28. Aneurysms + Carotid Artery Surgery Flashcards
Define aneurysm disease.
Dilatation of ALL layers of the aorta, leading to an increase in diameter of >50% (abdominal aorta >3cm)
What is the most common type of aortic aneurysm?
Infra-renal aortic abdominal aneurysm (abdominal aorta below the kidneys)
What layers of aortic wall do aneurysms affect?
Affect ALL 3 layers of the aortic wall: tunica intima, tunica media and tunica externa/ adventitia
What makes up tunica externa/adventita?
layer of collagen and connective tissue
What makes up tunica media?
layer of smooth muscle
What makes up tunica interna?
layer of epithelium (endothelium)
What are the main causes of aneurysm disease? (3)
- degenerative disease
- connective tissue disease (e.g. Marfan’s)
- Infection (mycotic aneurysm)
What are risk factors for degenerative abdominal aortic aneurysm disease? (5)
- male sex
- age
- smoking
- hypertension
- family history (prevalence of 30% in 1st degree male relatives)
What is the prevalence of abdominal aortic aneurysms in UK?
3%
Why are abdominal aortic aneurysms sometimes difficult to diagnose?
Appear asymptomatic; sometimes patients experience lower abdominal pain due to palpation, aneurysm will expand and move your hands sideways or lower back pain felt (often identified on scans incidentally)
Which family members on a family tree should be investigated for an abdominal aortic aneurysm if someone is suspected of having one?
the sons particularly (males)
Who can register for abdominal aortic aneurysm screening in UK?
Men who turned 65 years can have an ultrasound to identify possible aneurysms (swellings of the aorta)
What are the criteria that need to be met to perform a screening programme for a specific condition in the UK? (9)
- definable disease
- prevalence
- severity of disease
- natural history
- reliable detection (sensitivity and specificity needs to be reasonable)
- early detection confers advantage
- treatment options available
- cost effective
- feasibility and acceptability
What are the possible outcomes for abdominal aortic aneurysm screening (AAA)? (4)
- normal aorta, discharged
- small AAA
- medium AAA
- large AAA
What is a small AAA and what is the next step following screening?
- small AAA is 3-4.4cm
- will be invited for annual ultrasound scans to monitor
What is a medium AAA and what is the next step following screening?
- medium AAA is 4.5-5.5cm
- will be invited for 3 monthly ultrasound scans to monitor
What is a large AAA and what is the next step following screening?
- large AAA is >5.5 cm
- surgery is advised that replaces weakened section of aorta
How does AAA usually present?
without any symptoms
When do symptoms appear? (2)
- when aneurysm is impending rupture (nearly ruptured, at risk, inflammation around it)
- when aneurysm ruptures
What is the presentation of impending rupture AAA? (2)
- increasing back pain
2. tender abdominal aortic aneurysm (abdominal area/wall)
What is the presentation of ruptured AAA? (5)
- abdominal/ back/ flank pain
- painful pulsatile mass
- haemodynamic instability (single episode or progressive), bruising, unstable BP
- hyperfusion (patient cold, confused, urine output decreased)
- single episodes of collapse, loss of consciousness and recovery
What is the unusual presentation of AAA? (5)
- distal embolisation
- aortocaval fistula (AAA erodes into inferior VC)
- aortoenteric fistula(connection between aorta and small intestine)
- uretic occlusion
- duodenal obstruction
What questions should be asked for management of AAA in asymptomatic patients? (3)
- is the aneurysm a size to consider repair?
- is the patient a candidate for repair?
- is the aneurysm suitable for endovascular or open repair?
At what aneurysm size is treatment usually offered?
at 5.5cm
For aneurysms of which size does surgery have no benefit on?
aneurysms <5.5cm (need to be bigger to be considered for surgery)
How big does aneurysm have to be to have the greatest risk of rupture of 30-50%?
> 8cm in size
What is the risk of aneurysm rupture for aneurysms of <4cm?
<0.5% risk
What patient fitness tests need to be done on AAA patients to work out the right treatment method? (9)
- full history and examination
- bloods
- ECG
- ECHO (ultrasound of heart)
- PFTSs (pulmonary function tests)
- MPS (myocardial perfusion scan)
- CPEX (cardipulmonary exercise testing)
- end of best test
- patient preference
What is a myocardial perfusion scan? (MPS)
- radionuclide (radioactive chemical) travels through bloodstream into heart
- areas of heart that have a good blood flow will absorb the radionuclide and will emit more gamma rays
- areas with poor blood supply or damaged areas due to heart attack, stenosis, ischaemia etc will absorb less of the chemical and less gamma rays emitted
What imaging techniques can be used to detect AAA? (3)
- ultrasound scanning
2 CT angiography - MRA (magnetic resonance angiogram)
What are the pros of ultrasounds scanning? (3)
- no radiation
- no contrast
- cheap
What are the cons of ultrasound scanning? (2)
- operator dependent
2. inadequate for surgical planning
What are the pros of CT angiography and magnetic resonance angiogram (MRA)? (3)
- quick
- not operator dependent
- necessary for surgical planning (detailed anatomy seen)
What are the cons of CT angiography and magnetic resonance angiogram? (2)
- contrast needed
2. radiation
What is the conservative management approach if aneurysm is impossible to fix surgically?
Patient/ aneurysm not fit for repair in surgery so plan is made in event of aneurysm rupture
What 2 types of repairs are there for AAA?
- endovascular repair
2. open repair
What does an open repair involve?
- big incision which increases infection risk
- bowel dissected away from aneurysm sac
- general anaesthetic needed
What does an endovascular repair involve?
- needle put into femoral arteries and graft inserted inside aneurysm sac
- procedure takes 1-2 hours only and leaves a few incisions in groin which heal relatively quickly
What are the possible general complications of an open repair surgery for AAA? (4)
- would infection/ dehiscence
- bleeding
- pain
- scar
What are the possible technical complications of an open repair surgery for AAA? (6)
- damage to bowel, uterus, veins, nerves
- incisional hernia
- graft infection
- distal emboli
- renal failure
- colonic ischaemia
(risk of damaging major arteries)
What are the possible patient factors complications to consider for open repair surgery for AA? (4)
- DVT/ PE
- MI
- Stroke
- death
What are the possible general complications for endovascular repair for an AAA? (6)
- wound infection
- bleeding/haemorrhage
- pain
- scar
- contrast reaction/ kidney injury
- radiation
What are the possible technical complications for endovascular repair for an AAA? (5)
- endoleak
- femoral artery dissection/ pseudoaneurysm
- rupture
- distal emboli/ ischaemia/ colonic ischaemia
- damage to femoral vein/nerve
What are the possible patient factors complications for endovascular repair for an AAA? (4)
- DVT/PE
- MI
- stroke
- death
What is an endoleak in an aneurysm?
- somewhere from the body, the blood can leak back into aortic sac (from the top, from branches, backleak from other regions, join in graft can be loose, leak from the side etc)
- sac gets bigger and no one knows where leak is coming from
Is there a difference in longterm patient mortality between doing open repair or endovascular repair?
No difference in mortality
What is the management of AAA that is symptomatic? (4)
- ABDE (first aid)
- history and check records
- examination
- CTA; CT angiography
What is needed for an emergency open repair in an AAA?
- patient taken straight to theatre (pre/post CT)
- massive transfusion protocol
- prep abdomen +rapid anaesthetic
- laparotomy xiphisternum to pubic symphysis
- aorta occluded proximally
- local anaesthetic
What is the morbidity for an an emergency open repair?
30-50% as very complex procedure
Which surgical procedure is preferable usually?
Endovascular;
- preferred by patients who are anatomically stable
- can be done if all resources and staff available
- if AAA caught early, patient has quick recovery
Why are open repairs more common?
- more staff familiar with procedure
- more staff available for procedure and resources most likely in stock
What are 2 most common ways of finding an AAA?
- incidental finding through screening
2. patient presents with symptoms
What management of AAA should be undertaken cautiously?
- treatment?
- surveillance? (until AAA reaches 5.5. cm)
- conservative management
- is patient fit to wait for surgery?
- Endovascular or open repair?
What is atherosclerosis of carotid arteries associated with? (2)
- transient ischaemic attacks
- ischaemic stroke
Define transient ischaemic attack. (TIA)
Focal CNS disturbance caused by vascular events such as microemboli and occlusion leading to cerebral ischaemia. Symptoms last less than 24 hours and there are no permanent neurological sequelae/conditions afterwards.
Define stroke.
Clinical syndrome consisting of rapidly developing clinical signs of focal or global disturbance of cerebral function, lasting more than 24 hours or leading to death with no apparent cause other than that of vascular origin.
What are the main causes of stroke or TIAs (transient ischaemic attacks). (3)
- cerebral infarction (84%)
- primary intracerebral haemorrhage (10%)
- subarachnoid haemorrhage (6%)
What are the main causes of cerebral infarction? (7)
- atrial fibrillation (AF)
- carotid atherosclerotic plaque rupture/thrombus
- endocarditis
- MI
- carotid artery trauma/ dissection
- drug abuse
- haematological disorder e.g. sickle cell disease
What part of the atherosclerotic plaque causes infarction?
the thrombus which dislodges from the plaque which causes stroke or transient ischaemic attack (TIA)
What are components of Virchow’s triad of factors which contribute to thrombosis? (3)
- coagulability
- flow
- vessel wall
What are the risk factors for carotid artery atherosclerosis? (9)
- smoking
- diabetes
- family history
- male sex
- previous DVT, 2nd degree to flight
- hypertension
- hyperlipidaemia
- obesity
- age
What 4 things are needed to diagnose a stroke or a TIA?
- history
- examination
- CT
- carotid ultrasound
What is found on examination in stroke/ TIA patients? (3)
- NEUROLOGICAL: Contralateral symptoms of:
- paralysis
- paresis; muscular weakness
- visuospatial neglect
- dysphasia; large disorder
- ipsilateral amaurosis fagux symptoms; loss of vision - CARDIAC
- AUSCULTATE CAROTIDS
In carotid artery imaging what does increased velocity mean?
disease most likely to cause narrowing of artery
What is Poistulle’s Law?
As radius of vessel decreases (e.g. stenosis), velocity increases
What is the best management of stroke or TIA? (5)
- smoking cessation
- control of hypertension
- antiplatelet
- statin
- diabetic control
What imaging method is used to check carotid arteries in the neck?
carotid doppler (imaging that uses ultrasound); can show narrowing or possible blockage
What is the name of the anastomosis structure in the brain that supplies blood to the brain?
Circle of Willis (roundabout in the brain)
What arteries supply the Circle of Willis?
- carotid arteries
- vertebral arteries
(on both sides)
What leads to further stroke in terms of blood flow?
- If emboli are showered from high velocity blood flow in a disease carotid artery causing distal ischaemia.
- If there is no flow due to occlusion, then no risk of emboli
What is a carotid endarterectomy?
- procedure which may prevent stroke if severely narrowed carotid arteries
- clamp artery below and above diseased point
- incision made to open carotid artery
- plaque is removed
- repaired artery is then closed which leaves an open flow channel
What are the general complications from carotid endarterectomy? (5)
- wound infection
- bleeding
- scar
- anaesthetic risks
- nerve damage
Why are internal carotids the ones on which carotid endarterectomy is performed on and its lumen is opened?
Because internal carotids don’t have branches (it’s a terminal of common carotid) whereas external have branches (more chances of complications)
What nerves are at risk of being damaged in an carotid endarterectomy procedure? (3)
- vagus nerve
- hypoglossal nerve
- glossopharyngeal nerve (can cause hoarse voice)
What can cause a perioperative stroke as a complication risk to carotid endarterectomy?(3)
- plaque rupture
- hyperperfusion
- Virchow’s triad; raw intimal surface and thrombosis
What treatment options are there for patients at risk of stroke? (3)
- carotid endarterectomy
- stenting
- best medical therapy (drug/medications)
What should TIA/stroke be treated as?
as a “brain attack” and an emergency
What is the most risky period for further event happening following a stroke?
within first 2 weeks
What treatment option must ALL stroke patients have?
Best medical therapy (drugs/medicines)
What is surgery used as in stroke patients?
Used only as prophylaxis (prophylactic) to prevent deterioration
To what patients is carotid surgery offered? (3)
- To all symptomatic patients with >70% stenosis (except occluded patients)
- men with 50-69% stenosis
- asymptomatic stenosis >70%
