Aortic Aneurysm

Aortic aneurysms are a relatively common condition and potentially life-threatening.

  • Incidence: 33 / 100.000

Overview

When the aorta becomes dilated to more than 1.5 times its average size, the condition is defined as an aortic aneurysm [1]. There are different etiologies for this disorder, but an aortic aneurysm results in dilatation in all layers of the vessel wall no matter the cause. A person suffering from this ailment can experience pain which is usually a precursor to a rupture. This aortic rupture will cause internal bleeding and should be treated immediately. In individuals who do not receive timely treatment, it can cause shock or even death.

There are four different aortic aneurysms that are designated by location [2]:

  • Aortic root aneurysm – located in Valsalva sinus.
  • Thoracic aortic aneurysm – located within the chest and broken up into ascending, aortic arch and descending aneurysms.
  • Abdominal aortic aneurysm (AAA) – the most common aneurysm located in the aortal segment of the abdominal cavity.
  • Thoracoabdominal aortic aneurysm – located in the thoracic and abdominal aorta. 

Etiology

The exact etiology of an aortic aneurysm is usually not known. There are various lifestyle factors that are associated with aneurysms [3]. A family history of aneurysm can also increase the chances of one occurring. Other risk factors that can be associated with aneurysms are:

  • Atherosclerosis (present in 95 percent of aortic aneurysms)
  • Congenital disorders (eg. Marfan syndrome, Ehlers-Danlos syndrome Type 4)
  • Smoking
  • Hypertension 
  • Infection (eg. untreated syphilis
  • Trauma
  • Complications from other conditions

Epidemiology

In the United States, the likelihood of an abdominal aortic aneurysm occurring can range from as small as three in 100,000 up to 117 in the same amount of people [4]. On an international scale there is a chance of abdominal aortic aneurysm ranging from 4.8 to 13 occurrences in 100,000 people annually. The incidence of thoracic aortic aneurysms is estimated to be 6:100,000 person-years.

While an aneurysm can occur at any point in a person’s life, the possibility increases once a person passes the age of 50 for males and after the age of 60 for women. The likelihood of an aneurysm peaks around the age of 80 for everyone.

Pathophysiology

It is unclear if there are any inciting factors that cause aortic aneurysms but, it is obvious that there has to be a defect in collagen and elastin, probably the most important structural proteins, in order for an aortic aneurysm to develop [5]. This process and degeneration of the media cause weakening of the vessel wall and dilation. Heredity and hemodynamic factors also seems to play an important role in the occurrence of aortic aneurysms.

Prognosis

In general, the prognosis for an aortic aneurysm of any kind is positive [6]. Once an aneurysm is properly treated, the chances of death related to one are as low as 10 percent. In the cases where surgery is required mortality increases, but only to around 30 percent. 

Presentation

There are rarely any noticeable signs or symptoms associated with an aortic aneurysm [7]. Any symptoms that do occur only do so once the vessel walls are already enlarged. These symptoms are usually abdominal or back pain. As the nerve roots may become compressed, a person can experience leg pain and numbness. A hoarse voice is usually a common sign of an aortic aneurysm in the arch of the aorta because the laryngeal nerve is involved when the aortic aneurysm is located in this area.

If a patient is experiencing any of the vague symptoms and there is a history of aneurysms in the family, it mandatory to examine for an aortic aneurysm as early detection and treatment will lead to a better prognosis.

If an aortic aneurysm goes unnoticed and untreated it can increase in size at a variable rate. As the aneurysm grows in size, the likelihood of blood clots breaking off and causing embolism increases. This, however, does remain rare.

Usually, aneurysms are found during a patient’s normal physical examination. In order to confirm a diagnosis, a medical professional will use imaging which will confirm the presence of an aortic aneurysm and figure out the severity of the condition.

Workup

The best way to diagnose an abdominal aortic aneurysm is through an abdominal aortic ultrasound [8]. This is usually done after there is a suspicion of an aneurysm after a normal physical examination occurs and a family history is examined. If a thoracic aortic aneurysm is suspected, a chest X-ray should be done. The early detection of an aortic aneurysm is important as treatment for the condition can prevent ruptures from occurring. Early detection and treatment will also lower the chances of related mortality.

Treatment

Once an aortic aneurysm is diagnosed, there are a number of treatment options available [9]:

  • Risk factor reduction and control (eg. cessation of smoking, blood pressure control)
  • Stent grafting
  • Surgery to place a synthetic arterial graft in the affected area

Prevention

Lifestyle changes can lower a person’s chance of suffering from an aortic aneurysm. A low-cholesterol diet void of saturated fats can reduce atherosclerosis, therefore lowering the risk of aortic aneurysms [10]. High blood pressure should also be controlled, if present, or prevented if it’s likely to occur.

If there is a family history of aortic aneurysms, a person should be aware of their health and remain on the lookout for the usual signs and symptoms of the condition. By being aware of their own health an aortic aneurysm can be diagnosed early and the chances of a positive prognosis icreased. If a person is considered to be high risk, periodic screenings should be done.

Patient Information

An aortic aneurysm is defined as a bulge in the aortic walls. The aorta is the largest artery in the body which goes down into the chest and the abdominal region. The aorta then splits into two blood vessels, one for each leg. The bulge occurs due to weaknesses within the walls.

This ailment should be taken seriously as it can lead to a rupture of the vessel which will cause internal bleeding when left untreated. If a rupture does occur, it must be remedied quickly since the internal bleeding can lead to shock or death.

When an aortic aneurysm is caught early it can be treated through medications like beta blockers. More severe cases may need surgery to properly remedy the aneurysm.

References

  1. Johnston KW, Rutherford RB, Tilson MD, Shah DM, Hollier L, Stanley JC. Suggested standards for reporting on arterial aneurysms. Subcommittee on Reporting Standards for Arterial Aneurysms, Ad Hoc Committee on Reporting Standards, Society for Vascular Surgery and North American Chapter, International Society for Cardiovascular Surgery. Journal of Vascular Surgery : Official Publication, the Society for Vascular Surgery [and] International Society for Cardiovascular Surgery, North American Chapter 1991 13 (3): 452–8.
  2. Saratzis A, Bown MJ.The genetic basis for aortic aneurysmal disease. Heart. 2014 Jun;100(12):916-22.
  3. Nazari S, Salvi S, Visconti E, et al. Descending aorta substitution with expandable ends prosthesis. Case report. J Cardiovasc Surg (Torino) 1999 40 (3): 417–20.
  4. Cinà C, Abouzahr L, Arena G, Laganà A, Devereaux P, Farrokhyar F. Cerebrospinal fluid drainage to prevent paraplegia during thoracic and thoracoabdominal aortic aneurysm surgery: a systematic review and meta-analysis. Journal of vascular surgery: official publication, the Society for Vascular Surgery [and] International Society for Cardiovascular Surgery, North American Chapter 2004 40 (1): 36–44.
  5. Gopaldas RR, Huh J, Dao TK, et al. Superior nationwide outcomes of endovascular versus open repair for isolated descending thoracic aortic aneurysm in 11,669 patients. J. Thorac. Cardiovasc. Surg. 2010 140 (5): 1001–10.
  6. Crawford ES, Cohen ES. Aortic aneurysm: a multifocal disease. Presidential address. Arch Surg 1982; 117:1393.
  7. Pressler V, McNamara JJ. Aneurysm of the thoracic aorta. Review of 260 cases. J Thorac Cardiovasc Surg 1985; 89:50.
  8. Bickerstaff LK, Pairolero PC, Hollier LH, et al. Thoracic aortic aneurysms: a population-based study. Surgery 1982; 92:1103.
  9. Itani Y, Watanabe S, Masuda Y, et al. Measurement of aortic diameters and detection of asymptomatic aortic aneurysms in a mass screening program using a mobile helical computed tomography unit. Heart Vessels 2002; 16:42.
  10. Isselbacher EM. Thoracic and abdominal aortic aneurysms. Circulation 2005; 111:816.

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