aortic aneurysm Flashcards
define abdominal aortic aneurysm
focal dilatation of the abdominal aorta to more than 1.5 times its normal diameter
AAA is more common in
men
smokers
age 60-70
hypertension
ASCVD
hypercholesterolaemia
family history
pathophysiology
inflammation and proteolytic degeneraton of the connective tissue proteins (eg. collagen and elastin and/or smooth muscle cells)
loss of structural integrity of the aortic wall
widening of the vessel
mechanical stress eg. high blood pressure
diltation and rupture
is AAA usually symptomatic?
often asymptomatic and discovered incidentally in US or CT
clinical features if symptomatic of AAA
if symptomatic:
lower back pain
pulsatile abdominal mass at or above the level of the umbilicus
bruit on aauscultation
peripheral thrombosis and distal atheroembolic phenomena (eg. blue toe syndrome and lived reticularis)
decreased ankle-brachial index
diagnosis of AAA
no lab findings specific for AAA
imaging needed
abdominal US best for asymptomatic patients for screening/surveillance
CTA AP for symptomatic patients
classification of abdominal aortic aneurysm based on location
more commonly infrarenal (below the renal arteries)
classification of abdominal aortic aneurysm based on shape
when is it reasonable to do AAA screening
abdominal US for men 65-75 who have ever smoked
deciding if an AAA needs surgery
bigger than 5cm
expanding rapidly
symptomatic
complications eg. rupture
saccular shape
is thoracic or abdominal anurysm more common
abdominal
risk factors for thoracic aortic aneurysm
arterial hypertension
bicuspid aortic valve
tertiary syphilis
connective tissue disease eg. Marfan syndrome, ehlers-donlos syndrome
trauma
smoking
clinical features of TAA
feeling of pressure in the chest
thoracic back pain
signs of mediastinal obstruction eg. difficulty swallowing
how are AAAs classified
either aaffecting the suprarenal or infrarenal aorta
how are TAAs classified
either affecting the ascending aorta, descending aorta, or aortic arch
ascending aorta is most common
two types of procedures to repair AAA
endovascular aneurysm repair
open surgical repair
What is the preferred procedure for most aneurysms, especially in high operative risk patients?
Endovascular aneurysm repair (EVAR)
What is the procedure for endovascular aneurysm repair (EVAR)?
An expandable stent graft is placed via the femoral or iliac arteries intraluminally at the site of the aneurysm under fluoroscopic guidance.
What is a disadvantage of endovascular aneurysm repair (EVAR)?
Reintervention rates are higher for EVAR than for open surgical repair (OSR).
What are the indications for open surgical repair (OSR)?
- Mycotic aneurysm or infected graft
- Persistent endoleak and aneurysm sac growth following EVAR
- Anatomical contraindications for EVAR
What is the procedure for open surgical repair (OSR)?
A laparotomy is performed and the dilated segment of the aorta is replaced with a tube graft or Y-prosthesis.
preoperative care for AAA repair
IV antibiotic prophylaxis: first generation cephalosporin eg. cefazolin
anticipate and treat blood loss anaemia
central venous access and arterial line monitoring
consider post operative admission to ICU if complicated
multimodal pain management
VTE prophylaxis
checklist for symptomatic abdominal aortic aneurysm
Urgent vascular surgery consult for surgical repair
CT angiography abdomen and pelvis with IV contrast for preintervention planning if patient is hemodynamically stable
Transfer to OR.
NPO
IV access with two large-bore peripheral IV lines
Check CBC, type and screen, obtain patient consent for blood transfusion, and order pRBCs (prepare for massive transfusion protocol).
Consider IV fluid resuscitation.
IV opioid analgesics
