Screening for Abdominal Aortic Aneurysm
Abdominal ultrasonography is the recommended screening method for abdominal aortic aneurysm, offering 95% sensitivity and near 100% specificity while being non-invasive, cost-effective, and avoiding radiation exposure. 1
Primary Screening Modality
Ultrasound is the gold standard for AAA screening because it provides accurate measurements of aortic diameter, is widely available, and has been validated in multiple large randomized controlled trials demonstrating mortality reduction. 1, 2 The test is painless, uses sound waves to visualize the abdominal aorta, and measures the width to detect any bulging. 1
Why Ultrasound Over Other Modalities
CT scanning is not recommended as a first-line screening tool despite near 100% sensitivity and specificity, because it involves radiation exposure and higher costs. 1 Noncontrast CT may be considered only when obesity or poor sonographic windows make ultrasound technically inadequate. 1
Conventional aortography is inappropriate for screening due to its invasive nature, time requirements, and risks of embolization, perforation, and bleeding. 1
Physical examination (abdominal palpation) has poor accuracy and is not an adequate screening test. 1
Who Should Be Screened
Men Ages 65-75 Who Have Ever Smoked
One-time screening is strongly recommended for this highest-risk population, as screening reduces AAA-related mortality by approximately 42-43%. 1 "Ever smoking" is defined as having smoked at least 100 cigarettes in one's lifetime. 1
Men Ages 65-75 Who Have Never Smoked
Screening may be offered selectively, particularly for those with a strong first-degree family history of AAA requiring surgery. 1 The benefit is lower in this population, with approximately 1,783 never-smokers needing to be screened to prevent one AAA-related death over 5 years. 1
Women Ages 65-75 Who Smoke or Have Ever Smoked
Current evidence is insufficient to make a firm recommendation, though screening may be considered in healthy female smokers with a first-degree family history of AAA requiring surgery. 1 The prevalence of AAA in women is one-sixth that of men. 1
Women Who Have Never Smoked
Routine screening is not recommended due to very low prevalence and lack of demonstrated benefit. 1, 2
Screening Protocol
A single ultrasound examination is sufficient - there is negligible benefit in rescreening those with normal aortic diameter on initial screening. 1 Death from AAA rupture after a negative ultrasound at age 65 is rare, with incidence rates for new AAAs over 10 years ranging from 0-4%, and none exceeding 4.0 cm diameter. 1
Important Caveats
Age 75 years is generally considered an upper limit for screening because comorbid conditions decrease the likelihood of benefit from subsequent surgery. 1
Quality assurance is critical - ultrasound accuracy depends on adequate quality control measures; absence of quality assurance lowers test accuracy. 1
The SAAAVE Act provides Medicare coverage for one-time screening ultrasound at age 65 for men who have smoked at least 100 cigarettes and women with family history of AAA. 3