Diseases of thoracic aorta Flashcards
Name the three layers of the thoracic aorta
Tunica intima
Tunica media
Tunica adventitia
What is the tunica intima comprised of?
Endothelial cells
Subendothelial layer - elastic fibres and collagen
How is the tunica intima separated from the tunic media?
By the internal elastic membrane
What is the tunica media comprised of?
Smooth muscle cells
Secrete elastin in sheets, lamellae
What is the tunica adventitia comprised of?
Thin CT layer
Collagen and elastic fibres (not lamellae)
Function of collagen in tunica adventitia
Prevent stretch beyond physiological limit in systole
Risk factors for atherosclerosis
Hypertension Hypercholesterolaemia Smoking Diabetes Family history Male
What is the key event in atherosclerosis?
Endothelial dysfunction
Describe the process of atherosclerosis according to age
1st decade - foam cells form fatty streak
3rd decase - intermediate lesion forms atheroma
4th decade- fibrous plaque forms complicated lesion which can rupture vessel
What risks are associated with atherosclerosis?
Stroke
MI
Aneurysm
Classification of aneurysms
Saccular
Fusiform
False
Dissecting
Which types of aneurysms are true aneurysms?
Saccular#Fusiform
Classification of aortic aneurysm according to site
Ascending
Aortic arch
Descending
Abdominal
Signs and symptoms of aneurysmal disease in aorta
Asymptomatic Dyspnoea Heart failure Dysphasia Hoarseness Sharp chest pain radiating to back and shoulders Pulsatile mass Hypotension
Classfication of aortic Dissection
DeBakey
I - originates in ascending to arch
II- confined to ascending
III- originates in descending, extends distally or retrograde to arch, ascending
Stanford
A- Any ascending involvement
B-No ascending involvement
Aetiological factors for aortic dissection
Trauma
Connective Tissue disease- Marfans
Atherosclerosis
Hypertension
What sign of aortic dissection is shown in hisotlogy?
Cystic medial necrosis
Signs and symptoms of aortic dissection
Tearing, severe chest pain radiating to back
Collapse (tamponade, acute (NEW)Aortic regurgitation, external rupture)
Hypotension
Tachycardia
Signs of end organ hypoperfusion
Aortic dissection must be excluded when patient is presenting with signs of which condition?
Inferior stemi with back pain
Signs of aortic dissection on examination
Reduced peripheral pulse (BP mismatch) Hypo/hypertension Soft early diastolic murmur (AR) Pulmonary oedema Chest X ray - widened mediastinum Confirm by ECHO and CT
Treatment of aortic dissection
Type A Surgery
Type B - BP control, sodium nitroprusside and B blocker
Which other conditions can present with aortic aneurysm/dissection?
Takayasu’s vasculitis
Syphilis
Treatment of takayasu’s vasculitis
Steroids#Surgery
Three types of presentation in third degree syphilis
Late neurological
Gummatous
Cardiac - syphilitic aortitis, aortic regurgitation
2 types of congenital aortic aneurysm
Bicuspid aortic valve
Coarctation of aorta
3 shunts in immature heart
Ductus arteriosus
Foramen ovale
Ductus venosus
3 types of coarctation of aorta
Pre ductal
Ductal
Post ductal
Which type of coarctation is most common in adults?
Post ductal
What are the signs associated with post ductal aortic coarctation?
Hypertension in upper extremeties
Weak pulse in lower limbs
Rib notching - seen on CXR (collateral circulation)
Radial/Radial/Radial Femoral delay
Heart failure, FTT in infancy
Hypertension in later life
Which genetic mutation occurs in Marfan’s syndrome?
Fibrillin I Gene
Which murmur is associated with Marfan’s syndrome?
Regurgitation
Signs of marfan’s syndrome
Skeletal system affect Eyes - cataracts, lens dislocation Aneurysm dissection Hyperexpanded lungs prone to pneumothorax Arm span exceeeds height Pectus excavatum Arachnodactyly of hands and feet Steinberg sign - tips of thumb protrude when folded in fist
What is aortic dissection?
A tear in the intimal layer of the aortic wall.
Blood flows between and splits apart the tunica intima and tunica media
When is aortic dissection diagnosed as acute or chronic?
Acute - less than 14 days
Chronic - more than 14 days
Name some signs of end-organ hypoperfusion
Reduced urine output Paraplegia Lower limb ischaemia Abdominal pain secondary to ischaemia Deteriorating conscious level
Differential of aortic dissection
MI
PE
Pericarditis
Musculoskeletal back pain
How to differentiate pericarditis from thoracic aortic dissection
Pleuritic chest pain
ST elevation on ECG
Pericardial rub on auscultation
Investigations for aortic dissection
Bloods - FBC, U&Es, troponin, LFTs, coagulation ABG ECG CT angiogram Transoesophageal ECHO
Why are Type B dissections managed medically instead of surgically?
Endovascular repair carries risk of retrograde dissection
When is surgery considered in Type B dissections?
rupture renal visceral or limb ischaemia refectory pain uncontrollable hypertension
What is the most common complication of chronic Type B dissection?
Aneurysm
Complications of aortic dissection
Aortic aneurysm rupture Aortic regurgitation Myocardial ischaemia Cardiac tamponade Stroke Paraplegia
Mortality rate of aortic dissection
20% before reaching hospital
