Aneurysms Flashcards
What is an aneurysm?
An artery with a dilation >1.5x its original diameter.
What is the difference between a true and a false aneurysm?
- True - abnormal dilations involving all layers of arterial wall.
- False - collection of blood in outer layer only (communicates with lumen)
Where do >90% of AAAs occur?
Below the renal arteries
What is the underlying aetiology of an aneurysm?
- Media layer (smooth muscle) gives aorta strength.
- Enlarging atherosclerotic plaque causes degradation of aortic wall connective tissue, inflammation, infiltration of lymphocytes and decreased elastin.
- Aortic wall weakened and it dilates.
- Atheroma, trauma, connective tissue disorders, inflammation.
Where are the most common sites for aneurysm formation?
- Aorta (infrarenal)
- Iliac arteries
- Femoral arteries
- Popliteal arteries
In which patient groups is an unruptured AAA more common?
> 50 years old, M:F 6:1, less common in diabetics.
What symptoms may be present in an unruptured AAA?
- Often none
- May be abdominal/back pain
- Often discovered incidentally on abdominal exam
What are the risk factors for the development of an unruptured AAA?
- Atherosclerosis - cigarette smoking
- FHx of AAA
- Increased age - >55yrs in men, >65yrs in women
- HTN, high cholesterol
- Caucasian
- Connective tissue disorders
How do you investigate a suspected unruptured AAA?
- Presence of RFs
- Abdominal mass only tends to be felt when >5cm
- USS definitive test
What is the management for symptomatic unruptured AAA?
Repair indicated regardless of diameter.
What is the management for an asymptomatic unruptured AAA?
- Annual USS screening 3-4.5cm, quarterly 4.5-5.5cm
- Elective surgery >5.5cm/expanding >1cm per year/becomes symptomatic.
- Control RFs - smoking cessation, statins and antihypertensives.
Which patients are more likely to have a rupture of a AAA?
Female, HTN, smoker, +ve FHx
Which groups are invited for AAA screening in the UK?
All males >65 years of age
What is the surgical option in an unruptured AAA?
EVAR (endovascular aneurysm repair) - symptomatic AAA, less early mortality but higher graft complications.
What are the complications of a AAA?
- Rupture
2. Thrombosis and embolism
What is this a presentation of?
Intermittent or continuous abdominal pain (radiating to back, iliac fossa, or groins). Collapse, shock, expansile abdominal mass.
Ruptured AAA
What is the classic triad in ruptured AAA?
Abdominal pain, expansile abdominal mass, and hypotension.
What is the emergency management of a ruptured AAA?
- Call vascular surgeon and anaesthetist and warn theatre.
- ECG, bloods (amylase, Hb, crossmatch), catheterise.
- IV access with 2 large bore cannulas.
- Treat shock with O Rh- blood.
- Keep systolic BP <100mmHg to avoid rupturing contained leak.
- CT needed
- Prophylactic Abx (co-amoxiclav 625mg IV)
- Open surgery (clamping aorta, end organ ischaemia, reperfusion injury) vs EVAR
What is the difference between a fusiform and a saccular aneurysm?
- Fusiform - 360 degrees of vessel wall
2. Saccular - one area of vessel wall
