Aneurysm surgery Flashcards
What is aneurysm disease?
Dilation of all layers of the aorta, leading to an increase in diameter of at least 50%
How big does the aorta need to be before it is considered an aneurysm?
> 3.5cm
Where on the aorta can an abdominal aortic aneurysm take place?
95% are infrarenal
Between the branching of the left & right renal arteries and the bifurcation into the common Iliac arteries
What arteries branch off the aorta in the section in which AAA’s can be located?
Superior mesenteric artery (leaves at roughly the same level as the renal arteries)
Inferior mesenteric artery (about half way in between the renal branches & the Iliac bifurcation)
What are the 3 layers of an artery?
Tunica intima
Tunica media
Tunica externa
Where are the internal and external elastic membranes found?
Internal - Between the intima & media
External - Between the media & externa
What are the non modifiable risk factors for abdominal aortic aneurysm?
Male gender
Being old
Strong family history
CT diseases - Marfan’s, Ehlers-Danlos syndrome)
What are non-modifiable risk factors or secondary causes of AAAs?
Hypertension
Hypercholesterolaemia
Smoking
What diseases n shite can cause AAA’s?
Atherosclerosis
Infection (mycotic) - Syphilis, Ecoli, Salmonella
Trauma
Marfan’s, Ehlers-Danlos syndrome
Give an example of a connective tissue disease that would cause aneurysms
Marfan’s syndrome
what Michael Phelps has - fun fact
Give an example of an aneurysm that is associated with infection
What group of people is most likely to get this sort of infection?
Mycotic aneurysm
Caused by injection with non sterile needles - infection
Injected drug users often get mycotic aneurysms
What are the risk factors for degenerative AAA disease?
Male Elderly Smoker Hypertension Family history
Why is family history an important risk factor for degenerative AAA?
Prevalence of 30% in 1st degree male relatives
basically, if a man has a DAAA then his son has a 30% of also having a DAAA in his lifetime
How common is AAA in the UK?
3% prevalence
Aneurysms often present as asymptomatic
How are they identified?
Examination (for something else)
Identified as at risk on family tree and then found on investigation
Incidental finding on imaging (CT etc)
Screening programme for AAA
What are the 2 main criteria for the AAA screening programme?
1) Age 65 and above
2) Male
What imaging does the screening programme use?
An ultrasound scan
What are the 4 screening programmes in the uk?
Breast cancer
Cervical cancer
Bowel cancer
Aortic aneurysm
List the criteria to be considered for a screening programme to be introduced
Definable disease Prevalence Severity of the disease Natural history Reliable detection Early detection confers advantage Treatable Cost Feasibility Acceptability
For screening:
Why must the disease be definable?
Got to to know what we’re looking for
For screening:
Why is prevalence important?
The disease has got to be common enough for a screening programme to be worth doing
If some spicy disease only affects 1 in 200 million people, a multimillion pound screening programme is pointless
For screening:
Why must the disease be severe?
Screening programmes aim to stop people dying
If it’s not severe enough to kill people, then there’s no point investing money into preventing it
For screening:
Why is natural history important?
Screening programmes aim to detect the early stage of a disease, providing the disease ‘naturally’ progresses to become worse
For screening:
Why must detecting the disease early be advantageous & why must treatment options be available?
What the point in having a screening programme for something which can’t be cured once theyve found it
If spicy disease X is only detectable when it’s probably going to kill the person then screening serves no benefit to society
For screening:
What is meant by cost & feasibility?
Economically, the screening programme must save money
The costs of:
(screening programme + early treatment must be < cost of treating patients with late disease + loss to society)
So it must be cheap enough to actually save money overall, and feasible enough to introduce
For screening:
What does acceptability mean?
How acceptable the screening is:
How invasive/uncomfortable it is & whether or not the public are willing to have it done
Screening programmes must be specific & sensitive
What does this mean?
Must be specific to the disease they are screening for & only pick that up (no false +ves etc)
Must be sensitive enough to pick up on the disease in an early enough stage that treatment is beneficial
Describe the outcomes of screening for AAA
Depends on size of aneurysm:
A) Normal aorta:
- discharge
B) Small AAA (3.0 - 4.0 cm):
- Invited for annual USS scans
C) Medium AAA (4.5 - 5.5cm):
- Invited for 3 monthly USS scans
D) Large AAA ( > 5.5cm ):
- Urgent referral to vascular surgeon
Someone with symptomatic AAA has either got an impending rupture or there aorta has already ruptured
How would a patient with an impending rupture present?
Increasing back pain
Tended AAA
CT scan shows ‘stranding’ on the aortic wall
How would someone with a ruptured aneurysm present?
Severe abdominal/back/flank pain
Shock
Painful pulsatile mass
Haemodynamic instability (single episode or progressive)
Hypoperfusion
AAA’s can present unusually
How can they present unusually?
Distal embolisation (black toes due to small emboli trapped in small vessels)
Aortocaval fistula
Aortoenteric fistula
Ureteric occlusion
Duodenal obstruction
What must you consider for the management of asymptomatic aneurysms?
1) Is it big enough to need repaired?
2) Is the patient a candidate for repair?
3) Is the aneurysm suitable for endovascular or open repair?
The UK small aneurysm trial (Lancet, 1998) gives evidence about when an aneurysm becomes big enough to need repaired
What was the outcome of this trial?
Surgery did not confer any benefit (eg survival) for aneurysms less than 5.5 cm
Basically - only operate on aneurysms that are > 5.5 cm
How do you determine whether or not a patient is fit enough for surgery for an AAA?
Full history + examination
End of bed test
ECG ECHO PFTs MPS CPEX Patient preference
When assessing an AAA to decide on what type of surgery
What are 2 imaging routes that can be taken?
Ultrasound
CTA / MRA
What are the benefits and problems with CTA / MRA assessment of an AAA?
Quick
Not operator dependant
Necessary for surgical planning - gives detailed anatomy/image
However, uses contrast and radiation
Contrasts pose risks such as renal failure
What is conservative treatment?
When the patient/aneurysm is not fit for repair
Surgery only done in the event of a rupture (emergency)
What is the basic difference between open repair and endovascular repair?
Open repair = big incision to open up abdomen
Endovascular (EVAR) = minimally invasive operation doing up through the groin using mad special instruments
What are general complications involved with open repair?
Infection /dehiscence
Bleeding
Pain
Scar
What are technical complications involved with open repair?
Damage to bowel, ureters, veins, nerves
Incisional hernia
Graft infection
Distal emboli
Renal failure
Colonic ischaemia
What are the patient factor complications associated with open repair surgery?
Deep vein thrombosis / pulmonary embolism
Myocardial infarction
Stroke
Death
What general complications can happen in endovascular repair surgery (EVAR)?
Compare this to open repair
Infection
Bleeding / haematoma
Pain
Scar
Contrast - reaction/kidney injury
Radiation
EVAR done under guidance from CT/contrasts so has risks associated with those whereas open surgery does not use CT
What technical complications can happen during endovascular repair surgery (EVAR)?
Endoleak
Femoral artery dissection/pseudoaneurysm
Rupture
Distal emboli or ischaemia / colonic ischaemia
Damage to femoral vein / nerve
Compare the relative risk of EVAR and open surgery
EVAR has lower short term mortality than open surgery
Long term mortality is roughly the same
EVAR also has shorter hospital stays
What type of endoleak is most common?
Type 2
In basics, what is an endoleak?
Blood leaking out of the graft/stent thing
Which is better
EVAR or Open repair?
Neither
Which one you use depends on ‘which set of compromises best fits your patient’
Which type of AAA repair surgery is carried out in emergency situations?
Both EVAR and open repair
Describe the process of an Emergency open repair
Prep abdomen & give rapid anaesthetic
Laparotomy xiphisternum to pubic symphysis (literally a giant cut down their abdomen)
Occlude the aorta proximally
Carry out repair
What are the problems associated with an emergency open repair?
High mortality (30-50%)
Significant post op morbidity
