aortic dissection Flashcards

1
Q

definition of aortic dissection

A

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.

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2
Q

aetiology of aortic dissection

A

degenerative changes in the sm of the aortic media

Expansion of the false aneurysm may obstruct the subclavian, carotid, coeliac and renal arteries.

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3
Q

RF for aortic dissection

A
  • 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
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4
Q

epidemiology of aortic dissection

A

men

40-60yrs

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5
Q

sx of aortic dissection

A

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
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6
Q

signs of aortic dissection

A

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
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7
Q

IX for aortic dissection

A

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

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8
Q

mx for haemodynamically unstable aortic dissection

A
  • ALS with haemodynamic support (oxygen and fluids)
  • analgesia
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9
Q

mx for confirmed type A aortic dissection

A
  1. B blocker eg labetalol if not appropriate: non-dihydropyridine CCB (i.e., verapamil or diltiazem)
  2. opiod analgesia
  3. consider vasodilator if HR and BP not controlled with B blocker (sodium notroprusside)
  4. surgery/endovascular repair
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10
Q

mx of confirmed complicated type B aortic dissection

A
  1. B blocker eg labetalol if not appropriate: non-dihydropyridine CCB (i.e., verapamil or diltiazem)
  2. opiod
  3. consider vasodilator if HR and BP not controlled with B blocker (sodium notroprusside)
  4. surgery/endovascular repair
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11
Q

mx for confirmed uncomplicated aortic dissection

A
  1. B blocker eg labetalol if not appropriate: non-dihydropyridine CCB (i.e., verapamil or diltiazem)
  2. opiod analgesia
  3. consider vasodilator if HR and BP not controlled with B blocker (sodium notroprusside)
  4. 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

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12
Q

mx for chronic aortic dissection

A

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

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13
Q

pt discussions for aortic dissection

A
  • avoid heavy lifting
  • limit aerobic exercise
  • surveillance for imaging and BP
  • smoking cessation
  • lipid and BP control
  • diet
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14
Q

monitoring aortic dissections

A
  • 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
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15
Q

complications of aortic dissection

A

cardiac tamponade
aortic incompetence
myocardial infarction
aneurysmal degeneration/rupture
regional ischemia
left arm ischemia / subclavian steal syndrome
endoleak

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16
Q

px post aortic dissection

A

worse px is:
* syncope
* hypotension/shock (not syncope),
* lack of chest or back pain (presumably related to delay in diagnosis),
* branch vessel involvement