Diseases of thoracic aorta Flashcards
What are the big 3 most common risks associated with atherosclerosis?
Stroke - TE to brain
MI - TE to CA’s
Aneurysms boi
What is an aneurysm?
Localised enlargement of an artery caused by weakening of the vessel wall
What are the different types of aneurysm?
True:
- Saccular - balloons out in one direction
- Fusiform - balloons out in both directions
False
Dissecting
Define what a true aneurysm is
Aneurysm in which there is weakness & dilation of the arterial wall, involving all 3 layers
What causes True aneurysms?
Hypertension
Atherosclerosis
Smoking
Trauma
Collagen abnormalities:
- Marfan’s syndrome
- Cystic medial necrosis
Infection:
- Mycotic
- Syphilis
Although true aneurysms involve dilation of all 3 layers of the arterial wall, why might the medial layer become relatively enlarged?
Haemorrhage of Vasa vasorum into Tunica media
Define what a false aneurysm is
Rupture of wall of aorta with the haematoma either contained by the thin adventitial layer or by the surrounding soft tissue
What are the causes of false aneurysms?
Inflammation
- Endocarditis (septic emboli)
Trauma
Iatrogenic
What are the indications of a false aneurysm on examination?
Thrill
Bruit
Pulsatile mass
Hypotension
What are the clinical risks of false aneurysms?
Ischaemia
Rupture
What are the different classes of aneurysms by site?
Ascending aortic aneurysm
Aortic arch aneurysm
Descending aortic aneurysm
Abdominal aortic aneurysm
How are aortic aneurysms usually found?
Incidental finding as usually asymptomatic
What are the general signs and symptoms of an thoracic aortic aneurysm?
Shortness of breath
Possible heart failure (aortic regurgitation)
Hypotension
Pulsatile mass
Dysphagia and hoarseness
What signs/symptoms indicate an ascending aortic aneurysm?
Dysphagia & hoarseness (chronic)
Aortic regurgitation
What signs/symptoms indicate an aortic dissection?
Sharp chest pain radiating to the back, between the shoulder blades
What happens to the aorta in order for an aortic dissection to occur?
Tear in the tunica intima
Blood forces the walls apart and pushes into this tear
Is aortic dissection acute or chronic?
Can be either
If acute - medical/surgical emergency
In what two ways are aortic dissections classed?
DeBakey
Stanford
What are the DeBakey classes?
Type I:
- originates in the ascending aorta & propagates to the arch or beyond
Type II:
- Originates & confined to ascending aorta
Type III:
- Originates in descending aorta
- Extends distally or rarely in retrograde
What are the Stanford classes?
Type A:
- Involves the ascending aorta in any way
Type B:
- Doesn’t involve the ascending aorta in any way
What are the aetiological risk factors for an aortic dissection?
Hypertension
Atherosclerosis
Trauma
Marfan’s syndrome (collagen abnormality)
What is the main histological feature of aortic dissection
Cystic medial necrosis
“Dissecting aneurysms create a false ______, that may extend _______ or _________”
False lumen
May extend antegrade or retrograde
What risk is posed by ‘rupturing’ of aortic dissecting aneurysms?
Either back into the lumen, into the pericardium (tamponade) or into the mediastinum
Why is it that an aneurysm can lead to a diastolic murmur associated with the aortic valve?
Ascending aortic dilation can cause acute aortic regurgitation, causing a diastolic murmur
What are the symptoms of aortic dissection?
Tearing, severe chest pain (radiating to between Shoulder blades)
Collapse (tamponade, acute AR, external rupture)
Beware inferior ST elevation
~50% mortality pre-hospital
What are the signs of aortic dissection?
Reduced or absent peripheral pulses (BP mismatch between sides)
Hypotension/ hypertension
Soft early diastolic murmur (AR)
Pulmonary oedema
Chest x-ray usually shows a widened mediastinum
Diagnosis can be confirmed by echocardiogram or CT scanning
What would you look for on a CT and CXR for dissecting aneurysms?
False (darker) and true (lighter) lumen on cross section of vessel (CT)
Enlarged upper heart shadow caused by ascending aorta/arch dilation on CXR
Treatment for aortic dissecting aneurysms depends on…
What standford type it is
Type A:
- Surgery
Type B:
- Meticulous BP control
- Sodium nitroprusside plus beta blocker
What is Takayasu’s Arteritis?
granulomatous vasculitis - inflammation of the aorta and its major branches
What are the risks/problems that Takayasu’s arteritis causes?
Aneurysms Aortic stenosis Throbosis Renal artery stenosis Neurological sx
How is Takayasu’s arteritis treated?
Steroids
Surgery
What organism causes Syphilis?
Terponema pallidum
Sexually transmitted
What are the signs of Syphilis?
Chancre on fingers - primary
Diffuse rash - secondary
If untreated, a third of infected SYphilis patients develop one of three types of tertiary syphilis
What are these types?
Late-neuro syphilis
Gummatous syphilis
Cardiac Syphilis - the one we care about right now
What are the potential effects of Cardiac syphilis?
Syphilitic aortitis:
- Aneurysms
Aortic regurgitation
What are the causes of Congenital aortic anuerysms?
Marfan’s syndrome
Bicuspid aortic valve
Coarctation of the aorta
Why is a Bicuspid aortic valve bad?
Prone to stenosis +/- regurgitation
Associated with coarctation
The aorta itself is abnormal - reduced tensile strength is why it is a risk factor for aortic aneurysms
What is coarctation of the aorta?
Stenosis of the aorta distal to the left Sub-clavian artery
What are the 3 shunts related to coarctation of the aorta?
Ductus arteriosus
Foramen ovale
Ductus venosus
What are the 3 types of aortic coarctation?
Based on relation to ductus arteriosus
Pre-ductal (5% turner’s):
- can be life-threatening if severe narrowing
Ductal
Post-ductal:
–most common in adults
– hypertension in upper extremities, weak pulses in lower limbs
- associated with rib-notching (collateral circulation)
What are the signs of aortic coarctation?
Cold legs
Poor leg pulses
If before left subclavian artery then both:
- Radial–radial delay
- RIGHT radial-femoral delay
If after left subclavian artery:
- No radial-radial delay
- Right and left radio-femoral delay
What are the signs in infancy of coarctation of the aorta?
Heart failure
Failure to thrive
What are the signs of coarctation of the aorta in later life?
Hypertension
On a radiograph image, what feature of the ribs indicates coarctation of the aorta?
Small black areas on the inferior edge of ribs
Gives the inferior edge a bumpy, cracked appearance and kinda looks like a fracture
Which imaging technique is best for aortic dissection?
CT is most reliable and easy way to diagnose
What is a mycotic aneurysm?
An aneurysm caused by through infection damaging (weakening) the arterial walls
Give an example of a mycotic aneurysm?
Aneurysm due to Aortitis due to Cardiac syphillis
What imaging is useful for investigating coarctation of the aorta and why?
CMRI - coarctation is clearly defined
CXR - will show rib notching which is a sign of Coarctation of the aorta
Summarise the imaging used to investigate thoracic aneurysms and why each one is used/good
CT or MRI - assessment of aneurysm
Aortography - can be used to assess positions of key branches in relation to the aneurysm
ECHO - good for identifying dissections
