When a blood vessel such as the aorta has a weakness in part of its wall, the resultant bulge is called an aneurysm. Although aneurysms can occur anywhere in the body, the two most common places they are found are the aorta, especially the abdominal part, and the brain.
The aorta is the largest blood vessel in the body and it transports oxygen and nutrients in the blood to the rest of the body's organs. A small aortic aneurysm poses little risk and can simply be monitored. If however, the aneurysm grows to more than 5.5cm in diameter, there is a higher risk of rupture and massive internal bleeding. This is very uncommon (1 in 10,000) but is an extreme life-threatening condition. The actual prevalence of aortic aneurysms is approximately 6 in 100 men and 2 in 100 women aged over 65. The following diagram illustrates an aortic aneurysm.
The cause is unclear, though atherosclerosis- stiffening of the arteries due to fat deposition- is thought to play a role in disease development. Risk factors include hypertension, diabetes, high cholesterol levels, smoking and obesity. A genetic predisposition also contributes to the development of an aortic aneurysm.
This is often done as an incidental finding (e.g. pulsatile mass detected by a clinician) though occasional aneurysms can cause abdominal pain. In the acute setting, if the aneurysm ruptures, the patient is clinically very unwell. However, in the elective setting, an ultrasound or CT scan of the aorta can identify the aneurysm and measurements can be taken of its diameter and length.
Regular surveillance has helped patients introduce lifestyle measurements and take medications to slow the progression of the aneurysm, e.g. by not smoking, eating a low-fat diet, exercising regularly and not being overweight. Blood-pressure and cholesterol lowering medications also help reduce the strain on the bulge in the aortic wall. Preventative surgery is recommended when the aortic aneurysm grows to more than 5cm in diameter. A graft is usually placed across the aneurysm with less invasive techniques being used more frequently.