Aortic Dissection

An aortic dissection starts with a tear in the inner layer of the wall of the aorta, the largest artery in the body. Once a tear is present, blood leaks in between the inner and outer layers of the wall, causing separation of the tissues. The pressure of pumping blood on these thinner layers may disrupt blood flow to vital organs or cause a life-threatening rupture of the aorta.

Aortic dissections are most common in the portions of the wall that are under the most pressure from blood pumping from the heart: the ascending thoracic aorta and the descending thoracic aorta (see below).

Basic Anatomy

The aorta, which carries oxygenated blood to the body, is divided into four parts:

1. The ascending thoracic aorta which rises up from the left ventricle of the heart
2. The aortic arch, which curves like the hook connecting to the
3. Descending thoracic aorta which extends downward through the chest cavity to the
4. Abdominal aorta. The abdominal aorta splits and becomes the left and right common iliac arteries, carrying blood to the pelvis and legs.

An acute aortic dissection causes sudden, severe chest pain. It is often associated with a cold sweat. The pain is often described as tearing and may move as the dissection gets worse.

The causes of aortic dissection are unknown. But, the risk factors associated with it are:

• Age over 50
• Male gender (men are three times as likely as women to suffer dissection of the aorta)
• High blood pressure (hypertension, implicated in more than 60 percent of cases)
• Connective tissue disorders (e.g., Marfan's syndrome)
• Degenerative tissue diseases (e.g., cystic medical disease)
• Inflammation of the aorta (aortitis)
• Atherosclerosis
• Congenital heart valve defects (e.g., bicuspid valve)
• Trauma
• Narrowing of the aorta
• Excess fluid or volume in the circulation (hypervolemia)
• Polycystic kidney disease

The presence of an aortic dissection is confirmed by a CT scan or transesophageal echocardiogram (TEE).

Acute aortic dissection is an emergency requiring immediate treatment. The patient may be given medication to lower blood pressure and heart rate. Surgery may be required to repair the damage.

Endovascular aneurysm repair (EVAR)

Endovascular surgical repair (EVAR) is a less-invasive surgical treatment that involves a small incision in the groin and the insertion of a stent or stent graft through a catheter placed in the femoral artery. Physicians use X-ray imaging to guide the stent graft to the diseased area. The stent or stent graft is then expanded inside the aorta. Blood-flow is redirected to the correct channel of the aorta and back into the branches of the aorta.

The duration of the hospital stay is variable. Patients may return to their normal activities not long after endovascular repair. However, EVAR may not be for everyone. Patients must have aortic and arterial anatomy compatible with available stents or stent grafts. Vascular Center specialists are experienced in the surgical and endovascular repair of aortic dissection.

Alternative surgical procedures

New techniques for repairing a dissection are still being developed. One such technique, called aortic fenestration, involves inserting a balloon catheter and inflating it to create a hole downstream of the original tear to allow blood to flow back into the aorta. These newer techniques are also available at the Vascular Center.