The Aorta and Aneurysms Flashcards
What is the time taken for 20% of the circulating volume to pass from the heart to the aorta
12 seconds
What is the clinical implication of the short time taken for the circulating volume to pass from the heart to the aorta
If something goes wrong in the aorta, fast action is required as you can lose 20% of your cardiac output in 12 seconds.
What parts of the aorta are included under the term “thoracic aorta”
The ascending aorta, the arch of the aorta and the descending aorta.
What be a cause of abnormality in the thoracic aorta
Pathology of the aortic valve.
What condition tends to occur in the abdominal aorta particularly
Atherosclerosis
What are the non-paired arteries of the abdominal aorta
The coeliac trunk giving off the splenic artery, the hepatic artery and the gastric artery
What are the paired arteries of the abdominal aorta
The inferior and superior mesenteric arteries, the left and right renal arteries and the left and right iliac arteries.
What type of fibre is the aorta made up from which stains black in histology
Elastic
Why is the aorta an elastic artery
It needs to distend and contract in response to systole. It needs to respond to change in pressure.
What pathology can occur if there is degradation of the elastic wall of the aorta
Dissection of the aorta
What is an aneurysm
It is a localised, permanent, abnormal dilatation of a blood vessel.
What are the six types of aneurysm
- dissecting
- atherosclerotic
- berry
- micro
- syphilitic
- mycotic
What happens in a dissecting aortic aneurysm
There is separation of the layers of the aortic wall
What are the risk factors for aortic dissection
- hypertension
- atherosclerosis
- Marfan’s syndrome
- bicuspid aortic valve
- chest trauma
- cardiac surgery
- coarctation of the aorta
- cocaine use
- pregnancy
What are the risk factors for atherosclerotic abdominal aortic aneurysm
- age
- male sex
- genetics
- hyperlipidaemia
- hypertension
- smoking
- diabetes
What are the possible complications of atherosclerotic aneurysm
- rupture
- thrombosis
- embolism
What are the anatomical planes of view
Axial, saggital and coronal
What does the saggital plane of view show
Left and right
What does the axial plane of view show
Superior and inferior
What does the coronal plane of view show
Dorsal and ventral/posterior and anterior
What looks radiopaque on an x-ray
Dense objects which block the x-rays such as bone
What looks radiodense on an x-ray
Less dense objects which allow the beam of x-rays pass through such as air.
At what diameter is dilatation of the aorta considered to be an aneurysm
More than 3cm
At what diameter is intervention of an aneurysm considered
more than 5.5cm (55mm)
Where do abdominal aortic aneurysms often occur
In the infra-renal area
What symptoms may a patient experience when the aneurysm is intact
It is often asymptomatic
In which sex is aneurysm more common
Male
In which sex is rupture of an aneurysm more common
Female
What lifestyle factor majorly increases the risk of aneurysm rupture
Smoking
What are the symptoms of abdominal aortic aneurysm rupture
Sudden onset of severe abdominal pain
What investigations can be carried out to investigate possible aneurysm
Blood gas test, chest x-ray, ECG
What is the emergency investigation carried out for AAA
FAST scan
What are the next steps if the aortic aneurysm is shown to be unstable on a FAST scan
Proceed with treatment and no other investigations
What are the next steps if the aortic aneurysm is shown to be stable on a FAST scan
Carry out a CT angiogram
What is a CT angiogram
The use of intravenous contrast to demonstrate the vessel lumen on a CT scan.
What can be seen in imagine if the abdominal aortic aneurysm has ruptured
Blood outside the blood vessel wall.
What is used to treat ruptured AAA
Open surgery using a graft of EVAR (endovascular aneurysm repair).
What is the typical presentation of a ruptured AAA
An older male with sudden onset, severe central abdominal pain
What are some specialised imagining techniques for AAA
PET and wall stress maps.
What does a PET-CT involve in AAA imaging
It involves radiation and a radio tracer The radio tracer lights up areas of micro-calcification.
What does wall stress maps involve in AAA imaging
Gradation of biomechanical wall stress.
At what aortic diameter do most dissection occur
Above 5.5cm
What risk factors are associated with acute thoracic dissection
- age
- male sex
- atherosclerosis
- hypertension
- smoking
What is type A thoracic aortic dissection
Dissection in the ascending aorta
What is type B thoracic aortic dissection
Dissection In the descending aorta
What happens in the process of aortic dissection
A small tear develops between the intimal and medial layers of the blood vessel wall. Blood enters this tear and it extends. The layers of the wall are then pulled apart. A plaque can form.
What are the symptoms of aortic dissection
Severe pain that radiates through the chest and particularly between the scapula.
What are the clinical signs of aortic dissection
High blood pressure, reduced pulse volume in one arm compared to the other, loss of carotid pulses on one side compared to the other, aortic regurgitation, loss of femoral pulses.
What happens if the dissection involves the root of the aorta
There can be regurgitation of the aortic valve.
What is cardiac tamponade
A bleed from the root of the aorta into the pericardial cavity,
What type of treatment is key in aortic dissection
Surgical treatment.
How can aortic dissection lead to MI
If the root of the aorta is involved, the coronary arteries may be affected which can lead to MI.
What is the false lumen in aortic dissection
This is where blood forces itself between the intima and the media of the vessel wall.
What surgical treatment is used for dissection
Cardiopulmonary bypass to remove the dissected area and replace it with a graft.
What is the most important risk factor for aneurysm
Smoking
Which layers of the vessel wall are involved in an aneurysm
All three layers
What will you feel in the abdomen if there has been AAA rupture
Pulsation
What type of rupture is typical of patients with ruptured AAA who make it to hospital
Posterior rupture.
What condition is thought to be protective against dissection
Diabetes
What condition is significant in aortopathies
Marfan Syndrome
What gene mutation is associated with Marfan syndrome and aortopathies
Mutation of the fibrillin 1 gene. This is involved in the production of the ECM. Mutation causes weakness of the scaffolding around the aorta.
What is homocysteinuria
An autosomal recessive condition in which there are high levels of homocysteine present in the blood and the urine
What is homocysteinuria associated with
Aortic dissection and aneurysm
What was the first condition to suggest that aneurysm is not always due to wall weakness
Loeys-Dietz Syndrome
What gene is mutated in Loeys-Dietz syndrome
TGFBR1/2
What does mutation in TGFBR1/2 lead to in LDS
Abnormal cell signalling.
What are the main types of aneurysm
Dissecting and atherosclerotic
What can be important in early detection of aneurysm
Calcification
Why is monitoring of inflammation important in aneurysm management
It allows better prediction of expansion and rupture.
