aortic dissection Flashcards
definition of aortic dissection
a tear in the aortic intima allows blood to surge into the aortic wall, causing a split between the inner and outer tunica media, and creating a false lumen.
have a true lumen that is always smaller and a false lumen that dilates and forms an aneurysm
type A: with ascending aorta tear (most common);
type B: with descending aorta tear distal to the left subclavian artery.
aetiology of aortic dissection
degenerative changes in the sm of the aortic media
Expansion of the false aneurysm may obstruct the subclavian, carotid, coeliac and renal arteries.
RF for aortic dissection
- hypertension
- aortic atherosclerosis
- connective tissue disease - SLE, marfan’s, ehlers-danlos
- congenital cardiac abnormalities - aortic coarctation
- aortitis - Takayasu’s aortitis, tertiary syphilis
- iatrogenic - angiography/angioplasty
- trauma
- crack cocaine
epidemiology of aortic dissection
men
40-60yrs
sx of aortic dissection
sudden central tearing pain - may radiate to the cback (may mimic an MI)
can lead to occlusion of the aorta and its branches
- carotid obstruction: hemiparesis, dysphagia, blackout
- coronary artery obstruction: Chest pain (angina/inferior MI)
- subclavian obstruction: ataxia, loss of consciousness
- anterior spinal artery: paraplegia, acute limb ischemia
- coeliac obstruction: severe abdominal pain (ischemic bowel)
- renal artery obstruction: anuria, renal failure
signs of aortic dissection
murmur on the back below the L scapula, descending to the abdomen
BP
- HTN (BP discrepency of >20mmHG between arms)
- wide PP
- if hypotensive - tamponade, check for pulsus paradoxus
aortic insufficiency
- collapsing pulse
- early diastolic murmur over aortic area - aortic valve incompetence
- unequal arm pulses
- palpable abdo mass
IX for aortic dissection
blood - FBC, cross match 10units of blood, UE, clotting
CXR
- widened mediastinum
- localised bulge in the aortic arch
ECG
- normal
- LVH or inferior MI if dissection compromises the ostia of the R coronary artery
CT thorax - false lumen of dissection visualised
echo - transoesophageal is highly specific
cardiac catheterisation and aortography
mx for haemodynamically unstable aortic dissection
- ALS with haemodynamic support (oxygen and fluids)
- analgesia
mx for confirmed type A aortic dissection
- B blocker eg labetalol if not appropriate: non-dihydropyridine CCB (i.e., verapamil or diltiazem)
- opiod analgesia
- consider vasodilator if HR and BP not controlled with B blocker (sodium notroprusside)
- surgery/endovascular repair
mx of confirmed complicated type B aortic dissection
- B blocker eg labetalol if not appropriate: non-dihydropyridine CCB (i.e., verapamil or diltiazem)
- opiod
- consider vasodilator if HR and BP not controlled with B blocker (sodium notroprusside)
- surgery/endovascular repair
mx for confirmed uncomplicated aortic dissection
- B blocker eg labetalol if not appropriate: non-dihydropyridine CCB (i.e., verapamil or diltiazem)
- opiod analgesia
- consider vasodilator if HR and BP not controlled with B blocker (sodium notroprusside)
- consider endovascular repair if high risk of developing complications:
- bloody pleural effusion,
- aortic diameter >40 mm,
- malperfusion only detectable on imaging
perform in subacute phase - promote false lumen thrombosis and prevent aneurysmal degeneration
mx for chronic aortic dissection
B blocker
antiHTN
lifestyle and RF
consider EVAR or open surgery if type B and any of the following:
* rupture
* chronic visceral/limb malperfusion
* progressive aneurysmal enlargement >10mm/yr
* false lumen aneursyms (total aortic dm >60mm)
* persistent/recurrent pain
pt discussions for aortic dissection
- avoid heavy lifting
- limit aerobic exercise
- surveillance for imaging and BP
- smoking cessation
- lipid and BP control
- diet
monitoring aortic dissections
- imaging before discharge
- thoracic endovascular aortic repair (TEVAR): imaging at 1, 6, and 12 months postoperatively, and then annually thereafter. - CTA ior MRI
- open: CTA or doppler US at 5yrs
complications of aortic dissection
cardiac tamponade
aortic incompetence
myocardial infarction
aneurysmal degeneration/rupture
regional ischemia
left arm ischemia / subclavian steal syndrome
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