Abdominal Aortic Aneurysm Flashcards
(23 cards)
At what level does the abdominal aorta bifurcate
L4 (approx level of the umbilicus)
Bifurcation of the abdominal aorta into the common iliac arteries
In which patients are abdominal aortic aneurysms most common
Men Aged over 60 Smokers Hypertensive patients Often strong family history
What are the indications for surgery for repair of a AAA
Symptomatic aneurysms
Asymptomatic aneurysms:-
Over 5.5 cm diameter OR
Increase of diameter of greater than 1cm/yr (suggesting rapidly expanding aneurysm)
UK Small Aneurysm Trial:-
If aneurysm between 4.0 and 5.5cm diameter, open surgical repair not recommended
Aneurysms over 5.5cm diameter - patient will benefit from surgery
What symptoms might someone with an AAA present with
Back pain
Tenderness over the aneurysm on palpation
Distal embolic evens
Ruptured/leaked aneurysms
What is the risk of rupture of a greater than 5.5cm aneurysm
10% per year
Increasing with the size of the aneurysm
What is the operative mortality of AAA repair
Elective mortality is 5%
If the patient suffers a ruptured aneurysm:-
50% reach hospital alive
Of those, operative mortality is 50%
What is most often the cause of mortality in AAA repair
Haemorrhage
Subsequent MI
Renal failure
What are the surgical options for AAA
Endovascular AAA repair (EVAR)
Open repair
What is the principal behind an EVAR
Endovascular repair using grafts placed into the abdominal aorta from the femoral artery
Performed by a vascular surgeon and a radiologist
Operative mortality lower than for open repair
What are the complications of EVAR
Intraoperative:-
Local wound complications in groin
Access artery injury - thrombosis, dissection
25% operative mortality
Immediate:-
Clot formation or embolization into aortic side branches (eg. colonic, renal)
Renal/pelvic ischaemia - due to misplacement of stent graft covering side branch
Early and Late:- Endoleaks Stent-graft failure or migration Limb thrombosis Infection
What infectious agents are associated with AAA
Salmonella typhi - most common
Staphylococcal infection - sometimes
Syphilitic aneurysms - consigned to history
What is the MASS trial
Significantly reduced prevalence of aneursym-related death in the screened male population between 65 and 74
53% reduction
What age do we screen for AAA
65
What is the commonest way aneurysms present?
Incidental finding on scan for something else (e.g. prostate or renal USS)
What is the screening programme for aneurysms in the UK?
65 yo men have one-off USS
Normal at this stage- very low chance of aneurysm
What percentage of patients have an aneurysm identified on screening?
1%
What are the complications of aneurysms (AAA and popliteal)?
Rupture
Pain in back, tender aneurysm
Embolisation- “trash foot” (AAA- embolism formed from thrombosis, small ischaemic lesions visible on foot), missing pulses in popliteal artery aneurysm
Thrombosis- acutely ischaemic leg
Pressure- DVT due to popliteal aneurysm (occludes popliteal vein)
Fistulation- abnormal and permanent connection between two epithelial surfaces e.g. aorta and IVC (aortocaval fistula)
What percentage of patients with a AAA will also have a popliteal aneurysm?
10%
What is an intra-arterial digital subtraction angiogram?
Needle, wire and catheter passed into artery to insert contrast into artery.
X-ray of area then taken, then dye inserted, then another x ray taken
“One x-ray subtracted from the other”- left with inside of artery visualised
What is an intra-arterial digital subtraction angiogram used for?
Visualising where the normal artery is above and below an abnormality.
Not good for identifying an aneurysm or for sizing.
What is the definition of a AAA?
Abnormal dilatation of the abdominal aorta to over 50% its normal diameter i.e. 3cm+
What are the requirements for a conventional EVAR
The aneurysm needs a proximal neck of at least 5mm between the aneurysm and the renal arteries, that doesn’t contain a thrombus
How would you treat an aneurysm without a suitable neck
Fenestrated EVAR - side branches within the graft for visceral artery extensions
*Must be custom made and are very expensive
