[7] Thoracic Aortic Aneurysm Flashcards

1
Q

What is an aneurysm?

A

A persistent, abnormal dilation of an artery to 1.5x its normal diameter

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2
Q

What can a thoracic aortic aneurysm involve?

A
  • The ascending aorta or aortic root
  • Aortic arch
  • Descending aorta
  • Thoracoabdominal aorta segments
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3
Q

What % of thoracic aortic aneurysms involve the ascending aorta or aortic root?

A

60%

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4
Q

What % of thoracic aortic aneurysms are in the aortic arch?

A

10%

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5
Q

What % of thoracic aortic aneurysms are in the descending aorta?

A

40%

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6
Q

What % of thoracic aortic aneurysms are in the thoracoabdominal aorta segments?

A

10%

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7
Q

What is more common, abdominal or thoracic aortic aneurysms?

A

Abdominal

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8
Q

What has a higher mortality, abdominal or thoracic aortic aneurysms?

A

Thoracic

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9
Q

Why is the classification of aortic aneurysms important?

A

Because aneurysms in different locations present with different symptoms, and have different levels of surgical risk

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10
Q

What do thoracic aortic aneurysms develop due to?

A

Degradation of the tunica media

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11
Q

What is the tunica media?

A

The layer of the artery which provides tensile strength and elasticity to the wall

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12
Q

What is the result of the degradation of the tunica media in the thoracic aorta?

A

They artery looses structural integrity and dilates

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13
Q

What happens as the diameter increases in the development of thoracic aortic aneurysms?

A

The wall tension rises and further increases the diameter in a vicious cycle

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14
Q

What are the main causes of thoracic aneurysms?

A
  • Connective tissue disease
  • Bicuspid aortic valve
  • Trauma
  • Aortic dissection
  • Aortic arteritis
  • Tertiary syphillis
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15
Q

Give two examples of connective tissue diseases that can cause thoracic aortic aneurysms

A
  • Marfan’s syndrome
  • Erlers-Danlos syndrome
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16
Q

Why is there an increased risk of thoracic aortic aneurysm in patients with Turners syndrome?

A

Due to increased risk of bicuspid aortic valve

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17
Q

Give an example of an aortic arteritis

A

Takayasu arteritis

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18
Q

What is the mean rate of growth of thoracic aortic aneurysms?

A

1-2mm/year

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19
Q

When is the rate of growth of thoracic aortic aneurysms higher?

A
  • Marfan’s syndrome
  • Descending aneurysms
  • Dissected aneurysm
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20
Q

What are the main risk factors for developing thoracic aortic aneurysms?

A
  • Family history
  • Hypertension
  • Atherosclerosis
  • Smoking
  • High BMI
  • Male gender
  • Advancing age
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21
Q

How are thoracic aneurysms typically found?

A

Incidentally - typically are asymptomatic

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22
Q

What is the most common presenting complaint in those with symptomatic thoracic aortic aneurysms?

A

Pain

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23
Q

Why is it important to know where the pain is in thoracic aortic aneurysms?

A

It can potentially localise the aneurysm

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24
Q

Where does an aneurysm in the ascending aorta cause pain?

A

Anterior chest

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25
Q

Where does an aneurysm in the aortic arch cause pain?

A

Neck

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26
Q

Where does an aneurysm in the descending aorta cause pain?

A

Between the scapulae

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27
Q

What are the other symptoms of thoracic aortic aneurysms?

A
  • Back pain
  • Hoarse voice
  • Distended neck veins
  • Symptoms of heart failure
  • Dyspnoea or cough
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28
Q

Which thoracic aortic aneurysms can cause back pain?

A

Descending or thoracoabdominal

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29
Q

What causes back pain in thoracic aortic aneurysms?

A

Secondary to spinal compression

30
Q

Which thoracic aortic aneurysm can cause a hoarse voice?

A

Aortic arch aneurysms

31
Q

How can thoracic aortic aneurysms cause a hoarse voice?

A

Damage to the left recurrent laryngeal nerve

32
Q

How can thoracic aortic aneurysms cause distended neck veins?

A

From SVC compression

33
Q

How can thoracic aortic aneurysms cause symptoms of heart failure?

A

From involvement of the aortic valve

34
Q

How can thoracic aortic aneurysms cause dyspnoea or cough?

A

Secondary to tracheal or bronchial compression

35
Q

What are the clinical signs of thoracic aortic aneurysms on examination?

A

Clinical signs are not commonly found on examination, however chronic disease may present with the signs of aortic root disease or heart failure

36
Q

What is the risk with thoracic aortic aneurysms?

A

They have a risk of rupture or dissection

37
Q

How will an acute aortic syndrome present?

A

With sudden onset pain in the back, chest, neck, and/or abdomen

38
Q

Why are differential diagnoses rarely considered before a diagnosis of a thoracic aortic aneurysm is made?

A

Because most thoracic aneurysms are found incidentally on imaging

39
Q

What diagnoses should be considered in a patient presenting with chest or back pain?

A
  • ACS
  • PE
  • Pneumothorax
  • Aortic dissection
40
Q

How are thoracic aneurysms diagnosed?

A

Imaging

41
Q

What should initial inpatient and pre-operative testing involve in patients with thoracic aortic aneurysms?

A
  • Routine bloods, including FBC, U&Es, and clotting
  • Group and save
  • ECG
  • CXR
42
Q

What imaging can be used in the diagnosis of a thoracic aortic aneurysm?

A
  • CXR
  • CT chest scan with contrast
  • Transoesophageal echocardiography
43
Q

What are the signs of thoracic aortic aneurysm on CXR?

A
  • Widened mediastinal silhouette
  • Enlarged aortic knob
  • Possible tracheal deviation
44
Q

What is the limitation of a CXR in the diagnosis of a thoracic aortic aneurysm?

A

A CXR alone is not sensitive enough to make a definitive diagnosis, and further imaging is required

45
Q

What is the preferred imaging modality for thoracic aortic aneurysms?

A

CT chest scan with contrast

46
Q

When is a CT scan with contrast sufficient to definitively diagnose a thoracic aortic aneurysm?

A

If there is sufficient detail to ascertain the level and size of the aneurysm

47
Q

What care needs to be taken when measuring the size of a thoracic aortic aneurysm using a CT scan with contrast?

A

Due to the potentially tortous nature of the thoracic aorta, and the use of axial images in CT scans, care needs to be taken to ensure the actual aortic diameter is being measured, not simply measuring throug the aorta off-axis

48
Q

How can the issue with measuring the aortic diameter using CT scans be overcome?

A

Reconstructing axial imaging into 3D images via CT angiography or MR angiography

49
Q

How are confirmed thoracic aortic aneurysms intially be managed?

A

Start patients on medical management, alongside any concurrent further investigations and definitive management planned

50
Q

What medical management should people with thoracic aortic aneurysms be started on?

A

These patients are at increased cardiovascular risk, and therefore should be initiated on;

  • Statins
  • Antiplatlet therapy
  • Blood pressure management

They should also be encourged to stop smoking

51
Q

Why should patients with thoracic aortic aneurysms be started on statins and anti-platelet therapy?

A

To decrease the risk of myocardial infarction

52
Q

What is the surgical management of thoracic aortic aneurysms dependant on?

A

The location of the aneurysms

53
Q

What does the threshold for surgery in thoracic aortic aneurysms depend on?

A

The health of the patient

54
Q

Which patients often have a lower threshold for surgical intervention in thoracic aortic aneurysms?

A
  • Patients with Marfan’s syndrome
  • Those who have had a previous thoracic dissection
55
Q

Why do patients with Marfan’s syndrome or a previous thoracic dissection have a lower threshold for surgical intervention?

A

They are at higher risk of dissection and rupture

56
Q

What is an ascending aortic aneurysm treated surgically?

A

When the diameter >5.5cm

57
Q

How is an ascending aortic dissection treated?

A

The affected region of the aorta is excised and replaced with a dacron graft

58
Q

How is an ascending aortic aneurysm treated if the aortic root is involved?

A

A Bentall procedure is often performed, using a graft that also contains a prosthetic valve

59
Q

When is an aortic arch aneurysm considered for surgical treatment?

A

Once the aneurysm is over 5.5cm

60
Q

How is an aortic arch aneurysm treated surgically?

A

The affected aorta is replaced with a multi-limbed graft

61
Q

Why is a multi-limbed graft used in the surgical treatment of aortic arch aneursyms?

A

It allows for branching of the great vessels

62
Q

What is there a high risk of aortic arch aneurysm repair?

A

Cerebral ischaemia from embolisation

63
Q

When should surgery be considered for the management of a descending aortic aneurysm?

A

When the diameter exceeds 6.0cm

64
Q

How can descending thoracic aortic aneurysms be managed surgically?

A

Can be repaired using open technique or endovascular technique

65
Q

What is the advantage of endovascular repair over open repair in descending thoracic aortic aneurysms?

A

It has been shown to produce fewer post-operative complications and have lower mortality

66
Q

What is the result of the development of a second thoracic aortic aneurysm not being uncommon post-intervention?

A

Ongoing imaging studies as an outpatient are required following surgery

67
Q

What imaging studies are used in the follow-up of post-treatment thoracic aortic aneurysms?

A

CT or MRI

68
Q

What is the perioperative mortality of thoracic aortic aneurysms?

A

Between 2-17%

69
Q

Which kind of thoracic aortic aneurysms have the highest mortality?

A

Arch aneurysms, 25% mortality

70
Q

What is the annual risk of rupture or dissection of thoracic aortic aneurysms in patients who are monitored prior to surgery?

A
  • 2% when <5cm
  • 3% when 5-5.9cm
  • 7% when 6cm or above