[6] Carotid Artery Disease Flashcards
What is carotid artery disease?
The build-up of atherosclerotic plaque in one or more common and internal carotid arteries, resulting in stenosis or occlusion
Is carotid artery disease always symptomatic?
No, the majority of cases are asymptomatic
What % of ischaemic strokes are due to carotid artery disease?
15%
How can carotid artery disease cause ischaemic strokes?
Plaque rupture and/or atheroembolism
What is the pathophysiology of carotid artery disease?
Same as for atheroma elsewhere, starting with fatty streak, accumulating a lipid core, and formation of a fibrous cap
What predisposes the atheromatous process specifically at the carotid artery?
The turbulent flow at the bifurcation of the carotid artery
What is carotid artery disease usually classified based on?
Classified radiologically by the degree of stenosis
What is considered to be mild carotid artery disease?
<50% reduction in diameter
What is considered to be moderate carotid artery disease?
50-69% reduction in diameter
What is considered to be severe carotid artery disease?
70-99% reduction in diameter
What is considered to be total occlusion in carotid artery disease?
100% reduction in diameter
What are the major risk factors for carotid artery disease?
>65 years Smoking Hypertension Hypercholesterolaemia Obesity Diabetes mellitus History of cardiovascular disease Family history of cardiovascular disease
How does carotid artery disease present?
It will often be asymptomatic, however may present as a focal neurological deficit
How can carotid artery disease lead to focal neurological disease?
Can lead to transient ischaemic attack or stroke
How long does a TIA last before resolution?
24 hours
What is amaurosis fugax?
Transient visual loss that may be associated with TIA
How long does a stroke last?
24 hours or more without full resolution
How are strokes classified?
Oxford Stroke (Bamford) Classification
What is the Oxford Stroke Classification based on?
The stroke symptoms in relation to the arterial regions involved
What may be found on examination in carotid artery disease?
A carotid bruit may be auscultated in the neck
What proportion of carotid bruits auscultated in the neck are associated with carotid stenosis?
About half
Why is carotid stenosis likely to be asymptomatic if unilateral (apart from clinical features of stroke)?
Due to collateral supply from the contralateral internal carotid artery and vertebral arteries, via the Circle of Willis
What are the different classifications of stroke according to the Oxford Stroke Classification?
Total Anterior Circulation Stoke (TCAS)
Partial Anterior Circulation Stroke (PACS)
Lacunar Stroke (LACS)
Posterior Circulation Stroke (POCS)
What % of strokes are total anterior circulation strokes?
20%
What are total anterior circulation strokes?
Large cortical stroke in middle or anterior cerebral artery areas
What are the signs and symptoms of a total anterior circulation stroke?
Must have all of;
Motor weakness or sensory deficit of >2/3 of face, arm, and leg
Homonymous hemianopia
High cortical dysfunction
How can high cortical dysfunction manifest?
Dysphagia
Dyspraxia
Neglect
What % of strokes are partial anterior circulation strokes?
35%
What are partial anterior circulation strokes?
Cortical strokes in middle or anterior cerebral artery areas
What are the signs and symptoms of partial anterior circulation strokes?
Will present with either;
2/3 of TACS criteria
Limited motor or sensory deficit (1 of leg, arm, or face)
High cortical dysfunction alone
What % of strokes are lacunar strokes?
20%
What are lacunar strokes?
Occlusion of deep penetrating arteries
How will lacunar strokes present?
With any of;
Pure motor in 2 or 3 of face, arm, and leg
Pure sensory in 2 or 3 of face, arm, and leg
Pure sensorimotor in 2 or 3 of face, arm, and leg
Ataxic hemiparesis
What % of strokes are posterior circulation strokes?
20%
What are posterior circulation strokes?
Occlusion of vertebrobasilar or PCA circulation, affecting brainstem, cerebellum or occipital lobe
How do posterior circulation strokes present?
Variety of presentations can occur, but typically;
Ipsilateral CN palsy with contralateral motor or sensory defects
Bilateral motor or sensory defects
Isolated homonymous hemianopia
Cerebellar dysfunction
What is the most common form of carotid artery disease?
Atherosclerosis
What other pathologies can be involved in carotid artery disease?
Carotid dissection
Thrombotic occlusion of carotid artery
Fibromuscular dysplasia
Vasculitis
What suggests carotid dissection as the pathology rather than atherosclerosis?
Patients are often younger (<50 years) and have an underlying connective tissue disease
What might a carotid artery dissection be precipitated by?
Trauma or sudden neck movement
How can a thrombotic occlusion of the carotid artery be differentiated from atheromatous plaques?
Only on imaging
How will thrombotic occlusion of the carotid artery present clinically?
The same as atheroma
What happens in fibromuscular dysplasia of the carotid arteries?
There is non-atheromatous stenotic angiopathy causing hypertrophy of the vessel wall
Who does fibromuscular dysplasia predominantly affect?
Young (<50 years) females
What vessels are most commonly affected in fibromuscular dysplasia?
Renal arteries
How does carotid artery fibromuscular dysplasia present?
With focal neurological deficit
What vasculitidies can cause carotid stenosis?
Various great vessel vasculitidies, such as Giant Cell Arteritis or Takayasu’s Arteritis
How can carotid stenosis caused by vasculitides be differentiated from atherosclerotic causes?
Patients will typically have systemic symptoms, and other vessels may be affected
What non-cerebrovascular conditions can manifest neurologically?
Hypoglycaemia Todd's paresis Subdural haematoma SoL Venous sinus thrombosis Post-ictal state Multiple sclerosis
What is Todd’s Paresis?
Unilateral motor paralysis following a seizure
What investigations should be done in suspected stroke?
Urgent CT head
Bloods
ECG
What is the purpose of a CT head scan in suspected stroke?
Check for infarction potentially amenable to thrombolytic treatment
What bloods should be done in suspected stroke?
FBC U&Es Clotting Lipid profile Glucose
Why is an ECG done in suspected stroke?
Check for any potential source of clot
Which patients may warrant screening for carotid artery disease?
Those who have had TIA or stroke, to look for disease precipitating the presentation
Asymptomatic patients with risk factors
Symptomatic patients who may warrant prophylactic surgical intervention
How the carotid arteries be screened for disease precipitating stroke/TIA?
Duplex ultrasound scans
What is the use of Duplex ultrasound scans in carotid artery disease?
They give a good estimate of the degree of stenosis, and exclude any other possible differentials
Why are Duplex ultrasound scans good for screening asymptomatic patients for carotid artery disease?
It is cheap, non-invasive, and readily available
How should lesions found within the carotid artery be further investigated?
CT angiography
What is the use of CT angiography in carotid artery disease?
It gives a more accurate percentage stenosis, and characterises the diseased portion of the vessels for potential surgery if the USS scan shows a greater than 50% stenosis
What initial management should all patients admitted with suspected stroke receive?
Start on high flow oxygen
Optimise blood glucose (4-11mmol/L)
When should a swallowing screen assessment be made in suspected stroke?
On admission
What does the initial management of stroke depend on?
The nature of the stroke
How is an ischaemic stroke initially managed?
IV alteplase (r-tPA), if patients are admitted within 4.5 hours of symptom onset and meet the inclusion criteria
What medication should be started as an inpatient in ischaemic stroke?
300mg aspirin OD
How long should 300mg aspirin OD be given after ischaemic stroke?
14 days
How is a haemorrhagic stroke initially managed?
Referral to neurosurgery for potential clot evacuation
Correction of any coagulopathy
Is neurosurgery always advised for haemorrhagic stroke?
No, neurosurgery is often not advised for haemorrhagic stroke, unless superficial lobar bleed or ventricular bleed
What should all patients with a known stroke or TIA be started on?
Cardiovascular risk factor management
What is involved in cardiovascular risk factor management?
Long-term anti-platelet therapy
Statin therapy
Aggressive management of any hypertension and/or diabetes mellitus
Smoking cessation
What anti-platelet therapy is typically used following a stroke or TIA?
Aspirin 300mg OD for 2 weeks, then clopidogrel 75mg OD
What can be used if clopidogrel is not tolerated as anti-platelet therapy following stroke/TIA?
Trial combination therapy aspirin and dipyradimole
What statin therapy is ideally used following stroke/TIA?
Atorvastatin 80mg OD
When should patients with carotid artery disease be referred for surgical revascularisation?
Symptomatic carotid artery stenosis >50%
How quickly should revascularisation be performed in a symptomatic patient?
As soon as possible, with current targets within 2 weeks for patients with stabilised neurology and fit for surgical intervention
Are patients with asymptomatic carotid artery stenosis of >70% surgically treated?
Very rarely, unless they are young and have had symptomatic contralateral stenosis
What is advised for any dysphagia or dysphasia following stroke?
Referral to Speech and Language Therapy (SALT) team
What is advised for any ongoing mobility issues following stroke?
Physiotherapy and Occupational Therapy input
What do many stroke patients require for their long term recovery?
Rehabilitation
What is the mainstay of surgical treatment for ischaemic stroke prevention?
Carotid endarterectomy (CEA)
What does CEA involve?
Removing the atheroma and associated damaged intima, thereby reducing the risk of future strokes or TIAs
Why is CEA a superior option to carotid stenting?
Carotid stenting is associated with an early and sustained 55% increased hazard for long-term major adverse effects
How is a CEA performed?
The artery is isolated and clamped, before an arteriotomy is created and often a temporary bypass shunt placed for the duration of the procedure. The plaque and diseased intima are carefully dissected from within the artery. The arteriotomy is closed with a patch graft.
When is shunting especially important in a a carotid endartectomy?
For any contralateral occlusive disease to minimise any cerebral hypoperfusion
Why does careful attention need to be paid when dissecting the plaque and diseased intima from within the artery in a carotid endartectomy?
As to not create any free edge that could result in dissection
Why is the arteriotomy closed with a patch graft in carotid endartectomy?
To prevent iatrogenic stenosis, and reduce the risk of re-stenosis
What are the main risks of CEA surgery?
Stroke Nerve damage Myocardial infarction Local bleeding Infection
What nerves can be damaged in a carotid endartectomy?
Hypoglossal
Glossopharyngeal
Vagus nerve
What is the mortality of a stroke at 7 days?
12%
What is the mortality of stroke at 30 days?
19%
When does the most significant improvement from rehabilitation occur?
Between 4-6 weeks
What % of stroke survivors remain dependant at 1 year?
50%
In which patients is the rate of dependancy 1 year post stroke significantly lower in?
Patients who are fit for carotid endarterectomy
What are the complications of stroke?
Dysphagia Seizures Ongoing spasticity Bladder or bowel incontinence Depression and anxiety Cognitive decline
