Disease of the Thoracic Aorta Flashcards
What are the 4 sections of the aorta divided into?
Ascending aorta
Aortic arch
Descending aorta
Aortic root
Describe parts of the aortic root?
Right, left and non-coronary sinus
Left coronary ostium
Right coronary ostium
Sino-tubular junction
Describe the tunica intima?
Layer of endothelial cells
Subendothelial layer - collagen and elastic fibres
Separated from tunica media internal elastic membrane
Describe the tunica media?
Smooth muscle cells
Secrete elastin in the form of sheets or lamellae
Describe the tunica adventitia?
Thin connective tissue layer
Collagen and elastic fibres
The collagen in the adventitia prevents elastic arteries from stretching beyond their physiological limit
What are the risk factors of atherosclerosis?
Hypertension, hypercholesterolaemia, smoking, diabetes, family history, male over female till menopause
What can atherosclerosis cause?
Myocardial infarction
Stroke
Peripheral vascular disease
Aneurysm
What is the definition of an aneurysm?
A localised enlargement of an artery by weakening of the vessel wall
What are the types of aneurysms?
True aneurysms
False/ Pseudo aneurysm
Dissecting aneurysm
Describe a true aneursysm
Weakness and dilation of wall
Involves all 3 layers of artery
What is true aneurysm associated with?
Hypertension, atherosclerosis, smoking, bicuspid aortic valve, collagen abnormalities, infection and trauma
Describe a false aneurysm
Rupture of wall of aorta with the haematoma either contained by the thin adventitial layer or by surrounding soft tissue ex. subcutaneous fat
Have high risk of rupture and haemorrhage
What are the factors that could cause a false aneurysm?
Trauma
Iatrogenic
Inflammation
What are some signs and symptoms of thoracic aneurysms?
Asymptomatic
Shortness of breath, dysphagia and hoarseness (compression), back pain, pulsatile mass
Symptoms of dissection
All based on location of aneurysm
What are symptoms of dissection?
Sharp chest pain, radiating to back (between shoulder blades) and hypotension
What investigations are used for thoracic aneurysms?
CXR, Echocardiogram, CT angiogram and MRI aorta
TOE and invasive aortogram are rarely done
How does ECG help in investigating thoracic aneurysms?
Assess aortic root size and aortic valve
What investigations are used in diagnostics for thoracic aneurysms?
CT angiogram aorta and MRI aorta
MRI aorta used for follow up
Describe an aortic dissection
Tear in the inner wall of the aorta
Blood forces walls apart - the media
Acute - medical/ surgical emergency
What are some causes of aortic dissection?
Hypertension, atherosclerosis, Marfan’s syndrome (genetic condition affecting the connective tissue), bicuspid aortic valve and trauma
What does the histology of aortic dissection have?
Cystic medial necrosis
Replacement of medial layer with smooth and elastic fibres which weakens
What can happen in dissection?
False lumen can progress in an antegrade or retrograde direction
May occlude branches
Rupture - into lumen or mediastinum
Dilation of ascending aorta may cause acute aortic regurgitation
What is the most common thoracic aortic dissection classification?
Stanford
Type A - involves the ascending aorta
Type B - not involving the ascending aorta
Can also use DeBakey classification
What are the symptoms of aortic dissection?
Chest pain - severe, sharp, radiating to back - intrascapular
Collapse - tamponade, acute AR, external rupture
Stroke - involvement of carotid arteries
What are the clinical presentations of aortic dissection on examination?
Reduced or absent peripheral pulses
Hypertension or hypotension
BP mismatch between sides
Soft early diastolic murmur
Pulmonary oedema
Signs of CVA - cerebrovascular accident
What investigations can be used to investigate aortic dissection?
ECG - ST elevation which shows coronary involvement
CXR - widened mediastinum
Transthoracic echocardiogram (TTE) and CT angiogram aorta
Which investigation confirms diagnosis in aortic dissection?
CT angiogram aorta
What is the mortality rate of aortic dissection pre-hospital?
50%
What is treatment for type A aortic dissection?
Blood pressure control - beta blockers, IVI nitrate, CCB and IVI sodium nitroprusside if rest fail
Emergency surgery
What is the treatment for type B aortic dissection?
Blood pressure control - beta blockers, IVI nitrate, CCB and IVI sodium nitroprusside
Percutaneous intervention can also be considered
What is Takayasu’s Arteritis?
Granulomatous vasculitis
Aorta and main branches
Can get stenosis, thrombosis, aneurysms, renal artery stenosis and neurological sx
What is the treatment for Takayasu’s arteritis?
Steroids and immunosuppressive Tx
Surgery and percutaneous intervention may be required
Explain syphilis
STD
Treponema pallidum
Antibiotics prevent late stages
What can tertiary syphilis cause?
Cardiac syphilis
Syphilitic aortitis - aneurysm
Aortic regurgitation
What are congenital aortic aneurysms?
Bicuspid aortic valve
Coarctation
Marfan’s syndrome - connective tissue
Explain bicuspid aortic valve
2 cusps instead of 3
Associated with coarctation - aortic narrowing
Reduced tensile strength
Monitor with echo/ MRI
What is bicuspid aortic valve prone to?
Aortic valve stenosis and maybe regurgitation
Aneurysm/ dissection
Explain aortic coarctation
Aortic narrowing close to where ductus arteriosus inserts
Usually descending
What are the 3 types of coarctation?
Pre-ductal - can be life-threatening if severe narrowing
Ductal
Post-ductal - most common in adults, hypertension in upper extremities and weak pulses in lower limbs. Associated with rib-notching
What are the signs of coarctation?
Cold legs, poor leg pulses
If before left subclavian artery - radial-radial and right radial-femoral delay
If after - no radial-radial delay
Right and left radio-femoral delay
What are symptoms of coarctation in infancy if severe?
Heart failure
Failure to thrive
What are some later life symptoms of coarctation?
Hypertension - can be high in arms and low BP in legs
CV complications - heart failure, MI, CVA, aortic dissection
What imaging is used for coarctation?
CXR - show notching of ribs and enlargement of intercostal arteries
CMRI
What is the treatment of coarctation?
Percutaneous or surgical correction
What is Marfan’s syndrome?
Connective tissue weakness
Fibrillin 1 gene
Affects skeletal system, eyes, vascular (aneurysm and dissection), Lungs and Heart
Aortic/ Mitral valve prolapse -regurgitation
Risk is increased in pregnancy
