Unit 2 Duplex Arterial

normal artery appearance in 2D

anechoic, smooth, defined borders, filled from wall to wall on doppler

abnormal color findings

aliasing

reduced flow channel

color bruit (turbulence)

normal spectral findings

PSV that doesn’t increase

normal, high resistance waveform

triphasic

help classify disease severity

velocity ratios

arterial waveform change with disease

PSV increase > 100%

spectral broadening and turbulence

loss of reversal of flow

PSV velocity ratio and % of stenosis

PSV velocity ratio ≥2 = ≥50% stenosis

PSV velocity ratio ≥3 = ≥70% stenosis

PSV > 300 cm/s suggest a severe stenosis

normal or mildly diseased stenosis

< 50%

PSV ratio < 2

moderately diseased stenosis

50-69%

PSV ratio ≥ 2.0 - 2.5

severely diseased stenosis

70-99%

PSV ratio ≥ 3.0 - 3.5

occluded stenosis

no flow

waveform distal to significant stenosis

more low resistance characteristics (flow throughout diastole)

delayed upstroke

waveform proximal to occlusion

very high resistance pattern 

antegrade flow component only during systole

no flow during diastole

gold standard for diagnosis of arterial stenosis

contrast arteriography

management / conservative treatment for PAD 

control risk factors

exercise

pharmaceutical agents

endovascular treatment for PAD

revascularize limbs

endovascular procedures

endovascular procedures

angioplasty

endografts

atherectomy

thrombin injections

surgical treatment for PAD

bypass graft surgery

thrombectomy

endarectomy

most common treatment for PAD

bypass graft surgery

angioplasty

uses a balloon tipped catheter to open a blocked blood vessel and improve blood flow

atherectomy

utilizes a catheter with a sharp blade at the end to remove plaque from a blood vessel

stent

tiny expandable mesh tube that can be inserted into a blocked passageway to keep it open

Prosthetic (synthetic) bypass grafts

Made of various manufactured materials (PTFE, Dacron)

graft associated with poor long-term patency rates

Prosthetic (synthetic)

autogenous vein bypass graft

Vein is taken from the patient’s body and used as a bypass and must be carefully monitored in short term for early complications and failure

preferred graft material

autogenous vein

graft with better long-term patency rates

autogenous vein graft

autogenous: in situ

vein being used for bypass is left in its original anatomic position

valves must be lyzed to allow blood to flow downward

large end of vein is anastomosed to large end of artery, visa versa for better size match

vein usually used in autogenous grafts

great saphenous

autogenous: orthograde

involves lyzing valves

autogenous: retrograde

involves “flipping” the vein so valves do not have to be removed

large end is anastomosed to small end and visa versa

graft placement determined by

level of arterial disease

routine surveillance protocol usually consists of 

begins with 6 weeks, 3-6 months

first year: surveillance every 3 months

second year: surveillance every 6 months

annually thereafter

mechanism of graft failure within 30 days

retained valve or valve leaflet

intimal flap

suture defect

graft entrapment due to improper positioning

thrombosis

mechanisms of graft failure between 1 and 24 months

myointimal hyperplasia can develop, creating stenosis

stenosis at proximal or distal anastomosis 

most common cause of graft revision in the postoperative period between 1 and 24 months

stenosis at proximal or distal anastomosis

mechanisms of graft failure after 24 months

progression of atherosclerotic disease in inflow or outflow vessels

aneurysmal dilation

aneurysms more common at _____

anastomosis

appearance of normal walls of vein graft

smooth and uniform

intimal-medial layer should be visible

appearance of PTFE graft 

smooth and uniform

distinctive double line appearance

appearance of retained valves

bright echoes within graft lumen

myointimal hyperplasia

rapid proliferation of cells into intimal layer

typically occurs in areas where vein has sustained injury or valve sinus, but can occur at any point along bypass conduit

waveforms demonstrated by normal bypass

multiphasic waveforms with sharp upstroke and narrow systolic peak

may be an indication of hyperemia or arteriovenous fistula

forward flow in diastole (sharp upstroke maintained)

Normal velocities

below 150 cm/s

abdnormal PSV

> 180 cm/s

Velocity ratio of 2 consitent with 

≥ 50% stenosis 

PSV 180-300 cm/s

Velocity ratio of 3.5 consitent with

≥ 75% stenosis 

PSV > 300 cm/s

most commonly present in popliteal artery

peripheral arterial aneuryms 

risk of peripheral arterial aneurysms

threatening to limbs due to embolization

most common cause for pseudoaneurysm

trauma or puncture

risk of rupture in pseudoaneurysms

> 3cm