Thoracic aortic aneurysm (TAA) is the focal dilatation of the thoracic aorta to more than 1.5 times its normal diameter. TAAs are classified by location as affecting the ascending aorta, descending aorta, or aortic arch. Men of advanced age are at a higher risk of forming TAAs; other risk factors include trauma, connective tissue disorders, and hypertension. TAAs are frequently asymptomatic and therefore detected incidentally. If symptomatic, they may manifest with a feeling of pressure in the chest, thoracic back pain, and signs of mediastinal obstruction (e.g., difficulty swallowing). The initial test is often a chest x-ray, which may show a prominent aortic arch. CT with contrast is used to confirm the diagnosis and determine the extent of the aneurysm. Observation, close follow-up, and reduction of cardiovascular risk factors are indicated for small aneurysms whereas pronounced or rapidly expanding aneurysms require surgery. TAA rupture and dissection are life-threatening conditions that require emergency surgical repair to prevent cardiac tamponade, hemothorax, and death.
- Arterial hypertension
- Advanced age
- Tertiary (due to obliterative endarteritis of the vasa vasorum) 
- Connective tissue diseases (e.g., Marfan syndrome, Ehlers-Danlos syndrome)
- Bicuspid aortic valve 
- Positive family history
- Rare: vasculitis/infectious diseases with aortic involvement (e.g., Takayasu arteritis)
- Ascending thoracic aortic aneurysm: most often due to cystic medial necrosis
- Descending thoracic aortic aneurysm: typically a result of atherosclerosis
- Inflammation and proteolytic degeneration of connective tissue proteins; (e.g., collagen and elastin) and/or smooth muscle cells in high-risk patients → loss of structural integrity of the aortic wall → widening of the vessel
- The aneurysmatic dilatation of the vessel wall may cause disruption of the laminar blood flow and turbulence.
- Possible formation of thrombi in the aneurysm → peripheral thromboembolism
Aortic aneurysms are mostly asymptomatic or have nonspecific symptoms. They are often discovered incidentally on imaging.
- Indications: may be conducted as an initial imaging study in patients with chest pain and/or dyspnea
- Suggestive findings 
CT angiography chest
- Indications: best confirmatory test for TAAs
Supportive findings 
- Dilatation of the aorta 
- Possible mural thrombus (nonenhancing)
- Possible dissection, perforation, or rupture
- MR angiography chest with and without IV contrast
- Transthoracic echocardiography 
- Transesophageal echocardiography: allows for more accurate assessment than TTE 
Catheter angiography (aortography) 
- Evaluation and possibly treatment of coexisting coronary artery disease
- Assessment of aortic lumen and branch vessels
- Supportive findings: contrast column in the lumen of the aneurysm
- See “ .”
- See “ .”
The differential diagnoses listed here are not exhaustive.
- Unstable patients (e.g., in the case of rupture): emergency TAA repair (see “Thoracic aortic aneurysm rupture”)
- Symptomatic patients: urgent TAA repair
- Asymptomatic patients
- All patients: conservative management with reduction of cardiovascular risk factors
Invasive treatment: TAA repair 
- TAA rupture
- Symptomatic TAA
- Asymptomatic TAA when size or growth thresholds are passed
Indications for asymptomatic patients
The decision to perform elective TAA repair in asymptomatic patients depends on the size and expansion rate of the aneurysm. In all patients, the risks and benefits of aneurysm resection should be weighed carefully. 
|Indications for TAA repair in asymptomatic patients |
|Affected location of the aorta||Aortic diameter|
|Aortic arch (isolated)|| |
|Descending aorta|| |
Open surgical repair (OSR) is recommended for patients with TAA of the ascending aorta and aneurysms involving the aortic arch. For patients with descending thoracic or thoracoabdominal aortic aneurysms, thoracic endovascular aneurysm repair (TEVAR) or OSR can be performed.
Open surgical repair (OSR) 
Open surgical repair is a major operation with high associated morbidity and mortality. 
- Indications: preferred in young patients with few comorbidities and low surgical risk and patients with connective tissue disorders 
- Complications: 40% of all patients experience a perioperative complication 
Thoracic endovascular aneurysm repair (TEVAR) 
- Indications: Degenerative or traumatic descending aortic aneurysms
- Procedure: Under fluoroscopic guidance, an expandable stent graft is placed via the femoral or iliac arteries intraluminally at the site of the aneurysm.
- Complications 
- Other: requires lifelong postoperative surveillance
Concomitant diseases may require additional procedures, e.g., CABG, valve replacement or repair.
- Identify coronary anatomy and possible CAD before repair of the ascending aorta.
- In end-organ ischemia or stenosis, ancillary revascularization is recommended.
- See “ .”
Surveillance after repair 
CTA chest abdomen pelvis with IV contrast
- Initially: within the first month then at 3–12 months
- Then every 6–12 months depending on the stability of findings
- MRA chest/abdomen/pelvis with IV contrast: in patients with MR-compatible stent grafts (e.g., nitinol)
All patients should receive conservative treatment to reduce the risk of further aneurysm expansion or rupture. Regular aneurysm surveillance via CT or MR is recommended for patients in whom the diameter of the aneurysm has not reached the threshold defined as the indication for repair.
Reduction of cardiovascular risk factors 
Blood pressure management
- Optimal blood pressure goal to reduce aortic wall stress: the lowest blood pressure that the patient can tolerate 
- Preferred agents:
- Smoking cessation
- Lipid profile optimization: in patients with atherosclerotic aortic aneurysms
Lifestyle modification 
- No participation in most competitive sports
- No heavy weight lifting
Follow-up frequency for surveillance of thoracic aortic aneurysm or dilatation via CT or MR 
|Part of the aorta||Maximum diameter of the aorta||Recommended follow-up interval|
|Ascending aorta|| || |
| || |
|Aortic arch|| || |
| || |
|Descending aorta|| || |
| || |
Risk factors 
Clinical features 
It is difficult to tell TAA apart from other causes ofusing clinical features alone.
- Contained rupture
- Free rupture
More than half of patients with TAA rupture die before reaching the emergency department! 
- Hemodynamically unstable patients: no time for detailed assessment
- Hemodynamically stable patients: Obtain CTA of the chest, abdomen, and pelvis with IV contrast.
Additional diagnostic evaluation to consider (once patient has been stabilized)
- ECG: to rule out STEMI as a differential diagnosis
- Laboratory studies: There are no laboratory findings specific to TAA rupture.
- See “Chest pain” for workup and differential diagnoses.
Initial stabilization 
- As soon as TAA rupture is suspected, obtain an immediate cardiothoracic surgery consult.
- Start continuous telemetry, consider .
- Manage hypotension.
- For patients with acute respiratory failure, start and consider cautious .
- Initiate IV .
- Reassess frequently, as patients may rapidly decompensate.
Emergency surgical repair 
- Free rupture has a high mortality rate. 
- Obtain surgery consult.
- Make patient NPO.
- Establish IV access with two large-bore peripheral IV lines.
- Check CBC, type and screen, obtain patient consent for blood transfusion, and order pRBCs (prepare for massive transfusion protocol).
- Start IV fluid resuscitation using blood products as soon as available.
- Consider use of vasopressors.
- Manage associated complications, e.g., hypoxia.
- Initiate pain management.