Abdominal aortic aneurysm

 Abdominal aortic aneurysm

What is it?

Abdominal aortic aneurysm is a localized widening or dilation (in medical terms) of a blood vessel. Let’s divide the word and understand what it is.

Aneurysm is a Greek work which means localized blood filled balloon like bulge in the wall of a blood vessel.

Aorta is the largest artery in the body. It originates from the left ventricle of the heart and extends down to the abdomen, where it branches off into two smaller arteries. It circulates blood to all parts of the body.

Aortic aneurysm is general term for any swelling in the aorta. Aorta bulges and becomes a weak spot.

The abdominal aorta stands as the largest artery within the abdominal cavity. It is part of the aorta. So basically swelling in the abdominal aorta is referred to as abdominal aortic aneurysm.

Shapes and whereabouts

Most aortic aneurysms are fusiform. Fusus means spindle in Latin. Others are of balloon shape.

Normally they are of 3 cm diameter but Symptomatic and large aneurysms are of 5.5 cm diameter. Aortic Aneurysm is laminated blood clot like layers of plywood.

Rupture is very common if the size becomes more than 5.5cm.

Who develops it?

Men and women of age group above 60 years mostly develop it. 5% men above age of 60 develop abdominal aortic aneurysm.

Males are four times more likely to get affected of AAA than females. Out of one in every 250 people over the age of 50 gets affected by AAA in US whereas in India only 1 out of 1000 gets affected. Reason is difference in tobacco intake.  In case of family history you are more likely to get affected by AAA.

Risk Factors and Causes

Here are the causes/risk factors for AAA:

Tobacco smoking: 90% of AAA affected people suffer from this disease due to excessive smoking.

Genetic influences: Alpha 1-antitrypsin deficiency is considered as one of the cause for AAA, Also X-linked mutation theory also supported this idea. Both relapsing polychondritis and pseudoxanthoma elasticum have the potential to induce abdominal aortic aneurysm.  Connective tissue disorders, such as Marfan syndrome and Ehlers-Danlos syndrome are also considered as significant cause for AAA.

Atherosclerosis: This was considered as the cause for AAA since it affects the walls of the AAA heavily and frequently. This theory isn’t proved yet though.

Other causes: Trauma, Infection, Arteritis, and Cystic Medical Necrosis are some of the other causes of AAA.

Symptoms

Abdominal Aortic Aneurysm is mostly affecting a body very slowly so in most cases it is very difficult to get symptoms or no symptoms. But the following are several of those symptoms which were reported in cases of AAA:

• Abdominal Pain Which May Remain Constant Or Come And Go.
• Pain In The Lower Back That May Radiate Till Buttocks And Legs.
• Feeling Of Heart Beat In Abdomen.

Once the aneurysm bursts it may show symptoms like:

• Severe Pain In The Back And Abdomen.
• Dry mouth and excessive thirst.
• Vomiting and nausea like conditions.
• Dizziness, fainting, sweating, rapid heartbeat and sudden weakness.
• Paleness.

Diagnosis

Since AAA is an internal disease it is diagnosed using ultrasound or scan.

X-Rays: They tend to show excess of calcium deposits in aneurysm walls but plain X-Ray may not be very useful.

Ultrasound: They give clearer picture of the aneurysm and are safe as well. Hence this method is in best practice. But Ultrasound cannot determine the exact aneurysm extent and size  and hence for surgical purpose it cannot be used.

Computerized Tomography: This is the accurate way for knowing the size and extent of an aneurysm but it sends out high levels of radiations and also intravenous dyes needs to be used in the affected portion to check it. These dyes applied on your skin externally may cause you irritation or allergy or irritation on kidneys as well.

 

MRA and MRI: In cases where a patient already has skin problems or kidney problems MRA (magnetic resonance angiography) is used.

Treatment

Medicinal intake hasn’t proved to be of much use or hasn’t showed great results in case of AAA.

Hence surgical methods are most commonly used for treating Abdominal Aortic Aneurysm.

There are 2 types of surgery:

1. Open Repair Surgery: This is the traditional way of treating AAA. In this a part of the abdomen is replaced with a graft which is man-made and called as Dracon.
2. Endovascular Stent Grafting: This is done when there is bleeding or leaking in aneurysm. Since no open surgery is done in this case you may get well faster but it is only used for bleeding. It is also known as EVAR procedure. Only feasible in some cases of aneurysm and depends on the morphology of the aneurysm.  EVAR also results in introduction of man-made elements.

Effects:

Severe AAA may lead to more complications and have the following ill-effects:

• Arterial embolism.
• Heart attack.
• Hypovolemic shock.
• Kidney failure.
• Stroke.