Abdominal Aortic Aneurysm

One blood vessel has a very major role in supplying blood to the areas of the abdomen, pelvis and legs. This blood vessel is the aorta. Unfortunately, it can expand abnormally or balloon out, and this results in a medical condition known as abdominal aortic aneurysm (AAA).1 Abdominal aortic aneurysm is a common medical condition, especially in males over 65 years of age.2 In addition to age, the presence of peripheral atherosclerotic disease is also a risk factor.3 People with a medical history of smoking, chronic obstructive pulmonary disease (COPD), and hypertension are at increased risk for AAA. AAA is a life-threatening disease that is hard to predict since there are usually no symptoms until it ruptures.2 Sadly, when there is a complication of a rupture, at least 65% of patients die before they can get to a hospital.2 Patients with a ruptured AAA may also go into a state of shock presenting with symptoms such as cyanosis (bluish or purplish skin), mottling, altered mental status, tachycardia (rapid heart rate), and hypotension (abnormally low blood pressure).3

Cause

Although the underlying cause is unknown, what we know is that AAA happens when the elasticity of the aorta is greatly reduced due to inflammation, new vessel formation, and/or production and activation of some proteases and cytokines.4 Certain factors can increase the risk of AAA, including tobacco use, atherosclerosis, and an infection in the aorta.5 Tobacco smoking and atherosclerosis allow particles to build up in the aorta and these particles can weaken the structure of the blood vessel and affect the elasticity of the vessel. Infections usually lead to inflammation which in turn also leads to a build-up of substances that can weaken the aorta.

Diagnosis

When AAA has progressed, it will most likely be found during a routine physical examination by touching or feeling the skin on top of the ballooned aorta.2 AAA is asymptomatic, however, patients may complain about back, flank, abdominal, or groin pain before the aorta ruptures. Patients may also explain that they feel a pulsing mass in their abdomen.3 A diagnostic ultrasound or CT scan can be done to confirm the presence of AAA in the patient.

Treatment

Treatment depends on the size of aneurysm. For small- to medium-sized aneurysms, the doctor might recommend monitoring the site of aneurysm with intermediate scheduled ultrasounds as opposed to surgery. If the aneurysm is large-sized, growing too fast, or leaking, a surgery would be the preferred treatment as soon as possible.6 There are two types of surgery for AAA6:
  • Open-Abdominal Surgery. This is an intense surgery that requires removing a section of the affected region of the aorta and replacing it with an engineered tube or graft. Recovery is usually up to a month or more.
  • Endovascular Surgery. This is a less invasive surgery. It requires placing a graft at the end of a catheter, and transporting the catheter through an artery in the leg into the aorta. On reaching the affected site, the graft is fastened in place with pins or hooks to serve as reinforcement and prevent the future occurrence of rupture. Recovery time is shorter.
References
  1. MedLine Plus. Abdominal Aortic Aneurysm. http://www.nlm.nih.gov/medlineplus/ency/article/000162.htm. Accessed July 1, 2014.
  2. Pearce, W.H. Abdominal Aortic Aneurysm. Medscape. http://emedicine.medscape.com/article/1979501-overview. Accessed July 1, 2014.
  3. Pearce, W.H. Abdominal Aortic Aneurysm Clinical Presentation. Medscape. http://emedicine.medscape.com/article/1979501-clinical. Accessed July 1, 2014.
  4. Sakalihasan N, Limet R, Defawe OD. Abdominal Aortic Aneurysm. The Lancet. 2005;365(9470):1577-1589. doi:10.1016/S0140-6736(05)66459-8.
  5. Mayo Clinic. Abdominal Aortic Aneurysm: Causes. http://www.mayoclinic.org/diseases-conditions/abdominal-aortic-aneurysm/basics/causes/con-20023784. Accessed July 2, 2014.
  6. Mayo Clinic. Abdominal Aortic Aneurysm: Treatment and Drugs. http://www.mayoclinic.org/diseases-conditions/abdominal-aortic-aneurysm/basics/treatment/con-20023784. Accessed July 2, 2014.