What is a thoracic aortic aneurysm?
The aorta is the largest artery in the human body, responsible for transporting blood and oxygen to various organs, including the upper and lower extremities.
The aorta is divided into the ascending aorta, aortic arch, descending thoracic aorta, and abdominal aorta. When the diameter of the aorta enlarges beyond normal, it is called an aortic aneurysm or simply aortic dilation.
Thoracic aortic aneurysm can develop in the ascending aorta, aortic arch, or descending thoracic aorta. In Vascular Surgery, we address aneurysms involving the aortic arch and descending thoracic aorta. When combined with abdominal aortic aneurysm, it is referred to as thoracoabdominal aneurysm.
Causes and factors leading to an aneurysm
The main factors responsible for aneurysm development are smoking, hypertension, atherosclerosis, and hereditary causes. Heredity is a significant factor, so individuals with a first-degree family history should be screened for aneurysm.
Another significant category includes genetic connective tissue syndromes (Marfan syndrome, Ehlers-Danlos syndrome, Loeys-Dietz syndrome), where the aortic wall undergoes degenerative changes leading to aneurysm formation.
Other causes for development include infections, inflammatory reactions (aortitis), autoimmune diseases, and trauma.
Lastly, aortic isthmus narrowing, regardless of prior treatment, is a risk factor for thoracic aortic aneurysm development.
Diagnosis
In most cases, thoracic aortic aneurysms are asymptomatic, and a considerable amount of time may pass before they grow large enough for the patient to notice their presence.
One of the most common symptoms is chest or back pain. Depending on their location, they can also cause compressive effects on adjacent structures. For example:
- Difficulty swallowing (esophagus)
- Shortness of breath (trachea)
- Hoarseness (recurrent laryngeal nerve)
It is crucial for the patient to undergo evaluation since these symptoms may be attributed to other pathologies (angina, myocardial infarction, aortic dissection, gastroesophageal reflux, degenerative spine conditions).
Symptomatic aneurysms with impending rupture and ruptured thoracic aortic aneurysms present as acute, sudden, severe chest or back pain accompanied by hypotension and possible loss of consciousness, constituting life-threatening emergencies that require immediate attention from a Vascular Surgeon.
Most often, thoracic aortic aneurysms are diagnosed incidentally in imaging studies (CT scan, MRI, X-ray) conducted for other reasons.
The Vascular Surgeon evaluates the patient with a thorough history and physical examination. Depending on the findings and for a better analysis of the aneurysm characteristics, additional tests may be ordered:
- CT angiography (angiography with contrast or, in cases of renal insufficiency, plain CT)
- Magnetic resonance angiography
- Echocardiogram (to assess the size of the ascending aorta)
Treatment
Aneurysms do not regress without surgical intervention. They grow at a relatively slow rate, emphasizing the importance of close monitoring.
Appropriate treatment depends on the size of the aneurysm. Generally, surgical intervention is chosen for thoracic aneurysms larger than 5.2-5.5 centimeters. The rate of size increase, morphology, and the underlying cause of the aneurysm are taken into account to determine the most suitable approach. The patient’s physical condition and comorbidities also play a significant role in the treatment decision.
For aneurysms smaller than 5 centimeters, surveillance with imaging methods such as CT and MRI is recommended. The interval between checks is determined mostly by the size of the aneurysm.
Avoiding smoking, controlling blood pressure with appropriate diet and medications, and also improving cardiovascular risk with aspirin and lipid-lowering drugs are significant interventions in conservative management that may slow aneurysm progression.
When surgical intervention is chosen, the patient undergoes imaging (CT or MRI) before the operation. The majority of aneurysms are now treated with endovascular stent graft placement. In some cases, open surgery with aneurysm resection and synthetic graft placement is preferred.
Endovascular treatment of thoracic aortic aneurysm (TEVAR)
Prior to surgery, the patient undergoes a CT scan (CT angiography unless there is renal insufficiency) to analyze aneurysm characteristics and choose a suitable stent graft.
The procedure is performed under general anesthesia with bilateral femoral artery puncture for access. In some cases, small incisions in the groin area may be necessary. Special endovascular wires and catheters are used with the aid of fluoroscopy and contrast injection to precisely position the stent graft and exclude the aneurysm. The patient is typically mobilized around 3-6 hours after the procedure, and hospital stay lasts one to two days.
After discharge, a gradual return to daily activities is recommended, avoiding heavy lifting. Driving is also discouraged for approximately two to three weeks. The patient visits the clinic 10 days postoperatively, and imaging with CT is performed one month after the intervention.
The advantages of the method and potential complications are discussed in detail with the patient during clinic visits before surgical intervention.
Thoracic aortic aneurysm- Repair with TEVAR and creation of carotid- subclavian bypass
