Why Abdominal Aortic Aneurysm is Most Common?

An aortic aneurysm involves dilation or an enlargement of the human aorta to more than 1.5 times of its normal size. These do not cause any symptom except when they rupture. Occasionally, individuals may experience pain in the abdominal area or in leg or back area.

Aortic aneurysm usually remains present in the abdominal aorta and hence, called as abdominal aortic aneurysm. However, in some of the cases, they even remain present in the thoracic aorta. Aortic aneurysms make aorta walls weak and boost the risk related to an aortic rupture. Whenever rupture takes place, patients experience internal bleeding excessively and until they undergo with immediate treatment, they suffer death.

Aortic aneurysm creates many other problems in individuals. Particularly, it causes slow in the blood flow in the respective bulging section of any aortic aneurysm resulting in the formation of blood clots.

In case of blood clot breakage from any aortic aneurysm within the area of chest, it may travel towards the brain and results in stroke or cardiac problems. Blood clots, which break off from any aortic aneurysm in the person’s belly area may block the flow of blood to the legs or belly/stomach.

Doctors have until now classified the problem of aortic aneurysm based on the specific location of aorta in humans. These are

• Aortic root based aneurysm or Valsalva sinus aneurysm
• Thoracic aortic aneurysm in the chest, which further may be of aortic arch, descending and ascending aneurysm
• The most common form i.e. abdominal aortic aneurysms, abbreviated as Triple A or AAA. This involves the aorta’s segment that remains present inside the cavity of abdominal area in humans.

Abdominal aortic aneurysm or AAA is common as compared to its thoracic counterpart because of many reasons, which are-

Higher Reduction of Elastin in the Abdominal Aorta: Elastin is a principal and a load bearing type of protein remains present in the aorta’s walls. This protein reduces at a relatively higher rate in abdominal aorta than in the thoracic aorta. Reduction of protein thus results in bulge or enlarged form of aorta.

Vasa Vasorum Remains Absent in Abdominal Aorta: Another strong reason that justifies abdominal aortic aneurysm is common among individuals is that abdominal aorta does not contain an essential nutrient supplying blood vessels i.e. vasa vasorum within the aorta walls. Instead, most of the abdominal aortic aneurysm are of true aneurysms involving each of the three different layers named tunica media, tunica intima and tunica adventitia. Moreover, aortic aneurysm prevalence increases with age of a person at the time of performing diagnosis, while it attributes highly to atherosclerosis for the formation.

Rupture risk in abdominal aortic aneurysm has a close relationship with its diameter. This means, whenever the aneurysm crosses 5cm diameter, its yearly rupture risk increases the risks associated with surgical repair for any average risky patient.

Rupture risk also has a close relationship with the shape. This means, long or fusiform of abdominal aneurysm causes relatively less rupture prone as compared to bulbous, shorter or saccular aneurysm. This is because; saccular ones possess relatively higher wall tension in a specific location of the aneurysm wall.

Before any rupture takes place, abdominal aortic aneurysm represents itself a pulsatile and large mass above the patient’s umbilicus. However, rupture constitutes the first hint associated with aortic aneurysm and once rupture takes place, it highlights various classic symptoms related to severe, radiating and constant abdominal or back pain.

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