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Vascular 2 > Module 8 : Peripheral Arterial System Part 3 > Flashcards

Module 8 : Peripheral Arterial System Part 3 Flashcards

1
Q

what are the 3 roles of ultrasound in arterial bypass and stent surveillance duplex exam

A
  • establish baseline hemodynamics post revascularization
  • identify correctable lesions before graft thrombosis
  • provide information to aid in decision regarding treatment alternatives
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2
Q

what are 7 indications for graft/stent exam

A
  • post op follow up
  • new symptom of claudication or something
  • decreased ABI >0.15 compared to previous exam
  • absent peripheral pulses
  • pulsatile mass near an anastomotic site or intervention site
  • digital cyanosis
  • dependant rubor
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3
Q

what are 4 different types of bypasses/stents

A
  • aorta-iliac
  • aorto-fem
  • ax-fem
  • fem-fem
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4
Q

what are the 2 types fo lower extremity venous grafts

A
  • PTFE

- Dacron

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5
Q

what is an autogenous bypass

A
  • vein bypass
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6
Q

what are the 2 types of vein bypasses

A
  • in-situ vein

- reversed vein

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7
Q

what is an in-situ bypass

A
  • vein left in original location with valves cut and branches ligated
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8
Q

what is a reversed vein bypass

A
  • vein is ligated reversed and attaches to arteries
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9
Q

what are the 4 common autogenous veins commonly used

A
  • GSV
  • SSV
  • basilic vein
  • cephalic vein
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10
Q

what are the 3 modified biologic grafts

A
  • human umbilical vein
  • cryopreserved saphenous vein
  • bovine
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11
Q

what is a composite graft

A
  • synthetic graft connected to a vein
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12
Q

what are the 3 types of bypass anastomoses

A
  • end to end
  • end to side
  • side to side
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13
Q

what are 9 mechanisms of graft failure

A
  • early graft failure <30 due to errors in bypass construction
  • intimal hyperplasia can cause stenosis 1-2years
  • atherosclerotic progression can cause stenosis > 2years
  • undiagnosed hyper coagulable disorder
  • infection
  • aneurysmal detection
  • trauma to thrombosis
  • thromboembolism
  • early graft failure
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14
Q

what are 2 mechanisms of stent failure

A
  • stenting used to create complicated lesions and technical failures can occur <30days
  • recurrent stenosis >30days
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15
Q

where can disease be located in LE grafts

A
  • focal or diffuse

- one or multiple levels

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16
Q

what are 5 common location of graft obstruction

A
  • valve site
  • anastomoses
  • inflow tract
  • outflow tract
  • graft kink
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17
Q

what are the locations of images for graft/stent evaluation

A
  • inflow prox native artery
  • prox anastomiss
  • prox graft/stent
  • mid graft/stent
  • distal graft/stent
  • distal anastomoses
  • outflow dist native artery
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18
Q

why might the wave flow pattern early post op be low resistance

A
  • reactive hyperaemia
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19
Q

what should we analyze when there is a graft stenosis

A
  • ABI or TBI
  • PSV and flow direction
  • velocity ratios
  • waveform patterns and changes
  • image data
20
Q

what determines the severity of a graft stenosis

A
  • graft material
21
Q

what would a normal grayscale & color look like in a graft/stent

A
  • no intraluminal echoes
  • color fills the lumen from wall to wall in SAG and TRV
  • synthetic grafts have double line wall
  • stent walls seen within lumen but difficult in deeper grafts
22
Q

what is the waveform and VR of the inflow artery normally

A
  • triphasic

- Vr < 2.0

23
Q

normal characteristics of proximal anastomoses site

A
  • Vr < 2
  • bifurcations and branches have disturbed patterns
  • large inflow artery feeding a small diameter graft to produce higher Vr
  • asses for intraluminal echoes
24
Q

normal PSV and Vr in the body of a graft

A

< 180 cm/s

Vr < 2.0

25
Q

normal sized PSV of vein graft body

A
  • = 4mm

- PSV > 40-45 cm/s

26
Q

normal PSV and Vr in body of stent

A

< 190cm/s

Vr < 1.5

27
Q

normal waveform pattern in body of stent/graft

A
  • same as inflow artery through non obstructed graft
28
Q

what is the normal characteristics of the distal anastomosis site

A
  • size change from larger vessel to smaller vessel increases velocity
  • Vr < 3.0
  • asses for intraluminal echoes
  • may see disturbed pattern
29
Q

normal outflow artery characteristics

A
  • velocities unchanged
  • Vr < 2.0
  • waveforms similar to graft/stent body
30
Q

what would indicate an abnormal graft/stent

A
  • decrease ABI < 0.15 indicates disease progression
31
Q

what would be an abnormal grayscale & color with grafts/stents

A
  • lumen reduction
  • color doesnt fill lumen from wall to wall
  • aliasing within stenosis
  • residual valve cusps in vein grafts
  • aneurysmal dilatations and thrombus
32
Q

what would indicate and abnormal inflow artery in a graft/stent

A
  • Vr > 2.0
  • post stenotic turbulence
  • waveform changes with hemodynamically significant lesion
  • significant inflow artery obstruction is indicated by monophasic waveform
33
Q

what would be the characteristics of a hemodynamically significant stenosis in the prox anastomosis

A
  • Vr > 2.0
  • increased PSV
  • spectral broadening
  • post stenotic turbulence
  • echogenic material
34
Q

PSV and Vr in > 50% stenotic graft body

A

PSV 180cm/s

Vr > 2.0

35
Q

PSV and Vr in > 70% stenotic graft body

A

PSV > 300 cm/s

Vr > 3.5

36
Q

PSV and Vr in > 50% stenotic stent body

A

PSV > 190cm/s

Vr > 1.5

37
Q

PSV and Vr in > 70% stenotic stent body

A

PSV > 275 cm/s

Vr >/= 3.5

38
Q

what is impending vein graft failure indicated by

A

PSV < 40-45 cm/s

39
Q

what is an obstruction in the inflow tract indicated by

A
  • monophasic waveform in the graft
40
Q

what is a distal anastomoses or outflow tract obstruction indicated by

A
  • high resistance waveform pattern

- no end diastolic velocity and staccato pattern

41
Q

what would the Vr be in a > 50% stenosis in distal anasotmese site

A

Vr > 3.0

- post stenotic turbulence and distal waveform changes

42
Q

what determines the the severity of the stenosis

A
  • graft material
43
Q

what would indicate a graft/stent occlusion

A
  • no flow by spectral or color

- intraluminal echoes seen

44
Q

what are 3 other pathologies

A
  • pseudoaneuryms
  • aneurysmal dilation
  • entrapment of a graft
45
Q

what is a pseudoaneurysm

A
  • pulsatile mass identified by color and doppler sen to communicate with bypass or native artery through a patent neck
46
Q

what is aneurysmal dilatation

A
  • focal enlargement twice the proximal arterial segment

- intraluminal thrombus within the aneurysm

47
Q

what is an entrapment pf a graft

A
  • can occur at the knee
  • with the leg slightly bent normal flow seen
  • with the leg straight no flow is detected

Vascular 2 (9 decks)

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