Imaging. US is the preferred imaging procedure when screening for AAA, given its high sensitivity and specificity.17 If US yields poor image quality, noncontrast CT is suggested, with magnetic resonance angiography being another alternative.18 Handheld US has the potential to supplement the physical exam, and has been shown to be a viable method to detect AAA in an outpatient primary care setting at a reasonable cost.19 Typically, a formal aortic US requires a patient to go without food or liquids for 8 hours before the procedure to obtain the best image; however, a good estimate of aortic diameter can be obtained without this restriction.
Despite Medicare coverage and recs, few people are screened
In 2007, Medicare started the SAAVE Program (Screening Aortic Aneurysm Very Effectively), offering a one-time US screening for AAA for eligible patients, as part of the Welcome to Medicare Program. Eligible individuals are men between 65 and 75 years of age with a history of smoking at least 100 cigarettes in their lifetime, and men or women in the same age group with a family history of AAA.2
Despite these recommendations, few patients receive screening. Centers for Medicare & Medicaid Services data show that < 10% of eligible men were screened between 2004 and 2008,20 and Olchanski et al21 report that < 1% of eligible patients were screened from 2005-2009. A simulation model estimates that 131 additional life years could be gained per 1000 patients screened if the utilization rate could be increased to 80%, a seemingly achievable goal.21 Moreover, expanding the screening program to include female smokers could increase 10-year life expectancy by 13%.21 Reasons for underutilization of this Medicare screening benefit may include lack of awareness by physicians and patients, costs of co-pays, and underutilization of the basic Welcome to Medicare exam.21
An additional consequence of low utilization of AAA screening is a high percentage of patients who are identified only late in the course of the disease. Mell et al22 report that 39% of patients undergoing AAA repair were identified < 6 months prior to surgery, a higher percentage than would be expected in a well-screened population. They also determined that slightly more than one-third of patients undergoing surgery for ruptured AAA had diagnostic imaging performed > 6 months prior to surgery, suggesting the possibility that these patients may not have been properly surveilled for aneurysm expansion, although the authors note that other potential explanations include delays in treatment due to comorbidities, and patient-related factors such as refusal of surgery or noncompliance with follow-up.
CORRESPONDENCE
Jeffrey S. Todd, MD, 127 McClanahan Street, Suite 300, Roanoke, VA 24014; jstodd@carilionclinic.org.