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aortic_aneurysm_tx

thoracic aortic aneurysm

Introduction

  • aneurysm of the thoracic aorta is much less common than abdominal aortic aneurysm (AAA) and mainly occurs in those over the age of 60 yrs, although may occur in patients younger than 40yrs if they have a predisposing condition
  • they are rare, occurring in approximately 6-10 per every 100,000 people.
  • a dilated thoracic aorta is defined as having a diameter greater than 3.5cm, however in young or small adults, the descending aorta upper limit may be regarded as being 2.3cm, while in larger adults or the elderly, the upper limit for the ascending aorta may be regarded as being 4.3cm
  • a diameter greater than 4.5cm is regarded as aneurysmal and needs 6-12 monthly monitoring
  • surgery is offered when the risk of rupture is greater than the risk of the operation
    • thoracic aneurysms are much more difficult to repair and carry much greater risks from treatment than do abdominal aortic aneurysm (AAA)
    • elective surgical repair carries a 5% mortality rate
    • those larger than 6cm should be considered for endovascular or surgical intervention as they have much higher risks of rupture
    • those with Marfan's are often advised to have surgery once it reaches 4.5cm or if one is undergoing heart valve surgery
  • in contrast to these non-traumatic aneurysms, pseudoaneurysms of the thoracic aorta are usually the result of significant thoracic trauma, both penetrating and blunt, and carry a very high mortality, with 80-90% of patients dying before reaching hospital

Aetiology

Clinical features

  • most are asymptomatic and found incidentally on CXR, echo or CT scan
  • as they enlarge, some may cause:
    • chest pains, back pains, cough, SOB
    • dysphagia due to compression of the oesophagus
    • hoarse voice due to stretching of the recurrent laryngeal nerve
  • those with an impending potentially fatal complication such as rapid enlargement, tear or dissection
    • may present with severe chest pain as per aortic dissection
    • some may present with epigastric pain rather than chest pain
    • once bleeding occurs, the patient may present with hypotension, shock, raised inflammatory markers including raised C reactive protein (CRP) which may mimic septic shock, and may also cause nausea, vomiting, dizziness, clamminess and even haemoptysis (aorto-bronchial fistula), or haematemesis (aorto-oesophageal fistula)
    • once rupture occurs, mortality is 70-80%
      • some cease bleeding temporarily or survive long enough to allow emergency Open Aneurysm Repair which has a high rate of complications and only a 50% survival rate albeit with a prolonged recovery with lengthy ICU care being required. 1)

Mx of incidental asymptomatic non-traumatic thoracic aortic aneurysm

  • refer back to GP to arrange:
    • non-urgent CT aortogram (or perhaps echocardiogram)
    • referral to vascular surgeon as needed, especially if either:
      • greater than 6cm diameter, or,
      • cardiac valve surgery being considered, or,
      • Marfan's syndrome and diameter > 4.5cm
    • otherwise if greater than 4.5cm diameter:

Mx of symptomatic thoracic aortic aneurysm

  • urgent CT aortogram to exclude complications
  • if dissection or rupture evident, see as for aortic dissection
  • if no complication evident but symptomatic, discuss with vascular surgeon
aortic_aneurysm_tx.txt · Last modified: 2019/05/02 15:19 (external edit)