Seminars in Roentgenology
Volume 44, Issue 1 , Pages 1-2, January 2009

Letter from the Editor: Thoracic Aortic Disease: Some of the Facts

Article Outline

 

Thoracic aortic disease is the 15th leading cause of death in the United States, killing up to 20,000 people a year.1 Lucille Ball died of a thoracic aortic dissection despite a heroic and almost successful surgical attempt to save her life.2 John Ritter, an actor on the television show “Three's Company,” died when his thoracic aorta burst due to a dissecting aortic aneurysm.2 Jonathan Larson, creator of Broadway hit “Rent” and recipient of the 1996 Pulitzer Prize for Drama, died at age 35 from a ruptured thoracic aorta, believed to be due to Marfan Syndrome.3

The term “aneurysm” was probably written down for the first time by Rufus of Ephesus, and is derived from the Greek ana (on top of, towards the outside) and euruno (widening).4 An 1869 article in The Lancet reported that aortic aneurysm was caused by stress on the chest during exercise and by constriction of the neck by tight collars.4 In 1906, the truth was revealed when a study showed that 90% of patients with an aortic aneurysm suffered from syphilis.4 Today the most common cause of aortic aneurysm is atherosclerosis. Other causes include cystic medial necrosis, infection, inflammation, and trauma. Risk factors include age 55 or older, male sex, high blood pressure, cigarette smoking, inherited diseases such as Marfan or Ehlers-Danlos syndrome, unicuspid or bicuspid aortic valves, and family history of aortic aneurysm.5 Additionally, aortic aneurysms are more common in persons with chronic obstructive pulmonary disease than those without the disease.6

Although abdominal aortic aneurysms are far more common than thoracic aortic aneurysms, comprising up to 75% of aortic aneurysms, a recent population-based study suggests an increasing prevalence of thoracic aortic aneurysms.6 By definition, an aneurysm is a localized or diffuse dilation of an artery with a diameter at least 50% greater than the normal size of the artery.6 People with small aortic aneurysms are at increased risk for the following: 1) thrombus forming at the site, which can dislodge and lead to stroke, 2) increase in the aneurysm size, causing it to press on other organs, 3) aortic dissection, and 4) aneurysm rupture. Cigarette smoking alone is known to increase the rate of aneurysm growth by 20% to 25% per year, which significantly increases the risk of rupture.7 The U.S. Preventive Services Task Force (USPSTF) recommends an abdominal ultrasound screening test for men between the ages of 65 and 75 who have ever smoked.8 The recommendation does not apply to women or nonsmoking men as screening is not considered beneficial in these groups. People who have a strong family history of aortic aneurysms or who have Marfan syndrome, Ehlers-Danlos syndrome, or another condition that puts them at risk may benefit from screening.8

Thoracic aortic aneurysms often go unnoticed because patients rarely feel any symptoms. For this reason, aortic aneurysms are often referred to as a silent killer. When associated with Marfan syndrome, aortic dissection and rupture can occur in apparently healthy people, causing sudden death in young competitive athletes.9 Many well known athletes have been diagnosed with this disorder; even Abraham Lincoln was rumored to have had it. Most thoracic aortic aneurysms are discovered incidentally on chest radiographs or other imaging studies. Elective repair is recommended when ascending aneurysms are 5.5 cm and descending aneurysms are 6.5 cm for patients without any familial disorders such as Marfan syndrome.6 Aneurysms at the aortic root are prone to rupture at sizes closer to 5 cm and must be treated more aggressively.5 A growth rate of 1 cm/year or faster is another indication for elective surgical repair.

Aneurysm is the most commonly diagnosed condition of the thoracic aorta that requires surgery.6 The accepted standard treatment for an aortic aneurysm once it meets the indications for surgery is replacement of that portion of the aorta with an artificial graft, typically made from DacronTM. Dacron grafts allow ingrowth in the interstices to form a pseudoendothelial layer to minimize the risk of embolization.6 Ascending aortic replacement was first performed in 1956 by Cooley and De Bakey.6 More recently, less invasive therapy for descending thoracic aortic aneurysms has been developed. In March 2005, the US Food and Drug Administration (FDA) approved the first thoracic aortic stent graft, the GORE TAG graft (W.L. Gore and Associates; Neward, Del).6 Descending thoracic aneurysms with the appropriate anatomy may now be repaired by these nitinol-based stent grafts. Development of another aneurysm postoperatively is not uncommon and for this reason, serial evaluations (i.e., CT scans or MRI) are commonly performed every 3-6 months during the first postoperative year and every 6 months thereafter.

Because radiological imaging, particularly CT and MRI, is so important in the diagnosis, treatment and follow-up of patients with thoracic aortic disease, I asked Dr. Heyneman to Guest Edit an issue on this topic. I thank her and all the authors for providing a concise, up-to-date review of thoracic aortic disease that will be of value to all radiologists who interpret imaging examinations of the chest.

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References 

  1. Mann Lake D: $11.6 Million Grant Boosts Study of Often-Fatal Aortic Diseases. Available at: http://publicaffairs.uth.tmc.edu/distinctions/archive/2006/September/grant.html. Distinctions, University of Texas Houston Health Science Center at Houston Public Affairs. Accessed July 7, 2007
  2. An Anthology of Death — Fun Facts, Questions, Answers, Information. http://funtrivia.com/en/subtopics/An-Anthology-of-Death-186870.htmlAccessed July 7, 2007
  3. Larson J. Angelfire. http://www.angelfire.com/musicals/rentsitepa/jon_larson.htmlAccessed July 10, 2007
  4. Suy R. The varying morphology and aetiology of the arterial aneurysm: a historical review. Acta Chir Belg. 2006;106:354–360
  5. eMedicineHealth. Aortic Aneurysm. http://www.emedicinehealth.com/script/main/art.asp?articlekey=58677&pf=3&page=1Accessed July 9, 2007
  6. Tseng E. emedicine from WebMD (Thoracic Aortic Aneurysm). http://www.emedicine.com/med/topic2783.htmAccessed July 9, 2007
  7. WebMD. Heart Disease Health Center: Aortic Aneurysm — Treatment Overview. http://www.webmd.com/heart-disease/tc/Aortic-Aneurysm-Treatment-Overview?print=trueAccessed July 9, 2007
  8. WebMD. Heart Disease Health Center: Aortic Aneurysm — Exams and Tests. http://www.webmd.com/heart-disease/tc/Aortic-Aneurysm-Exams-and-Tests?print=trueAccessed July 9, 2007
  9. Amado JA, Thomas DJ. Early recognition of Marfan's syndrome. J Am Acad Nurse Pract. 2002;14:201–206

PII: S0037-198X(08)00069-2

doi:10.1053/j.ro.2008.10.001

Seminars in Roentgenology
Volume 44, Issue 1 , Pages 1-2, January 2009

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