aortic dissection

Question 1

definition of aortic dissection

Answer 1

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.

Question 2

aetiology of aortic dissection

Answer 2

degenerative changes in the sm of the aortic media

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

Question 3

RF for aortic dissection

Answer 3

• 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

Question 4

epidemiology of aortic dissection

Answer 4

men

40-60yrs

Question 5

sx of aortic dissection

Answer 5

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

Question 6

signs of aortic dissection

Answer 6

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

Question 7

IX for aortic dissection

Answer 7

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

Question 8

mx for haemodynamically unstable aortic dissection

Answer 8

• ALS with haemodynamic support (oxygen and fluids)
• analgesia

Question 9

mx for confirmed type A aortic dissection

Answer 9

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

Question 10

mx of confirmed complicated type B aortic dissection

Answer 10

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

Question 11

mx for confirmed uncomplicated aortic dissection

Answer 11

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

Question 12

mx for chronic aortic dissection

Answer 12

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

Question 13

pt discussions for aortic dissection

Answer 13

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

Question 14

monitoring aortic dissections

Answer 14

• 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

Question 15

complications of aortic dissection

Answer 15

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

Question 16

px post aortic dissection

Answer 16

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