Vascular surgery

Question 1

Definition of AAA

Answer 1

Abdominal aortic aneurysm (AAA) is a permanent pathological dilation of the aorta with a diameter >1.5 times the expected anteroposterior (AP) diameter of that segment, given the patient’s sex and body size. Commonly adopted threshold is >3cm.

Question 2

Where does AAA happen

Answer 2

More than 90% of aneurysms originate below the renal arteries.

Question 3

Epidemiology of AAA

Answer 3

Prevalence among men is 4 to 6 times higher than in women.

Question 4

Risk factors of AAA

Answer 4

SMOKING, male, >60, family history, atherosclerosis.

Question 5

Pathophysiology of AAA

Answer 5

Elastin fibres become disrupted and collagen becomes degraded resulting in loss of elasticity in the aortic wall.

Question 6

Key findings on history of AAA

Answer 6

new abdominal and/or back pain, cardiovascular collapse, or loss of consciousness. Index of suspicion should be particularly high if they are aged over 60, male, HTN, smoker, previous AAA, FH AAA

Question 7

Key findings on examination of a ruptured AAA

Answer 7

Classic triad of a pulsatile abdominal mass with hypotension and abdominal and/or back pain is present in about 50% of patients with a ruptured AAA. There can be pallor, haemodynamic collapse, and abdominal distension

Question 8

History and examination findings in an unruptured AAA

Answer 8

Can be asymptomatic until rupture. May complain of abdominal pain

Question 9

Differentials of AAA

Answer 9

Diverticulitis (typically localises to left lower quadrant), ureteric colic (severe abdominal pain that starts in the flank and radiates anteriorly to the groin), IBS, IBD, appendicitis, ovarian torsion, GI haemorrhage

Question 10

Investigations for AAA

Answer 10

1st line: aortic ultrasound 2ns line: contrast-enhanced computed tomography angiography [CTA]
*if ruptured AAA is suspected; cross match which is necessary for blood transfusion.

Question 11

When is USS used in AAA

Answer 11

• confirm the presence and size of an AAA, but cannot definitively rule out a ruptured AAA.
• Surveillance of asymptomatic AAA to guide treatment
• Follow-up after surgery with endovascular aneurysm repair (EVAR) (using colour duplex ultrasound).

Question 12

When is CTA used in AAA

Answer 12

• definitive imaging modality for AAA rupture

- contrast-enhanced CTA is used to assess the extent and anatomy of disease and to assist with operative planning

Question 13

What would bloods in a AAA patient indicate?

Answer 13

• Full blood count may show anaemia if there is haemorrhage due to ruptured AAA.
• Leukocytosis and a relative anaemia with positive blood cultures are indicative of infectious AAA.
• Elevated ESR and CRP support a diagnosis of possible inflammatory AAA

Question 14

Management of symptomatic and ruptured AAA

Answer 14

1st line: urgent surgical repair. EVAR is recommended in most patients >70 with ruptured infrarenal AAA. Open surgery is recommended for patients <70.
In addition to resus measures (supplemental oxygen, IV access, catheter), perioperative antibiotic therapy, analgesia, VTE prophylaxis.

Question 15

Management of incidental finding of AAA

Answer 15

Surveillance for a small <5.5cm AAA or >4cm rapidly growing AAA. aggressive cardiovascular risk management (smoking cessation services, antiplatelet therapy, antihypertensives.

If AAA >5.5cm or >4cm and rapidly growing - elective surgical repair

Question 16

Complications of AAA

Answer 16

• abdominal compartment syndrome (ACS) 55% chance after open repair of ruptured AAA
• Ileus has been reported in 11% of patients
• haemorrhage and mortality

Question 17

Prognosis of AAA

Answer 17

• most patients with rupture will not survive to reach the operating theatre.
• 70% 5 year survival rate after open repair