Aortic aneurysms Flashcards
what is an aneurysm?
artery that has a localised dilation with a permanent diameter of >1.5 times that of expected for that particular artery
what are the classification of the different types of aneurysm?
true or false
pulsatile or expansile
fusiform or sac-like
true aneurysm
the wall of the artery forms the wall of the aneurysm
false aneurysm
aka pseudoaneurysm
other surrounding tissues form the wall of the aneurysm
most common in femoral artery
what are the possible shapes of the aneurysm?
fusiform
sac-like
fusiform aneurysm
tapered at both ends like a rain drop
sac-like aneurysm
rounded
expansile aneurysm
expands and contracts
pulsatile aneurysm
doesn’t expand and contract
transmits pulse
most frequent locations of aneuryms
abdominal aorta iliac artery popliteal artery femoral artery thoracic aorta aorta in general
risk factors for aortic aneurysms?
hypertension smoking age diabetes obesity high LDL levels sedentary lifestyle genetics - 10% have 1st degree relative with aneurysmal disease co-arctation of aorta marfan's syndrome connective tissue disorders previous aortic surgery pregnancy - 3rd trimester trauma being male COPD
complications of aortic aneurysm
local obstruction impaired blood flow thrombosis embolism dissection rupture
where does an aortic aneurysm most commonly rupture?
into retroperitoneal space
presentation of aortic aneurysm
often asymptomatic
often incidentally discovered
mean age of presentation = 65
risk of dissection/rupture increases with increased diameter
diagnosis of aortic aneurysm
examination AXR - 65% show up ultrasound CT ultrasound used for staging
when to treat aortic aneurysm?
> 5.5cm in diameter
below this the risk of dissection is outweighed by the risk of surgery
smaller symptomatic aneurysms may be operated on
presence of thrombo-embolism
annual rupture risks
5.5cm diameter = 25%
6.5cm diameter = 35%
>7cm diameter = 75%
risk factors for aneurysm rupture
pain
what are the treatment options for aortic aneuryms
open laparotomy
endoluminal surgery
open laparotomy
affected segment of aorta is clamped and replaced by prosthetic segment - Dacron graft
graft failure is rare
affected artery segment can be bypassed
endoluminal surgery
endovascular aneurysm repair
aortic graft inserted through femoral artery and into abdominal aorta
suitability for endoluminal surgery
must be 2.5cm at least of normal aorta between aneurysm and renal arteries
preferred method
complications and risks associated with open laparotomy
complications are rare kidney proplems paraplegia ischaemic colitis fistula formation with small bowel infection
mortality with open laparotomy
5-8% elective asymptomatic AAA repair
10-20% in symptomatic AAA repair
50% for ruptured AAA repair
long-term survival is similar to general population
complications of endoluminal
more common graft complications graft failure cannot treat rupture lower risks than open laparotomy
how many people with a ruptured AAA will die?
10%
AAA rupture
wall of aorta completely fails and blood escapes into body
usually into abdominal cavity
dissection vs rupture
different things
dissection often leads to rupture
what is AAA dissection?
blood escapes through innermost layer of artery wall and prises apart the tunica media creates a new lumen can create a double-barelled aorta may be stable or may rupture can compromise aortic valve medical emergency
classification of dissecting AA
type A
type B
type A AA
2/3 of cases
involving the ascending aorta and potentially descending aorta
type B AA
affects only descending aorta
symptoms of AAA
pain - sudden onset, severe, tearing pain radiates to back hypotension expansile mass in abdomen shock tachycardia anaemia sudden death testicular similar to renal colic/diverticulitis non-specific back pain
what causes non-specific back pain in AA
erosion of vertebral bodies with long-standing aneurysm
AA of ascending aorta pain
pain in chest
AA of descending aorta pain
pain in back
investigations for AA
clinical diagnosis
need to diagnose quickly
treatment for AA dissection
type A = emergency open surgery using Dacron graft
type B = less urgent than A, endoluminal surgery but open laparotomy is preferred
AAA
most commonly in infrarenal segment of aorta
pain below level of renal artery
rapid expansion/rupture causes epigastric pain
pain radiates to the back
pain in groin, iliac fossa and testicles
contant or intermittent pain
think of renal colic as differential
thoracic aortic aneurysm
asymmetrical brachial/radial/carotid pulses if dissection involves aortic arch
different BP in each arm
pathogenesis of AAA
permanent dilation of vessel wall
atheromatous degeneration most common cause of true aneurysm
ischaemia of aortic media due to atherosclerotic plaque - release of macrophage enzymes which break down elastic fibres, collagen and elastin
loss of normal elastic nature of media so it can expand
what is marfan’s syndrome
connective tissue disorder
very common
causes of marfan’s syndrome
mutation of fibrinin gene on chromosome 15
inheritance of marfan’s syndrome
autosomal dominant
25% de novo mutation
males and females equally affected
testing for marfan’s syndrome
genetic testing for fibrillin-1 gene
the mutation in 80% of cases
clinical features of marfan’s syndrome
arachnodactyly - long and thin fingers bent back at MCP joint hypermobility scoliosis chest deformity high arched palate dislocation of eye lens patients are tall/thin/long limbs heart valve defects predisposition to aneurysms lung disorders dura disorders
treatment of marfan’s syndrome
beta blockers
monitoring of aortic dilatation
elective replacement of ascending aorta to prevent dissection
avoid endurance sports/ activities
monitoring aortic dilatation in marfan’s syndrome
CXR MRI Echo CT needs close attention in pregnancy as both pregnancy and marfans are risk factors for aortic aneurysms
pregnancy, marfans syndrome and aortic aneurysms
if aortic root >4cm then C section
beta blocker can be continued through pregnancy to reduce risk of aortic dilatation
prognosis of marfan’s syndrome
good
less than general population
surgical interventions increase life-expectancy by 13 years
how does a leaking/ruptured AAA present?
pain - flank/back collapse hypotension pulsatile abdominal mass cold sweaty faint syncope vomiting pale tachycardia thread/weak pulse tender mass bruit
management of ruptured AAA
large bore cannula IV access group and cross match need large supplies of blood products - FFP, blood and platelets arrange theatre immediately resuscitation of hypovolaemic shock NICE recommends open surgery
screening for AAA
ultrasound of abdomen
10-15 minutes
instant results
who is eligible for AAA screening?
men during the year they turn 65
not offered to those already being treated for AAA
can request a screening
if there is a family history and GP believes it is important will be done 5 years younger than the age of the relative when they were found to have an AAA
it is optional
People with marfan’s syndrome are extensively monitored/screened
AAA screening possible results
no aneurysm - <3cm diameter
small AAA
medium AAA
large AAA
Small AAA
3-4.4cm diameter of aorta no treatment needed as risk of rupture is small annual scans to check size treated if it becomes large advice on how to prevent enlargement 1% of cases
medium AAA
4.5-5.4cm diameter of aorta no treatment needed 3 monthly scans to check size treated if enlargement occurs advice to prevent enlargement 0.5% of cases
large AAA
5.5cm < diameter of aorta
high risk of bursting if untreated
referral to specialist surgeon within 2 weeks of result to discuss treatment
smaller risk of surgery than if left untreated
how to prevent AAAs or enlargement of AAAs?
stop smoking balanced/healthy diet maintain healthy weight regular exercise reduce alcohol intake treat underlying health conditions
what are the types of aortic aneurysms?
abdominal and thoracic
cerebral aneurysms - not aortic
abdominal aortic aneurysms
most common
severe internal bleeding can occur from rupture
risk of dissection
thoracic aortic aneurysm symptoms
back pain
hoarseness
shortness of breath
tenderness/pain in chest prior to rupture
complications of aortic aneurysms
local obstruction impaired blood flow to lower limbs thrombosis embolism dissection and rupture life-threatening internal bleed surgical complications
signs/ symptoms of thoracic aortic aneurysm rupture
sudden intense and persistent chest/back pain pain radiates to back trouble breathing low BP loss of consciousness SOB dysphagia stroke weakness/paralysis
cerebral aneurysms
above aorta in brain most common in aged 30-60 can be tiny - large rupture causes bleeding on brain potentially fatal
