Abdominal Aortic Aneurysm (AAA)
Definition
>50% fusiform dilatation of abdominal aorta, >3cm across. Risk of rupture increases >6cm across and if HTN, F, smoker, strong FHx.
Epidemiology
3% of >50yo, M>F, there is a genetic component
Aetiology
atheroma, trauma, infection (endocarditis, syphillis etc), CT disorders (Marfans, Ehlers danlos), inflammatory (Takasuya’s aortitis, giant cell temporal arteritis)
Clinical Features
Symptoms
intermittent or continuous abdo pain that radiates to back, iliac fossa or groin, collapse
Often asymptomatic if not ruptured
Signs
shocked, expansile and pulsatile abdominal mass
Investigations
USS
Management
Monitoring - <5.5cm, risk of rupture is <1%/yr; >6cm, risk of rupture, >75% require surgical repair
Modify cardiovascular risk factors
Stenting - endovascular stent inserted via femoral artery, less early mortality but graft complications
Elective surgery for symptomatic + those prone to imminent rupture
Emergency Mx (Mortality 40% if treated; 100% if untreated):
Resus, DRABCs, IV access 2 large bore cannulas, IVF or ORh -ve bloods, maintain systolic BP < 100mmHg to avoid rupturing a contained leak
Inform operating team and theatre (don’t delay surgery)
Preop - ECG, catherisation, bloods and crossmatch, Abx (cefuroxamine + metronidazole)
Surgery (clamping aorta above the leak, inserting graft)
Complications
rupture, thrombosis, embolism, pressure on other structures
Source
OHCM 9th Ed 2014
Harrison's 18th Ed 2012
Toronto Notes 2012
>50% fusiform dilatation of abdominal aorta, >3cm across. Risk of rupture increases >6cm across and if HTN, F, smoker, strong FHx.
Epidemiology
3% of >50yo, M>F, there is a genetic component
Aetiology
atheroma, trauma, infection (endocarditis, syphillis etc), CT disorders (Marfans, Ehlers danlos), inflammatory (Takasuya’s aortitis, giant cell temporal arteritis)
Clinical Features
Symptoms
intermittent or continuous abdo pain that radiates to back, iliac fossa or groin, collapse
Often asymptomatic if not ruptured
Signs
shocked, expansile and pulsatile abdominal mass
Investigations
USS
Management
Monitoring - <5.5cm, risk of rupture is <1%/yr; >6cm, risk of rupture, >75% require surgical repair
Modify cardiovascular risk factors
Stenting - endovascular stent inserted via femoral artery, less early mortality but graft complications
Elective surgery for symptomatic + those prone to imminent rupture
Emergency Mx (Mortality 40% if treated; 100% if untreated):
Resus, DRABCs, IV access 2 large bore cannulas, IVF or ORh -ve bloods, maintain systolic BP < 100mmHg to avoid rupturing a contained leak
Inform operating team and theatre (don’t delay surgery)
Preop - ECG, catherisation, bloods and crossmatch, Abx (cefuroxamine + metronidazole)
Surgery (clamping aorta above the leak, inserting graft)
Complications
rupture, thrombosis, embolism, pressure on other structures
Source
OHCM 9th Ed 2014
Harrison's 18th Ed 2012
Toronto Notes 2012