Diseases of the thoracic aorta Flashcards
Describe the histology of thw aorta
Tunica Intima
- layer of endothelial cells
- subendothelial layer - collagen and elastic fibres
- seperated fro T.media and internal elastic membrane
Tunica media
- smooth muscle cells
- secretes elastin in the form of sheets/lamelle
Tunica adventitia
- thin connective tissue layer
- collagen fibres and elastic fibres
Function of collagen in T.adventia
-the collagen in T.adventia prevents the elastic arteries from stretching beyond their physiological limits during systole
State the risk factors of atherosclerosis
Hypertension Hypercholesterolaemia smoking diabetes FMX M>F ( untill menopause)
What can severe atherosclerosis lead to?
- Stroke
- MI
- aneurysm
What is an aneurysm
-localised enlargement of an artery caused by the weakening of the vessel
Types of anerysm
- True(saccular[unequal]/fusiform[equal])
- False
- Dissecting
What is a true aneurysm
-aneurysm that involes all 3 layers
Causes of true aneurysms
- Hypertension
- atherosclerosis
- smoking
- collagen abnormalities ( marfan’s, cystic medial necrosis)
- ttrauma
- infection ( mycotic/syphillis)
What is a false aneurysm
-rupture of a wall of aorta with the haematoma contained by T.adventia or surrounding tissue
Causes of false aneurysms
- inflammation ( endocarditis with septal emboli)
- trauma
- iatrogenic ( catheters)
What is an aortic dissection?
tear in T.intima of aorta + blood forces the walls apart
-acute(E)/chronic
Types of thoracic aortic dissections
Debankey
Type I
Type II
Type III
Stanford
Type A - dissection involving ascending aorta
Type B - all dissections except asending aorta
Risk factors of aortic dissection
- hyper tension
- atherosclerosis
- trauma
- marfan’s syndrome
Problems of aortic dissection
- occlude branches ( mesenteric, carotid, renal, spinal)
- Can rupture back into the lumen/externally into meiastinum/pericardium( tamponade)
Dilation of ascending aorta in an aortic dissection
-dilation of ascending aorta may cause acute aortic regurgitation
What can a false lumen lead to?
-antegrade/retrograde direction
Symptoms of aortic dissection
- chest pain that radiates to back
- collapse ( tompanade, acute AR external rupture)
Examination of aortic dissecion
-low/absent peripheral pulses ( BP mismatch between sides )
-hypotension/hyper
-diastolic murmur ( AR)
-pul.oedema
-CXR shows widened mediastinum
-
Investigation of aortic dissection
- CXR shows widened mediastinum
- CT scan
- ECHO
Treatment of aortic dissection
Type A
-surgery
Type B
- meyiculous blood pressure control
- sodium nitroprusside + beta blocker
Microbes responsible of infection and inflammation of AI
Infection;syphillis
inflammation; takayasu’s arteritis
What is Takayasu’s arteritis
a family of rare disorders characterized by inflammation of the blood vessels, which can restrict blood flow and damage vital organs and tissues.
What does granulomatous vasculitis affect?
- aorta and main branches
- causes stenosis, thrombosis, aneurysms, renal artery stenosis and neurological sx
What is granulomatous vasculitis?
- a type of takayasu’s arteritis
Risk factors of takayasu’s arteritis
F>M
Treatment of granulomatous vasculitis
-steroids, surgery
Where is syphillis from?
Primary(chancre)/Secondary
- STD
- trepenoma pallidum
Treatment of syphillis
Primary/secondary
Abx
Tertiary
Without treatment of teritiary syhphillis what cant this lead to?
- late neurosyphillis
- gummatous syphillis
- cardiac syphillis ( sypillitic aortitis which is an aneurysm and aortic regurgitation)
State conditions that can lead tocongenital aneurysms?
- bicuspid aortic valve
- marfan’s syndrome
- coarctation
What can bicuspid aortic valve lead to?
- associated with coarctation
- cbnormal aorta ( reduced tensile steength)
- prone to aneurysm/disssection/stenosis
Monitoring bicuspid aortic valve
ECHO
MRI
3 shunts in coarctation
- ductus arteriosus
- foramen ovale
- cutus venosus
Types of coarctation
- aortic narrowing to where ductus arteriosus inserts ( ligamentum arteriosum)
3 types:
- preductal( can be life threatening if severe narrowing)
- ductul
- postductal ( most common in adults, hypertension in upper extemeties, weak pulses in lower limbs) ; associated with rib notching ( collateral circulation)
Clinical signs of coarcation
-cold legs
-poor leg pulses
-if before subclav then
radial- radial + right radial-femoral delay
-If after subclav then no radial-radial delay
-right and left radio-femoral delay
Symptoms of coarctation
Infancy(severe)
-HF, failure to thrive
Adults
-Hypertension
Imaging of Coarctation
CXR
CMRI
