quiz 3 Flashcards
what is the gold standard for preoperative assessment of patients for carotid intervention?
arteriography
what are some non-invasive techniques?
- MRA
- Duplex and TCD combined
- CT
discribe non-invasive techniques
- No contrast used
- No catheter related complications
is arteriography invasive?
yes-catherdar based
what does arteriography assess?
the aortic arch,subclavian and carotid arteries(intracranial and extracranial vessels)
what are reported complications in arteriography?
Stroke and death are reported complications in 0.2- 0.7% of patients
plain CT
Provides 2 and 3 dimensional images to -identify silent infarcts
- determining the timing of surgery
- evaluating the risk of surgery
- ruling out other causes of disease or symptoms
CTA
- Invasive
- Administration of contrast dye
- Highlights the cerebrovascularity
Digital subtraction angiography
pre contrast image is taken and as dye is injected, it subtracts out the pre image and only filled vessels are seen
what is the method of choice for visualizing the entire cerebral arterial system?
Digital subtraction angiography
is MRA invasive?
no
what is MRA accurate at identifying?
carotid occlusion
is MRA or duplex dopper more reliable for categorizing stenosis in areas of moderate to severe narrowing?
duplex doppler and angiography
in MRA what can it overestimate?
where flow is turbulent
what s angioplasty?
technique of mechanically widening narrowed or obstructed arteries typically being a result of atherosclerosis
what is placed into narrowed locations in angioplasty?
An empty and collapsed balloon on a guide wire, known as a balloon cathete
how is the cathedar inflated in angioplasty?
inflated to a fixed size using water pressures some 75 to 500 times normal blood pressure
what happpens to plaque in angioplasty?
The balloon forces expansion of the inner plaque deposits and the surrounding muscular wall, opening up the blood vessel for improved flow
if an artery is not strong enough to stay open after balloon is deflated and taken out, what is done?
a stent would be inserted at the time of ballooning to endure the vessel remains opens
what can placement of stent alter?
biochemical properties
what can a stent cause with flow?
- increase in velocities
- some turbulence
- PSV can increase throughout the patent stent area up to 150cm/s
what is considered not norma for PSV in a stent?
Gradual PSV increase is expected,but an abrupt increase is not normal
what velocity in a stent identifies a degree of restenosis?
2:1 ratio
what must you obatin in a post stent assessment?
prestent, mid stent, post stent
what is the stent assessed for?
- intimal thickening
- plaque formation
- thrombus to diagnose restenosis
what is gray scale useful for?
evaluate deformity in stent (kinks, buckling)
what do vascuar surgeons recommend as the first line treatment?
CEA (endartectomy)
when is CEA done on a patient?
- For most symptomatic patients with stenosis of 50% to 99%
- And asymptomatic patients with stenosis of 60% to 99%
The perioperative risk of stroke and death in asymptomatic patients must be __________to ensure benefit for the patient
<3%
who should CAS (stenting) be reserved for?
symptomatic patients with stenosis of 50% to 99% at high risk for CEA for anatomic or medical reasons
who is CAS not recommended for?
asymtomatic patients
Asymptomatic patients at high risk for intervention or with _______ life expectancy should be considered for medical management as the first-line therapy
<3 years
what significantly reduces risk of major and fatal stroke in patients with symptomatic, high-grade (70-99%) carotid stenosis?
carotid endartectomy in addition to medical therapy
how is CEA done?
The surgeon will make a cut in the blocked part of the artery to remove the plaque, or will remove the inner lining of the artery around the blockage
what may a surgeon do in a CEA to block blood flow?
- A clamp is placed on the artery to stop blood from flowing through it
- A tube may also be used to shunt blood around the narrowed or blocked carotid artery
how does blood get to the brain during a CEA?
from the contralateral carotid artery or can be from a shunt
when may a patch be placed over a cut?
if the patient has small arteries or has already has a CEA
what does a patch do?
reduce the risk of stroke for some patients
post CEA what needs to be ruled out?
restonosis followung revascularization
where does PSV increase when doing a post CEA assessment?
pre CEA area and within stenosis
what is gray scale useful for in a post CEA stenosis?
evaluate for changes in the vessel wall consistent with sutures,patches,stent material,early intimal proliferation or late atherosclerotic plaque formation
what are complications associated with CEA?
- Residual plaque at the end of the CEA site
- intimal flap
- dissection
- occlusion
- infected patch
- hematoma
- pseudoaneaursym
- restenosis
Residual plaque at the end of the CEA site
Color and spectral Doppler may display turbulence or elevated PSV depending on severity
Intimal flap
- Disruption along the vessel wall with moving material observed within the lumen
- Disturbed color flow patterns and elevated PSV often present
dissection
Intimal layer separates from the wall and may stenose or occlude vessel
occlusion
No color fill in
- no lumen detected
- no spectral Doppler signal
Infected patch
Irregular buckling of patch material along the vessel wall;perivascular fluid accumulation
Hematoma
Nonvascular mass adjacent to the vessel;may appear cystic or contain various levels of echogenicity
Pseudoaneurysm
Dilated area attached to the vessel with flow demonstrated on color and doppler spectrum: to- and-fro pattern with a neck connecting to the vessel
-colour swirling (ying-yang appearance)
restenosis
Focal area of elevated velocities with poststenotic turbulence;hyperplasia along the wall in the stenotic zone
what does coarctation mean?
narrowing
what isAortic coarctation-CoA or COAo?
congenital condition whereby the aorta is narrow
where is Aortic coarctation-CoA or COAo most common?
aortic arch
- usually in area where ductus arteriosus ((ligamentum arteriosum after regression) inserts
- May be pre or post ductal
how do you detect an Aortic coarctation-CoA or COAo?
Difference of 70 mmHg or more between the brachial and ankle systolic pressures at rest
what could happen to patients with coarctation of the thoracic aorta?
may not have claudication and little or no change in ankle pressure following exercise
why may thoracic aorta coarctation have no change in ankle pressur following exercise?
This is due to the development of extensive
collateralization that provides
compensatory flow to the exercising muscles of the lower limbs
what is the repair of coarctation?
resection and end-to end anastomosis
angioplasty can be used
when is resection and end-to end anastomosis technique used?
widely especially in older children and older adults
describe the repair of coarctation?
The aorta is transected proximal to the coarctation at a level that ensures removal of any narrowed portion of the isthmus as well as the coarctation
what is a stroke caused by?
- atrial fibrillation
- hardening of arteries
- high blood pressure
what are some rare causes of a stroke?
- vasospasm
- FMD
- radiation induced vasculopathy
what is an ischemic stroke?
strokes occur as a result of an obstruction within a blood vessel supplying blood to the brain`
what is the underlying condition for ischemic stroke?
atherosclerosis-fatty deposits lining the vessel walls
what are 2 types of obstruction that may occur with ishemic stroke?
- cerebral thrombosis
- cerebral embolism
cerebral thrombosis
thrombus(blood clot) that develops at the clogged part of the vessel in the brain- from atherosclerosis
what is a cerebral embolism?
Refers generally to a blood clot that forms at another location in the circulatory system
- a portion of the blood clot breaks loose,enters the bloodstream and travels through the brains blood vessels until it reaches a vessel too small to let it pass
where does the blood clot in cerebral embolism come from?
usually from heart or larger arteries of the neck such as carotids
what is a vasospasm?
blood vessel spasms or contracts causing less blood flow
when may cerebral (brain) vasospasm happen?
after an operation for a bleed that occurs between the brain and the thin tissue covering the brain (subarachnoid hemorrhage)
what increases the risk of an ischemic stroke?
cerebral vasospasm
when does vasospasm typically occur?
4-10 days after subarachnoid hemorrhage
`
what is arteriovenous malformations (AVMs)
When an arteriovenous malformation (AVM) occurs, a tangle of blood vessels in the brain or on its surface bypasses normal brain tissue and directly diverts blood from the arteries to the veins
`
how many people usualy get a AVM?
1% (200-500 people)
who are AVM’s more common in?
males
what are the symtoms to a AVM in more than 50% of patients?
intracranial hemorrhage
what are the symtoms of a AVM in 20-25% of patient?
focal or generalized seizures
what is a symtoms wit the head that patients with AVM have?
localized pain in the head due to increased flow around an AVM
what may 15% of patients have difficutly with for an AVM?
difficulty with movement, speech, or vision
what are the chances of having an AVM bleeding?
1% to 3% percent each year
what is a cerebral aneurysm?
a weak or thin spot on a blood vessel in the brain that balloons out and fills with blood
what can a bulging aneurysm put pressure on?
a nerve or surrounding brain tissue
who does brain aneurysms occur in?
anyone, at any age but more common in adults than children
where os cerebral aneurysms more common in?
women
adults (30-60)
who is at a higher risk for cerebral aneurysm?
people with certain inherited disorders
what do all cerebral aneruyms have a potential of?
rupture and cause bleeding within the brain
what are the risk factors for cerebral aneurysms?
- hypertension
- alcohol abuse
- drug abuse (mainly cocaine)
- smoking
what affects the risk of rupture?
the condition and size
when an cerebral aneurysm bursts and bleeds into the brain, what complications can this cause?
- hemorrhagic stroke
- permanent nerve damage
- death
- more commonly: subarachnoid hemorrhage
what is a subarachnoid hemorrhage?
bleeding into space between skill bone and brain
what is a second importnt cause of cerebral embolism?
irregular heartbeat known as “atrial fibrillation”
what does atrial fibrillation cause?
creates conditions where clots can form in the heart and dislodge and travel to the brain
_____of patients with cerebrovascular events will have a cardiac thrombus as the source of emboli
26%
what is the most common type of arrhythmia?
atrial fibrillation
what is atrial fibrillation?
The heart can beat too fast,too slow or irregularly-disorganized electrical signals are the cause
-Fibrillate means to contract very fast and irregularly
what happens in the heart with atrial fibrillation?
blood ppools in the atria and is not completely pumped into ventricles
what does stasis cause?
clotting
thrombus forms
and embolism ensues
what is chronic heart failure?
inability of the heart to supply sufficient blood flow to meet metabolic needs of the body
what is CHF associated with?
with increased risk of thrombus formation and risk of stroke due to a hypercoagulable state-leading to embolism
how is CHF treated?
anticoagulation therapy
what doubels the mortality up to 29% in cardiac thrombus?
The finding of a right heart thrombus in the setting of PE and RV strain
what require a more aggresive treatment with cardiac thrombus and what is the treatment?
A right heart thrombus usually requires more aggressive treatment such as embollectomy or lytic therapy compared to heparin alone
cardiac thrombi may be seen following what?
- ventricular dysfunction
- cardiomyopathy
- myocardial infarction
- ventricular aneurysm
what are some non atherosclerotic vascular diseases?
Dissection Pseudoaneurysm Arteriovenous fistula(AVF) Carotid body tumor Fibromuscular disease(FMD) Buerger’s disease Takayasu’s arteritis Giant cell arteritis
what is the most common cause of stroke in YOUNG ADULTS?
carotid artery dissection
what are carotid artery dissection ischemic signs and symtoms?
transient vision loss and ischemic stroke
what are the 2 classes of causes of CA dissection?
Spontaneous or traumatic
where does carotid artery dissection originate and extend?
Usually originates at the aortic arch and extends to the bifurcation and may extend into ICA
who does spontaneous dissection usually effect?
70% of patients are between ages 35 and 50
what are the risk factors for spontaneous dissection?
- Family history of stroke
- Hereditary connective tissue disorder
what are dissection-connective tissue disorders?
Marfan syndrome Ehlers-Danlos syndrome ADPKD Fibromuscular dysplasia Osteogenesis imperfecta
how is dissection more comonly caused?
severe trauma to the head or neck
what are other causes to traumatic dissection?
include pseudoaneurysm,thrombosis or fistula
what is the mechanism of injury for traumatic dissection?
- rapid deceleration with resultant hyperextension and rotation of the neck
- This stretches the ICA over the upper cervical vertebrae producing a tunica intimal tear
what are the symptoms of traumatic dissecton?
may remain asymptomatic, have a TIA or suffer a stroke
what does an intimal tear allow for?
blood to enter the space between the layers of the vessel which creates a false lumen
what can a false lumen cause?
stenosis or occlusion
what may complete occlusions lead to?
ischemia
what is the pathophysiology of dissection?
blood clots form and break away from site of tear and form emboli that travel to the brain causing a stroke (cerebral infarction)
what does dissecton cause to the brain?
irreversible damage to the brain
what is the treatment of dissection?
prevent the development of continuation of neurological deficits
- observation
- anticoagulation
- stent implantation
- carotid artery ligation
what is a sonographers role in dissection?
- Doppler spectrum of the common carotid artery
- different flow velocities within true and false lumens
- We must R/O occlusion or high grade stenosis
what is the sonographic appearance of dissection?
- Intima may flutter in the flow stream with each cardiac cycle
- Severe flow disturbances are caused by flapping intima
- Classic presentation of ICA dissection is a smooth tapering stenosis usually seen in younger individuals without atherosclerosis
- Regardless of age,consider dissection in a patient with a smooth tapering ICA without visible plaque
what is the most specific sonographic finding of arterial dissection?
double lumen sign
what does an intramural hematoma look like?
be demonstrated as an eccentric echogenicity that surrounds a relatively narrowed arterial lumen
in vertebral arterial dissection what is the flow?
the absence of arterial flow or low blood velocities in the dissected artery, often with a compensatory increased blood flow in the contralateral vertebral artery
what is a true aneurysm?
true aneurysm occurs when the artery wall layers are intact but stretched
Pseudoaneurysm
false aneurysm -is a vascular mass that results from a hole in the arterial wall with circulating blood flow that is confined by soft tissue and hematoma
what do patients present with for a pseudoaeurysm?
palpable pulsatile mass
what must a pseudoaneurysm have to be considered a pseudoaneurysm?
communicate with the artery
pseudoaneurysms are rare and _________
lethal
what are the causes of CCA pseudoaneurysms?
- Blunt or penetrating trauma
- Infection and vasculitis
- Iatrogenic and unknown causes
what are causes of ICA pseudoaneurysms?
- Penetrating trauma
- Post head and neck surgeries
- Carotid endarterectomies
- Infiltrating metastatic lymph nodes and neoplasms
what is the managment for ICA pseudoaneurysms?
- Ultrasound guided compression
- percutaneous thrombin injection
- coil embolization
- endovascular stent graft insertion
- and surgery
pseudoaneurysm on doppler?
Bidirectional turbulent flow within the neck connecting the vessel
to the pseudoaneurysm
what is a fistula?
opening that connects two epithelialized structures
what does an AVF alomost always result from?
traume-either violentor iatrogenic
what can inadvertent arterial injury result in?
development of
- hematoma
- pseudoaneurysm
- AVF
how does Arteriovenous fistula occur?
Complication of Internal Jugular Vein Catheterization
how is Arteriovenous fistula seen on doppler?
- aliasing
- arterial and venous flow simultaneously
- communication between SCA and IJV
- bruit or thirlll
what will the flow proximal to a fistula be?
monophasic
what will flow within the fistula vein be?
“arterialized” flow signal with lack of respiratory phasicity
I ended at slide 40, check if thats when we end
finnish if have to
