Lipp Vis Nursing ChaptLWBK1630_C02_p013-068

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

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.

Type of Aneurysm Location

• Originates below the renal arteries • Most common

Infrarenal

• Aneurysm extends to but does not involve the renal orifices

Juxtarenal

• Aneurysm is limited to the abdomen • Involves the visceral vessels • Involves the aorta at the level of the renal arteries • Renal artery involvement

Pararenal

• Renal and visceral artery involvement

Paravisceral

Sizing of Aneurysms Sizing of aneurysms: > 3.0 cm considered aneurysmal in most adult patients

Sizing of Aneurysms

Vessel Diameter (cm)

< 4.0

Small

Medium

4.0–5.5

≥ 5.5

Large

≥ 6.0

Very large

Risk Factors for AAA Development • Tobacco use • Hypercholesterolemia • Hypertension • Male gender • Family history (male predominance)

Risk Factors for AAA Expansion Risk Factors for AAA Rupture

• 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