This is a prospective observational cohort study that will collect data from the point of referral through to secondary care, aiming for 3 years median follow-up (range 1-5 years). The data collected will allow estimation of the success of any intervention (in terms of reducing rate of aneurysm growth, rupture or dissection) as well as estimation of the risks associated with the three procedures. Clinical outcomes in the three treatment groups will be described.

Aims

We aim to answer the following questions:

1. Without procedural intervention for chronic thoracic aortic aneurysm (CTAA), what is the risk of aneurysm growth, dissection, rupture, permanent neurological injury or death? What is the effect on quality of life (QoL)?

2. If a patient has endovascular stent grafting (ESG) or open surgical repair (OSR), what is the risk of growth, dissection, rupture, permanent neurological injury or death?

3. How does QoL change from pre- to post intervention?

4. Can aneurysm or patient related predictors of good/poor treatment outcomes be determined?

5. What is the most cost-effective strategy in:

   1. Patients eligible for either ESG or OSR?
   2. Patients eligible for either ESG or best medical therapy (BMT)?
   3. Patients eligible for either watchful waiting (WW) or intervention (ESG/ OSR)?

6. What further research is required? What would be the most important research to pursue?

Inclusion Criteria:

• Thoracic Aortic Aneurysm > 4cm
• Age ≥18 years
• Able to give informed consent

Exclusion Criteria:

• Intervention required below the level of the coeliac axis
• Acute dissection or malperfusion syndromes (such as myocardial infarction,acute stroke or limb ischaemia)

Patients being referred to a specialist centre for diagnosis and treatment of their aneurysm