Identification of the main determinants of abdominal aorta size: a screening by Pocket Size Imaging Device

BACKGROUND: Ultrasound exam as a screening test for abdominal aorta (AA) can visualize the aorta in 99% of patients and has a sensitivity and specificity approaching 100% in screening settings for aortic aneurysm. Pocket Size Imaging Device (PSID) has a potential value as a screening tool, because of its possible use in several clinical settings. Our aim was to assess the impact of demographics and cardiovascular (CV) risk factors on AA size by using PSID in an outpatient screening. METHODS: Consecutive patients, referring for a CV assessment in a 6 months period, were screened. AA was visualized by subcostal view in longitudinal and transverse plans in order to determine the greatest anterior-posterior diameter. After excluding 5 patients with AA aneurysm, 508 outpatients were enrolled. All patients underwent a sequential assessment including clinical history with collection of CV risk factors, physical examination, PSID exam and standard Doppler echoc exam using a 2.5 transducer with harmonic capability, both by expert ultrasound operators, during the same morning. Standard echocardiography operators were blinded on PSID exam and viceversa. RESULTS: Diagnostic accuracy of AA size by PSID was tested successfully with standard echo machine in a subgroup (n = 102) (rho = 0.966, p < 0.0001). AA diameter was larger in men than in women and in ≥50 -years old subjects than in those <50 -years old (both p < 0.0001). AA was larger in patients with coronary artery disease (CAD) (p < 0.0001). By a multivariate model, male sex (p < 0.0001), age and body mass index (both p < 0.0001), CAD (p < 0.01) and heart rate (p = 0.018) were independent predictors of AA size (cumulative R (2) = 0.184, p < 0.0001). CONCLUSION: PSID is a reliable tool for the screening of determinants of AA size. AA diameter is greater in men and strongly influenced by aging and overweight. CAD may be also associated to increased AA diameter.