Aortic Disease - Pathophysiology, Presentation, Investigation and Therapy

Question 1

How is the thoracic aorta divided?

Answer 1

It is divided into four sections. First part is the aortic root, second part is the ascending aorta, third part is the aortic Arch and last part is the descending thoracic aorta.

Question 2

Where does the aortic root begin and end?

Answer 2

Starts at the level of the aorta valve until the sinotubular junction

Question 3

Where does the ascending aorta begin and finish?

Answer 3

Starts at the level of the sinotublar junction and the origin of the barciocephalic artery

Question 4

Where does the aortic arch begin and finish?

Answer 4

Starts at the indominant artery until the left subclavian artery

Question 5

Where does the descending aorta begin and finish?

Answer 5

Starts after the left ssubcalvian artery at the diaphragm

Question 6

What is the main structure in the aortic root?

Answer 6

Main structure in the aortic root is the sinus of valsalva

Question 7

How many sinuses does the aortic root has?

Answer 7

There is normally three sinus’s: right sinus of vasalva (right coronary artery originates here), left sinus of valsalva (left coronary artery artery ostium is here) and non coronary sinus.

Question 8

What is the sinotubular junction?

Answer 8

The junction between the sinus of vasalva and the ascending aorta

Question 9

How is the aortic root measured on the CT?

Answer 9

The aortic root is measured at three levels on CT. At the level of the annulus known as the annulus diameter (where aortic valve leaflets hinge or get attached to the myocardium) , Sinus of vasalve diameter and sinotubular junction diameter.

Question 10

What are the three layers of the aorta?

Answer 10

tunica media, tunica initima and tunica adventitia.

Question 11

What are the characteristics of tunica intima?

Answer 11

Inner most layer, made of layer of endothelial cells and some collagen and elastic fibres

Question 12

What is the characteristics of tunica media?

Answer 12

It is made of smooth muscle cells and some elastin sheets

Question 13

What is the characteristics of tunica adventitia?

Answer 13

It is the outermost layer which is made of collagen and elastic fibres, toughest layer

Question 14

What is the main disease of the aorta?

Answer 14

Atheroscelorisis. Cause may cardivascular diseases such as stroke, aneurysms, myocardial infarction and peripheral vascular disease

Question 15

What are the risk factors of athersclerosis?

Answer 15

Hypertension, hypercholesteremia, smoking, diabetes, family history and more prevelant in males.

Question 16

Define an aneurysm

Answer 16

A localised enlargement of an artery which is caused by the weakness of vessel walls

Question 17

What is aortic dissections?

Answer 17

Caused by tear in inner wall of the aorta. As a result of this tear the blood enters and splits the wall of the aorta. Splits the tunica media. May be caused due to hypertension, athersclorisis, bicuspid valve syndrome, trauma and marfans and even aortic aneurysm will cause dissection.

Question 18

What is cystic media necrosis?

Answer 18

Cystic media necrosis is found in histology of dissection. This is muco-pollyscharide cycts which replaces smooth muscles and the elastins you would normally see in the media. Causes weakness and hence tear of the artery more likely to happen

Question 19

What are complications of dissection?

Answer 19

Complication of dissection include false aneaurysm which may occlude branches, ruputre

Question 20

What are the signs and symptoms of dissection aneurysms

Answer 20

• May be asymptomatic, Could be found accidentally.
• Symptoms depend on their size and location
• Sever aortic regurgilations may show signs of shortness of breath and signs of heart failure
• Compression to nearby structures may show signs of dysphagia (problems in swallowing), hoarsness or back pain
• Symptoms of dissection - oatients present with sharp chest pain radiating to the back

Question 21

What are the investigations of thoracic aneurysms?

Answer 21

• Chest X-ray - show widened mediastinum.
• Echocardiagram. - asses aortic root size and aortic valvle
• CT aniogram aorta - test of choice. Quick test but risk of radiation
• MRI aorta - test of choice. MRI does not have risk of radiation.

Question 22

What is the symptoms of aortic dissections?

Answer 22

• sever sharp chest pain which is radiating to the back into the scapula region
• Patient can also present with collapse due to temponade or external rupture or an acute aortic reguritation
• May also present with symptoms of stroke if it involves the carotid arteries

Question 23

What is found on examination of aortic dissection?

Answer 23

• Reduced or abset peripheral pulses
• Hypertension (majority display hypertension) or hypotension ( rupture or temponad they may be hypotensive)
• BP mismatch between sides
• Soft early diastolic murmur
• Pulmonary eodema - due to aortic reguritation
• Signs of CVA

Question 24

What are the investigation of Aortic Dissection?

Answer 24

• ECG - Might show ST/ischeamia indication coronary involvement
• CXR - Widened mediastinum
• Transthoracic echocardiogram - asses aortic root, aortic valves for aortic reguritation and pericardium for pericardial effussion. Limitation of transthroacic echocardiogram only shows the aortic root and the proximal part of the ascending aorta
• CT angiogram aorta - confirms diagnosis. best choice of investigation

Question 25

How is aortic dissection treated?

Answer 25

Type A and type B are treated in different ways.

Question 26

How is type A aortic dissection treated?

Answer 26

Type A dissection (involves the ascending aorta) - Surgical emergency is required. Blood pressure need to be controlled. Blood pressure is controlled by intravenous beta blockers, intravenous nitrate, calcium channel blocker. If these fail IV Sodium nitroprusside can be used.

Question 27

How is Type B aortic dissection treated?

Answer 27

Type B dissection (doesn’t invovle the ascending aorta) - Medical treatment, surgery is not required. Main treatment is to control the blood pressure. Blood pressure is controlled by intravenous beta blockers, intravenous nitrate, calcium channel blocker. If these fail IV Sodium nitroprusside can be used. There may be need for percuraneous intervention is the aorta if dissection is expanding, there is a risk of rupture or there is involvement of branches of the aorta and that is causing significant ischeamia.

Question 28

Takaysu Arteritis

Answer 28

This is granulomatous vasculitis which effects the aorta and the main branches of the aorta. It can result in stenosis, aneurysms, thrombosis of either aorta or of other branches of the aorta It affects more femals than males Presentation depends on which arteries are involved Treatment of this conditon is by steroids or immunosuppressive therapy. Occasionally patients may be reffered for surgery or percutaneous intervention if there is organ ischaemia

Question 29

Syphillis

Answer 29

It is condition that is associated with thoracic aortic disease Syphillis is a sexually transmitted disease. It is caused by treponema pallidum Treatment of syphillis is done by antibiotics and will prevent late stage syphhilus

Question 30

How many valves does the bicuspid aortic valve have?

Answer 30

Aortic valve normally has three cusps but in bicuspid aortic valve there is only two cusps because two of the leaflets have fused

Question 31

What are patients with a bicsupid valve prone too?

Answer 31

Bicuspid aortic valve is associated with the weakness of the thoracic aortic wall and therefore these patients are prone to having aortic aneurysms or dissection

Question 32

What is bicuspid valve associated with?

Answer 32

It is associated with aortic coarction.

Question 33

What is the meaning of coarction?

Answer 33

Coarction means narrowing or stenosis of the aorta.

Question 34

Where does coarction occur?

Answer 34

This normally occurs in the descending aorta after the origin of the left subclavian artery. The location of coarction is described in relation to the ligamentum arteriosum (remnant of the ductus arteriosis which is the congenital connection between the primary artery and the aorta which closes at birth). Pre-ductal (before the ligament), ductal(at the ligament), and post-ductal (after the ligament)

Question 35

What are the signs of coarction?

Answer 35

Cold legs Poor lug pulses If before the left subclavian artery there may be a radial femoral delay

Question 36

What are the symptoms of coarction?

Answer 36

Sever in infancy. May present with heart failure and failure to thrive Less severe if it is presented later in life. May be hypertension (high in arms and lower in legs) and cardiovascular complications

Question 37

How is the diagnosis of coarction?

Answer 37

Diagnosis is made from CT/MRI or chest x-ray (will show notching of the ribs

Question 38

What is the treatment of coarction?

Answer 38

Can be treated percutaneous (use of stent) or surgical correction

Question 39

What is Marfans Syndrome?

Answer 39

Caused by mutations in the fibrillin 1 gene. Conective tissue disease but it is a multisystem manifestation of marfans. It affects the skeletal system, the eyes, the vascular and the lungs and heart.

Question 40

What are the cardiac manifestation of Marfans?

Answer 40

Cardiac manifestation of Marfans is aortic and mitral valve prolapse and regurtitation, thoracic aortic aneurysms and dissection