Aetiology and risk factors

Aetiolgy of aortic dissection is multifactorial. Both acquired degenerative disease and inherited susceptibility are thought to be responsible.

Important risk factors for aortic dissection include:

• systemic hypertension
  • is the most important risk factor and seen in 40-75% of patients as the presenting condition
• connective tissue disorders - inherent weakness of the aortic wall leads to subsequent dissection and is especially important in patients under the age of 40 years
  • Marfan’s syndrome
    • develops in 20-40% of patients with Marfan's syndrome
    • this condition often underlies dissection in teenagers
  • Ehlers-Danlos syndrome
  • Turners syndrome
• congenital cardiovascular abnormalities
  • bicuspid aortic valves
    • a cross sectional study has revealed that there is fivefold to 18fold increased risk of dissection in patients with bicuspid aortic valves
  • coarctation
    • because of its association with hypertension and congenital disorders of the aortic valve
• pregnancy - 50% of dissections in the under 40's are in pregnant women. Most at risk are primiparous women in the last trimester of pregnancy
• cocaine misuse
• iatrogenic
  • surgery to the aorta - following aortic cannulation for cardiopulmonary bypass or aortic valve replacement - but uncommon
• dceleration trauma e.g. – accident, fall from a height
• aortic vasculitic disease

Reference:

• (1) Thrumurthy SG et al. The diagnosis and management of aortic dissection. BMJ. 2011;344:d8290.
• (2) Hebballi R, Swanevelder J. Diagnosis and management of aortic dissection. Contin Educ Anaesth Crit Care Pain (2009) 9 (1): 14-18