What are Aortic Aneurysms?
Aortic aneurysms are anomalous (irregular) bulges in the aorta wall. The aorta is the largest artery in the human body, carrying oxygen-rich blood.
Roughly the diameter of a garden hose, this artery extends from the heart down through the chest and abdominal region, where it divides into 2 blood vessels suppling each leg. Although an aneurysm can develop anywhere along your aorta, most occur in the section running through the abdomen (abdominal aneurysms).
Aneurisms may also occur in the section of the aorta running through the chest (thoracic aneurysms).
As the heart pumps blood through the arteries, it is possible for a weakened artery wall to stretch. Symmetrical bulges are referred to as “fusiform” and are somewhat less likely to rupture than localized weakness of the artery wall, known as “saccular.”
Aortic aneurysms are serious. They can rupture and create life-threatening internal bleeding, and as the aneurism grows larger, the risk of rupture increases. Approximately 15,000 Americans die of a ruptured aortic aneurysm every year. However, when detected in time, aortic aneurysms can be repaired surgically.
Types of Aortic Aneurysms
The aorta’s wall is composed of three layers: the endothelium, the thin inner layer of smooth cells; the media, the middle layer which is muscular with elastic fibers; and the adventitia, the tough outer layer. Aortic aneurysms are classified by their location on the aorta, their shape, and how they are formed.
When an aneurysm’s walls include all three layers, they are referred to as true aneurysms. Pseudoaneurysms occur when the wall of the aneurysm has only the outer layer, and can occur as a result of trauma when the inner layers tear apart.
Fusiform aneurysms are commonly true aneurysms. The weakness is frequently along an extended section of the aorta, involving the full circumference of the aorta. The weakened part of the aorta appears as a fairly symmetrical bulge.
Saccular aneurysms appear as a small, asymmetrical blister on the aorta’s side. Pseudoaneurysms are typically caused by trauma( like a car accident or similar blunt force), or as the result of a penetrating aortic ulcer.
The most common type of aneurysm is a degenerative aneurysm, which occurs as the product of breakdown of the muscular layer and connective tissue. Common causes include high blood pressure, cigarette smoking, and genetic conditions.
Dissecting aneurysms happen when a tear starts within the aorta wall, creating separation of the different layers. This separation of the layers (or dissection) weakens the wall of the aorta, and the aorta enlarges. Dissections can happen anywhere along the aorta, and treatment depends upon the location.
Commonly, aneurysms in the ascending aorta are treated with emergency surgery. Aneurysms in the descending thoracic aorta can be treated with medication. While dissections are not common, they are the most common of the acute aortic syndromes, and are lethal if left untreated.
Thoracic Aortic Aneurysms
Thoracic aneurysms can happen at any location on the aorta above the diaphragm, including the ascending aorta, the aortic arch, and the descending thoracic aorta.
The shape of the aorta is like a candy cane, with the smaller section of the curve coming out of the heart, curling through the aortic arch, giving off branches to the head and arms. The aorta then descends through the chest cavity, down into the abdomen, and branches to provide blood to the abdominal organs and the legs.
Causes of Aortic Aneurysms
Aortic aneurysms are most frequently caused by damage to the artery’s wall due to Athersclerosis. Athersclerosis is generally referred to as the hardening of the arteries, caused by a buildup of cholesterol and other fatty deposits in the arteries and hypertension(high blood pressure).
Other causes of aortic aneurysms include:
- Congenital weakness of the artery wall
- Weakening of the artery wall from high blood pressure or smoking
- Dissection/tearing of the artery wall
- Trauma/injury from accidents such as motor vehicle accidents or falls
The cause of an aneurysm is not always known. Aneurysms sometimes run in families. This raises the risk of a patient for aneurysms.
The Symptoms of Aortic Aneurysms
Most patients with aortic aneurysms will not experience any symptoms. Most aortic aneurysms are diagnosed via chest X-rays or CT scans done while evaluating other conditions, or during routine exams.
Symptoms can occur if the aneurysm creates pressure on nearby organs or tissue, or if it leads to dissection.
If a dissection occurs, symptoms may include abdominal pain, severe tearing pain in the chest or back, stroke, or cold, numb extremities.
A doctor may diagnose an abdominal aortic aneurysm during a physical exam. Occasionally, patients may experience a pulsating mass in their abdomen. Or, an abnormal chest X-ray may be the first sign of an aortic aneurysm. Other tests carried out to diagnose an aneurysm include:
- Computerized tomography (CT)
- Magnetic resonance imaging (MRI)
Treatment of Aortic Aneurysms
Treatment for an aneurysm depends on the general location of the patient and the aneurism’s size and location.
A doctor may recommend a “watch-and-wait” approach if the aneurysm is small and no symptoms are present. This approach involves regularly scheduled imaging of the aneurysm to monitor its size. But, if the aneurysm is large enough, or if it grows at a rate of more than 1 centimeter per year, surgery is frequently the best option.
Medical Treatment of Aortic Dissections
With a dissection, patients usually experience severe pain in the back or chest, sometimes described as a “tearing” discomfort. Most commonly, patients seek emergency care and diagnosis of a dissection will be made in the emergency room. Dissections can involve the ascending aorta, the descending thoracic and abdominal aorta, or the entire aorta.
Risk of death depends on the dissection’s extent. Risk is highest for aneurysms involving the ascending aorta. Most of these aneurysms are treated in emergency surgery.
Frequently, dissections of the descending thoracic aorta may be treated with blood pressure control. While the aorta heals, medical treatment of aortic dissection involves aggressive control of the patient’s blood pressure and heart rate.
Adequate control of blood pressure may eliminate the need for surgery, once an acute dissection is healed. Because a previously dissected descending thoracic aorta can enlarge and rupture, lifelong monitoring of the diameter of the aorta will be required.
Open Abdominal or Open Chest Surgery
Once an aneurysm meets indications for surgery, the accepted standard treatment involves replacement of the affected portion of the aorta with an artificial graft. The graft is typically made from DacronTM, a durable material sewn in place with permanent sutures.
The type of operation and incision depends on where the aneurysm is located. When the aneurysm is located close to the aortic valve, the surgeon may make an incision in the front of the chest, such as a median sternotomy. When the aneurysm is close to the aortic valve, it may have to be repaired or replaced.
Surgery on the aortic arch is generally done from the front of the chest as well. If the aneurysm involves the descending thoracic aorta,( located on the left of the chest), or the thoracic abdominal aorta an incision on the left side of the chest is usually required. If the aneurysm is localized in the abdomen, an incision in the abdomen or on the side or flank may be needed.
Prognosis for an Aortic Aneurysm
With open abdominal or open chest surgery, the length of the operation and its risks depend on the how extensive the repair required is, as well as the general health of the patient. While recovery time can vary, most patients require about a month to six weeks to recover from aneurysm surgery. The patient will generally spend a week in the hospital, depending on their condition and the operation performed.
If you are in need of aortic aneurysm surgery or to find out if you are a candidate for minimally invasive robotic surgery, please contact us.