Aortic Disease

Aortic Dissection

Aortic dissection is a serious condition in which the inner lining of the body’s main artery (aorta) tears. Blood flows through the tear, causing the inner and middle layers of the aorta to separate (rupture). If blood passes through the outer wall of the aorta, aortic dissection is often fatal.

Aortic dissection is relatively rare. It usually occurs in men in their 60s and 70s. The symptoms of aortic dissection can mimic those of other diseases and can often lead to delays in diagnosis. However, if an aortic dissection is detected early and treated promptly, the chance of survival is greatly increased.

Where is the aorta?

The aorta runs through your body. It starts in your heart’s main pumping chamber, the left ventricle, runs up through the front center of your chest, curves from front to back in your lower neck, and then runs down through the front of your spine, inside your ribcage. In your chest, it’s called the thoracic aorta, and in your abdomen, it’s called the abdominal aorta. It ends just below your navel, where it splits into two other branches called the right and left common iliac arteries.

Are there different types of aortic dissection?

There are two main types of aortic dissection:

Stanford Type A Aortic Dissection: This type of dissection occurs in the first part of the aorta, closer to the heart, and can be immediately life-threatening. It usually requires emergency open-heart surgery to replace the first segment where the tear begins (the ascending aorta +/- arch and/or aortic valve). This is a more common type of dissection than Type B, and the tear usually extends the entire length of the aorta.
Stanford Type B Aortic Dissection: This type of tear begins lower in the aorta (beyond the arch in the descending aorta) and farther from the heart. Like Type A dissection, it usually extends from the descending aorta to the abdominal aorta. However, it does not involve the first part of the aorta in front of the chest. Depending on where the dissection is and whether it is cutting off blood flow to your organs, surgery may or may not be needed immediately. This type of dissection can usually be treated without open surgery, with a stent-graft device placed in the aorta.

Another classification system, the DeBakey Classification, identifies three types of dissection. Type 1 originates in the ascending aorta and extends down the descending aorta. Type 2 originates in the ascending aorta and is limited to it (both considered Stanford Type A). Type 3 originates in the descending aorta and extends downward (similar to Type B).

What is the difference between aortic aneurysm, aortic rupture and aortic dissection?

An aortic aneurysm is a balloon-like swelling that occurs in a weakened area of the aortic wall or in the entire aorta. An aortic aneurysm can cause aortic rupture and aortic dissection.

An aortic rupture is a full-thickness puncture or tear in the aortic wall through all three layers of the aorta. Blood gushes out of the puncture into the surrounding body cavity.

An aortic dissection is a tear in the inner aortic layer that allows blood to enter and further separate the inner and middle layers of the aortic wall, typically extending the length of the aorta in both directions and may extend into the branches of the vessels that branch off the aorta.

What are the signs and symptoms of aortic dissection?

The symptoms of aortic dissection can be similar to those of other heart problems, such as a heart attack. Typical signs and symptoms include:

Sudden, severe chest or upper back pain, often described as a tearing or ripping sensation, that radiates to the neck or back
Sudden, severe stomach pain
Loss of consciousness
Shortness of breath
Stroke-like symptoms, such as sudden vision problems, difficulty speaking, and weakness or loss of movement (paralysis) on one side of your body
A weak pulse in one arm or thigh compared to the other
Leg pain
Difficulty walking

When should you consult a doctor?

If you have severe chest pain, fainting, sudden shortness of breath or signs of a stroke, call 911 or your local emergency number. These signs and symptoms are not always caused by a serious problem, but it is best to see a doctor as soon as possible. Early detection and treatment can help save your life. Once diagnosed, you may need to be transferred by the emergency room transport team to a referral center with expertise to manage this vital condition.

What causes aortic dissection?

Aortic dissection occurs due to a slow, underlying breakdown of the cells and structural elements that make up the walls of your aorta. The weakened area of the aortic wall may lie dormant for many years until it tears, leading to an aortic dissection. One day, a sudden increase in your blood pressure, such as anger, heavy lifting, straining, or falling, can tear the inner lining of your weakened aortic wall, causing a dissection.

Why does the aortic wall weaken in some people and not others? It is believed that most aortic dissections are due to an underlying condition that may be hereditary. In others, the stress placed on the aortic wall by persistent high blood pressure can weaken the aortic wall in susceptible individuals, resulting in a tear and dissection.

Aortic dissection occurs in the ascending aorta, where the pressure is highest, closest to the heart, almost twice as often as in the descending aorta. Tears in the aorta typically occur in areas where the stress on the aortic wall is highest.

What factors may increase the risk of developing aortic dissection?

Factors that may increase your risk of developing an aortic dissection include:

Ongoing high blood pressure (hypertension). This is the most important risk factor. High blood pressure directly damages the layers of the aortic tissue, causing loss of elastic fibers, deterioration of the wall structure, and increased wall stiffness.
Atherosclerosis (or plaque buildup in the arteries)/high cholesterol and smoking.
Aortic aneurysm. This is an abnormal widening or ballooning of the aortic wall.
Aortic valve disease.
Congenital (“born”) heart conditions, such as bicuspid aortic valve (an aortic valve with two leaflets instead of the normal three) or Turner syndrome.
Connective tissue disorders, such as Marfan syndrome and Ehlers-Danlos syndrome. These are genetic problems that can be passed down from family members.
Other inherited thoracic aortic disorders that primarily affect the aorta and are also genetic.
A family history of aortic dissection.
Vasculitis, an inflammatory disease affecting the body’s blood vessels.
Traumatic injuries to the ribcage (for example, after a high-speed car accident or a fall from a height).
Being pregnant and having high blood pressure at the time of delivery.
Activities that can cause high blood pressure, such as cocaine or amphetamine use.
Lifting weights can increase the rate of aneurysm or dissection in susceptible individuals.

What complications can aortic dissection cause?

Aortic dissection can cause:

Stroke.
Aortic valve damage.
Organ damage, such as kidney failure or life-threatening bowel damage.
A buildup of fluid (blood) between the heart muscle and the membrane covering the heart. This condition, called cardiac tamponade, puts pressure on the heart and prevents it from working properly.
Death.

How is aortic dissection diagnosed?

Aortic dissection needs to be diagnosed quickly in case emergency surgery is needed. Your healthcare team will need to determine if you have an aortic dissection or other medical conditions that can cause similar symptoms, such as heart attack or stroke. Tests that may be ordered include:

Chest X-ray: This test uses a small amount of radiation to create images of the structures in your chest, including your heart, lungs, blood vessels (including your aorta), and bones. This test is not very specific, but it is quick and can guide a diagnosis.
Computed tomography (CT) scan: This test provides the best image of your aorta in an emergency situation and can be done fairly quickly to detect an aneurysm or dissection. Intravenous (IV) contrast may be needed for imaging your aorta.
Transthoracic echocardiogram (TTE): This test is an ultrasound imaging procedure that provides moving pictures of your heart valves and chambers and the first part of the aorta (aortic root).
Transesophageal echocardiogram (TEE): This test provides more detailed pictures of your heart valves and chambers than a transthoracic echocardiogram and provides better views of your thoracic aorta. The ultrasound probe is inserted through your mouth into your esophagus, which runs directly behind your heart and down through your descending aorta.
Magnetic resonance imaging (MRI): This test uses a large magnet and radio waves to create detailed images of your organs and aorta. It shows moving pictures of your heart valves and chambers and blood flow through your aorta. This test can take more time to perform than a typical CT scan and is therefore less commonly used in emergency situations.

How is aortic dissection treated?

Treatment for an aortic dissection depends on the location of the tear in the inner layer of the aorta and the dissection. A type A aortic dissection (i.e., when it involves the first part of the aorta close to the heart) requires immediate surgery. A type B aortic dissection requires immediate surgery if the dissection cuts off blood flow to vital organs, such as your kidneys, intestines, legs, or spinal cord. Additionally, emergency surgery is also required if certain high-risk features are noted on the CT scan. Less severe cases may be treated initially with medication, allowing surgery to be delayed until complications develop.

Surgical and endovascular treatment

Graft (artificial vessel) replacement: This approach involves removing a portion of the damaged section of the aorta and sewing a synthetic fabric tube (graft) directly in its place.
Endovascular stent-graft repair: This approach uses a stent graft, a synthetic fabric tube supported by metal wire stents, to repair the aorta from the inside. The endovascular procedure involves performing the repair from inside your aorta. A small incision is made in your groin, and a catheter with a fabric-covered stent is advanced and placed into the aorta under x-ray guidance. The stent graft is released at the repair site and opens like a spring or umbrella, providing reinforcement for the weak area in the aorta.
Hybrid approach: This approach uses a combination of traditional open surgery and endovascular stent-graft techniques to repair the aorta. This is used when the repair needs to extend all the way to the aortic arch (archus aorta), where the blood vessels to the brain and arms emerge. This can be done during an emergency operation for a Type A dissection, or as a two-stage repair with a bypass from a vein in the neck to aid in endovascular repair for a Type B dissection. The most common hybrid procedure is called the “elephant trunk” or “frozen elephant trunk” procedure. First, the part of the aorta closest to the heart and the aortic arch (the part of the aorta that supplies blood to the brain) are replaced and repaired. An additional graft, or stent graft, is left within the descending aorta, like an elephant’s trunk. When the second operation is performed, the graft is ready to be connected to the endovascularly placed stent-graft.

Treatment with medication

Medications such as beta blockers may be prescribed to lower heart rate and blood pressure. In some cases of Type B aortic dissection, medication alone may be used to initially treat the dissection. Depending on the severity of the tear and the extent of the dissection, surgery may be delayed for months to years.

Is it possible to prevent aortic dissection?

Many of the factors that increase your risk of developing an aortic dissection, such as being born with a heart condition, having a connective tissue disorder, or having a family history of aortic dissection, cannot be changed. However, like many other medical conditions and illnesses, you can reduce your risk by avoiding risk factors that can be changed. These factors include:

Lowering high blood pressure to a goal of 120/80 mm/Hg with medications, dietary changes, and other measures recommended by your health care provider.
Quitting smoking and other tobacco use and maintaining a healthy weight.
Wearing your seat belt to prevent injury to your chest in the event of a crash.
Getting regular checkups.

It is important to screen first-degree relatives of a person who has had an aortic dissection for aortic disease. They can be closely monitored and treated before an aortic event occurs.

What outcome should I expect if I am diagnosed with aortic dissection?

Aortic dissection can be a life-threatening event. People with acute aortic dissection (sudden onset, Type A) have a high mortality rate. On average, 15% to 30% of people die even after surgery. People who survive the acute phase often have a chronic dissection in the untreated portion of their aorta that may require treatment later. Despite all the advances in modern medicine, unfortunately, the life expectancy of people with aortic dissection is shortened compared to the general population.