Carotid Disease

Question 1

blood supply to brain?

Answer 1

circle of willis

• left and right internal carotid arteries (no branches in neck, arise from common carotids)
• left and right vertebral arteries (arise from subclavian - 1st branch and travel within transverse foramina of C6-C1)

Question 2

purpose of carotid endartectomy?

Answer 2

remove atherosclerostic plaque which is narrowing the carotid artery
reducing risk of ischaemic event (prophylactic procedure)

Question 3

describe circle of willis?

Answer 3

..

Question 4

how many strokes arise from asymptomatic ICA stenosis?

Answer 4

10-15%

…

Question 5

medical management of carotid artery disease following TIA?

Answer 5

dual antiplatelet
statin
manage hypertension

Question 6

definitive management of carotid artery disease after TIA?

Answer 6

urgent carotid artery duplex

if stenosis is 70-90% of vessel then urgent referral for carotid endartectomy within 2 weeks

Question 7

indication for endartectomy?

Answer 7

> 70% stenosis in affected artery
should be done within 2 weeks
should have confirmed on 2 imaging methods (duplex + CT (or sometimes MRI)) but duplex alone can sometimes be enough

Question 8

benefits and risks of doing carotid endartectomy after TIA?

Answer 8

there is a high risk of further stroke/TIA in the 2-4 weeks following TIA
procedure greatly reduces this risk
there is however a 3% risk of disabling stroke during the procedure (still less than otherwise though)

Question 9

contraindication for carotid endartectomy?

Answer 9

100% eclusion

Question 10

is procedure done if 50-70% occlusion in vessel?

Answer 10

grey area
can be done depending on guideline, gender, time since event, surgeon and patient preference
multiple TIA (crescendo TIAs) in a short time would be an indication for the procedure even if only 50% occluded

Question 11

what type of anaesthetic is used?

Answer 11

depends on hospital
regional/local = can check for signs of ischaemia during operation
general = still surgical field
studies show no benefit of one over the other

Question 12

how is procedure done?

Answer 12

incision along anterior margin of sternocleidomastoid
pull back sternocleidomastoid allowing exposure of carotid sheath
dissection and control of common, internal and external carotid arteries (maximal stenosis occurs at ostium/bifurcation)
clamp the artery
insert a shunt into common and internal carotid (if under GA) to bypass hole in artery and restore blood flow to brain
remove plaque, intima and media of vessel
closure with patch of bovine pericardium

Question 13

complications of operation?

Answer 13

pain
infection
bleeding and haematoma (haematoma can lead to airway obstruction due to enclosed space in neck)
damage to surrounding structures
stroke
death

Question 14

how is bleeding/haematoma risk managed?

Answer 14

heparin during procedure as well as dual antiplatelets

Question 15

what surrounding structures can be damaged?

Answer 15

hypoglassal (most common as it crosses over internal carotid), recurrent laryngeal and facial nerves

Question 16

what causes carotid disease>

Answer 16

atherosclerosis

Question 17

risk factors for carotid disease?

Answer 17

smoking
hypertension
diabetes
hyperlipidaemia

Question 18

clinical features of carotid artery disease?

Answer 18

asymptomatic or symptoms of reduced blood flow

• contralateral motor/sensory deficit
• speech related deficit
• ipsilateral eye signs (amaurosis fugax)

Question 19

investigations in carotid artery disease?

Answer 19

duplex US
CT (brain and carotids)
MRI (Brain and carotids)

Question 20

management of carotid disease?

Answer 20

stop smoking and control risk factors
antiplatelet agents (aspirin, clopidogrel)
carotid endarterectomy

Question 21

what is a stroke?

Answer 21

acute loss of focal cerebral function for over 24 hrs (can be global in case of coma and sub-arachnoid haemorrhage) with no possible cause other than vascular origin

Question 22

causes of stroke?

Answer 22

emboli from an atherosclerosis in the internal carotid or other source
cardiac (A fib, valvular disease etc)
iatrogenic trauma to aortic arch (during endovascular surgery)
intra cranial vessel disease

Question 23

carotid disease on which side can cause brocas/expressive dysphasia?

Answer 23

left (in most people) as brocas area is usually on the left side of brain

Question 24

CVA vs TIA?

Answer 24

CVA = symptoms lasting >24 hrs or lead to death
TIA = symptoms fully resolve within 24 hrs

Question 25

what is amaurosis fugax?

Answer 25

transient visual disturbance in the eye on the same side as the carotid disease often described as a curtain coming down

Question 26

when is surgical intervention useful in carotid disease?

Answer 26

only when symptoms develop | most people are asymptomatic and medical management is more useful and surgery wont add much so not worth the risk

Question 27

what investigations should all people with focal neurological deficit have?

Answer 27

duplex US of carotid and vertebral arteries ECG ( to exclude dysrhythmia as a source of embolus) full assessment of lipid profile exclude diabetes

Question 28

what will duplex US of carotids and vertebrals show?

Answer 28

whether stenosis is significant (>50%) will show character of the plaque and whether it has an ends point which is within reach of surgeon (otherwise theres no point in surgery)

Question 29

what is done if a duplex is not able to clarify lesion/plaque accurately?

Answer 29

CT/MRI scan of the brain +/- CT/MR angiogram of carotids excludes intracranial haemorrhage (haemorrhagic infarct = contraindication to surgery), space occupying lesions or areas of infarct

Question 30

what happens if stenosis >50% is seen on duplex after a TIA and the patient has made a good recovery with return to nearly normal activities?

Answer 30

may benefit from carotid surgery so should make urgent referral to vascular surgery for assessment

Question 31

why urgent referral to vascular surgery?

Answer 31

carotid endarterectomy is prophylactic so reduces risk of further stroke/TIA highest risk of another stroke/TIA within first 30 days, esp first 2 weeks so quicker surgery reduces risk the most

Question 32

how fast should surgery be done after a TIA/stroke in patients with good recovery?

Answer 32

``` females = within 2 weeks of event (little benefit after 4 weeks) males = within 2 weeks (but still some benefit up to 12 weeks) ```

Question 33

why dont patients suffer a reduction in cerebral blood flow during carotid endarterectomy even though the carotid is clamped above and below the plaque?

Answer 33

excellent collaterals at the base of the brain (circle of willis)

Question 34

what is done if patient does experience reduced cerebral blood flow during surgery?

Answer 34

inert plastic shunt can be used to divert blood around the clamped artery while the operation continues