Abdominal aortic aneurysm (AAA) Flashcards
What is an abdominal aortic aneurysm?
A condition where an area of the abdominal aorta bulges out.
This is usually asymptomatic; however, it has the potential to rupture, leading to haemorrhage and rapid death.
What is “AAA repair”?
A surgical procedure is performed where there is a significant risk of rupture to the aorta or where the AAA has ruptured.
It is performed as “open” surgery, or as an “endovascular repair”.
What does atherosclerosis cause?
Inflammation, which leads to infiltration by macrophages and deposition of immune complexes in the aortic wall.
There is then an elastin depletion, collagen degradation and smooth muscle loss.
This results in dilation in all layers of the aortic wall.
Aetiology of AAA?
→ Affects more males than females, with a prevalence of 1.3% in men >65 in the UK
→ Although the exact aetiology is unknown - believed to be due to atherosclerosis
Risk factors for abdominal aortic aneurysm?
- tobacco smoking
- family history
- increased age
- hyperlipidaemia
- history of atherosclerosis (inc. peripheral vascular disease + coronary artery disease)
- history of other aneurysms
- hypertension:increases risk of AAA and rupture
- COPD: associated with elastin degradation due to smoking
- european ancestry
- history of connective tissue disorders
What is the normal anatomy of the abdominal aorta?
→ continuation of the descending thoracic aorta
→ supplies all of the abdominal organs - it’s terminal branches supply pelvis + LL
→ also supplies the undersurface of the diaphragm and parts of the abdominal wall
→ the abdominal aorta begins at T12 and ends at L4, dividing into the right and left common iliac arteries
→ normal diameter = <2cm
Clinical features of AAA?
→ pts. usually asymptomatic and clinically well
→ most patients diagnosed due to screening programmes or when AAA ruptures
→ if the AAA ruptures patients can present with rapid onset abdominal, flank or back pain, shock and rapid loss of consciousness * usually with MI.
Prompt clinical assessment + escalation to vascular unit is critical
Diagnosis and investigations?
- AAA usually diagnosed by screening US
- Defined as abdominal aortic dilation of >1.5 times the expected anterior-posterior diameter; this is usually >3cm.
- If AAA is >5.5cm, they should be seen by vascular specialist within 2 weeks
- If AAA is <5.5cm, they should continue surveillance by the screening programme
Surgical management of AAA?
Surgery should be considered for an AAA >5.5cm in diameter, AAA expanding at >1cm a year, or symptomatic AAA in a patient who is otherwise fit.
The main treatment options are open repair or endovascular repair.
What is an open repair?
Involves a midline laparotomy or long transverse incision, exposing the aorta, and clamping on the aorta proximally and the iliac arteries distally, before the segment is removed and replaced with a prosthetic graft.
Midline laparotomy is likely to be more painful than a transverse incision.
What is an endovascular repair?
- Choice of procedure depends on anatomical suitability for endovascular repair and patient fitness
- EVAR is perfomred by inserting a stent graft through the femoral arteries under radiological guidance.
- The stent allows the blood to be diverted through the graft instead of the aneuysm sac.
What is the difference/similarity between an endovascular and an open repair?
Endovascular repair has an improved short-term outcome in decreasing hospital stay and decreasing 30-day mortality yet has a higher rate of reintervention and aneurysm rupture.
After 2 years the mortality for both procedures in the same, therefore in young fit patients, open repair is more appropriate.
Physiotherapist considerations for a pt. with AAA?
- immobility
- consider effects of surgery (open vs EVAR, length of time in theatre, effects of general anaesthetic, incision)
- PMh/SH of person - how does this impact their risk/management?
- oxygen requirements
- post-operative pain
