Screening for abdominal aortic aneurysms during lower extremity arterial evaluation in the vascular laboratory.

PURPOSE

The purpose of this study was to evaluate the cost-effectiveness of screening for abdominal aortic aneurysms (AAA) during noninvasive lower extremity arterial examination in the vascular laboratory.

METHODS

Over 30 months we screened 531 patients who underwent lower extremity arterial evaluations in the vascular laboratory. The patients had fasted overnight, and, after the regular noninvasive lower extremity arterial examination, the abdominal aorta was screened with B-mode ultrasonography.

RESULTS

The aorta was adequately visualized in 475 patients (89%). Mean aortic diameter was 19.6 +/- 4.1 mm at the juxtarenal level and 18.8 +/- 7.2 mm in the lower infrarenal aorta. The aortic diameter was larger in men (p < 0.001) and in smokers (p < 0.001). AAA (diameter greater than 3.0 cm) were identified in 32 patients (6.0% of the 531 patients screened), and 15 of the aneurysms were equal to or larger than 4.0 cm. The best predictors for AAA by logistic regression analysis were male sex (p < 0.005), advanced age (greater than 65 years, p < 0.01), and a history of smoking (p < 0.01). The prevalence of AAA was 6.7% (32/475) in the population in whom the aorta was visualized and 15.2% (19/125) in male smokers over 65 years of age. Aneurysms of 4.0 cm or greater were identified in 3.2% of the entire population screened and 8.8% of male smokers over age 65. Limited aortic scanning prolonged the vascular laboratory examination by an average of 5 minutes. Thus detection of one aneurysm required 83 minutes of scanning time for the whole population studied and 36 minutes of scanning of male smokers over age 65, at a cost of $240 to $553 per aneurysm identified.

CONCLUSION

Screening for AAA during lower extremity arterial evaluation in the vascular laboratory addresses a high-risk population, is cost-effective, and should be considered an appropriate and valuable addition to the examination protocol.