Abdominal aortic aneurysm Flashcards
What age does AAA usually occur in?
-60-70 years
What is the definition of AAA?
- Localised dilation of all 3 layers(intima,media and adventitia) to more than 50% of its original size
What are the causes/risk factors for AAA?
- Old age
- Family history
- Smoking hx
- Hypercholesteraemia and arterial hypertension
- Atherosclerosis
What is the pathophysiology of AAA?
- inflammation and degeneration of connective tissue by proteloytic enzymes
- mechanical stress(high blood pressure )can cause further dilation and rupture
Where does the AAA usually develop?
- infrarenal-95%
- juxtrarenal-5%
What are the clinical features of a patient with AAA?
-Back pain
-mostly asymptomatic
-trash feet(gangrenous foot)
-
How do we diagnose AAA?
- Ultrasound-best initial and confirmatory test
- CT-determines AAA rupture
What is the treatment for an AAA?
- Cessation of smoking
- decreased BP to <120/80
How many times do we need to monitor the patient according to the aortic diameter?
- <3 cm- no ultrasound
- 3-4 cm do a yearly ultrasound
- 4-4.5 cm- ultrasound every 6 months
- 4.5-5.5 cm ultrasound every 3 months
When do we consider elective surgery?
- aneurysm >5.5cm
- expanding more than 1 cm per year
When do we we consider emergency surgery?
- leaking or ruptured AAA
- Acutely symptomatic
What are the surgical procedures we can do?
- EVAR which is preferred over
- open(tube graft and y-prosthesis)
What are the complications of an AAA?
-Rupture
What does EVAR stand for?
Endovascular aneurysm repair
What is the clinical features for a ruptured AAA?
- Throbbing abdominal pain that radiates towards the flank, the back, the buttocks, legs and groin
- nausea and vomiting
What is the treatment for a ruptured AAA?
- emergency open surgery
- sometimes endoscopic surgery
- high mortality rate(90%) if it occurs outside the hospital
What is the possible differential diagnosis for upper abdominal pain with surgery
- Pale: ruptured AAA, ruptured hepatoma, ruptured spleen in trauma
- Not pale: sepsis, pancreatitis, pyenephrosis
Why should we not intubate these patients?
-neuromuscular blocking agents will reduce the tamponade effect and cause haemorrhage
What kind of graft is used?
-a synthetic graft called Dacron
What is the most common complication post-operatively?
Renal insufficiency
How can we stop the complication of renal insufficiency?
-by giving furosemide or mannitol pre-operatively
What are the peri-operative complications of doing EVAR?
- Stroke because of hypotension
- Myocardial infarction
- renal insufficiency
- colon ischaemia
- haemmorrhage
- Infection of the graft
- Gangrene foot when an embolism travels from a thrombus
What is a late complication of EVAR?
- late infection
- aortoenteric fistula
How can you tell the difference between a saccular and fusiform aneurysm?
Fusiform is symmetrical and saccular is asymmetric and bulges out
What are the 4 ways to classify aortic aneurysms?
- pathology
- anatomy
- morphology
- etiology
What is the etiology of aneurysms?
- inflammatory: Takayasus
- degenerative (most common)
- Infections-HIV, TB, Infective endocraditis, salmonella, staphdissecti aureus
- Traumatic-false anurysms
- Anastomatic- false anurysms
- dissection-thoraco-abdominal aneurysm
What is the gold standard special investigation for aneurysms?
- CT scan because you can see the thrombosis, angiogram only shows the dilatation
How do degenerative aneurysms present?
- The present with older white males that smoked
- Usually fusiform in shape
- Infra-renal, aortic. popliteal and thoracic aneurysms
How do HIV related anurysms present?
They are multiple an saccular
How do we classify aneurysms anatomically?
- Aortic- by the umbilicus
- Supra-renal- under ribs
- infra renal-below costal margin
- popliteal
- carotid
- visceral
What are the possible complications of aneurysms?
- rupture
- embolus
- compression
- infection
How do people with symptomatic anurysms present?
abdominal or back pain or pain above the enurysm
Needs urgent medical care immediatey
Into which organs can an abdominal aneurysm rupture?
- retroperitoneal space
- IVC
- GIT-duodenum
- Ureter
- left renal vein
What are the 3 managment options?
- conservative
- surgical
- EVAR
What are the indications for conservative management?
- If the aneurysm is < 5,5cm
- The patient is not fit for surgery
- Thepatient is asymptomatic
If <4 cm then yearly ultrasound must be done
If 4-5,5cm then 6 monthly ultrasound should be done
What are indications for surgery?
- High rupture risk: >5,5cm
2. Healthy individuals
What are the complications of EVAR?
- limb occlusion
- migration
- dilatation
- endoleaks
What is different about the management of popliteal aneurysms?
We bypass instead of putting in a stent
