An aneurysm is a bulging or ballooning in the wall of a blood vessel. It is caused when a portion of the artery wall weakens. Like a balloon, as the aneurysm expands, the artery wall grows progressively thinner, increasing the likelihood that the aneurysm will burst. The most common location an aneurysm can develop is within the aorta, the main artery through which blood flows from the heart to the rest of the body, in the segment of the aorta that runs through the abdomen (called an abdominal aortic aneurysm). The second most common site for an aortic aneurysm can develop is in one of the aortic segments that lies very near the heart (called a thoracic aortic aneurysm). Aneurysms can develop in other blood vessels:

Popliteal: an aneurysm in the artery behind the knee
Renal: an aneurysm in the kidney; a very rare condition

Many diseases and conditions, such as atherosclerosis (hardening of the arteries), hypertension, genetic conditions (such as Marfan Syndrome), a connective tissue disorder (such as Ehler-Danlos disorder, polychondritis, scleroderma, osteogenesis imperfecta, polycystic kidney disease, and Turners Syndrome) and injury, can cause the aorta to dilate (widen) or dissect (tear), placing you at increased risk for future life-threatening events. Those with disease of the aorta should be treated by an experienced team of cardiovascular specialists and surgeons. Connective tissue provides support to many structures within the body, such as the heart, blood vessels, eyes, bones, nervous system and lungs, therefore, these patients require a multi-disciplinary approach to their care and long-term follow-up.

The aorta is the largest artery in the body and is the blood vessel that carries oxygen-rich blood away from the heart to all parts of the body. The section of the aorta that runs through the chest is called the thoracic aorta and, as the aorta moves down through the abdomen it is called the abdominal aorta.

When an artery wall in the aorta weakens, the wall abnormally expands or bulges as blood is pumped through it, causing an aortic aneurysm. The bulge or ballooning may be defined as a...

• Fusiform: Uniform in shape, appearing equally along an extended section and edges of the aorta.
• Saccular aneurysm: Small, lop-sided blister on one side of the aorta that forms in a weakened area of the aorta wall.

An aneurysm can develop anywhere along the aorta:

• Aneurysms that occur in the section of the aorta that runs through the abdomen (abdominal aorta) are called abdominal aortic aneurysms.
• Aortic aneurysms that occur in the chest area are called thoracic aortic aneurysms and can involve the aortic root, ascending aorta, aortic arch or descending aorta.
• Aneurysms that involve the aorta as it flows thru both the abdomen and chest are called thoracoabdominal aortic aneurysms.

Thoracic aortic aneurysms affect approximately 15,000 people in the United States each year.
Up to 47,000 people die each year from all types of aortic disease; more than from breast cancer, AIDS, homicides, or motor vehicle accidents, making aortic disease a silent epidemic.

A thoracic aortic aneurysm is a serious health risk because, depending on its location and size, it may rupture or dissect (tear), causing life-threatening internal bleeding. When detected in time, a thoracic aortic aneurysm can often be repaired with surgery or other less invasive techniques.

Small aneurysms place one at increased risk for:

• Atherosclerotic plaque (fat and calcium deposits) formation at the site of the aneurysm
• A clot (thrombus) may form at the site and dislodge, increasing the chance of strokeIncrease in the aneurysm size, causing it to press on other organs, causing pain
• Aortic dissection, or tearing of the layers of the aorta, a potentially fatal complication and a medical emergency.
• Aneurysm rupture, because the artery wall thins at this spot, it is fragile and may burst under stress. A sudden rupture of an aortic aneurysm may be life threatening and is a medical emergency

Thoracic aortic aneurysms are most often caused by atherosclerosis, a hardening of the arteries that damages the artery’s walls. While your arteries are normally smooth on the inside, as you age they can develop atherosclerosis. When atherosclerosis occurs, a sticky substance called plaque builds up in the walls of the arteries. Over time, excess plaque causes the aorta to stiffen and weaken.

Your risk for atherosclerosis increases if you:

• Are a smoker
• Have high blood pressure
• Have high cholesterol
• Are overweight
• Have a family history of cardiovascular or peripheral vascular disease (a narrowing of the blood vessels)

Certain diseases can also weaken the layers of the aortic wall and increase the risk of thoracic aortic aneurysms, including:

• Marfan syndrome (a genetic connective tissue disorder)
• Other non-specific connective tissue disorders (characterized by a family history of aneurysms)
• Presence of a bicuspid aortic valve
• Syphilis
• Tuberculosis

Rarely, trauma, such as a severe fall or car accident can cause a thoracic aortic aneurysm.

As you age, your risk of developing a thoracic aortic aneurysm increases. More men than women are diagnosed with thoracic aortic aneurysms, and are often affected with the condition at a younger age.

Recent research indicates that a substantial amount of aneurysms have familial patterns, or are inherited from previous generations. It is important to tell your physician if there is a history of aortic aneurysms in your family to ensure that the best preventative screenings are completed.

Thoracic aortic aneurysms often go unnoticed because patients rarely feel any symptoms. While only half of those with thoracic aortic aneurysms complain of symptoms, possible warning signs include:

• Pain in the jaw, neck, and upper back
• Chest or back pain
• Coughing, hoarseness, or difficulty breathing

Aortic dissection occurs when the layers of the aorta tear and separate from each other. The presence of an aortic aneurysm increases your risk of having an aortic dissection, but aortic dissection can also occur in people with a normal sized aorta.

Aortic dissection can occur suddenly, causing severe sharp, tearing pain in your chest or upper back. Yet, like all types of aneurysms, there may be no symptoms of an aortic dissection.

Most commonly associated with high blood pressure, an aortic dissection forces the layers of the wall of the aorta apart through increased blood flow. If not treated early, aortic dissection weakens the aorta and can lead to a thoracic aortic aneurysm by causing the weakened area of the aorta to bulge like a balloon, stretching the aorta.

If you do experience any symptoms of a thoracic aortic aneurysm or aortic dissection, notify your physician immediately. If left untreated, these conditions could lead to a fatal rupture.

Early diagnosis of a thoracic aneurysm is critical to managing the condition. The larger the thoracic aortic aneurysm, or the faster it grows, the more likely it is to rupture. The risk of rupture increases when the aneurysm is larger than about twice the normal diameter of a healthy aorta blood vessel.

Diagnosing a thoracic aneurysm is difficult because often there are no symptoms, and often the condition goes undiagnosed until a rupture occurs. If a thoracic aortic aneurysm is suspected, your physician may order the following tests:

• Chest x-ray
• Computed tomography (CT) scan
• Magnetic resonance imaging (MRI)
• Echocardiography (an ultrasound of the heart)
• Abdominal ultrasound (to look for associated abdominal aneurysms)
• Angiography (an x-ray of the blood vessels)

Treatment for an aneurysm depends on its size, location and your overall health.

If the thoracic aortic aneurysm is small and not causing any symptoms, your physician may recommend “watchful waiting.” By closely monitoring your condition with CT or MRI scans every 6-12 months, the aneurysm will be watched for signs of changes.

If you have high blood pressure, your physician will prescribe blood pressure medication to lower your overall blood pressure and the pressure on the weakened area of the aneurysm. Additionally your physician may prescribe a “statin” (or cholesterol lowering medication) to maintain the health of your blood vessels.

If the thoracic aortic aneurysm is large or causing symptoms, you will need prompt treatment to prevent a rupture from occurring. The weakened section of the vessel can be surgically removed and replaced with a graft of artificial material. If the aneurysm is close to the aortic valve (the valve that regulates blood flow from the heart into the aorta), a valve replacement may also be recommended during the procedure.

Repairing the aneurysm surgically is complex and requires an experienced thoracic surgical team. However, neglecting the aneurysm presents a higher risk. Repairing a thoracic aneurysm may require open-chest surgery, general anesthesia and a minimum hospital stay of five days.

Instead of an open aneurysm repair, your surgeon may consider a newer procedure called an endovascular aneurysm repair (EVAR, TEVAR, TA-EVAR). Endovascular means that surgery is performed inside your aorta using thin, long tubes called catheters. By entering through small incisions in the groin, the catheters are used to guide and deliver a stent-graft through the blood vessels to the site of the aneurysm. The stent graft is then positioned in the diseased segment of aorta to “reline” the aorta like a sleeve to divert blood flow away from the aneurysm.

This endovascular approach is currently used to treat abdominal and descending thoracic aneurysms, and is being evaluated as a treatment for thoracoabdominal and arch aneurysms. While current results are positive, further research is needed to determine who the best candidates for this type of procedure may be.

Your surgeon will advise you regarding the best option for treating your thoracic aneurysm

A thoracic aortic aneurysm, an abnormal bulge in a weakened wall of the aorta in the chest area, can cause a variety of symptoms and often life-threatening complications. Due to the serious risks it presents, timely diagnosis and treatment of a thoracic aneurysm are critical.

The standard surgical treatment for thoracic aortic aneurysms is open-chest aneurysm repair, but Cleveland Clinic surgeons are now able to treat many thoracic and thoracoabdominal (occurring in the lower part of the thoracic aorta and the upper part of the abdominal aorta) aneurysms with a minimally invasive procedure called an endovascular stent graft.

Endovascular means that surgery is performed inside your aorta using thin, long tubes called catheters. Through small incisions in the groin, the catheters are used to guide and deliver a stent-graft through the blood vessels to the site of the aneurysm. The stent graft is then deployed in the diseased segment of the aorta and "relines" the aorta like a sleeve to divert blood flow away from the aneurysm.

An endovascular stent graft is a fabric tube supported by metal wire stents (also called a scaffold) that reinforces the weak spot in the aorta. By sealing the area tightly with your artery above and below the aortic aneurysm, the graft allows blood to pass through it without pushing on the aneurysm.

Endovascular repair of thoracic aneurysms is generally less painful and has a lower risk of complications than traditional surgery because the incisions are smaller. Endovascular aorta aneurysm procedures also allow you to leave the hospital sooner and recover more quickly after your aorta repair.

You may be eligible for endovascular stent grafting if your thoracic aneurysm has not ruptured and the aneurysm is 5 centimeters or more in size.
Your physician can determine if aortic aneurysm repair is the best treatment by performing one or a combination of imaging studies, which may include:

• High resolution, computed tomography (CT) scan
• Magnetic resonance imaging (MRI)
• Angiography (an x-ray of the blood vessels)
• Transesophageal echocardiography (TEE), to record ultrasound images of your heart from inside your esophagus, or food pipe
• Intravascular ultrasound

Physical characteristics of the aorta and the aortic aneurysm itself are very important in determining if endovascular aorta repair is the best treatment.

Your surgeon will make small incisions in the skin above the femoral artery (the large artery that supplies blood to each leg) in the groin. A guide wire is threaded through the artery beyond the area of the thoracic aneurysm.

By using x-ray guidance, your surgeon inserts the device over the guide wire. The stent-graft device is constrained within a catheter to make it easier to deliver the stent-graft through your blood vessels. Once the graft is guided to the thoracic aneurysm site, the catheter is withdrawn, exposing the stent-graft in place. The stent-graft then expands like a spring to fit against the walls of the aorta on either side of the aneurysm, and delivers blood flow through the weakened section.

Once the stent-graft is in place, the blood flows through the graft, avoiding the aneurysm. Over time, the aneurysm typically shrinks due to the blood pressure being diverted away from the aneurysm.

• Red arrow: left subclavian artery
• Yellow arrow: left common carotid artery
• Green arrow: proximal extent of thoracic aortic aneurys

• Thoracic aorta stented
• Red arrow: stent within the proximal subclavian artery
• Yellow: stent in left common carotid artery

Cleveland Clinic surgeons are also using fenestrated and branched endografts to treat more complex thoracic aneurysms involving the aortic arch and thoracoabdominal aneurysms (those which involve the aorta both in the chest and the abdomen). Additionally, branched and fenestrated grafts are used to extend thoracic grafts to repair those aneurysms that involve the vessels leading to the intestines or the brain and arms.

For those patients with extensive aortic or multiple aneurysms, the best approach may require a combination of open surgery and endovascular repair. This combined therapy is referred to as a hybrid approach and most often includes what is known as an elephant trunk procedure.

Although endovascular surgery reduces recovery time to a few days, there are still potential risks. The possible complications of endovascular repair include:

• Leaking of blood around the graft, known as “endoleak”
• Movement, or migration, of the graft away from its initial placement
• Stent fracturing

Additional complications that are rare but serious include:

• Paralysis
• Delayed rupture of the aneurysm
• Infection

Your surgeon will discuss the benefits and potential risks of the procedure with you.

In 2005, more than 1,000 aortic aneurysms were treated by Cleveland Clinic’s Aortic Center.

The long-term durability of endovascular stent grafting to treat a thoracic aneurysm is yet unknown because this is a fairly new procedure. For this reason, patients who have endovascular repair of their thoracic aneurysms must be monitored closely on a regular basis with examinations and imaging studies.

Your hospital stay following endovascular stent grafting is usually 2 to 3 days. While your recovery will take less time than recovering from open-chest thoracic aneurysm surgery, the early restrictions are similar and include:

• No driving until approved by your physician (usually within 1-2 weeks after the procedure, and no longer taking pain medication)
• No baths until the groin incisions heal; showers and sponge baths around the incision are permitted
• Avoid lifting more than 10 pounds for approximately 4 - 6 weeks after the procedure

You will return for a follow-up visit within one month of the procedure. Follow-up imaging tests will take place 1 and 6 months following the procedure to make certain the stent is still functioning and in the proper location. If you aneurysm is shrinking and no problems are found, your subsequent imaging tests will take place yearly.

After you’ve had an endovascular repair of an aneurysm, it is recommended you adopt the same heart-healthy lifestyle led by other heart surgery patients. Your health care team can provide more information