How to Approach Thoracic Aortic Aneurysm Treatment

• A thoracic aortic aneurysm is an abnormal dilation of the aorta between the diaphragm and the aortic valve.  
• The most common symptom of an aortic aneurysm is severe chest, neck, and back pain.  
• Patients diagnosed with aortic aneurysms should be compelled to eat healthily, maintain an optimal weight, quit smoking, take medications on time, and attend follow-up visits with the physician.  

In the United States, aortic aneurysms caused 9,904 deaths in 2019, according to the Centers for Disease Control and Prevention, and about 59% of those deaths included men. Moreover, 75% of cases of aortic aneurysm had a smoking history. Therefore, the U.S. Preventive Services Task Forces recommends that men aged 65 to 75 who have ever smoked should get an ultrasound screening for aortic aneurysm, even if they have no symptoms. 

What is Thoracic Aortic Aneurysm?

A thoracic aortic aneurysm is an abnormal dilation of the aorta between the diaphragm and the aortic valve. It causes the aorta to dilate more than 50% of its average diameter. A diameter greater than 3.5cm is considered a dilated thoracic aorta, while a diameter greater than 4.5cm is aneurysmal.

Around 25% of aneurysms cases are thoracic aneurysms, and approximately 25% of people with thoracic aneurysms also have abdominal aneurysms. They may be on the ascending, or transverse (aortic arch), or descending part of the aorta that may involve the entire thoracic aorta. An aneurysm forms because of weakening of the medial layer of the aorta, which stretches outwards, causing a protrusion of the aortic wall.

Thoracic aortic aneurysms occur in four forms: fusiform, saccular, dissecting, and false aneurysms. In a fusiform aneurysm, a spindle-shaped bulge encompasses the entire aorta’s circumference. In the saccular aneurysm, a unilateral pouchlike bulge occurs with a narrow neck, commonly at a bifurcation that involves only a portion of the vessel’s circumference. In a dissecting aneurysm, a hemorrhagic separation occurs between the medial and intimal layers, developing a false lumen. In a false aneurysm, a pulsating hematoma occurs due to a rupture of the aorta, secondary to trauma.

Aortic dissection can occur with or without an aneurysm, but commonly, it’s associated with a preexisting aneurysm. If left untreated, thoracic aneurysms can lead to fatal complications, such as rupturing into the pericardium, leading to cardiac tamponade, cardiac arrest, and hemorrhagic shock. 

What Causes Thoracic Aortic Aneurysm?

The most common cause of thoracic aneurysm is atherosclerosis. The formation of an atherosclerotic plaque damages the arterial wall, weakening the medial muscle layer and distending the lumen. Destruction of the medial layer enables the artery to increase in circumference, forming a fusiform shape, or sometimes, the artery develops a saccular protrusion at the weakened site. Tobacco consumption can also lead to the formation of an aneurysm. Other contributing factors include:  

• Marfan’s syndrome: a hereditary musculoskeletal disorder. 
• Ehlers-Danlos syndrome: an inherited disorder of elastic connective tissue. 
• Fungal infections of the aortic arch causing mycotic aneurysm. 
• A bicuspid aortic valve. 
• Aortitis: inflammation of the aorta. 
• Coarctation of the aorta  
• Trauma that can be external, blunt, or iatrogenic occurs during invasive diagnostic procedures. 

Nursing Assessment

History: A detailed history can help you diagnose an aortic aneurysm. Check if the patient has a history of atherosclerosis, elevated blood cholesterol levels, hypertension, obesity, diabetes, smoking, familial tendencies, or aortic aneurysm. Ask about pain history, including its description and location.   

Keep in mind the location of the aneurysm, its pain location, and type as follows:  

• If the aneurysm occurs in the ascending aorta, it causes substernal chest pain that extends to the shoulder, neck, lower back, or abdomen but generally not to the jaw or arms. It is severe on the right side and described as dull, severe, and ripping pain.   
• If the aneurysm occurs in the transverse arch of the aorta, it causes neck pain that radiates to the shoulders, causing a sudden and sharp tearing pain.   
• If an aneurysm occurs in the descending aorta, it causes back and shoulder pain that radiates to the chest, causing sharp and tearing pain. 

Check if the patient has pulmonary symptoms, such as coughing, wheezing, stridor, or dyspnea, which may be caused by descending aortic aneurysm compressing the tracheobronchial tree. Inquire if the patient has difficulty swallowing, dry cough, dyspnea, or hoarseness. All these symptoms can occur because of a transverse arch thoracic aortic aneurysm.   

Physical Examination: The most common symptom of an aortic aneurysm is severe chest, neck, and back pain. Upon physical examination, the thoracic aortic aneurysm does not reveal the presence of the aneurysm itself. However, specific findings may raise your suspicion toward aortic aneurysm.  

Elicit a complete neurological examination to determine the adequacy of tissue perfusion. The patient’s blood pressure should be taken from both arms because the ascending thoracic aortic aneurysm may cause changes in blood pressure readings from both arms. Also, take the pulse from the patient’s right carotid and left radial pulse and note any difference. Chest auscultation also is performed to check for pericardial friction rub and aortic valve insufficiency, which indicates the extension of an ascending aortic aneurysm proximally into the aortic valve. Monitor the patient’s pulse for bradycardia.

Assess the patient and their caregiver’s understanding of the implications of an aortic aneurysm. Assess their abilities to cope with the onset of sudden life-threatening conditions that may require prolonged hospitalization. Check the patient’s level of anxiety, knowing about their illness, potential surgery, and complications.

Since an aortic aneurysm does not cause any symptoms as such, a diagnosis is made with the help of diagnostic imaging tests that include a chest X-ray and chest CT scan. Other tests may include ECG, MRI, transthoracic echocardiography with Doppler color flow mapping, transesophageal echocardiography, and aortic angiography.

Collaborative: A thoracic aortic aneurysm measuring 4cm in size or less is often treated with oral antihypertensive agents, including beta blockers and nitroprusside. Frequent diagnostic testing is required every six months to determine the size of the aneurysm. Moreover, a thoracic aortic aneurysm having a size of 5 cm or greater is usually treated surgically. Surgical intervention is also done when the patient has intractable pain, dissection, and an unstable aneurysm that changes in size. A primary complication of thoracic aortic aneurysm is dissection. Monitor the patient for any changes in the quality of the peripheral pulses, changes in the level of consciousness, changes in vital signs, and the onset of severe, sudden, tearing, or ripping pain in the neck, back, chest, or shoulders.

A ruptured thoracic aneurysm needs immediate surgical intervention. Before surgery, assess the patient’s peripheral pulses and monitor pulses from both sides. Take the patient’s blood pressure from both arms and auscultate for an aortic insufficiency murmur to determine the preoperative and postoperative progress.

Administer large volumes of fluids intravenously and maintain circulation until surgery is performed. The surgical procedure varies depending on the location of the aneurysm. An ascending arch aneurysm may be replaced with an interposition graft, supra coronary graft, or composite valved conduit. However, a transverse arch aneurysm is repaired with reconstructions and anastomosis. A graft helps repair the thoracoabdominal and descending thoracic aneurysms. Once the surgery is done, administer morphine or fentanyl to control postoperative pain. Also monitor the cardiopulmonary status of the patient, especially in those with congestive heart failure, because beta-blockers may worsen the preexisting congestive heart failure if the patient has elevated blood cholesterol levels that are not being controlled with a diet, a cholesterol-lowering agent is prescribed.

Independent: When an aortic aneurysm is diagnosed, it is essential to maintain adequate circulation, prevent complications, and implement patient education. If the patient does not undergo surgical interventions, educate them to consume a low-fat and low-cholesterol diet to prevent the progress of atherosclerotic plaques and prescribe statins to treat hypercholesterolemia.

Compel the patient to stop smoking and help them with smoking cessation. If they find it arduous to stop smoking, refer them to rehabilitation. For the patient undergoing surgery, focus on adequate blood circulation pre- and postoperatively. Postoperative surgical care is the same as that of patients who undergo general anesthesia, and postoperative care is similar to that of patients who undergo chest surgery. Provide aggressive pulmonary hygiene every one to two hours. Assist the patient with mobility and range of motion exercises to lower the effects of immobility. Emotional support should also be provided to the patient and their caregivers.

Discharge and Home Health Care Guidelines: Patients who do not require surgical interventions can be discharged early; however, those undergoing surgery must stay longer at the hospital. If they do not have any support at home to take care of after being discharged from the hospital, an extended care facility may be required where they can recover. Ensure that the patient and their caregivers understand all prescribed medications, including dose, route, side effects, and actions. 

If the patient is overweight or obese, suggest they adhere to a low-fat and low-cholesterol diet. It is a good idea to work with a dietician who can create a customized diet plan for them that focuses on their health condition. Ensure that the patient understands why controlling blood pressure and cholesterol is imperative, as it can lead to atherosclerotic plaque progression. Encourage patients to stop smoking if they do and highlight the importance of smoking cessation. Inform them that smoking can increase the risk of hypertension and atherosclerosis. 

The Bottom Line

A thoracic aortic aneurysm is the abnormal widening of the aorta — a life-threatening condition. The most common risk factor is atherosclerosis. For your patients diagnosed with aortic aneurysms, compel them to maintain a healthy diet, maintain an optimal weight, quit smoking, take medications on time, and attend follow-up visits with the physician.  

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