria for carotid occlusion?

Answer 36

-absent flow in dist ICA -increase resistance, peaked waveform with absent diastolic flow or reversal prox -decreased blunted flow in ipsilat MCA -decreased resistance with increased diastolic flow in ipsilat ECA -evidence of collats

Question 37

-during occlusion or stenosis, flow velocities in contralat carotid will be increased -if also occluded on ipsilat, stenosis may be overestimated -can look like CCA velocities, are increased on side with stenosis and diminished on side with occlusion -the ICA/ CCA ratio indicates lower level of stenosis than velocity criteria

Answer 37

compensatory flow

Question 38

what is a carotid compression test?

Answer 38

-performed by physician only -used to eval presence of collat formation -compress unilat CCA for about 5 mon, if no symptoms occur, cerebral collats are present

Question 39

what are the false positives for stenosis?

Answer 39

-increased cardiac output -vessel tortuosity -inappropriate angle of insonation -compensatory flow

Question 40

false negatives for occlusion?

Answer 40

-improper sample location -low cardiac output -stenosis at bulb -inappropriate angle of insonation -doppler angle > 60degrees -incorrect placement -collat formation