Disease of the Aorta Flashcards
Why is the aorta prone to injury and disease?
due to it’s constant exposure to high pulsatile pressure and shear stress
What are the 3 layers of the aorta?
- Intima- the thin inner layer
- Media- the thick middle layer that gives the aorta strength, elasticity and distensibility
- Adventitia- the thin outer layer
What are the two anatomical divisions of the aorta?
- The thoracic aorta- within the thoracic cavity.
2. The Abdominal aorta- the section below the diaphragm.
what are the 3 distinct segments of the thoracic aorta?
ascending aorta
aortic arch
descending aorta
what are the two distinct segments of the ascending aorta?
aortic root
ascending aorta
Ascending aorta begins where?
what else is found here?
Begins at the level of the aortic valve
- Supports the aortic valve leaflets
- Extends into the sinotubular junction
- Area where right and left main coronaries arise
Where does the descending thoracic travel too?
runs distally to the diaphragm
What is the aortic isthmus and why is it important?
The point at which the aortic arch joins the descending aorta
This is the point at which the aorta is vulnerable to trauma due to its fixation to other structures within the chest cavity
Where does the Abdominal aorta start and what are their 2 segments
Extends from the thoracic aorta at the level of the diaphragm to the bifurcation of the right and left common iliac arteries
Consists of two segments:
Suprarenal- the segment above the renal arteries
Infrarenal- the segment below the renal arteries
What happens to the aorta as we age?
Elasticity and distensibility decreases with age
These changes occur earlier and more rapidly in men than in women
Loss of elasticity is accelerated in patients with HTN, Hypercholesterolemia and coronary artery disease
what is the definition of aortic aneurysms?
Pathologic dilation of the aorta that can occur anywhere along the course of the aorta
What are the two types of aneurysms?
Fusiform
Saccular
what is the definition of a sccular aneurysm?
involves only a portion of the circumference (outpouching of a vessel)
what is the definition of a fusiform aneurysm?
Fusiform- affects the entire circumference of a segment of a vessel
how are aneurysms classified?
by location
Abdominal- below diaphragm
Thoracic- above diaphragm
Thoracolumbar- involves the descending thoracic aorta and abdominal aorta
what are the complications with aneurysms?
dissection
acute rupture
what is the average growth of thoracic aneurysms?
0.1-0.2cm/year
Those with marfans syndrome expand at a greater rate
The risk of aneurysm is related to what?
size and presence of symptoms
what is the most common cause of ascending aortic aneurysms?
Cystic medial necrosis is most common cause
What is the most common cause of aortic arch and descending thoracic aneurysms?
Aortic arch and descending thoracic aneurysms
Atherosclerosis is the most common cause
what are the risk factors for thoracic aneurysms?
Atherosclerosis
Connective tissue disorders such as Marfan’s and Ehlers-Danlos syndrome
Hypertension
Familial thoracic aortic aneurysm syndromes
Infections: Syphilis (rare), tuberculosis
Vasculitis (ex. Takayasu’s arteritis, giant cell arteritis)
Trauma (penetrating or non-penetrating)
What are the signs and symptoms of thoracic aortic aneurysms
most are asymptomatic and found on routine physical exam or chest X-ray
If symptoms are present they coincide with the size and loctation of aneurysms
Aortic root: CHF, aortic regurgitation
Aortic arch: may compress the trachea (deviation, cough) or hoarness
Descending aortic: dysphagia
chest and back pain which is steady and deep