An aneurysm develops when a diseased blood vessel dilates or “balloons” outward. Arterial aneurysms can be found in many locations throughout the body, but typically involve the abdominal aorta below the kidneys.
Risk factors for developing an aortic aneurysm include:
- High cholesterol
- Genetic factors
- Male gender
An abdominal aortic aneurysm can develop in anyone, but it is most frequently seen in males over 60 with one or more risk factors. Aneurysms usually develop slowly over many years and often have no symptoms. They are frequently discovered during a work-up for vague abdominal or back pain. The larger the aneurysm, the more likely it is to rupture. If an aneurysm expands rapidly, tears open or blood leaks along the wall of the vessel, symptoms may suddenly develop. Small aneurysms without symptoms can be followed with periodic ultrasound evaluation to detect changes in aneurysm size. Surgery is generally recommended for larger aneurysms and those that rapidly increase in size. The goal is to perform surgery before complications or symptoms develop.
Another condition affecting the aorta is called a "dissection". This problem occurs when there is a split in the layers of tissue that comprise the aortic wall. Blood can then “dissect” between the layers and cause bleeding or obstruction of blood flow to vital organs.
Risk factors for developing an abdominal aortic aneurysm
Men are four times more likely than women to develop an abdominal aortic aneurysm. In fact, it's the ninth leading cause of death in men over age 55.
- Age - Aneurysms usually affect patients who are 50 to 80 years of age.
- Atherosclerosis (e.g., hardening of the arteries) – The large majority of aortic aneurysms are associated with this condition.
- High blood pressure - Increased pressure inside the arteries can create stress on weakened areas within the wall of the aorta.
- Injuries and hereditary disorders - This includes Marfan's syndrome, a connective-tissue disorder that is occasionally associated with sudden death due to aortic dissection.
- Smoking – Smoking at any time in your life increases your risk for developing an aneurysm and other manifestations of atherosclerosis.
Most aneurysms, especially small ones, have no symptoms. In fact, less than 25 percent of patients with aneurysms do not show obvious symptoms until the aneurysm ruptures. Vague symptoms can occur as the aneurysm begins to enlarge and press on nerves, organs or other blood vessels. For an aortic aneurysm, common symptoms generally include:
- Throbbing or pulsation in the abdomen.
- Abdominal pain - if severe, this could mean the aneurysm has ruptured.
- Back or flank pain – if severe, this could mean the aneurysm has ruptured.
An aneurysm that occurs in the chest (called a "thoracic aneurysm") may have the following symptoms:
- Pain between the shoulder blades, lower back, neck or abdomen
- A dry persistent cough.
- Hoarse voice (due to pressure from the aneurysm on the nerve that stimulates the vocal cords).
- Symptoms of a thoracic aneurysm or acute aortic dissection are frequently misdiagnosed.
Screening and Diagnosis
Even if an aneurysm does not cause symptoms, it may be detected during a routine physical examination. An abdominal aortic aneurysm can sometimes be felt in the abdomen and thoracic aneurysms can often be seen on a routine chest X-ray. Ultrasound of the abdomen is a highly accurate screening tool that can be used to make the initial diagnosis. More sophisticated imaging technology, such as computed tomography (a "CT scan") or magnetic resonance imaging (an "MRI") is then used to further evaluate a newly found aneurysm.
Highly trained and experienced physicians within the St. Joseph Hospital Vascular Institute are able to offer the latest treatments for thoracic and abdominal aortic aneurysms as well as acute (sudden onset) and chronic (long duration) aortic dissections. In short, acute aortic dissection may require immediate surgery, but in some situations aggressive blood pressure control with IV/oral medication is also appropriate for certain types of aortic dissections. Chronic aortic dissections are generally followed with periodic imaging, and repaired if complicating circumstances arise despite good blood pressure control. Large or rapidly growing thoracic aneurysms usually require surgical repair. Without surgery, the risk of life-threatening aneurysm rupture increases with time and with aneurysm size.
There are two types of surgery offered at the St. Joseph Hospital Vascular Institute to repair an aneurysm:
- Traditional surgery - Involves an incision in the chest or abdomen through which the aneurysm is opened and replaced with artificial graft material. This method of aneurysm repair offers proven and durable results with a low incidence of long-term complications. However, recovery from this relatively invasive procedure usually requires more time than less-invasive alternatives. The vascular specialists in the Vascular Institute can also perform an open abdominal aortic aneurysm repair using a less-invasive approach in which the skin incision is made in either the right or left flank area. This surgical approach offers better exposure of the abdominal aorta and its arterial branches, as well as results in a shorter hospital stay and a quicker recovery than the traditional open repair.
- Endovascular surgery - Involves two relatively small incisions at each groin to expose the common femoral arteries. A stent graft is then inserted through the femoral arteries and appropriately positioned using catheter/guidewire and video techniques. Once the stent graft is deployed within the aneurysm, it effectively diverts blood flow away from the aneurysm sac. Thus, pressure within the bulging aneurysm sac is reduced and the risk of aneurysm rupture is greatly diminished. This type of minimally invasive surgery has a relatively short recovery time and in general causes less physiologic trauma to the body. However, there is increased risk of blood vessel trauma using this technique and long-term periodic imaging is required because there is a small chance that the stent graft may move (i.e. migrate) or that blood flow may enter the aneurysm sac from the ends of the stent graft or from back-bleeding arteries, causing it to once again become pressurized and potentially rupture.