Aortic Disease Flashcards
What are the component parts of the aortic root
What are the layers of the aortic wall
Tunica intima
Tunica media
Tunica adventitia
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 adventita
Thin CT layer
Collagen and elastic fibres (not lamellae)
Collagen prevents elastic arteries from stretching beyond their physiological limits during systole
What is an aneurysm
localised enlargement of an artery caused by weakening of vessel wall
What are the different types of aneurysm
True aneurysm - saccular, fusiform
False aneurysm, Dissecting aneurysm
What is a true aneurysm
Weakness & dilation of wall
Involves all 3 layers
What is a true aneurysm associated with
- Hypertension
- Atherosclerosis
- Smoking
- Bicuspid aortic valve
- Collagen abnormalities (Marfan’s)
- Infection (mycotic/syphillis)
- Trauma
What is a false aneurysm
Rupture of wall of aorta with haematoma either contained by thin adventitial layer or by surrounding soft tissue
What is the aetiology of false aneurysm
- Trauma
- Iatrogenic
- Inflammation ( eg endocarditis with septic emboli)
What are the different sites of aneurysms
Normal
Asceding aortic aneurysm
Aortic arch aneurysm
Descending aortic aneurysm
Abdominal aortic aneurysm
What are the signs and symptoms of aneurysms
Asymptomatic
Based on location of aneurysm.
* SOB (associated aortic regurgitation)
* Dysphagia and hoarseness
* Back pain
* Symptoms of dissection - sharp chest pain radiating to back (between shoulder blades), hypotension
* Pulsatile mass
What are the investigations for thoracic aortic aneurysms
CXR – widened mediastinum
Echocardiogram – assess aortic root size and aortic valve (limited views of distal ascending aorta and arch)
CT angiogram aorta – diagnostic
MRI aorta – diagnostic and follow-up
Other tests: TOE and invasive aortogram – rarely done
What is an aortic dissection
Tear in the inner wall of aorta
Blood forces walls apart
Acute –medical/surgical emergency
Chronic
What is the aetiology of dissections
Hypertension
Atherosclerosis
Marfan’s syndrome
Bicuspid aortic valve
Trauma
What is the histology of a dissection
cystic medial necrosis
False lumen can progress in antegrade or retrograde direction
What is the consequnces of dissections
May occulde branches
Rupture - back into lumen, externally into mediastinum or pericardium (temponade)
Dilation of acsending aorta may cause acute aortic regurgitation
What is the Stanford classification of dissections
Type A
Type B
What is type A dissection
All dissections involve acsending aorta, regardless of site of origin
What is type B dissection
All disections not involving acsending aorta
What are the symtpoms of dissection
Chest pain – severe, sharp, radiating to back (inter-scapular)
Collapse (tamponade, acute AR, external rupture)
Stroke (involvement of carotid arteries)
What is the examination (signs) for dissection
Reduced/absent peripheral pulses
Hyper or hypotension
BP mismatch between sides
Soft early diastolic murmur (aortic regurgitation)
Pulmonary oedema
Signs of CVA
What are the investigations for dissection
ECG
CXR
Transthoracic echogardiogram (TTE)
CT angiogram aorta
What will an ECG show
Might show ST elevation/ischaemia indicating coronary involvement
What will a CXR show
Widened mediastinum
What will a TTE show
Assess aortic root (limited views), aortic regurgitation, pericardial effusion
What will a CT angiogram aorta tell us
Confirms diagnosis
What is the treatment for type A dissection
Blood Pressure control
* beta blocker
* IVI nitrate
* calcium channel blocker
* IVI Sodium nitroprusside
Emergency Surgery
What is the treatment for type B dissection
Blood pressure control
* beta blocker
* IVI nitrate
* calcium channel blocker
* IVI Sodium nitroprusside
Percutaneous (endo-vascular) intervention
What can cause congenital aortic aneurysm
Bicuspid Aortic Valve
Coarctation
Marfan’s Syndrome
Describe bicuspid aortic valve
2 cusps instead of 3
Most common congenital abnormality
1-2% prevalence
Abnormal aorta (reduced tensile strength)
Monitor with echo/MRI
What is the risk of bicuspid aortic valve
Prone to aortic valve stenosis +/- regurgitation
Associated with coarctation
Prone to aneurysm/ dissection
What is coarctation
Aortic narrowing close to where
Ductus arteriosus inserts
What are the 3 types of coarctation
Pre-ductal - (5% turner’s) can be life-threatening if severe narrowing (B)
Ductal (A)
Post-ductal (C) –most common in adults – hypertension in upper extremities, weak pulses in lower limbs
What are the signs of coarctation
Cold legs
Poor leg pulses
If before left subclavian artery:
*Palpate radial and RIGHT femoral, shows delay
If after left subclavian artery:
* No radial-radial delay
* Right and left radio-femoral delay
What are the symptoms or coarctation
Infancy (severe)
* Heart failure
* Failure to thrive
Later life
* Hypertension
* CV complications (heart failure, MI, CVA, aortic dissection)
What is the treatment of coarctation
Percutaneous or surgical correction
What is marfans syndrome
Disorder that affects Fibrillin 1 gene
What can marfans syndrome cause
CT weakness
Aortic/ Mitral valve prolapse – regurgitation
Aneurysm and dissection
What else can marfans syndrome effect
Skeletal system
Eyes (cataract, lens dislocation)
Lungs (pneumothorax)
Risk increased during pregnancy
