The aorta, the largest artery in the body, begins in the left ventricle of the heart. It arches above the heart then down through the chest to the abdomen. It sends branches to the head, arms, the organs in the abdomen, and the legs to supply the body with oxygen and nutrients.
An aortic aneurysm is a bulging or ballooning of a weakened part of the aortic artery wall. An aneurysm forms when blood pumping out of the heart pushes against and stretches the weakened portion of the aorta wall. When the bulging portion is more than two times the aorta’s normal diameter it is considered an aneurysm. Aortic aneurysms are named according to their location. Regardless of their location, aortic aneurysms are dangerous because of the risk that they will rupture, causing life-threatening bleeding or hemorrhage.
- Thoracic aortic aneurysms are those that form in the chest cavity
- Thoracoabdominal aneurysms extend from the chest into the abdomen
- Abdominal aortic aneurysms occur in the abdominal portion of the aorta
An aortic dissection is a split or tear along the inner layer of the aorta’s wall. Dissections occur more frequently in regions of the aorta where pressure on the artery wall from blood flow is high, such as its first arching segment above the heart. When the aortic wall tears, blood fills the pocket between the inner and outer layers, often increasing the length of the tear. As the blood-filled space between the layers expands, it can weaken the aortic wall resulting in an aneurysm formation or the flap of the tear can block off critical blood vessels going to the bowels, kidney, or legs.
The most common cause of aortic aneurysms is atherosclerosis, which weakens the wall of the aorta. However, the most common cause of aortic dissection is high blood pressure. Other risk factors associated with either type of aortic disease include:
- Cigarette smoking
- Inflammatory diseases of the aorta (aortitis)
- Inherited diseases, such as Marfan’s or Ehlers-Danlos syndrome
- A family history of aortic disease
Most people with thoracic or abdominal aortic aneurysms have no symptoms and are discovered while the patient is having an x-ray study for another reason or on physical exam. Some patients complain of vague pain in the chest or abdomen and they may have a persistent cough and hoarseness. Large abdominal aneurysms can result in a pulsing feeling in the abdomen or chest.
When an aneurysm ruptures, the internal bleeding can cause intense back, abdominal, or chest pain. People with a ruptured aneurysm may also experience signs of shock such as shaking, dizziness, fainting, sweating, rapid heartbeat, and sudden weakness.
Symptoms of aortic dissection include sudden, intense pain across the chest, and sometimes in the back between the shoulder blades. Doctors commonly diagnose aortic aneurysm and dissection using tests including ultrasound, angiography, a CT scan or MRI.