aortic Flashcards
RFs for aortic dissection
- medial degeneration
- genetic syndromes (marfan, turner, noonan, ehlers-danlos IV, loeys-Dietz) - dissection in 3rd or 4th decade
- nonsyndromic familial thoracic aortic aneurysm and dissection (older than 2, younger than non-genetic)
- annloectasia without marfan syndrome
- BAV (9x more dissections as TAV)
- dilated asc aorta
- aortic coarctation
- intramural hematoma
- pregnancy?
- closed chest trauma/aortic cannulation/aortic clamping
- severe acute hypertension (i.e. weight lifters)
- cocaine
#
what proportion of type A aortic dissection is complicated by AI
35-60% #
mean age of pts with:
- type A dissection
- type B dissection
- 56 y.o.
- 64 y.o.
#
arch vessel occlusion causing stroke occurs in ? number of type I dissection pts
5-10% #
which leg is normally occluded with distally propagating dissection
left #
paraplegia occurs due to?
shearing off of intercostal arteries in 2-5% of pts #
TEE Sensitivity and specificity for type A and Type B dissections
Type A: 88-100%; 86-100%
Type B: 98-100%; 96-100%
CT censitivity and specificity for dissection
100%; 98-99%
cons of CT for dissection diagnosis
- may be obScured by complete thrombosis of one lumen or similar opacification of both lumens
- location of enry site and presence of AI cannot always be detected
- contrast allergy
- renal insufficiency
#
acute aortic dissection and associated 1. ST elevation 2. ST depression
- rare (thrombolysis for STEMI safe)
- 35% (need further study before thrombolysis for NSTEMI/ACS to r/o dissection)
#
what is triple rule-out CT
64slice CT to r/o aortic dissection, acute PE, and obstructive coronary artery dissease
what is D-dimer
-degradation product of cross-linked fibrin in thrombus
-sensitive for ongoing intravascular thrombosis
- sensitivity 94%, but specificity low (40-100%)
#
RF for death after acute aortic dissection
- involvement of asc aorta and arch
- HTN
- large size of the dissected aorta
- complete or near-complete thrombosis of false lumen REDUCES RISK FOR RUPTURE AND DEATH
#
GOAL Of type A dissection operation
- to prevent death from cardiac tamponade or exsanguination by ecising and repairing or replacing areas of actual or impending rupture
- where possible restore blood flow to occluded branches
- correct acutely developed or chronic coexisting AI
*surgery is palliative, not curative
#
How to size ascending aortic graft for RAA
diameter should be 10-15% smaller than the diameter o the aortic annulus to enure adequate coaptation of the aortic cusps #
if coronary artery is dissected
vein bypass end to end or end to side; if end to side, must ligate the coronary artery proximal to anastomosis #
Retrograde cerebral perfusion via SVC flow rate and max CVP - used to flush out air after open distal
300-500 mL/min
CVP below 35mmHg
At which level should intercostal arteries be preserved
6th intercostal space
Human cerebral Q10?
safe time of circulatory arrest @ 15degrees
Q1O = ratio of metabolic rates at temperatures 10 degrees apart
Human brain Q10 = 2.3
@17 degrees = predicted safe HCA time is ONLY 26min!!
selective antegrade cerebral protection through innominate artery flow rate?
10-15ml/kg/min
ie. 70-100 ml/min
types of malperfusion
- dynamic (most freq); Rx by resecting primary tear and restoring flow through the true lumen
- static (local process); will persist despite true lumen flow; branch stenting or extra-anatomic bypass
- mixed
incidence of malperfusion with right axillary cannulation
3.5%
“malperfusion first” approach to DeBakey type 1 dissection carries …….. risk of interim rupture of aorta?
5-23%
early surgical repair followed by rx of malperfusion may b more prudent
define intramural hematoma
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
define true aortic aneurysm
permanent, localized dilation of aorta, of diameter 50% or greater than normal, contained by all layers of the normal wall
time cut off between acute vs. chronic aortic dissection
14 days
penetrating arteriosclerotic ulcer
arteriosclerotic lesion that penetrates the internal elastic lamina of the aortic wall
define diffuse arteriosclerotic disease
sessile, mobile, or pedunculated atheroma involving lipid depositio in large areas of the intimal layer of the aorta
crawford extents of aortic aneurysm
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
etiology of aortic aneurysms
- congenital or developmental (Marfan, ehlers-danlos, loeys-dietz; BAV-TAA)
- degenerative (cystic medial degeneration, arteriosclerotic)
- chronic posttraumatic (blunt, penetrating)
- inflammatory (takayasu, Behcet, kawasaki, Giant cell arteritis, ankylosing spondylitis)
- infected (bacterial, fungal, spirochetal, viral)
- mechanical (poststenotic, arteriovenous fistula)
- anastomotic (post arteriotomy)
describe zones of aorta (Creato classification)
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
describe Montgomery classification of aortic atheroma
- normal intimal
- intimal thickening
- atheroma less than 5mm
- atheroma more than 5mm
- mobile atheroma
