1 - Aorta Flashcards
What are the anterior branches of the abdominal aorta?
Coeliac artery
Superior mesenteric
Inferior mesenteric
What are the 3 lateral branches of the abdominal aorta?
Renal arteries
Infra-renal arteries
Gonadal arteries
What three branches come off the arch of the aorta?
Brachiocephalic
Left common carotid
Left subclavian
What are the first vessels to arise from the aorta?
Left + right coronary vessels
What level do the 3 main structures cross the diaphragm?
Vena cava = T8
Oesophagus = T10
Abdominal aorta = T12
How many embryological arches form the adult arch of the aorta?
6
What vessels does the 3rd aortic arch form?
Common carotid
Head and neck vessels
What vessels does the 4th aortic arch form?
Aortic arch
Subclavian
What major vessel does the 6th aortic arch form?
Pulmonary trunks
In the context of congenital abnormalities, which arches fuse together in a ‘bovine arch’?
3 and 4
Bovine arch results in fusion of which vessels?
Brachiocephalic
Left common carotid
What is the problem with ‘coarctation of the aorta’?
Narrowing of the aorta
Where does coarctation usually occur?
Just after the subclavian artery, at the site of the embryological ductus arterosius
What effect will coarctation have on the heart?
Pumping against increased resistance - LV hypertrophy which eventually leads to HF
What finding, in the context of BP, will also occur from coarctation?
Upper limbs = high BP
Lower limbs = low BP
Can also cause headaches, fluid imbalance.
What pathology occurs in the case of an ‘Aberrant subclavian’, specifically dysphagia lusoria ?
Right subclavian leaves arch in the wrong place, and obstructs the oesophagus
What kind of circulation occurs in a state of chronic obstruction?
Collateral circulation
Which 2 vessels can connect the coeliac artery to the SMA?
Gastroduodenal
Dorsal pancreatic
What vessel can connect the SMA to the IMA?
Marginal artery of drummond
Which 2 vessels can connect the IMA to the internal iliac artery?
Superior rectal
Middle rectal
What defines an abdominal aortic aneurysm?
Diameter greater than 50%
What is the normal diameter of the abdominal aorta?
2cm
What are the 3 layers of the abdominal aorta?
Tunica intima
Tunica media
Tunica adventitia
What cell forms the tunica intima?
Endothelium
What 3 components make up the tunica media?
Smooth muscle
Collagen
Elastic fibres
What 2 components make up the tunica adventitia?
Connective tissue Vasa vasorum (blood vessels - supplying the cells)
Marfan’s syndrome results is genetic disease which results in what mutation?
Mutation in the gene that encodes fibrillin (part of the elastic fibres)
What consequence is more likely to occur in Marfan’s as a result of this mutation?
AAA
And even rupture!
Aneurysms occur through the action of what enzyme?
Where do they work?
Matrix metalloproteinases
Adventitia
What are the two forms of surgical repair for aneurysms?
Open EVAR (endovascular aneurysm repair)
How does EVAR work?
Femoral artery, into the aneurysm.
Depositing a mesh frame into the artery, restoring integrity.
Where is the most common place along the abdominal aorta for aneurysms to occur?
What %?
Infra-renal position
90%
What complications can arise from open surgery, as a result of aortic clamping (which is necessary)?
Heart = myocardial infarction - heart pumps FASTER and HARDER (less time for systole)
Legs = anaerobic conditions –> lactate + inflammatory mediators –> unclamping results in systemic vasodilation –> SIRS, can lead BP crashing –> death
What checks do you have to do to the infra-renal neck to confirm EVAR is a suitable option?
> 1.5cm long
<60 degree angle
What term is used if EVAR is unsuccessful and blood leaks?
Endoleak
Despite the numerous benefits, what disadvantages occur with EVAR?
More likely will require a revisit due to an endoleak.
However, mortality rates are the same.
What is the issue that occurs in an aortic dissection?
The tunica intima separates away from the media
What two risk factors predispose dissection?
HTN = mechanical
Smoking = chemical
What types of dissection are there, and which classification is used?
Type A and Type B
Stanford classification
What is a Type A dissection?
A dissection that involves the ARCH OF AORTA as well as the thoracic
what is a type B dissection?
One that doesn’t involve the arch
Why is Type A surgically managed immediately?
Tunica intima can impede flow to coronary artery, thus requires surgery immediately.
How is Type B dissection managed?
Medications and lifestyle options to reduce mechanical stress.
Why do dissections always start at the edge of the left subclavian?
First 3 major vessels form a hold of the arch in place.
Point after it acts like a hinge and is subjected to a lot of force.
What are the main blood supplies to the brain (and their branches)?
Internal carotid (from common carotid)
Vertebral (from subclavian arteries)
What are the 4 complications of aortic dissection?
Rupture
Heart failure (aortic valve incompetence)
Stroke (branch compromisation)
Aneurysm
What are the logistics / steps to a surgical treatment of Type A dissection?
Open surgery. Divert blood supply.
Stent the entire ascending arch + completely replace the aortic valve.
Surgical treatment or aortic dissection depends on what staging system?
Ishimaru zones
How are the zones separated?
0 - ascending + brachio
1 - left com carot
2 - left subclavian
3 - descending
4 - thoracic
Treatment of zone 0 requires what kind surgery?
Open
Treatment of zone 1 requires what type of surgery?
Hybrid (frozen elephant)
open + stent
Treatment of zone 2 requires what type of surgery?
Stent with carotid revascularisation
Treating zone 2 Ishimaru involves which artery?
Why is it not a problem?
Left subclavian
Collateralisation of bloodflow - blood from the brain can divert towards high–>low resistance into the arm.
