What are the SVS treatment guidelines for unruptured abdominal aortic aneurysm (AAA)?

Updated: Jan 08, 2019
  • Author: Saum A Rahimi, MD, FACS; Chief Editor: Vincent Lopez Rowe, MD  more...
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Answer

Even patients who do not have symptoms from their AAAs may eventually require surgical intervention because the result of medical management in this population is a mortality of 100% over time as a consequence of rupture. In addition, these patients have a potential for limb loss from peripheral embolization.

The decision to treat an unruptured AAA is based on operative risk, the risk of rupture, and the patient’s estimated life expectancy. In 2009, the Society for Vascular Surgery (SVS) published a series of guidelines for the treatment of AAAs based on these principles. [20]

Operative risk is based on patients’ comorbidities and hospital factors (see Table 1 below). Patient characteristics, including age, sex, renal function, and cardiopulmonary disease are perhaps the most important factors. However, lower-volume hospitals and surgeons are associated with higher mortality. [21]

Table 1. Operative Mortality Risk With Open Repair of Abdominal Aortic Aneurysm (Open Table in a new window)

</tbody>

Lowest Risk

Moderate Risk

High Risk

Age <70 y

Age 70-80 y

Age 80 y

Physically active

Active

Inactive, poor stamina

No clinically overt cardiac disease

Stable coronary disease; remote MI; LVEF >35%

Significant coronary disease; recent MI; frequent angina; CHF; LVEF < 25%

No significant comorbidities

Mild COPD

Limiting COPD; dyspnea at rest; O2 dependency; FEV1</td></tr>

...

Creatinine 2.0-3.0 mg/dL

...

Normal anatomy

Adverse anatomy or AAA characteristics

Creatinine >3 mg/dL

No adverse AAA characteristics

...

Liver disease (↑PT; albumin </td></tr>

Anticipated operative mortality, 1-3%

Anticipated operative mortality, 3-7%

Anticipated operative mortality, at least 5-10%; each comorbid condition adds ~3-5% mortality risk

AAA = abdominal aortic aneurysm; CHF = chronic heart failure; COPD = chronic obstructive pulmonary disease; FEV1 = forced expiratory volume in 1 second; LVEF = left ventricular ejection fraction; MI = myocardial infarction; PT = prothrombin time.

Abdominal ultrasonography can provide a preliminary determination of the aneurysm’s presence, size, and extent. Rupture risk is in part indicated by the size of the aneurysm (see Table 2 below).

Table 2. Abdominal Aortic Aneurysm Size and Estimated Annual Risk of Rupture (Open Table in a new window)

AAA Diameter (cm)

Rupture Risk (%/y)

<4

0

4-5

0.5-5

5-6

3-15

6-7

10-20

7-8

20-40

>8

30-50

AAA = abdominal aortic aneurysm.

In addition to aneurysm diameter, factors such as sex, aneurysm expansion rate, family history, and chronic obstructive pulmonary disease (COPD) also affect the risk of rupture (see Table 3 below).

Table 3. Factors Affecting Risk of Abdominal Aortic Aneurysm Rupture (Open Table in a new window)

Factor

Low Risk

Average Risk

High Risk

Diameter

<5 cm

5-6 cm

>6 cm

Expansion

<0.3 cm/y

0.3-0.6 cm/y

>0.6 cm/y

Smoking/COPD

None, mild

Moderate

Severe/steroids

Family history

No relatives

One relative

Numerous relatives

Hypertension

Normal blood pressure

Controlled

Poorly controlled

Shape

Fusiform

Saccular

Very eccentric

Wall stress

Low (35 N/cm2

Medium (40 N/cm2

High (45 N/cm2)

Sex

...

Male

Female

COPD = chronic obstructive pulmonary disease.


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