Abdominal Vasculature - Part 5 Flashcards
Dissection aneurysm
Is an aneurysm in which the wall of an artery rips (dissects) longitudinally
- rupture of the intima of the aorta which separates from the media with a column of blood between the two layers
Why does dissection aneurysms occur?
Because of the bleeding into the weakened wall splits the wall
What do dissecting aneurysms tend to affect?
The thoracic aorta
When are dissecting aneurysms particularly dangerous?
In Marfan syndrome
What are causes of dissection aneurysms? (4)
- Hypertension
- Marfan syndrome
- Pregnancy
- Chest trauma
What is a dissection aneurysm a result of? (2)
- Congenital defect
- Iatrogenic event
- man made nick in a vessel
How do you measure an aneurysm?
From the outer wall to the other outer wall
What does a dissection aneurysm look like on US? (2)
- Identification of an intimal flap in the arctic lumen
2. Arterial pulsations
What is demonstrated in the dissection aneurysm between the membranes during diastole?
Opposite flow direction
What is the sonographic findings of a rupture?
Is a hematoma in soft tissue adjacent to the dissected area
What is the average measurement of the aorta at the level of the suprarenal?
2.5cm
What is the average measurement of the aorta at the level of the renal?
2cm
What is the average measurement of the aorta at the level of the infrarenal?
1.5cm
What is the average measurement of the aorta at the level of the common iliac?
1cm
Aneurysm
Is a permanent focal dilation of an artery 1.5x its normal diameter involving all three layers of the wall
What are the clinical signs and symptoms of AAA? (3)
- Pulsatile mass at or above the umbilicus AAA
- Usually asymptomatic
- Symptoms = back pain
What are common causes of AAA? (5)
- Hypertension
- Atherosclerosis
- Infection
- Trauma
- Hereditary or acquired connective tissue disorders
- eg. Marfan syndrome or Ehlers-Danlos syndrome
What layers of the vessel are involved with AAA? (2)
- Media layer
2. Adventitia layer
What happens to the media and adventitial layer when you have a AAA?
There is s significant decrease in elastin and collagen in both layers
When is an aneurysm considered present?
When the infrarenal diameter is 3cm or greater
What are 7 risk factors of AAA?
- Over age 50
- More common in males
- Grows faster in women and ruptures at a smaller diameter
- Smoking
- Family history history of peripheral vascular disease
- Cardiovascular disease
- Hypertension
What is common in an AAA?
A thrombus
What is important to note with an AAA?
Its location
- above or below renals
What diameter should be reached in order to have surveillance done every 6 months?
4-4.5cm
