What is a thoracic aneurysm?
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An aneurysm is a bulging, weakened area in the wall of a blood vessel resulting in an abnormal widening or ballooning greater than 50 percent of the normal diameter (width). An aneurysm may be located in many areas of the body, such as the blood vessels of the brain, the aorta (the largest artery in the body), the intestines, the kidneys, the spleen, and the vessels in the legs. The most common location of an aneurysm is the aorta.
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Descending aortic aneurysm
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The aorta extends upward from the top of the left ventricle of the heart in the chest area (ascending thoracic aorta), then curves like a candy cane (aortic arch) downward through the chest area (descending thoracic aorta) into the abdomen (abdominal aorta). The aorta delivers oxygenated blood pumped from the heart to the rest of the body.
An aneurysm can be characterized by its location, shape, and cause. A thoracic aortic aneurysm is located in the chest area. The thoracic aorta can be divided into segments: ascending aorta, aortic arch, and descending aorta, as described above. An aneurysm may be located in one of these areas and/or may be continuous throughout the aorta. An aneurysm called a thoracoabdominal aneurysm involves a thoracic aortic aneurysm extending down to the abdominal aorta. |
Types of thoracic aortic aneurysms
The shape of an aneurysm is described as being fusiform or saccular which helps to identify a true aneurysm. A true aneurysm involves all three layers of the arterial blood vessel wall. The more common fusiform-shaped aneurysm bulges or balloons out on all sides of the aorta. A saccular-shaped aneurysm bulges or balloons out only on one side.
The aorta is under constant pressure from blood being ejected from the heart. With each heartbeat, the walls of the aorta expand and spring back. This exerts continual pressure or stress on the already weakened aneurysm wall. Therefore, there is a potential for rupture (bursting) or dissection (separation of the layers of the thoracic aortic wall), which may cause life-threatening hemorrhage (uncontrolled bleeding).
Once formed, an aneurysm will gradually increase in size and there will be a progressive weakening of the aneurysm wall. Preventing rupture of an aneurysm is one of the goals of therapy. The larger an aneurysm becomes, the greater the risk of rupture (bursting). With rupture, life-threatening hemorrhage (uncontrolled bleeding) may result. Treatment for a thoracic aneurysm may include surgical repair or removal of the aneurysm to prevent rupture.
The aorta is under constant pressure from blood being ejected from the heart. With each heartbeat, the walls of the aorta expand and spring back. This exerts continual pressure or stress on the already weakened aneurysm wall. Therefore, there is a potential for rupture (bursting) or dissection (separation of the layers of the thoracic aortic wall), which may cause life-threatening hemorrhage (uncontrolled bleeding).
Once formed, an aneurysm will gradually increase in size and there will be a progressive weakening of the aneurysm wall. Preventing rupture of an aneurysm is one of the goals of therapy. The larger an aneurysm becomes, the greater the risk of rupture (bursting). With rupture, life-threatening hemorrhage (uncontrolled bleeding) may result. Treatment for a thoracic aneurysm may include surgical repair or removal of the aneurysm to prevent rupture.
What are the symptoms of a thoracic aortic aneurysm?
Aortic disease is often insidious. Most people with aortic aneurysms experience no symptoms, unless they are extremely large or an aortic dissection occurs. About three of every four abdominal aortic aneurysms are asymptomatic.
When present, symptoms may occur with different types of aneurysms may include, but are not limited to, the following: constant pain in abdomen, chest, back or groin area or a pulsatile mass in the abdomen.
The pain associated with a thoracic aneurysm may have the following characteristics:
The occurrence of pain is often associated with the imminent (about to happen) rupture of the aneurysm. Acute, sudden onset of severe pain in the back and/or abdomen may represent rupture and is a life-threatening medical emergency.
When present, symptoms may occur with different types of aneurysms may include, but are not limited to, the following: constant pain in abdomen, chest, back or groin area or a pulsatile mass in the abdomen.
The pain associated with a thoracic aneurysm may have the following characteristics:
- pain in the jaw, neck, and/or upper back
- pain in the chest and/or back
- wheezing, coughing, or shortness of breath as a result of pressure on the trachea (windpipe)
- hoarseness as a result of pressure on the vocal cords
- difficulty swallowing (dysphagia) due to pressure on the esophagus
The occurrence of pain is often associated with the imminent (about to happen) rupture of the aneurysm. Acute, sudden onset of severe pain in the back and/or abdomen may represent rupture and is a life-threatening medical emergency.
How is an descending aneurysm diagnosed
For most people, their aortic condition is discovered incidentally while being tested for other reasons. An aneurysm may also be discovered by x-ray, computed tomography scan (CT scan), or magnetic resonance imaging (MRI) that is being done for other conditions. Since abdominal aneurysm may be present without symptoms, it is referred to as the "silent killer" because it may rupture before being diagnosed.
3D CT reconstruction of a descending thoracic aneurysm
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CT of a descending thoracic aneurysm
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If my aneurysm is not causing symptoms, why do I need surgery?
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The risk of aortic catastrophe, including dissection and rupture, increases dramatically after the aneurysm reaches 5 cm.
The objective of surgical repair of an aneurysm is to prevent potential complications related to the aneurysm. These include: |
Likelihood of an aortic catastrophe by aortic size
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- heart attack
- aortic valve regurgitation
- heart failure
- hoarseness due to left vagus or left recurrent laryngeal nerve compression
- diaphragmatic paralysis due to phrenic nerve compression
- difficulty breathing due to airway compression
- difficulty swallowing due esophageal compression
- swelling of the head or arm due superior vena cava syndrome
- blood clots
- aortic dissection
- rupture of the aorta
Do I need surgery?
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Surgery is generally recommended when the proximal aorta is larger than 5cm. However, depending on other factors, including other vascular conditions or the need for additional surgery (particularly heart surgery), this threshold varies with individual patients.
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Indications for aortic aneurysm replacement
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What is the treatment for a thoracic aortic aneurysm?
Treatment options for an aortic aneurysm may include one or more of the following:
- Controlling or modifying risk factors: such as quitting smoking, controlling blood sugar if diabetic, losing weight if overweight or obese and controlling dietary fat intake may help to slow the progression of the aneurysm
- Observation: routine ultrasound, CT, or MRI procedures to monitor the size and rate of growth of the aneurysm
- Medication: to control factors such as hyperlipidemia (elevated levels of fats in the blood) and/or high blood pressure
- Open Aneurysm Repair: the diseased area of the aorta if replaced with a fabric graft
- Stent graft or endograft: used to treat aneurysms of the descending and abdominal aneurysm; it is comprised of a layer of impermeable reinforcement material enclosed by a self-expanding metal support mesh and is placed across the aneurysm site
Open aneurysm repair
The type of surgical repair of a thoracic aortic aneurysm will depend on several factors: the location of the aneurysm, the type of aneurysm, and the patient's tolerance for the procedure. For an ascending or aortic arch aneurysm, a incision may be made through the breastbone (median sternotomy). If an ascending aneurysm involves damage to the aortic valve of the heart, the valve may be repaired or replaced during the procedure. For a descending aneurysm, a large incision may extend from the back under the shoulder blade around the side of the rib cage to just under the breast (thoracotomy). These approaches allow the surgeon to visualize the aorta directly to repair the aneurysm.
Endovascular aneurysm repair (TEVAR)
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TEVAR is a procedure that requires only small incisions in the groin, along with the use of X-ray guidance and specially designed instruments, to repair the aneurysm by inserting a tube, called a stent-graft, inside the aorta. In this minimally invasive procedure, the stent graft (comprised of a layer of impermeable reinforcement material enclosed by a self-expanding metal support mesh) is placed across the aneurysm site. To achieve stent graft placement, the surgeon inserts a catheter through the femoral artery in the groin. The stent graft is then delivered through the catheter in a collapsed state and deployed at the site of the aneurysm. The device replaces and reinforces the diseased aortic wall, ensuring continuity of blood flow. The potential benefits of the procedure include greatly reduced risk, a shorter hospital stay, and a more rapid recovery. Not all thoracic aneurysms can be repaired by means of TEVAR
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Endovascular repair of a descending aortic aneurysm
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Hybrid Repair
Not all thoracic aneurysms can be repaired by means of endovascular stenting alone. Hybrid procedures use endovascular stenting along with open surgery to take advantage of the benefits of each while minimizing the limitations and related risks. Often, hybrid procedures can be custom designed for the patient in an effort to decrease size of the incision, duration of the procedure, and avoid the need to stop blood flow to the heart and/or brain. This is intended to improve recovery and ensure the best possible outcome for the patient.
Hybrid repair with debranching of the aorta using a carotid subclavian bypass and thoracic endovascular stent graft for an arch and descending thoracic aortic aneurysm
Specific treatment will be determined by your physician based on: age, overall health and medical history; size, location, and extent of the disease; signs and symptoms; tolerance of specific medications, procedures or therapies; expectations for the course of the disease; and preference.
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