CR - AAA
intro
dilation of abdo aorta > 3cm
widening of lumen secondary to weakness in wall
may extend proximally or distally
male preponderance (4:1)
10th commonest cause of death in men > 55 (silent killer)
25% have coexisting femoral or popliteal (usually) aneurysms
risk factors
smoking
hyperlipidaemia
hypertension
PAD
family Hx
doubles risk
20% of aneurysms have a familial link
risk actually decreases with DM! (walls calcified)
usually below renal art (above more complex)
Clinical exam
lower BP on left
peripheral pulses
TFTs
chol
classification
true
false (pseudo) - often secondary to trauma
anatomically
aetiology
degenerative - most common
inflamm
infective
traumatic
post-dissection
Symptoms
asymptomatic 75% of time
incidental find
routine exam
US
plain film abdo
patient notices pulsatile mass
distal embolisation (blue toe syndrome)
leak (usually contained in retroperitoneum - abdo/back/flank pain)
rupture (free, usually fatal, hypovolaemic shock, sudden epigastric/back pain)
fistulation
v rare for untxed aneurysms
usually from previous open aneurysm surgery
aorto-caval (with IVC)
aorto-enteric (with bowel)
v poor unless patient v thin
inspect for visible abdo pulsations @ eye level
feel for expansive pulsatile mass in 2 planes
listen for bruits
poor clinical sign
turbulent flow in art
listen over xiphisternum
examine pop + fem arts
US
for Dx + size (rupture risk assessment)
v good unless stomach full of food/gas
rupture risk
increases exponentially with size
<4cm: 0%
4-5cm: 0.5-5%
5-6cm: 3-15%
operate @ 5.5cm in men + 5 cm in women
surgery indications
rupture
asymtomatic @ 5.5cm (exact lower limit controversial)
symptomatic
fistulation
rapid increase in size (>1cm/yr)
must consider rupture risk, operative mortality + life expectancy (stents fail after 10 yrs so if life expectancy > 2yrs do open surgery)
CT-angiography
size
site
extension
tortuosity
involvement of renal arts
evidence of leak
Tx
endovasc aneurysm repair (EVAR)
placement of expandable stent graft via a catheter
blood flows through graft instead of dilated aorta
suitable for older patients with significant comorbidities
avoids the 3 major insults of an open repair
aortic clamping
reperfusion injury (radicals deposit in lungs, kidneys, brain, heart)
laparotomy (large incision through abdo wall)
open repair
incisions either
midline
retroperitoneal
TV
preferred in a hostile abdo, inflamm, perivisceral AAA, horseshoe kidney
complications
mortality >1%
endoleaks
graft migration/erosion
limb occlusion
pelvic ischaemia
1) proximal dissection, cross-clamping (distal + proximal), evacuation of haematoma
2) ligation of lumbar arts (come off back of aorta @ T4-6) + IMA (supplies large bowel) to preventing bleeding
3) aortic reconstruction
complications
suitability based on exercise tolerance - can you climb a flight of stairs?
mortality = 5-10%
fistulation (further increases mortality)
CR problems
bleeding
colonic ischaemia (post/op diarrhoea)
limb ischaemia
hernia
sexual dysfunction
type 1 = high pressure (must fix)
type 2 = low pressure
type 3 = holes in stent
persistent blood flow outside of graft