aortic

Question 1

RFs for aortic dissection

Answer 1

1. medial degeneration
2. genetic syndromes (marfan, turner, noonan, ehlers-danlos IV, loeys-Dietz) - dissection in 3rd or 4th decade
3. nonsyndromic familial thoracic aortic aneurysm and dissection (older than 2, younger than non-genetic)
4. annloectasia without marfan syndrome
5. BAV (9x more dissections as TAV)
6. dilated asc aorta
7. aortic coarctation
8. intramural hematoma
9. pregnancy?
10. closed chest trauma/aortic cannulation/aortic clamping
11. severe acute hypertension (i.e. weight lifters)
12. cocaine
    #

Question 2

what proportion of type A aortic dissection is complicated by AI

Answer 2

35-60%
#

Question 3

mean age of pts with:

1. type A dissection
2. type B dissection

Answer 3

1. 56 y.o.
2. 64 y.o.
   #

Question 4

arch vessel occlusion causing stroke occurs in ? number of type I dissection pts

Answer 4

5-10%
#

Question 5

which leg is normally occluded with distally propagating dissection

Answer 5

left
#

Question 6

paraplegia occurs due to?

Answer 6

shearing off of intercostal arteries
in 2-5% of pts
#

Question 7

TEE Sensitivity and specificity for type A and Type B dissections

Answer 7

Type A: 88-100%; 86-100%

Type B: 98-100%; 96-100%

Question 8

CT censitivity and specificity for dissection

Answer 8

100%; 98-99%

Question 9

cons of CT for dissection diagnosis

Answer 9

1. may be obScured by complete thrombosis of one lumen or similar opacification of both lumens
2. location of enry site and presence of AI cannot always be detected
3. contrast allergy
4. renal insufficiency
   #

Question 10

acute aortic dissection and associated 1. ST elevation 2. ST depression

Answer 10

1. rare (thrombolysis for STEMI safe)
2. 35% (need further study before thrombolysis for NSTEMI/ACS to r/o dissection)
   #

Question 11

what is triple rule-out CT

Answer 11

64slice CT to r/o aortic dissection, acute PE, and obstructive coronary artery dissease

Question 12

what is D-dimer

Answer 12

-degradation product of cross-linked fibrin in thrombus
-sensitive for ongoing intravascular thrombosis
- sensitivity 94%, but specificity low (40-100%)
#

Question 13

RF for death after acute aortic dissection

Answer 13

1. involvement of asc aorta and arch
2. HTN
3. large size of the dissected aorta
4. complete or near-complete thrombosis of false lumen REDUCES RISK FOR RUPTURE AND DEATH
   #

Question 14

GOAL Of type A dissection operation

Answer 14

1. to prevent death from cardiac tamponade or exsanguination by ecising and repairing or replacing areas of actual or impending rupture
2. where possible restore blood flow to occluded branches
3. correct acutely developed or chronic coexisting AI
   *surgery is palliative, not curative
   #

Question 15

How to size ascending aortic graft for RAA

Answer 15

diameter should be 10-15% smaller than the diameter o the aortic annulus to enure adequate coaptation of the aortic cusps
#

Question 16

if coronary artery is dissected

Answer 16

vein bypass end to end or end to side; if end to side, must ligate the coronary artery proximal to anastomosis
#

Question 17

Retrograde cerebral perfusion via SVC flow rate and max CVP - used to flush out air after open distal

Answer 17

300-500 mL/min

CVP below 35mmHg

Question 18

At which level should intercostal arteries be preserved

Answer 18

6th intercostal space

Question 19

Human cerebral Q10?

safe time of circulatory arrest @ 15degrees

Answer 19

Q1O = ratio of metabolic rates at temperatures 10 degrees apart
Human brain Q10 = 2.3
@17 degrees = predicted safe HCA time is ONLY 26min!!

Question 20

selective antegrade cerebral protection through innominate artery flow rate?

Answer 20

10-15ml/kg/min

ie. 70-100 ml/min

Question 21

types of malperfusion

Answer 21

1. dynamic (most freq); Rx by resecting primary tear and restoring flow through the true lumen
2. static (local process); will persist despite true lumen flow; branch stenting or extra-anatomic bypass
3. mixed

Question 22

incidence of malperfusion with right axillary cannulation

Answer 22

3.5%

Question 23

“malperfusion first” approach to DeBakey type 1 dissection carries …….. risk of interim rupture of aorta?

Answer 23

5-23%

early surgical repair followed by rx of malperfusion may b more prudent

Question 24

define intramural hematoma

Answer 24

rupture of vasa vasorum in the outer 1/3 of aortic Media, leading to accumulation of blood or clot or both within the wall, in the absence of intimal defect

Question 25

define true aortic aneurysm

Answer 25

permanent, localized dilation of aorta, of diameter 50% or greater than normal, contained by all layers of the normal wall

Question 26

time cut off between acute vs. chronic aortic dissection

Answer 26

14 days

Question 27

penetrating arteriosclerotic ulcer

Answer 27

arteriosclerotic lesion that penetrates the internal elastic lamina of the aortic wall

Question 28

define diffuse arteriosclerotic disease

Answer 28

sessile, mobile, or pedunculated atheroma involving lipid depositio in large areas of the intimal layer of the aorta

Question 29

crawford extents of aortic aneurysm

Answer 29

``` I: left subclavian to renal 2: left subclavian to aortic bifurcation 3. 6 rib to aortic bifurcation 4: diaphragm to aortic bifurcation 5 (new): 6 rib to renal ```

Question 30

etiology of aortic aneurysms

Answer 30

1. congenital or developmental (Marfan, ehlers-danlos, loeys-dietz; BAV-TAA) 2. degenerative (cystic medial degeneration, arteriosclerotic) 3. chronic posttraumatic (blunt, penetrating) 4. inflammatory (takayasu, Behcet, kawasaki, Giant cell arteritis, ankylosing spondylitis) 5. infected (bacterial, fungal, spirochetal, viral) 6. mechanical (poststenotic, arteriovenous fistula) 7. anastomotic (post arteriotomy)

Question 31

describe zones of aorta (Creato classification)

Answer 31

0: STJ to end of innominate 1: distal innominate to distal LCCA 2: distal LCCA to distal LSA 3. distal LSA to 2 cm distal. 4. 2 cm distal to LSA to T6

Question 32

describe Montgomery classification of aortic atheroma

Answer 32

1. normal intimal 2. intimal thickening 3. atheroma less than 5mm 4. atheroma more than 5mm 5. mobile atheroma