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Chapter 2
•
Cardiovascular Care
41
ABDOMINAL AORTIC
ANEURYSM
Abdominal aortic aneurysm (AAA)
is a dilatation of the abdominal
aorta with no general agreement
on how to define an AAA. Proposed
definitions exist and are based on
the diameter of the abdominal aorta.
An AAA is classified by location,
primarily with regard to its proximal
extent. Factors that are important
Type of Aneurysm Location
Infrarenal
•
Originates below the renal arteries
•
Most common
Juxtarenal
•
Aneurysm extends to but does not involve the renal orifices
Pararenal
•
Aneurysm is limited to the abdomen
•
Involves the visceral vessels
•
Involves the aorta at the level of the renal arteries
•
Renal artery involvement
Paravisceral
•
Renal and visceral artery involvement
Risk Factors for AAA
Development
Risk Factors for
AAA Expansion Risk Factors for AAA Rupture
•
Tobacco use
•
Hypercholesterolemia
•
Hypertension
•
Male gender
•
Family history (male
predominance)
•
Advanced age
•
Severe cardiac
disease
•
Previous stroke
•
Tobacco use
•
Cardiac or renal
transplant
•
Female gender
•
Decreased FEV1
•
Aneurysm diameter and rate of
growth
•
COPD
•
Higher mean blood pressure
•
Current tobacco use
•
Cardiac or renal transplant
•
Critical wall stress–wall strength
relationship
•
Elevate mean arterial pressure
when evaluating the aortic diameter
include age, gender, and body size.
AAA is a common and potentially life-
threatening condition.
TIP:
Ruptured AAA, without repair,
is nearly always fatal.
AAAs are described relative to the
involvement of the renal or visceral
vessels.
Sizing of Aneurysms
Sizing of aneurysms:
>
3.0 cm considered aneurysmal in most adult patients
Sizing of Aneurysms
Vessel Diameter (cm)
Small
<
4.0
Medium
4.0–5.5
Large
≥
5.5
Very large
≥
6.0