An aneurysm is a balloon-like bulge in an artery. Aneurysms happen when the artery has a weak spot, and the pressure of blood passing through the artery makes the vessel bulge outward in that spot. Aneurysms can form in arteries of all sizes.
All aneurysms need to have follow-up by a physician familiar with the disease. Depending on the size of the aneurysm, and the height and weight of the patient, a surgical procedure may be required. Not all aneurysms are life-threatening. But if the bulging stretches the artery too far, the vessel may burst, causing death from major internal bleeding.
If an aneurysm is located in the brain, and it bleeds, the bleeding can cause stroke or death.
A dissection occurs when the layers of the wall of an artery become separated or torn; this allows blood to flow between those layers, which forces them to separate further. Like an aneurysm, dissection can weaken the wall of an artery, sometimes to the point that it could burst.
Where do aneurysms and dissections occur?
- Aneurysms can form in the arteries that supply blood to the brain. This is called a cerebral aneurysm.
- Aneurysms and dissections can occur in parts of the aorta. The aorta is the large artery that carries blood from the heart to other parts of the body.
- Aortic aneurysms can occur in the area below the stomach (abdominal aneurysm) or in the chest (thoracic aneurysm). An abdominal aortic aneurysm is usually located below the kidneys.
- Aortic dissection can occur in the aorta and its main branches. Aortic dissections are classified by the part of the aorta where they occur. Type A aortic dissection occurs in the ascending aorta, which is the part of the aorta that starts from the aortic valve (where blood exits the heart) and extends up to the bend of the aorta (the aortic arch). Type A dissections sometimes extend even farther, going down the whole length of the aorta to the aortic bifurcation, where the aorta splits into the arteries that supply blood to the legs. Type B aortic dissection occurs in the descending aorta, which is the part of the aorta that starts after the left subclavian artery (the artery that supplies the left arm and hand) and extends into the abdomen or all the way down to the aortic bifurcation.
- Aneurysms can occur in the heart’s main pumping chamber (the left ventricle). If a section of the heart wall becomes damaged after a heart attack, scarring occurs, and the heart wall grows thinner and weaker. This may cause a ventricular aneurysm to form. The aneurysm makes the heart muscle in that part of the ventricle weaker, so the rest of your heart has to work harder to pump blood to the rest of your body. Ventricular aneurysms can cause shortness of breath, chest pain, or an irregular heartbeat (arrhythmia). If a ventricular aneurysm leads to congestive heart failure, left ventricular heart failure, or arrhythmia, your doctor may want you to have surgery.
How do aneurysms happen, and who is at risk?
Any condition that causes the walls of the arteries to weaken can lead to an aneurysm. The following conditions can increase a person’s risk of an aortic aneurysm or dissection:
- Atherosclerosis (a buildup of fatty plaque in the arteries)
- High blood pressure
- Smoking
- Deep wounds, injuries, or infections of the blood vessels
- A congenital abnormality (a condition that you are born with)
- An inherited disease such as Marfan syndrome, Loeys-Dietz syndrome, or other heritable thoracic aortic diseases
- A defective gene. Researchers have found that people who have a defect in 1 of 3 specific genes have a greater chance of having an aortic aneurysm or dissection in their lifetime.
How are aneurysms detected?
Depending on the location of the aneurysm, it can be found with abdominal ultrasound, echocardiography, or radiological imaging such as arteriography, magnetic resonance imaging (MRI), and computed tomography (CT) scanning.
What are the symptoms?
Symptoms depend on the type and location of the aneurysm and result from the pressure caused by an aneurysm pressing against nearby organs, nerves, and other blood vessels. For example,
- Aortic aneurysms located in the chest can cause shortness of breath, a croaky or raspy voice, backache, or pain in your left shoulder or between your shoulder blades. Most of the time, however, these aneurysms don’t have symptoms. Often, they are found during a routine examination for another reason, or because aortic dissection develops on top of the aneurysm.
- Aortic dissection may cause sudden and severe pain, and patients often feel like something is ripping or tearing inside of them. The pain can be felt in the chest, in the back, or between the shoulder blades. Aortic dissection may also cause sudden stomach pain, lower-back pain, or flu-like symptoms. If blood leaks from the dissection and builds up in the chest, the blood may enter the pericardial space (the sac that surrounds the heart) and prevent the heart from filling properly. This can lead to a life-threatening condition called cardiac tamponade.
- Abdominal aortic aneurysms may cause abdominal or lower-back pain.
- Cerebral (brain) aneurysms may have no symptoms, or they may cause headaches, pain in your neck and face, or trouble seeing and talking.
How are aneurysms and dissections treated?
Treatment depends on the size and location of the aneurysm and your overall health. Aortic aneurysms in the chest (that is, in the ascending aorta or the descending aorta), if they are large enough, should be operated on (with surgical or endovascular procedures; see below) to prevent rupture or dissection. Abdominal aortic aneurysms should be also operated on if they are large enough.
All aneurysms should be watched regularly. Depending on the size of the aneurysm, your doctor may recommend imaging studies every year. Surgery may be recommended if the aneurysm grows to a size of 5 or 5.5 centimeters (2 or 2.2 inches), but whether your doctor recommends surgery can also depend on your general health, whether you have genes that make you prone to aortic aneurysms, and your height and weight. For example, a 5-centimeter aneurysm in the ascending aorta is more likely to need surgery if you are short and thin than if you are big.
For patients with aortic dissection, surgery is usually recommended right away for Type A dissections, which are dissections in the part of the aorta closest to the heart and to the aortic valve. For Type B dissections, which are farther from the heart, patients may first be given medicines (such as beta-blockers to lower blood pressure), and the dissection will be watched closely. Depending on the patient’s symptoms and the results of their imaging studies, a stent graft inserted through a puncture in the groin may be required for Type B aortic dissection. Only rarely does Type B aortic dissection require open surgery, which is done through an incision in the back.
Medication
If you have an aortic aneurysm that doesn’t need surgery, your doctor may prescribe medicines that lower blood pressure (like beta blockers) to relieve the stress on the wall of your aorta. This reduces the risk of the aneurysm getting bigger.
Surgery
Surgery for aortic aneurysms often involves replacing the weakened section of the aorta with a graft: a tube made of fabric. This is done through an incision in the chest or the back.
Minimally invasive, endovascular procedures
Interventionalists at The Texas Heart Institute (cardiologists, cardiac surgeons, and vascular surgeons) were among the first to use a minimally invasive technique to treat high-risk patients with abdominal aortic aneurysms. This technique is called endovascular repair of abdominal aortic aneurysm, or EVAR. In this procedure, a stent graft—a tube made of fabric and wire mesh—is inserted into the artery in your leg through a small puncture in the groin. Then the stent graft is threaded through the artery and up into the aorta until the stent graft is inside the aneurysm. There, the stent graft is expanded into a tube so that blood will flow through the graft instead of the aneurysm. This reduces the pressure on the aneurysm’s weak walls and prevents the aneurysm from expanding or bursting. The EVAR technique is routinely used today to treat patients with abdominal aortic aneurysms as long as the patient’s blood vessels are suitable for this kind of treatment.
Interventionalists at The Texas Heart Institute were also among the first to also perform endovascular repair of aneurysms and dissections of the descending thoracic aorta in the chest. The endovascular repair of a descending thoracic aneurysm is called TEVAR (for thoracic endovascular aortic repair). Like EVAR, TEVAR involves expanding a stent graft inside the diseased part of the aorta.
Benefits of EVAR and TEVAR include faster recovery and a shorter hospital stay compared to surgery. Sometimes these procedures can be done without general anesthesia (you are awake for the procedure). Instead, a local anesthetic is used to numb the groin area where the puncture is performed to insert the stent graft.