Carotid artery surgery Flashcards
“Atherosclerosis of the carotid arteries is associated with ______”
Transient ischaemic attacks & ischaemic stroke
What is a transient ischaemic attack?
Focal CNS disturbance
Caused by vascular events such as microemboli & occlusion leading to cerebral ischaemia
Symptoms last less than 24 hours & there are no permanent neurological effects
What is a stroke?
Clinical syndrome consisting of rapidly developing clinical sings of focal or global disturbance of cerebral function
Lasting more than 24 hours or until death
With no apparent cause other than vascular origin
What is the main simple difference between a stroke and a TIA?
TIA lasts < 24 hours and isn’t life changing
Stroke lasts > 24 hours and aint good
Summarise the causes of strokes
Cerebral infarction - 85%
Haemorrhage - 15%
List the types of cerebral infarction
Atrial fibrillation
Carotid atherosclerosis plaque rupture/thrombus
Endocarditis
MI
Carotid artery trauma/dissection
Drug abuse
Haematological disorder - eg sickle cell disease
There are two types of haemorrhage that cause strokes
What are they?
Primary intracerebral haemorrhage (more common):
- Vessel within the brain bursts
Subarachnoid haemorrhage:
- Bleeding into space around the brain
What causes TIA’s?
Cerebral infarctions
List the risk factors for carotid artery atherosclerosis
Smoking Diabetes Male Old Family history Hypertension Hyperlipidaemia & hypercholesterolaemia Obese
Describe the diagnosis route for TIA
History
Examination
CT scan
Carotid USS
What is important to examine in diagnosing TIA?
Neurological:
- Paralysis/paresis/visuospatial neglect
- Dyshpasia: ipsilateral amaurosis fugax symptoms
Cardiac
Auscultation of carotids
What are typical statements you would hear from a patient with a TIA?
Numb, tingling sensation shooting down a leg
Drooping around eye
Loss of control of limbs / motor skills
Slurring words (sound drunk)
What is the effect of stenosis on the velocity of blood flow through a vessel?
Stenosis causes an increase in velocity
Velocity is used to measure how badly stenosed a vessel is:
- < 125 cm/s = < 50% stenosis
- > 125 cm/s = 50-69% stenosis
- > 270 cm/s = 70-79% stenosis
- EDV of > 140 cm/s = 80-99% stenosis
Management of carotid atherosclerosis includes ‘Best medical therapy’
What does this include?
Smoking cessation Control hypertension Antiplatelet medication Statin Diabetic control
A patient has TIA with left sided symptoms
Which carotid artery is likely to be occluded?
Right internal carotid
Even if an internal carotid artery is occluded by a thrombus or some shite, the brain is still largely perfused
What allows this?
Circle of willis
circuit of arteries in the brain allows blood to take another route basically
After a patient presents with TIA/stroke, it is a risk that they will have another stroke
What causes this?
Despite the circle of willis allowing alternative flow routes for blood in the brain…
Risk of emboli being ripped up from the diseased carotid artery by high flow velocity (high velocity due to stenosis) and causing distal ischaemia
Risk of further event is highest within the first 2 weeks
What is a carotid endarterectomy?
Procedure to remove a plaque from a highly stenosed carotid artery
For example, if someone had a TIA and a doppler showed 90% stenosis of the internal carotid, then this would be done
This aims to prevent a stroke from happening
List the branches of the external carotid artery
Posterior auricular Occipital Facial Lingual Ascending pharyngeal Superior thyroid
What unusual risks do carotid endarterectomies pose?
Risk damaging nerves
Perioperative stroke
What nerves are at risk during a carotid endarterectomy?
Hypoglossal nerve (XII) - passes over the external & internal carotid arteries
Vagus nerve (X) - Runs inferior alongside the common & internal carotid arteries
Glossopharyngeal nerve (IX) - less at risk but is still cutting about
What can happen during a carotid endarterectomy that would cause a stroke?
Plaque rupture
Hypoperfusion
Operation causes raw intimal surface & may cause thrombosis
Summarise the management of carotid atherosclerosis to reduce the risk of stroke
Best medical therapy
Carotid endarterectomy
Stenting
According to NASCET, NEJM 1998
How large does carotid artery stenosis need to be, before surgery becomes beneficial?
No benefit to surgery if <50% stenosis
Summarise the difference in stroke management in women compared to men
Surgery only becomes beneficial for women if stenosis is 70-99%
For men, stenosis only needs to be 50% or above for surgery to become beneficial
So what are the 2 basic treatment routes for someone with a stroke or TIA?
1) If patient has carotid stenosis of <50% (NASCET criteria) or <70% (ECST criteria):
- Best medical treatment
2) If patient has stenosis of >50% (NASCET) or >70% (ECST):
- Best medical treatment
- Carotid endarerectomy
- Carotid stenting
Describe the management options for asymptomatic carotid stenosis
CEA (endarterectomy) should only be considered for asymptomatic patients with high grade stenosis >70%
Only should be done with patients <70 years old
(ACAS trial shows no benefit to patients >75 y.o)
Only should be done by surgeons with low perioperative stroke or death rate
