Week 9: Lower Extremity Arterial Scanning Flashcards
CHRONIC ATHEROSCLEROTIC OBSTRUCTIVE DISEASE
- Individuals usually suffer from ____
- Pain is most located in the ____
- Arterial obstruction will be ____ to the site of claudication symptoms
- claudication
- calf
- proximal
FLOW CHARACTERISTICS: STENOSIS
- Pre stenotic: flow velocity is _____
- At the site of stenosis, flow _____ within the stenosis and becomes turbulent distally
- Arterial stenosis eliminates the ____ phase
- Flow distal to the stenosis or post stenotic can be characterized as _____
- decreased
- accelerates
- diastolic
- biphasic or monophasic
FLOW CHARACTERISTICS: STENOSIS
- Proximal pulsatility changes, flow velocity ____
- ____ velocity in the stenotic zone
3.____ flow in the post stenotic zone
4.Distal pulsatility changes, flow velocity decreased, ____ waveform noted
- decreased
- Increased
- Disturbed (turbulent)
- tardus-parvus
FLOW CHARACTERISTICS: STENOSIS
Always take a PW sample prestenosis, at the area of stenosis, and post stenosis
ARTERIAL STENOSIS GRADING
- ____ - Divide the maximum PSV recoded across the stenosis by the PSV recoded in a normal area of the artery just proximal to the stenosis
2.____: focal doubling of the velocity suggests a > 50% arterial stenosis (If the maximal stenotic PSV doubles the pre stenotic PSV)
- Peak systolic velocity ratio
- Rule of thumb
ARTERIAL STENOSIS GRADING
Jean Ellison at Cedars-Sinai Medical Center in LA:
> 2:1 ratio for ____ stenosis
> 50%
ARTERIAL STENOSIS GRADING
Jean Ellison at Cedars-Sinai Medical Center in LA:
> 4:1 ratio for ____ stenosis
> 75%
ACUTE ARTERIAL OCCLUSION
- Symptoms are ____, severely ____, and _____
- _____ have not had time to develop
- immediate, painful, cyanotic
- Collaterals
*note: no color/PW Doppler flow or collaterals formes yet
What are the causes of acute arterial occlusion? (2)
- Thrombotic: from thrombus formation at an aneurysm or pseudoaneurysm
- Embolic: from thrombus or other material traveling from a proximal level to plug a stenotic segment of the artery
HEMATOMA VS PSEUDOANEURYSM
What are they caused by?
Both can occur after a patient undergoes a cardiac catheterization procedure
Both are caused from the artery not closing well after accessing the femoral artery resulting in
blood escaping into the surrounding tissues
What are the difference between hematoma and pseudoaneurysm?
Hematoma
- blood escaped the artery then clots and forms a mass
- homogenous and grainiy appearance sonographycally
- DO NOT have blood flow within
Pseudoaneyrysm
- blood continues to flow into and out of a discrete area in the tissue through the interrupted arterial wall (fails to seal)
- Sonographically the color flow pattern will look like a “yin-yang symbol”
- Treated by ultrasound guided thrombin injection
What is this?
hematoma
What is this?
pseudoaneurysm
*key is to find the neck. notice that there’s severe aliasing, it won’t close its own unless applying the pressure or use thrombin to clot the blood
- PW Doppler waveform within the pseudoaneurysm will demonstrate a____ pattern
- Systole- ____ flow through the neck/tract into the pseudoaneurysm
- Diastole- ____ flow out of the pseudoaneurysm due to the pressure being higher in the pseudoaneurysm than in the arterial lumen
- “to-fro” flow *note: “to-fro” or “to and fro” - constant movement backward and forward.
- antegrade
- retrograde
What are the 2 common treatment for pseudoaneyrysm?
- Thrombin injection-most common
- Hold transducer pressure over the area
What is this?
arteriovenous (AV) Fistula
What is AV fistula?
An abnormal communication between an artery and a vein
*appears arterial flow/pulsatation in veins = a sign of AV fistula
AV Fistula:
1. can be ____ or ____
2. Caused when the ____ and ____ are punctured simultaneously
3. It can steal flow from distal circulation, causing ____
4. In severe an AV fistula it can reduce distal resistance so significantly it can cause some degree of ____
5. Most close on their own, do not need surgical intervention
- congenital or acquired (from a femoral stick at cardiac cath)
- artery, vein
- ischemic symptoms
- heart failure
ARTERIOVENOUS (AV) FISTULA
1.Blood typically shunts from the ____ into the ____ at the site of the fistula
2.Loss of the triphasic waveform within the artery ____ to the fistula
3.Decreased blood flow within the artery ____ to the fistula
4.Increased pulsatile blood flow within the vein ____ to the fistula
- artery, vein
- proximal
- distal
- proximal
BYPASS GRAFT SURVEILLANCE
- Checks for graft ____ and to try to spot impending graft failure
- Easily ____ and ____
- Better to repair a narrowed graft than to start all over with a new one
- Most lower extremity grafts are made using the patient’s ____*Better patency rate than synthetic material
- patency
- repeatable, harmless
- greater saphenous vein (GSV)
When a vein graft is not possible surgeons use a synthetic material
- ____: sonographically has *a double-wall appearance
- ____: sonographically has a fuzzier, wavy/woven appearance
- Gore-Tex
- Dacron
What is this?
Gore-tex
*double walls
What is this?
Dacron
BYPASS GRAFTS
Grafts using the patient’s own GSV have 2 configurations (2 ways to get around the problem if valves allowing flow to only go cephalad)
What are 2 configuration?
- in situ
- reversed
LOWER EXTREMITY BYPASS GRAFTS: TYPES (5)
-
Aortoiliac and aortofemoral
-Provide flow around inflow obstructions
-Frequently bilateral -
Femrofemoral
-Used when the iliac artery on one side is severely obstructed -
Axillofemoral
-Run from the axilla artery down to the common femoral artery
-Commonly used in combination with femrofemoral grafts -
Femropopliteal
-Run from the common femoral artery down to the popliteal artery
-Usually used to bypass obstructions in the superficial femoral artery
5.** Femrotibial and popliteal-tibial**
-Can be used to try to perfuse a foot that is threatened by ischemia
BYPASS GRAFT SURVEILLANCE
- ____ : the attachment or connection of one vessel to another
- Most common type of anastomosis in the lower extremities is the ____ (The end of the graft is joined to the side of the native artery).
- Obstruction often develops at the ____ and ____ anastomoses due to the altered hemodynamics in these areas
- ____ more commonly due to the** lower velocities** there
- ____ sites also promote obstructive disease
Spectral velocities can be high within a graft shortly after it is installed, and lower over time
- Anastomosis
- end-to-side
- proximal, distal
- Distal
- Valve
What type of graft is this?
end-to-side
most common type of graft
femropopliteal
What type of graft is used to bypass obstruction in the superficial femoral artery?
femropopliteal
What type of graft is used to perfuse a foot that is threatened by ischemia?
femrotibial or popliteal-tibial
What type of graft commonly used with femrofemoral grafts?
axillofemoral
What type of graft is used when the iliac artery on one side is severely obstructed?
femrofemoral
What type of graft is used to provide flow around inflow obstruction and frequently bilatreral?
aortoiliac or aortofemoral
