AAA

Question 1

What is the equation for the law of Laplace?

Answer 1

Tension = (pressure x radius)/ wall thickness.

Question 2

What are risk factors for AAA?

Answer 2

Smoking, increasing age, being male, family history, PVD. Being Caucasian also incidence is raised in more deprived groups.

Question 3

What is the marker of a true arterial aneurysm?

Answer 3

50 % increase in normal diameter.

Question 4

What is the ratio of males to females with AAA?

Answer 4

5:1.

Question 5

What percentage of aneurysms are Asymptomatic?

Answer 5

75%

Question 6

What are the symptoms of a AAA when there are any?

Answer 6

Pain (abdominal, back, renal colic).
Trashing.
Collapse.

Question 7

What is trashing in relation to AAA?

Answer 7

Emboli to peripheral small vessels causing occlusion.

Question 8

What are the signs and symptoms of a ruptured AAA?

Answer 8

May look well.
May have a tachycardia or not.
Hypotensive or not.
Pulsation expansive mass +/- tenderness.
Transmitted pulse - a mass lying over the aorta transmitting its pulse.

Question 9

What two types of AAA rupture do we get in relation to the peritoneum?

Answer 9

Most retroperitoneal contained rupture.

Free intraperitoneal rupture is rapidly fatal.

Question 10

What investigations do we do for a AAA?

Answer 10

Ultrasound and CT scan.

Question 11

What are differences between a CT scan and an ultrasound scan for AAA?

Answer 11

Ultrasound is for screening/surveillance and tells you if aneurysm present, if the iliac arteries are involved and what its AP diameter is.
CT scan - uses IV contrast in the arterial system. It allows us to see the morph only e.g. Size and shape. Also allows us to see the extent of iliac involvement and allows us to formulate a better management plan.
CT is also the only imaging type we can use to identified a ruptured aneurysm.

Question 12

How are elective aneurysms managed differently form emergency aneurysms?

Answer 12

Elective - the risk of rupture is balanced against the risk of the procedure.
Emergency balances the expectation of death against the risks of the procedure.

Question 13

How much do abdominal aneurysms expand roughly per year?

Answer 13

2-3mm.

Question 14

What size of aneurysms have the greatest chance of rupture?

Answer 14

> 5cm have a 22% chance in 4 years.

Question 15

What is the management of an elective AAA?

Answer 15

Surveillance and possible active intervention with an EVAR or open procedure. May decide to do nothing.

Question 16

What is the management of an emergency AAA?

Answer 16

an EVAR or open procedure. May decide to do nothing.

Question 17

What is an EVAR?

Answer 17

Endovascular aneurysm repair. It excludes the AAA from inside the vessel. Inserted via peripheral artery. X-ray guided. Basically parts of a tube are fitted into the artery which stops the outside part from filling with blood.

Question 18

What happens during an open repair of AAA?

Answer 18

Laparotomy, clamp aorta plus iliacs and use a Dacron graft.

Can use a tube vs bifurcated graft.

Question 19

How does an EVAR compare to an open procedure in terms of availability, risks, recovery etc?

Answer 19

EVAR- not possible in 25% of patients, lower mortality risk than open. Much faster recovery and needs follow up. May need further intervention.
Open - possible in everyone, greater mortality risk. Much slower recovery. Rarely needs further intervention.

Question 20

What assessments do we do to see if patients are fit for AAA intervention?

Answer 20

Cardiac assessment.
Respiratory assessment.
Cardiopulmonary exercise testing.
Renal assessment 
Vascular assessment
Anaesthetic assessment.
End of bed or eyeball test.

Question 21

What is the epidemiology of AAA?

Answer 21

Males over 60.

Question 22

What are the causes of AAA?

Answer 22

Smoking, hypertension, diabetes, high cholesterol, CVS disease.

Question 23

What is the pathology of AAA?

Answer 23

Medial degeneration

Law of Laplace.

Question 24

What are the outcomes of AAA procedures in terms of mortality?

Answer 24

Elective 2-5% mortality

Emergency 30-50% mortality.

Question 25

What is the pathogenesis of aortic aneurysm?

Answer 25

Medial degeneration, Regulation of elastin/collagen in aortic wall. Aneurysmal dilatation, increase in aortic wall stress. Progressive dilatation.

Question 26

What do we do if an aneurysm is under 5.5cm?

Answer 26

Monitor it.

Question 27

What do we do if an aneurysm is 5.5cm or over?

Answer 27

An elective repair.