[11] Aortic Dissection

Question 1

What is an aortic dissection?

Answer 1

A condition in which the inner layer of the aorta tears, and blood enters between the layers, forcing them apart

Question 2

Can an aortic dissection be fatal?

Answer 2

Yes, if blood ruptures through the outer aortic wall

Question 3

What layers is the aorta made up of?

Answer 3

• Intima
• Media
• Adventita

Question 4

What is the intima of the aorta?

Answer 4

The layer in direct contact with the blood inside the vessel

Question 5

What does the intima of the aorta consist of?

Answer 5

Mainly a layer of endothelial cells on a basement membrane

Question 6

What does the media of the aorta contain?

Answer 6

Muscle and connective tissue

Question 7

What is the role of the adventita of the aorta?

Answer 7

It protects the vessel on the outside

Question 8

What happens in an aortic dissection?

Answer 8

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

Question 9

How can an aortic dissection spread once blood has got inbetween the layers?

Answer 9

It can propagate along the length of the aorta for a variable distance forwards or backwards

Question 10

What is produced when an aortic dissection propagates along the length of the aorta?

Answer 10

A false lumen

Question 11

What seperates the false lumen from the true lumen in aortic dissection?

Answer 11

A layer of intimal tissue known as the intimal flap

Question 12

What can happen as blood flows down the false lumen in aortic dissection?

Answer 12

Secondary tears in the intima can occur, allowing blood to re-enter the true lumen

Question 13

What causes tears in the intima?

Answer 13

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

Question 14

What are the causes of aortic dissection?

Answer 14

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

Question 15

What are the potential classification of aortic dissections?

Answer 15

Type A and type B

Question 16

Which is the more common and dangerous type of aortic dissection?

Answer 16

Type A

Question 17

What does a type A aortic dissection involve?

Answer 17

A tear in the part of the aorta where it exists the heart, or a tear in the ascending aorta

Question 18

What does a type B aortic dissection involve?

Answer 18

A tear in the descending aorta only

Question 19

What are the risk factors for aortic dissection?

Answer 19

• 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

Question 20

What are the symptoms of an aortic dissection?

Answer 20

• 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

Question 21

How is an aortic dissection investigated?

Answer 21

• Chest x-ray
• Transoesophageal echocardiogram (TOE)
• CT scan
• Magnetic resonance angiogram

Question 22

Where should an acute aortic dissection be managed?

Answer 22

ICU or HDU

Question 23

What is involved in the medical management of aortic dissection?

Answer 23

• 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

Question 24

What systolic BP should be aimed for in the management of aortic dissection?

Answer 24

100-120mmHg

Question 25

Why might blood products be required in aortic dissection?

Answer 25

Due to sequesteration of blood

Question 26

Why is accurate assessment essential prior to surgery in aortic dissection?

Answer 26

As there may be entry, re-entry, and multiple years

Question 27

What might surgical intervention in aortic dissection involve?

Answer 27

Placing of stents or grafts to the aorta

Question 28

What is the aim of surgery in type A aortic dissections?

Answer 28

• Prevention of aortic rupture and pericardial tamponade
• Relieve aortic regurgitation

Question 29

What are the surgical options in type A aortic dissections?

Answer 29

• Implantation of graft in ascending aorta
• Total arch replacement or hemiarch replacement

Question 30

How are type B aortic dissections managed?

Answer 30

Thoracic endovascular aortic repair in addition to optimal medical treatment

Question 31

Why does open repair still have a significant role in the management of type B aortic dissections?

Answer 31

As endovascular repair is not always suitable, and there are some concerns over the durability of the technique

Question 32

Which aortic dissection patients may be managed conservatively?

Answer 32

Those with involvement solely of the descending aorta

Question 33

What is involved in conservative management of aortic dissection?

Answer 33

• Medical therapy
• Regular clinic and ultrasound follow up

Question 34

What is the advantage of avoiding surgery in aortic dissection?

Answer 34

Surgery is associated with a significant risk of paraplegia

Question 35

When should surgery be considered in chronic aortic dissection?

Answer 35

When there is evidence of progression of the dissection

Question 36

How can a chronic aortic dissection be treated surgically?

Answer 36

By open surgical techniques, or increasing by an endovascular approach

Question 37

What are the potential complications of an aortic dissection?

Answer 37

• Aortic haemorrhage
• Organ damage, such as kidney failure or intestinal ischaemia
• Stroke
• Aortic regurgitation
• Cardiac tamponade