Aortic Dissection Flashcards
What is an aortic dissection?
A tear in the tunica intima of the aortic wall.
This leads to blood flowing between the tunica intima and media splitting them apart
What is acute AD?
Diagnosed within 14 days
What is chronic AD?
Diagnosed after 14 days
Who gets ADs?
More common in men
Connective tissue disorders
Peak onset between 50-70 years
AD can progress anatomically either backwards or forwards.
Explain
The initial intimal tear can progress proximally or distally or in both directions.
Anterograde dissections propagate towards the iliac arteries
Retrograde dissections propagate towards the aortic valve at the root of the aorta. This can also cause prolapse of aortic valve, bleeding into pericardium and cardiac tamponade.
Two systems classifying AD
Stanford Classification
DeBakey Classification
Explain Stanford classification
Group A - Involves the ascending aorta and can propagate to the aortic arch and the descending aorta.
Group B - Dissections do not involve the ascending aorta and include DeBakey Type III
Explain DeBakey Classification
Type I - Originiates in the ascending aorta and propagates at least to the aortic arch
Type II - Confined to the ascending aorta (classically in elderly patients with atherosclerotic disease and HTN)
Type III - Originates distal to the subclavian artery in the descending aorta
Risk factors
HTN
Atherosclerosis
Male
Marfan’s and EDS
Bicuspid aortic valve
Clinical features
Tearing chest pain radiating to the back
Tachycardia
Hypotension
New aortic regurgitation murmur
SIgns of end-organ hypoperfusion like reduced urine output, paraplegia, lower limb ischaemia, abdo pain.
Dx
MI
PE
Pericarditis
MSK back pain
Investigations
Routine bloods like FBC, U&Es, LFTs, troponin, coagulation
Crossmatch of at least 4 units
ABG
ECG should also be done
Imaging
CT angiogram is first line imaging for diagnosis
This allows for classification, establish anatomy of dissection and planning.
Transoesophageal ECHO can also be done but is user dependent
Initial management
High flow O2 + IV access 2x large bore cannulae
Fluid resus should be done cautiously and kept under 110mmHg systolic
General idea of management of Type A vs Type B stanford dissections
Type A = Managed surgically as it involves ascending aorta
Uncomplicated Type B = Managed medically
Post initial management therapy
Antihypertensive therapy lifelong
Surveillance imaging 1, 3 and 12 months post-discharge
Further scans at 6-12 months intervals depending on size of aorta
Type A dissections management
Transfer to a cardiothoracic centre + surgery
Removal of the ascending aorta with or without the arch and replace with a synthetic graft
If dissection damaged the suspensory apparatus of the aortic valve this also needs repair.
Additional branches of the aortic arch require reimplantation into the graft.
Long type A that involve descending and possible even AA require staged procedures.
Management of Type B dissections
Managed medically
First line = Management of hypertension with IV labetalol or CCB 2nd line.
Rapidly lower the systolic pressure, pulse pressure and pulse rate to minimise stress.
Why are type B dissections not treated surgically?
Due to the risk of retrograde dissection
When is surgical intervention indicated in Type B dissection?
Complicated disease
Rupture
Renal involvement
Visceral or limb ischaemia
Uncontrollable hypertension
Refractory to medical management
Complications
Type B dissections can go on to be chronic and form an aneurysm, even if a stent is placed.
Aortic rupture
Aortic regurgitation
MI
Cardiac tamponade
Stroke or paraplegia
Death (20%)
