Aneurysms

Abdominal Aortic Aneurysm

AAA is screened for men or women between 65-75 who have smoked 100 or more cigarettes in their lifetime. Alternatively, men and women with a family history of AAA can be screened at age 50. For patients with AAA, screening in first-degree relatives should be considered who are between age of 65 to 75 or in those older than 75 years and in good health.

Currently, the SVS and USPSTF recommend against AAA screening between 65-75 who never smoked and has negative family history.

Ultrasound is routinely used for screening given its low cost, essentially free of risks, and with sensitivity of 93% and specificity of 97%. Ultrasound does underestimate maximum AAA diameter by 2 mm.

The Society for Vascular Surgery recommends the following guidelines for follow up based on aneurysm diameters:

  • Abdominal Aorta < 2.5 cm: Ectatic, no follow up needed.
  • Abdominal Aorta >2.5 – <3 cm: Ectatic, re-screening after 10 years.
  • Abdominal Aorta 3.0 – 3.9 cm: 3-year follow up.
  • Abdominal Aorta 4.0 – 4.9 cm: Yearly follow up.
  • Abdominal Aorta 5.0 – 5.4 cm: 6-month follow up.

When to refer to vascular surgery:

  • For an asymptomatic AAA that is 4.5 cm or greater, vascular surgery referral is recommended for closer monitoring and consideration for elective repair if it reaches the recommended size thresholds.
  • Any AAA with saccular morphology as this is felt to be at a higher risk for rupture compared to fusiform AAA morphology.
  • Any AAA that is symptomatic.

When should an AAA undergo surgical repair:

  • Any ruptured AAA.
  • Any symptomatic AAA.
  • Any saccular aneurysm.
  • AAA equal to or greater than 5.5 cm in men.
  • AAA equal to or greater than 5.0 cm in women.
  • For patients undergoing chemotherapy, radiation therapy, or solid organ transplantation with AAA 4.0 cm or greater, shared decision making for early repair is recommended
  • Although not explicitly recommended by the SVS, AAAs that demonstrate rapid growth (greater than 0.5 cm every 6 months or 1.0 cm every 12 months) should be considered for repair.

Source: The Society for Vascular Surgery Practice Guidelines

Iliac Aneurysms

Literature and natural history of iliac artery aneurysms are less well supported by literature. Elective repair is recommended for iliac aneurysm > 3.5 cm.

Popliteal Artery Aneurysm

  • Normal popliteal artery diameter < 1.0 cm
  • Considered aneurysmal 1.5 cm or greater
  • Is the most common peripheral aneurysm
  • It carries a risk of thrombosis and distal embolization, rather than rupture
  • Bilateral in 50% of the patients
  • In patients with bilateral popliteal aneurysms, there is a 62% prevalence of concomitant AAA
  • SVS recommends elective repair at 2.0 cm, or wait until 3.0 cm for high risk patients if there is is no mural thrombus present
    • However, if the popliteal aneurysm is smaller than 2.0 cm and there is significant mural thrombus and/or limited tibial outflow, repair is justified to prevent limb ischemia
    • Open repair is recommended for patients with life expectancy 5 years or greater. Saphenous vein bypass is the conduit of choice. If no adequate saphenous vein is available, prosthetic material is acceptable
    • For patients with <5 years of life expectancy, endovascular repair is acceptable. 2-vessel tibial runoff is said to be adequate outflow to maintain stent patency

Femoral Artery Aneurysm

  • Common femoral artery is considered aneurysmal when it is 1.5-2.0 times larger than its proximal or distal normal vessels.
  • Superficial femoral artery aneurysms are rare, but more common in elderly men. They can present as painful pulsatile mass, and actually carries a higher rupture risk than embolic risk.
  • Has 85% chance of having an AAA.

Association between Aortic Aneurysm and Dissection and Antibiotics

Fluoroquinolones such as ciprofloxacin and levofloxacin are associated with aortic aneurysms in all forms, including thoracic, abdominal, and iliac aneurysms.