Vascular Surgery Flashcards
Definition of AAA
Abnormal dilaiton of abdominal aortia (1.5>2 x normal) forming a true aneurysm
Name the branches of the descending abdominal aorta?
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- Phrenic [inferior]
- Celiac
- Superior mesenteric
- Suprarenal [middle]
- Renal
- Testicular [“in men” only]
- Lumbars
- Inferior mesenteric
- Sacral
Aetiology of AAA
- atherosclerotic -95%
- inflammatory - 5%
Prevalence
- older males, positive family history, hypertension, tobacco smoking
- 5% of all adults >65
- Male to female ratio is 6:1
Common site
- 85% - Infra-renal artery (below levels of the renal arterys
- 15%- Extends down to involve the origins of the common iliac arterys
- associated with other operipheral aneurysm
Symptoms of AAA
May be
- Asymptomatic (60%) - detected on routine physical examination, plain x-ray or most commonly, abdominal ultrasound scan conducted for another reason
-
Symptomatic (10%)
- pain in the central abdomen, back, loin, illiac fossa
- becomes inflamed and compresses surrounding structures (ureter, inferior vena cava)
- distal embolisation
-
Rupture (30%)
- AAA may rupture in to the retroperitoneum
Signs of AAA
- hypotension
- palpable mass felt at/above umbillicus
- bounding femoral pulses
- distal pulses inact
Investigations of AAA
- Physical exam
- ultrasound (confirm AAA with initially)
- CT scan (accurate visualisation, size, positioning, and involvement of surrounding structures )
- Angiography
Complications of AAA
- free rupture
- collpase
- hypotension
- tachycardia
- retroperitoneal rupture - abck pain, nausea, vomitting, hypotension
- distal embolisation - thrombus from the sac may disperse distally and block the small vessels in the foot and lower leg causing acute ischaemia
- aorto-caval fistula - plethora
- aorto-duodenal fistula - haematemsis, melaena
- aortic occlusion
Screening of AAA
- All men > 65 years are invited to attend screening
- screen using ultrasound scan
Treatment of AAA
- Blood pressure control and stop smoking
- incidental asymptomatic small AAA
- repair is deferred until the theortical risk of rupture exceeds the estimated risk of operative mortality - until AAA reaches 5.5cm
- ultrasound is only accurate to 0.5cm and will therfore underestimate AA.
- Perform CT once 5.0cm is reached
- Symptomatic
- if the patient is having pain concurrent with their abdominal aortic aneurysms they should always be considered for surgery as pain often preceds rupture
- surgical repair - synthetic graft
- endovascular graft
Two types of AAA surgical repair
- Open repair
- Endovascular aneuryms repair (EVAR)
Open repair process, adv and disadvantages
- involves replacing the anuerysmal segment with a prosthetic graft
- the graft is straight forward if the aneuryms is confined to the aorta or bifurcated
- If there are common iliac anuerysms as well the aorta must be clamped off during surgery
Advantages
- increased durability and long term mortality
Disadvantages
- Recovery period is 7-10 days
- return to preoperative functional status is 4-6 months
EVAR process, advantages and disadvantages
A guidewire is passed through the right common femoral artery. A catheter containing the main body of the stent graft is passed over the guidance wire and placed in position inside the aneurysms. Deployment of main body and right limb of stent graft. Deployment of short leg or stent fraft over second wire guide. Requires two incisions
Advantages
- performed under regional or local anaesthesia
- patient is fit to go home with 48 hours
- rapid return to preoperative functional status
- decreased immediate mortality
Disadvantges
- decreased durability
- expensive
- large amount of AAA not suitable
- life-long surveillance
- no long term survival rates beneft over open repair
- high re-intervention rate
Leading cause of postoperative death in a patient undergoing elective AAA treatment>
Myocardial infarction (MI)
Normal abdominal aortic diameter
2cm
Possible operative complications
- MI
- atheroembolism
- declamping hypotension
- acute renal failure (especially if the anerysm involves the renal arteries)
- uretar injury
- haemorrhage
- colonic ischaemia
Emergency management of rutured AAA
resuscitation
- call for senior surgical assistance
- transfer to theatre
- permissive hypotension- dont worry if not normal BP after fluids as may worsen the rupture
- If patient is critically hypotensive, consider calling a peri-arrest cardiac emergency
- IV access via two large bore cannulae, catheterize, cross match blood, order FFP and plateles
- high flow O2 via a non-rebreather mask
- give modest doses of analgesia
- alert anaesthesit, theatres, ITU
- Witnesses verbal consent for surgery may be the only practical way and is accectable here