[11] Aortic Dissection Flashcards
What is an aortic dissection?
A condition in which the inner layer of the aorta tears, and blood enters between the layers, forcing them apart
Can an aortic dissection be fatal?
Yes, if blood ruptures through the outer aortic wall
What layers is the aorta made up of?
- Intima
- Media
- Adventita
What is the intima of the aorta?
The layer in direct contact with the blood inside the vessel
What does the intima of the aorta consist of?
Mainly a layer of endothelial cells on a basement membrane
What does the media of the aorta contain?
Muscle and connective tissue
What is the role of the adventita of the aorta?
It protects the vessel on the outside
What happens in an aortic dissection?
Blood penerates the intima through a tear, and enters the media layer. The high pressure rips the tissue of the media apart, along the laminated plane, splitting the inner 2/3 and outer 1/3 of the media apart
How can an aortic dissection spread once blood has got inbetween the layers?
It can propagate along the length of the aorta for a variable distance forwards or backwards
What is produced when an aortic dissection propagates along the length of the aorta?
A false lumen
What seperates the false lumen from the true lumen in aortic dissection?
A layer of intimal tissue known as the intimal flap
What can happen as blood flows down the false lumen in aortic dissection?
Secondary tears in the intima can occur, allowing blood to re-enter the true lumen
What causes tears in the intima?
It is not clear what causes tears in the intima, although it often involves the degeneration of the collagen and elastin that make up the media
What are the causes of aortic dissection?
Aortic dissections occur due to a weakened area of the aortic wall, which can be caused by;
- Chronic high blood pressure
- Marfans syndrome
- Traumatic injury to the chest area
What are the potential classification of aortic dissections?
Type A and type B
Which is the more common and dangerous type of aortic dissection?
Type A
What does a type A aortic dissection involve?
A tear in the part of the aorta where it exists the heart, or a tear in the ascending aorta
What does a type B aortic dissection involve?
A tear in the descending aorta only
What are the risk factors for aortic dissection?
- Uncontrolled hypertension
- Atherosclerosis
- Pre-existing aortic aneurysm
- Bicuspid aortic valve
- Aortic coarctation
- Turners syndrome
- Erhers-Danlos syndrome
- Giant cell arteritis
- Syphilis
- Male gender
- Age
- Cocaine use
- Pregnancy
- High-intensity weightlifting
What are the symptoms of an aortic dissection?
- Sudden severe chest, upper back, or abdominal pain
- Loss of consciousness
- Shortness of breath
- Sudden difficulty speaking
- Loss of vision
- Weakness or paralysis of one side of the body
- Radial-radial delay
- Leg pain
- Difficulty walking
How is an aortic dissection investigated?
- Chest x-ray
- Transoesophageal echocardiogram (TOE)
- CT scan
- Magnetic resonance angiogram
Where should an acute aortic dissection be managed?
ICU or HDU
What is involved in the medical management of aortic dissection?
- Adequate analgesia, e.g. morphine
- Aggressive management of hypertension to reduce further damage
- IV ß-blockers to reduce the force fo ventricular contraction. Can use vasodilators in combination
- Administration of blood products if evidence of blood loss
What systolic BP should be aimed for in the management of aortic dissection?
100-120mmHg
