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Aortic Aneurysms

Aortic Aneurysms

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.

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 imperfect, polycystic kidney disease, and Turners Syndrome) and injury, can cause the aorta to dilate (widen) or dissect (tear), placing one at increased risk for future life-threatening events.

  • 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 through both the abdomen and chest are called thoracoabdominal aortic aneurysms.

Is a thoracic aortic aneurysm serious?

  • 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 or stroke increase 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.

What causes a thoracic aortic aneurysm?

Thoracic aortic aneurysms are most often caused by atherosclerosis, a hardening of the arteries that damages the artery’s walls. While the arteries are normally smooth on the inside, as one ages these 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.

Risk for atherosclerosis increases if

  • a smoker
  • high blood pressure
  • high cholesterol
  • overweight
  • 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 one ages, 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.

What are the symptoms of a thoracic aortic aneurysm?

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

What is an aortic dissection?

  • Aortic dissection occurs when the layers of the aorta tear and separate from each other. The presence of an aortic aneurysm increases the 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 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 one experiences any symptoms of a thoracic aortic aneurysm or aortic dissection, notify the physician immediately. If left untreated, these conditions could lead to a fatal rupture.

Thoracic Aortic Dissection

  • Aortic dissection is the tearing of the inner layer of the aortic wall, allowing blood to leak into the wall itself and cause the separation of the inner and outer layers. It is usually associated with severe chest pain radiating to the back.

Type A Dissection

  • Dissection beginning in the ascending aorta is called Type A dissection. Type A dissection often begins just above the coronary arteries. Dissection occurring here, where the aorta is the largest, thinnest, lacks support from surrounding structures and experiences the greatest amount of wall tension, is life threatening. Type A dissection is always treated as a surgical emergency. Left untreated it is associated always with death

Type B Dissection

  • Whenever the ascending aorta is not involved, it is referred to as Type B dissection. This type always involves the descending aorta. Type B dissection begins just beyond the aortic arch. Type B dissection is initially stabilized medically. However, if complications with blood flow to the lower body arise, whether as a result of narrowing of the true aorta (true lumen) or disruption and blockage of one of the aortic branches, the patient will require an interventional procedure.

How is a thoracic aortic aneurysm diagnosed?

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)

How is a thoracic aortic aneurysm treated?

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

Watchful Waiting and Medication

  • If the thoracic aortic aneurysm is small and not causing any symptoms, treating physician may recommend "watchful waiting". By closely monitoring the condition with CT or MRI scans every 6-12 months, the aneurysm will be watched for signs of changes.
  • If one has high blood pressure, the physician will prescribe blood pressure medication to lower the high blood pressure and the pressure on the weakened area of the aneurysm. Additionally the physician may prescribe a "statin" (or cholesterol lowering medication) to maintain the health of the blood vessels.

Surgical Repair

  • If the thoracic aortic aneurysm is large or causing symptoms, one 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 8 days.

Endovascular Repair

  • Instead of an open aneurysm repair, treating 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.

Thoracic Aortic Aneurysm

Natural History

  • Growth rate: 0.42 cm/yr
  • 0.23 cm/yr for abdominal aneurysms
  • 0.56 cm/yr for aortic arch aneurysms
  • Onset of symptoms to mean interval to rupture is 2 years
  • Rate of rupture : 50-75%, more frequent with aortic dissection

Mortality rate for rupture : 95%
Five year survival : 20%

Early treatment of these aneurysms is less risky than the risk of developing complications