Thoracic aortic aneurysm

Question 1

What is an aneurysm?

Answer 1

• Perisistent abdominal dilatation of artery to 1.5 its normal diameter

Question 2

What does a thoracic aortic aneurysm involve?

Answer 2

Can involve:
* Ascending aorta or
* Aortic root or
* Aortic arch or
* Descending aorta or
* Thoracoabdominal aorta segments

Question 3

Thoracic aortic aneurysm vs AAA

Answer 3

• Less common but high mortality

Question 4

Cause of thoracic aortic aneurysm - what happens

Answer 4

• Degradation of tunica media
• Artery loses structural integrity and dilates
• Diameter increases = wall tension rises and further increases diameter –> cycle

Question 5

Main causes of thoracic aneurysm - underlying

Answer 5

• Connective tissue diseases
• Bicuspid aortic valve
• Other - trauma, aortic dissection, aortic arteritis, tertiary syphilis

Question 6

Growth of thoracic aortic aneurysm

Answer 6

• Usually grow mean rate 1-2mm per year
• Rate higher in Marfans and descending aneurysms (compared to ascending) and dissected (compared to non)

Question 7

RF for thoracic aortic aneurysm

Answer 7

• FH
• HTN
• Atherosclerosis
• Smoking
• High BMI
• Male
• Advanced age

Question 8

Presentation of TAA

Answer 8

• Often asymptomatic - found incidentally
• If symptomatic –> chest pain
• Location of aneurysm determines location of pain
• Ascending –> anterior chest pain
• Aortic arch –> neck pain
• Descending –> posterior thoracic

Question 9

Other symptoms of TAA

Answer 9

• Back pain - spinal compression
• Hoarse voice - damage to left recurrent laryngeal nerve in arch aneurysm
• Heart failure - if invovlement of aortic valve
• Can get distended neck veins if SVC compression

Question 10

TAA risk

Answer 10

• Risk of rupture or dissection –> lethal
• = sudden onset chest/back pain and hypovolaemic shock

Question 11

Bedside and bloods for TAA

Answer 11

• Routine bloods - FBC, U&E, clotting
• ECG

Question 12

Imaging for TAA

Answer 12

• CXR - see widened mediastinum, enlarged aortic knob and possible tracheal deviation BUT NOT sensitive enoigh to definitive diagnose
• Need CT angiogram
• TOE can also be used to detect aortic dissection etc

Question 13

Management TAA - medical

Answer 13

• Medical management - statin and antiplatelet therapy (eg Clopidogrel)
• Decrease risk of MI
• Control BP and smoking cessation

Question 14

When to surgically manage TAA?

Answer 14

• Dependent on location and patient factors
• eg Marfans or previous thoracic dissection have greater risk of dissection/rupture = lower threshold to intervene

Question 15

Location of TAA and when to surgically intervene

Answer 15

• Ascending aorta - when diameter >5.5cm, excised and replaced with graft. Bentall procedure if aortic root involved (replaces valve too)
• Aortic arch - >5.5cm, multilimbed graft (for branching vessels)
• Descending aorta - >6cm - open or endovascular

Question 16

Prognosis for TAA

Answer 16

• 2nd aneurysm not uncommon
• Ongoing imaging needed
• F/u with CT or MRI