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