TOPIC 8 thoracic and AORTIC Surgery Flashcards
Ascending Aorta: location
Begins at the AV annulus and extends to the
proximal innominate artery
Transverse Arch: location
Where 3 brachiocephalic branches arise
Are Treatment for Ascending and Transverse Arch are similar?
very similar
More likely to see dissection or aneurism?
dissection?
Descending Thoracic and Thoracoabdominal Aorta: Location?
Lies just beyond the subclavian to the aortoiliac bifurcation
Dissection - what happens?
Occurs when blood penetrates the intima of the Aorta
Creates an expanding hematoma between medial layers
True lumen is not usually dilated
Compressed by dissection
Branching vessels may not be affected
Aneurysm what happens
Dilation of all 3 layers
Aortic Dissection Occurence?
Occurs in 3.2 dissections per 100,000 autopsies
Results in more deaths than aneurysm rupture
Aortic Dissection Risk Factors? (7)
- Hypertension
- advanced age
- male sex
- Marfan’s Syndrome
- Coarctation
- Bicuspid AV
- Pregnancy
Aortic Dissections: Predisposing conditions?
Hx HTN?
~90% of patients
Aortic Dissections: Predisposing conditions?
Advanced age?
> 60 yo
Aortic Dissections: Predisposing conditions?
congenital Heart diseases?
Coarctation of aorta, bicuspid aorta
Aortic Dissections: Predisposing conditions?
Pregnancy?
Uncommon
AORTIC DISSECTIONS
Causes (Inciting Events) – 3 main
Increased Physical Activity Emotional Stress Blunt Trauma Can also occur without any physical activity Ie: Cannulation for bypass
Aortic Dissections: Mechanism
Intimal Tear
Presence of a weakened aortic wall
Areas experiencing greatest mechanical shear forces (Points where the aorta is fixed like ductus arteriosa, there is increased shear stress applied to the aortic wall)
Ascending Aortic Dissection %?
61%
Descending Aortic Dissection %?
24%
Isthmus (Distal to Left Subclavian) Aortic Dissection %?
16%
Arch Aortic Dissection %?
9%
Abdominal Aortic Dissection %?
3%
Propagation of an aortic dissection can occurs how quick? and is driven by what?
Occurs within seconds
Driven by pulse pressure and ejection velocity
Propagation of an aortic dissection what other arteries can be involve?
Origin of arteries (including coronary arteries) may be involved in Aortic Dissections
—-Vessel occlusions can also occur (Due to compression by the false lumen)
DeBakey Classification
3 types based upon location of intimal tear and which section of the aorta is involved
TYPE I, II, III A III B
Type II DeBakey
Intimal Tear: ?
Dissection:?
Intimal Tear: Asceding Aorta
Dissection: Ascedng Aorta only
Stops before innominate artery
Type I DeBakey
Intimal Tear: ?
Dissection:?
Intimal Tear: Asceding Aorta
Dissection: All parts of thoracic aorta (ascending, arch, and descending)
Type IIIA DeBakey
Intimal Tear: ?
Dissection:?
Intimal Tear: Descending Aorta
Dissection: Descending Thoracic only distal to left subclavian, ends above diaphragm
Type IIIB DeBakey
Intimal Tear: ?
Dissection:?
Intimal Tear: Descending Aorta
Dissection: Below diaphragm
STANFORD (DAILY) CLASSIFICATION
Type A
where? usually what kind of cases?
Ascending Aorta Any involvement regardless of where tear is Regardless of how far it propagates Usually emergent/ urgent cases More virulent course
STANFORD (DAILY) CLASSIFICATION
Type B where?
Distal aorta
Any part of aorta distal to left subclavian
Prognosis for untreated ascending dissection
DISMAL
2 day mortality
50%
Prognosis for untreated ascending dissection
DISMAL
3 month mortality
90%
Usual cause of death of an Aortic dissection?
Rupture of the false lumen into the pleural space or pericardium
Lower incidence of death with what type of aortic dissection?
Lower incidence with DeBakey Type III or Stanford B dissections
Other causes of death from an Aotic dissection? (4)
Progressive heart failure (AV involvement)
MI (Coronary Involvement)
Stroke (Occlusion of cerebral vessels)
Bowel Gangrene (Mesenteric artery occlusion)
AORTIC DISSECTIONS
Surgical Mortality %
highest and lowest types?
3-24%
Depends on affected section of aorta
Aortic Arch–Highest mortality
Descending Thoracic-lowest mortality
ANEURYSMS Incidence:
European Studies show 460/100,000 Thoracic
Aneurysms
ANEURYSMS Incidence:
Involved Ascending Aorta % occurrence?
45%
ANEURYSMS Incidence:
Involved Descending Aorta % occurrence?
35%
ANEURYSMS Incidence:
Involved arch and Thoracoabdominal % occurrence?
Both have a 10% occurrence rate
Fusiform Aneurysm what?
Entire circumference of the aortic wall