Abdominal aortic aneurysm

Question 1

What are aneurysms?

What is the difference between true and false aneurysm?

Answer 1

Aneurysms = permanent dilation of the artery to twice the normal diameter.

Aneurysms can be true or false:

a) True aneurysm => the arterial wall forms the wall of the aneurysm commonly seen in abdominal aorta, iliac, popliteal and femoral arteries.
b) False aneurysm (pseudoaneurysm) => surrounding tissues form the wall of the aneurysm commonly seen after femoral artery puncture.

Question 2

Who does abdominal aortic aneurysm commonly affect?

Answer 2

Increases with age

5% in >60years

Men > women [5:1]

1 in 4 male children of an affected individual

Question 3

What causes abdominal aortic aneurysm?

Answer 3

Commonly occurs below the renal arteries (infra-renal)

Aneurysm may be caused by
=> atherosclerosis
=> infection i.e. syphillis, E.coli, salmonella
=> trauma
=> genetics i.e. Ehler’s Danlos syndrome ; Marfan’s

Aneurysm => degeneration of elastic lamellae + smooth muscle loss

Question 4

What are the risk factors for abdominal aortic aneurysm?

Answer 4

Age

Male

Strong family hx

Smoking

Hypertension

Hypercholesterolaemia

Question 5

Abdominal aortic aneurysm screening:

Screening is offered to men aged 65-74 years

Abdominal ultrasound

=> Normal or <3cm aortas = no treatment

=> Small (3-4.4cm) aortas = annual ultrasound surveillance and GP review to optimize lifestyle

=> Medium (4.5-5.4cm) aortas = quarterly ultrasound surveillance and CVS secondary prevention

=> Large (>5.5cm) aortas = referred to assessment possible elective repair

Answer 5

INFO CARD

Screening reduces mortality!

Elective surgery mortality = 3.5%

vs

Emergency mortality = 50%

Question 6

What are the symptoms of abdominal aortic aneurysm?

Answer 6

Most are asymptomatic & found during routine abdo exam or plain x-ray

Rapid expansion or rupture of AAA => severe epigastric pain radiating to the back, iliac fossa or groin

Ruptured AAA causes hypotension, tachycardia, profound anaemia and sudden death

Aneurysm may embolise distally => lower limb ischaemia

Inflammatory aneurysm can obstruct adjacent structures i.e. ureters, duodenum, vena cava

Question 7

Symptoms of abdominal aortic aneurysm rupture may mimic which conditions?

Answer 7

Symptoms of AAA rupture may mimic:

=> renal colic
=> diverticulitis
=> severe lower abdominal or testicular pain

Question 8

What are the signs of abdominal aortic aneurysm?

Answer 8

Pulsatile, expansible abdominal mass

Presence of AAA => possibility of popliteal aneurysm?

“Trash feet” => dusky discolouration of the digits 2nd to emboli from aortic thrombus

*aorta is retroperitoneal => in an overweight person there may be no signs

Question 9

What is the criteria for elective surgery to go ahead?

Answer 9

Patient had best outcome if operated for:
=> >5.5cm aorta diameter or
=> expanding at a rate of >1cm/year or
=> symptomatic

Operation mortality 5%

Complications:
=> spinal / visceral ischaemia
=> distal emboli from dislodged thrombus

Question 10

What is the management for abdominal aortic aneurysm?

Answer 10

Medical:
=> Control of hypertension, smoking cessation and statins to lower lipids.
=> <5.5cm AAA need regular ultrasound follow up

Surgical:
=> Elective surgery - open aneurysm repair, hand-assisted or total laparoscopic repair

=> Endovascular aneurysm repair (EVAR) - endovascular stent insertion via femoral or iliac arteries

Question 11

What are the complications of abdominal aortic aneurysm?

Answer 11

Rupture

Thrombosis

Embolism

Fistula

Pressure on other structures

Question 12

What are thoraco-abdominal aneurysm?

Who does it affect?

Answer 12

Ascending, arch or descending thoracic aorta can become aneurysmal.

Ascending thoraco-abdominal aneurysms common in
=> Marfan’s syndrome
=> Hypertension

Descending or arch thoraco-abdominal aneurysm common in
=> secondary to atherosclerosis
=> syphillis

Question 13

What are the clinical features of thoraco-abdominal aneurysm?

Answer 13

Asymptomatic and found on routine chest x-ray or cardio investigation

Rapid expansion => severe chest pain radiating to upper back

Rupture => hypotension, tachycardia and death

Chest symptoms from expansion
=> stridor (compressed bronchial tree),
=> haemoptysis (aortobronchial fistula)
=> hoarseness (compression of recurrent laryngeal nerve)

Aorto-oesophageal fistula uncommon cause of haematemesis

Question 14

What are the investigations for thoraco-abdominal aneurysm?

Answer 14

CT / MRI

Aortography

Transoesophageal echocardiogram (TOE)

Question 15

How do you manage thoraco-abdominal aneurysm?

Answer 15

Bigger >6cm => operative repair or stenting

But it’s technically difficult and carries a high risk of mortality and paraplegia

Endovascular aneurysm repair (EVAR) for descending thoracic aneurysm