Abdominal Aortic Aneurysm

Question 1

Define an aneurysm

Answer 1

An abnormal localized dilation of a blood vessel

Question 2

What are the types and causes of aneurysm?

Answer 2

1. True aneurysm
   
   • Fusiform (symmetrical) or saccular
   • Contain all 3 layers of artery wall
   • Usually atherosclerotic
   • May be infective, Marfan’s and Ehlers-Danlos syndromes (collagen and elastin abnormalities)
2. False aneurysm
   
   • Pseudoaneurysm
   • Do not contain all 3 layers of artery wall
   • Usually secondary to penetrating trauma

Question 3

What are the risk factors of abdominal aortic aneurysm?

Answer 3

• Sex: male
• Age : older
• Diabetes mellitus
• BP high
• Elevated cholesterol (hyperlipidaemia, hypercholesterolaemia)
• Tobacco (4x more common in smokers)
• Family history of CV diseases

Question 4

What are the symptoms of an unruptured AAA?

Answer 4

• Majority asymptomatic
• Isolated back pain or epigastric/ umbilical pain radiating to the back (suggests sac expansion)
• Pulsatile abdominal mass
• Malaise & weight loss (suggests inflammatory aneurysm)
• Related;
  
  • Acute lower limb ischaemia (due to embolisation/ occlusion), intermittent claudication, TIA/ stroke
  • Exertional chest pain, palpitations, dyspnoea (difficult breathing), orthopnoea (SOB lying flat)

Question 5

What are the symptoms of a ruptured AAA?

Answer 5

• Sudden onset abdo/ back pain as with unruptured
• Hpovolaemic shock/ sudden collapse
• Pulsatile abdominal mass

Rarer presentations;

• Aorto-enteric fistula (ruptures into duodenum - massive upper GI bleeding)
• Aorto-caval fistula (ruptures into IVC)
• Haematuria with flank pain (rule out AAA before diagnosing ‘renal colic’

Question 6

What investigations can be undertaken to detect an AAA?

Answer 6

• Ultrasound scan of abdomen
  
  • Confirms presence and size of AAA
  • May show if suprarenal
  • Cannot confirm rupture
• CT scan of abdomen (& chest if thought to be thoraco-abdominal)
  
  • Shows AAA morphology & relationship to renal/ visceral arteries
  • Confirms rupture

Question 7

What are some differential diagnoses?

Answer 7

• Renal colic (keep AAA in mind)
• MI
• Acute pancreatitis
• Peptic ulcer
• Mesenteric infarct
• Diverticulitis
• Lumbar spine pathology

Question 8

What are the surgical treatments for abdominal aortic aneurysm?

Answer 8

1. Elective surgery
   
   • Open repair by graft
   • Laparoscopic repair is better
2. Endovascular repair
   
   • Endovascular aneurysm repair (EVAR) with a stent graft

Question 9

What is the non-surgical treatment of AAAs?

Answer 9

• Reduction of risk factors
• Antiplatelet medication
• Statins

If ruptured;

• Oxygen
• Large IV cannula; normal saline & colloid (not 5% dextrose) fast infusion
• Blood transfusion
• Analgesia
• Urinary catheter
• THEATRE

Question 10

What is endoleak and what are the classifications?

Answer 10

An endoleak is a leak into the aneurysm sac after endovascular repair

Types 1-5;

1. Related to graft itself
2. Due to retrograde flow from collateral branches
3. Due to fabric tears, graft disconnection, or disintegration
4. Due to ‘porosity’
5. Endotension - persistent pressurisation of sac with no endoleak

Question 11

How would you treat type 1 & 3 endoleak?

Answer 11

• Moulding balloon
• Proximal or distal extension
• Extra stent graft

Question 12

How would you treat type 2 endoleak?

Answer 12

• Most can be left if no expansion of aneuysm
• Embolization, laparoscopic clipping, polymer injection (onx)