Question ) What is aortic aneurysm and how is it formed?
Answer ) Aortic aneurysm is dilatation of the aorta. It can be thoracic or abdominal. Thoracic aortic aneurysm means a segmental full thickness dilatation of the artery with 50% increase in diameter as compared to the normal artery.
Thoracic aneurysms are classified by location as:
From the aortic valve to the innominate artery (60 percent)
Involve brachiocephalic vessels (10 percent)
Descending aortic aneurysms are those distal to the left subclavian artery (40 percent)
Thoracoabdominal aneurysms (10 percent)
Abdominal aortic aneurysms are more common and means dilatation of the aorta, more than 3 cms. It is seen between the renal and the inferior mesenteric arteries.
Small aneurysms have a diameter <4.0 cm
●Medium aneurysms have a diameter between 4.0 and 5.5 cm
●Large aneurysms have a diameter ≥5.5 cm
●Very large aneurysms have a diameter ≥6.0 cm
In case of Aortic Aneurysms treatment is based on the symptoms and size. A rapid increase in size is considered when there is an increase of 5mm in 6 months or 1 cm in 12 months.
Epidemology: How are aortic aneurysm formed?
1. Most are degenerative and age related due to weakening of wall of the aorta. They are associated with atherosclerosis.
2. Other risk factors include smoking, high cholesterol level, hypertension etc.
3. Diseases of the other blood vessels such as arteritis or Marfan's syndrome
4. Previous surgery on the aortic segment
5. Chest Trauma
6. Infections and Inflammations- Bechet's disease, SLE, rheumatoid arthritis, ankylosing spondylitis, wegner's granulomatosis,
7. Genetic factors also play an important role such as Marfan's, Ehler danlos, Turner Syndrome, Bicuspid Aortic Valves