Flashcards in AAA Deck (27):
What is the equation for the law of Laplace?
Tension = (pressure x radius)/ wall thickness.
What are risk factors for AAA?
Smoking, increasing age, being male, family history, PVD. Being Caucasian also incidence is raised in more deprived groups.
What is the marker of a true arterial aneurysm?
50 % increase in normal diameter.
What is the ratio of males to females with AAA?
What percentage of aneurysms are Asymptomatic?
What are the symptoms of a AAA when there are any?
Pain (abdominal, back, renal colic).
What is trashing in relation to AAA?
Emboli to peripheral small vessels causing occlusion.
What are the signs and symptoms of a ruptured AAA?
May look well.
May have a tachycardia or not.
Hypotensive or not.
Pulsation expansive mass +/- tenderness.
Transmitted pulse - a mass lying over the aorta transmitting its pulse.
What two types of AAA rupture do we get in relation to the peritoneum?
Most retroperitoneal contained rupture.
Free intraperitoneal rupture is rapidly fatal.
What investigations do we do for a AAA?
Ultrasound and CT scan.
What are differences between a CT scan and an ultrasound scan for AAA?
Ultrasound is for screening/surveillance and tells you if aneurysm present, if the iliac arteries are involved and what its AP diameter is.
CT scan - uses IV contrast in the arterial system. It allows us to see the morph only e.g. Size and shape. Also allows us to see the extent of iliac involvement and allows us to formulate a better management plan.
CT is also the only imaging type we can use to identified a ruptured aneurysm.
How are elective aneurysms managed differently form emergency aneurysms?
Elective - the risk of rupture is balanced against the risk of the procedure.
Emergency balances the expectation of death against the risks of the procedure.
How much do abdominal aneurysms expand roughly per year?
What size of aneurysms have the greatest chance of rupture?
>5cm have a 22% chance in 4 years.
What is the management of an elective AAA?
Surveillance and possible active intervention with an EVAR or open procedure. May decide to do nothing.
What is the management of an emergency AAA?
an EVAR or open procedure. May decide to do nothing.
What is an EVAR?
Endovascular aneurysm repair. It excludes the AAA from inside the vessel. Inserted via peripheral artery. X-ray guided. Basically parts of a tube are fitted into the artery which stops the outside part from filling with blood.
What happens during an open repair of AAA?
Laparotomy, clamp aorta plus iliacs and use a Dacron graft.
Can use a tube vs bifurcated graft.
How does an EVAR compare to an open procedure in terms of availability, risks, recovery etc?
EVAR- not possible in 25% of patients, lower mortality risk than open. Much faster recovery and needs follow up. May need further intervention.
Open - possible in everyone, greater mortality risk. Much slower recovery. Rarely needs further intervention.
What assessments do we do to see if patients are fit for AAA intervention?
Cardiopulmonary exercise testing.
End of bed or eyeball test.
What is the epidemiology of AAA?
Males over 60.
What are the causes of AAA?
Smoking, hypertension, diabetes, high cholesterol, CVS disease.
What is the pathology of AAA?
Law of Laplace.
What are the outcomes of AAA procedures in terms of mortality?
Elective 2-5% mortality
Emergency 30-50% mortality.
What is the pathogenesis of aortic aneurysm?
Medial degeneration, Regulation of elastin/collagen in aortic wall. Aneurysmal dilatation, increase in aortic wall stress. Progressive dilatation.
What do we do if an aneurysm is under 5.5cm?