Aortic Aneurysm

Question 1

What is an aneurysm defined as?

Answer 1

• AAA dilatation > 1.5 times normal AP diameter
• True aneurysm: dilatations involve all layers of the arterial wall
• False (pseudo)aneurysm: blood collection in outer layer (adventitia) only

Question 2

What are the two forms of aneurysms?

Answer 2

• Fusiform (most AAAs)
• Sac-like (Berry aneurysms)

Question 3

Causes of aneurysms?

Answer 3

• Atheroma
• Infections
• Inflammatory
• Connective tissue disorders

Question 4

Complications of aneurysms?

Answer 4

• Fistulae
• Rupture
• Thrombosis/embolism
• Pressure on other structures

Question 5

Screening of aneurysms?

Answer 5

• Men offered abdominal US from 65-75
• Selective screening based on risk factors

Question 6

Symptoms & signs of a ruptured AAA?

Answer 6

• Abdominal pain radiating to the back
• Expansile abdominal mass (expands and contracts)
• Shock

Question 7

Describe an unruptured AAA?

Answer 7

• >3cm diameter
  
  • Normal after 50 yrs(Men 1.7cm, women 1.5cm)
• Failure of elastic proteins within the ECM
• Often asymptomatic and incidental finding on abdominal exam

Question 8

What makes AAA rupture more likely?

Answer 8

• Smoking
• Female sex
• Hypertension
• Positive family history

Question 9

Describe surgery for unruptured AAA?

Answer 9

• Surgery for:
  
  • Aneurysms >5.5cm, expanding >1cm/yr, symptomatic
• Stenting (EVAR) procedure

Question 10

Describe overview of open AAA repair?

Answer 10

• Laparotomy, dissection to the AA
• Clamping of the artery below renal arteries and in the iliac arteries
• Aneurysm is opened:
  
  • IMA and lumbar arteries ligated
  • Tube or bifurcated graft are sutured into the aorta to exclude the aneurysm
• Aneurysms sac is sutured over the graft to reduced infection rates

Question 11

Describe EVAR?

Answer 11

• Endovascular stent inserted via the femoral artery
• Less mortality than major surgery but higher graft complications
  
  • eg endoleak: blood may leak into aneurysm

Question 12

Complications of open AAA repair?

Answer 12

• Intra-operative complications:
  
  • Haemorrhage
  • Injury to surrounding structures
• Early complications:
  
  • Infection
  • Blood clots
• Late complications:
  
  • Hernia
  • Adhesions

Question 13

Describe the emergency management of a ruptured abdominal aneurysm?

Answer 13

• Inform vascular surgeon, experienced anaesthetist
• Crossmatch blood, catheterise
• Insert 2 large bore cannulase
  
  • Treat shock with O rhesus negative blood
• Prophylactic antibiotics eg co-amoxiclav
• Surgery:
  
  • Clamping of aorta above the leak
  • Tube graft inserted
  • If iliac aneurysm: trouser graft, leg attached to each iliac artery

Question 14

What infectious disease is an ascending aortic aneurysm associated with?

Answer 14

Tertiary syphilis

Question 15

Name another cause of an adominal pulsatile mass?

Answer 15

• Tumour of pancreas or stomach
  
  • Aortic passess between these structures

Question 16

Abdominal aorta anatomy

Answer 16

Question 17

Pathophysiology of AAA?

Answer 17

• Obliteration of collage and elastin in the media and adventitia
• Smooth muscle loss
• Infiltration of lymphocytes and macrophages

Question 18

What are the different classifications of AAA?

Answer 18

• Congenital
  
  • Accelerated in patients with Biscupid AV or Marfans
• Infectious
  
  • Staphylococcus and salmonella are most common causes
• Inflammatory

Question 19

Common presentations of AAA

Answer 19

Question 20

Differentials for AAA?

Answer 20

• Diverticulitis
  
  • No pulsatile abdominal mass
  • CT scan shows normal aorta
• Irritable bowel syndrome (IBS)
  
  • Bloating, stool frequency
  • More common in women
• Appendicitis

Question 21

What is the most common site for aneurysmal disease required treatment?

Answer 21

Infrarenal aorta

Question 22

What reasons might a patient survive a ruptured AAA?

Answer 22

• Bleed into retroperitoneum which tamponades the leak
• Intense vasoconstriction of nonessential circulatory beds
• Development of an intense prothrombotic state
• BP drops which limits blood loss

Question 23

What must be screened for in patients with AAA?

Answer 23

• Popilteal aneurysms
  
  • Ultrasound

Question 24

Describe the management of popliteal aneurysms?

Answer 24

• Exclusion of the aneurysm
• With bypass using the long saphenous vein