Most thoracic aneurysms are discovered incidentally on imaging studies as they are rarely detectable by physical exam. Patients can present with chest pain, back pain, or flank pain. Uncommonly, the aneurysm can compress adjacent structures and cause hoarseness (recurrent laryngeal nerve), dysphagia (esophagus), dyspnea (bronchus), or superior vena cava syndrome. Rarely, distal embolization from thrombus in the aneurysm sac can cause mesenteric or lower extremity ischemia. Rupture typically causes severe chest pain and shock.

CT angiography provides virtually all the required information for diagnosis and operative planning and has become the test of choice for imaging all thoracic aortic pathology. Multi-row detector CT scans with thin-slice axial reconstructions (0.6–2.5 mm) can be obtained with a single breath hold and give accurate measurements of the aneurysm size and its relation to major aortic branches. Three dimensional and multiplanar reconstructions can improve the evaluation of the aneurysm especially with tortuous and angulated anatomy and provide excellent assessment of the proximal and distal landing zones for endografting. MRA is an alternative to CTA in specialized centers. It is inferior to CTA in assessing aortic wall characteristics and calcifications.

Since most aneurysms are asymptomatic and discovered incidentally, management decisions are based on their natural history. No prospective studies are available and the risk of rupture is estimated based on size from observational retrospective series. A 1–3 % yearly risk is estimated for an aneurysm 50–60 mm in diameter. It increases to 5–7 % when the size of the aneurysm is larger than 60 mm. The decision to intervene should be individualized taking into consideration the patient’s age, comorbidities, and life expectancy. Traditionally, using open repair, the risk benefit ratio in an average patient would suggest a procedure when the aneurysm reaches 60 mm. Patients with Marfan syndrome are treated earlier when the aneurysm reaches 50 mm in size. A rapid growth more than 10 mm per year is another indication for surgery. Saccular aneurysms are presumed to have a higher rupture risk and are treated at a smaller size. Aneurysms that cause symptoms should be treated regardless of size.

Open repair of descending thoracic aneurysm is performed through a left thoracotomy or a left thoracoabdominal incision depending on the extent of the aneurysm, using single lung ventilation. Exposure may require the resection of a rib with extensive disease. Proximal control is obtained distal to the left subclavian artery or between the left subclavian and the left common carotid artery. The aneurysm is replaced with a dacron graft using monofilament sutures. Several techniques are employed to decrease major complications such as ischemia to the viscera and the spinal cord:

Thoracic endovascular aneurysm repair (TEVAR) can be performed under general, regional, or local anesthesia. There are three endografts currently available commercially in the US for the treatment of descending thoracic aneurysms: Gore TAG, Medtronic Talent, and Cook TX2. There are inherent differences between these devices that are important to understand and are illustrated in Table 15.1.