duplex arterial scanning and interventional treatment

reasons for noninvasive arterial testing

arterial disease, pulsatile masses, suspected arterial trauma, angioplasty / stent placement

lower extremity arterial duplex imaging

aorta through entire limb

upper extremity arterial duplex imaging

innominate through entire limb

What are some limitations of lower extremity arterial imaging examination 

nonvisulization of iliac system because of bowel gas or obesity, shadowing because of calcification, imaging of popliteal trifurcation/anomalies, difficulty evaluation lesions distal to tight stenoses because of low velocities in these segments 

scanning technique document in

grayscale, color doppler and spectral doppler

normal color flow should 

completely fill the vessel lumen, be uniform and limited to lumen only 

abnormal color findings include 

aliasing, reduced flow channel, color bruit 

Spectral doppler is used as primary tool to caregorize ___

disease

record __ in all major vessels

PSV

When disease is present (stenosis), record ___ 

velocities - proximal, in, and distal to stenosis 

normal findings include

PSV that does not increase, normal, high resistive spectral waveform, triphasic

__ ___ can be used to help classify disease severity

velocity ratios

What are 3 major changes in the arterial waveforms 

increase in PSV > 100%, spectral broadening and turbulence, loss of reversal of flow 

abnormal findings PSV velocity ratio > 2 =

>50% stenosis

abnormal findings PSV velocity ratio >3 =

>70% stenosis

PSV > 300 cm/s suggests 

a severe stenosis 

hemodynamic information can influence ___ ____

patient management

percent stenosed <50

normal or mildly diseased

percent stenosis 50-69 

moderately  diseased  > 2 - 2.5 

percent stenosis 70-99

severely diseased >3-3.5

percent stenosis occluded

occluded - no flow

Waveform prox to stenosis 

normal - high velocity if severe 

waveform in a stenosis

high velocity

waveform right after stenosis

turbulent

waveform way after stenosis 

tardas parvus 

distal to a hemodynamically significant stenosis

more low resistance characteristics ( flow throughout diastole) delayed rise to peak systole

proximal to an occlusion

very high resistance pattern, antegrade flow component only during systole, no flow during diastole

contrast arteriography is considered 

The gold standard for diagnosis of arterial stenosis, can be used when duplex imaging is limited 

Treatments for PAD

aim to decrease patients symptoms and improve prognosis by preventing the risk of further cardiovascular events

PAD treatments can be categorized into 3 types

medical management/ conservative, endovascular, surgical

management / conservative treatments 

control risk factors, exercise, pharmaceutical agents  

endovascular treatments

revascularize limbs, endovascular procedures ( angioplasty, endografts, arthrectomy, thrombin injections)

surgical treatments 

bypass graft surgery, thrombectomy, enterectomy 

What is angioplasty

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

What is an atherectomy

a procedure that utilizes a catheter with a sharp blade on the end to remove plaque from a blood vessel.

What is a stent 

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

What are the types of bypass grafts

prosthetic (synthetic) bypass graft, autogenous vein

Prosthetic ( synthetic ) bypass graft is

made of varus manufactured materials (PTFE, dacron)

Associated with poor long term patency rates

autogenous vein

preferred graft material

better long term patency rates

must be carefully monitored in short term for early complications and failure

Autogenous : in situ bypass graft

vein being used for bypass graft is left in its original anatomic position, usually the great saphenous vein

branches must be ligated

Autogenous : in situ bypass graft - vavles must be ___ 

layzed to allow blood to flow downward 

Autogenous : in situ bypass graft large end of the vein -_

anastomosed to large end of artery: small end of veun anastomosed with small end of artery ( better size match)

orthograde involves

lyzing valves

retrograde involves 

flipping the vein, valves do not need to be removed = - large end of vein now astomosed to small end of artery and vice versa 

bypass graft placement is determined by —

level of arterial disease - prox anastomosis will be above disease, typically at CFA or SFA

distal anastomosis will be ___

below disease - typically at popliteal artery or tibial artery (PTA, ATA, or peroneal)

bypass graft relates to ___ 

level of disease 

fem pop -

SFA disease

fem tibial

multiple levels of disease below the CFA

fem - fem 

iliac disease 

Ax - Fem - fem -

extensive aortoiliac disease

Aorto- bifem -

distal aortoiliac disease

routine surveillance protocol usually consists of 

6 week, 3 - 6 months 

first year - surveillance every 3 months 

second year - surveillance every 6 months 

annually thereafter 

direct scanning is used in conjunction with ___

indirect physiologic testing

graft failure within 30 days

retained valve or valve leaflet, intimal flap, suture defect, graft entrapment due to improper positioning, thrombosis

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 this postoperative period. 

graft failure after 24 months

progression of atherosclerotic disease in inflow or outflow vessels

aneurysmal dilation (conduit or anastomotic site)

Normal walls od vein graft should appear

smooth and uniform - intimal - medial layer should be visible

PTFE grafts have a distinctive - 

double line appearance of graft wall  - should also be smooth and uniform 

retained valves -

valve or valve remnants that remain due to incomplete valve disruption during surgery

larger remnants or valve leaflets can produce flow - limiting stenosis

appears as bright echoes within graft lumen

myointimal hyperplasia

rapid proliferation of cells into intimal layer

can occur any point along bypass conduit

typically occurs in areas where vein has sustained injury or valve sinus

can result in stenosis

normal bypass should demonstrate ____

multiphasic waveforms with sharp upstroke and narrow systolic peak 

Forward flow in diastole may also be an indication of___

hyperemia or arteriovenous fistula - sharp upstroke will be maintained

stenosis categorization in bypass graft - normal velocities are typically

below 150 cm/s

stenosis categorization in bypass graft - PSV >

180 cm/s considered abnormal

stenosis categorization in bypass graft - PSV velocity ratio of 2 consostant with

> 50% stenosis (PSV 180-300 cm/s)

stenosis categorization in bypass graft - PSV ratio of 3.5 and PSV of 300 cm/s consistant with

> 75% stenosis

peripheral arterial aneurysms are most commonly presented in the

popliteal artery

although unlikely to rupture, peripheral arterial aneurysms can be limb threatening due to ____ 

distal embolization which occurs in approximately 35% of cases left untreated 

pseudoaneurysm is a

perivascular collection that communicates with artery or graft and has presence of pulsating blood entering collection

___ of variable length connects native vessel to collection

track ( neck )

pseudoaneurysm may be ___ or ____ and may partially contain __ 

unilocular, multilocular, thrombus 

is risk of rupture in pseudoaneurysms >

3cm

treatments for pseudoaneurysms

compression therapy, ultrasound guided thrombin injection, surgery.