abdominal aortic aneurysm

Question 1

what is an aneurysm

Answer 1

A permanent, localised dilatation of an artery of more than 50% of the normal arterial diameter

or

Aneurysms are a permanent dilation of the artery to twice the normal diameter - this is > 3cm for abdominal aorta.

Question 2

what does AAA increase with

Answer 2

age - AAAs are present in 5% of the population over 60 years of age

Question 3

who is more likely to get AAA

Answer 3

• Arise 5x more frequently in men
• Higher risk if patient has 1st degree relative with AAA
• older people

Question 4

when may Aneurysms occur:

Answer 4

• After atherosclerosis (most common)
• Infection (syphilis, Escherichia coli, Salmonella) and Trauma
• Genetic (Marfan’s or Ehlers–Danlos syndrome)

Question 5

Pathophysiology

Answer 5

• Degeneration of tunica media of the artery
• During atheroscrelosis, macrophages release enzymes which break down collagen and elastin of tunica media so media expands
• AAAs inferior to renal arteries (infrarenal), superior to illiac bifurcation

Question 6

asymptomatic clinical presentation

Answer 6

75% asymptomatic (incidental finding) until rupture

Question 7

symptomatic clinical presentation

Answer 7

• Proximal AAA: upper abdomen, back pain
• Distal AAA: lower abdomen, back pain
• Unruptured aneurysm: vauge, non-specific pain
• Ruptured aneurysm: sudden onset severe pain

Question 8

other signs of AAA

Answer 8

• 5.5cm AP diameter
• Rapid expantion of >1cm per year
• Patients present with ‘trash feet’, dusky discoloration of the digits secondary to emboli from the aortic thrombus
• Collapse (due to hypotension)
• Tachycardia

Question 9

investigations

Answer 9

• Monitoring - Ultrasound Scan (USS)
• Ruptured AAA - CT Angiography

Question 10

Monitoring - Ultrasound Scan (USS)

Answer 10

• Shows whether there is an AAA or not, its AP diameter, and whether there is iliac involvement
• There is a monitoring program for all men over 65 in the UK

Question 11

Ruptured AAA - CT Angiograph

Answer 11

CT: only imaging method for identification of ruptured AAA

Diagnosis usually clinical - needs to be made quickly and vascular surgeon contacted

Question 12

medical mangement

Answer 12

Control of risk factors - antihypertensives, smoking cessation, statin (lipid-lowering medication)

Question 13

surgical asymptomatic management

Answer 13

• Elective Aneurysm repair: is a prophylactic operation to reduce the risk of rupture balanced against the risk of the procedure.
  
  • > 5.5 cm in diameter or rapid expansion

Question 14

surgical symptomatic management

Answer 14

• Emergency Aneurysm repair: is a therapeutic procedure balancing the expectation of death against the risk of the procedure
  
  • Graft - EVAR (Endovascular Aneurysm Repair) or Open Lap

Question 15

Fitness of intervention

Answer 15

• Cardiac assessment - Echo/ Ejection Fraction
• Respiratory assessment - PFT
• Cardiopulmonary exercise test - CPX testing
• Renal assessment - U&Es
• Vascular Assessment - peripheral pulses / ABPI
• Anaesthetic assessment
• EBT - ‘end of bed or eyeball’ test