Arterial Stiffness and Peripheral Arterial Disease as Indicators of Abdominal Aorta Diame-ters: The Atherosclerosis and Risk in Communities Study

Abstract

Background: Abdominal aorta (AA) dilatation (AAD) and aneurysms result from remodeling that includes atherosclerotic and arteriosclerotic components. The latter frequently coexist across different arterial territories. Peripheral arterial disease (PAD) is an ischemic manifestation of atherosclerosis, while arterial stiffening (AS) primarily reflects arteriosclerosis. Our aim was to examine PAD and AS as potential indicators of AAD. Methods: Cross-sectional analysis of data from the 5th examination of the Atherosclerosis Risk in Communities cohort (2011-2013). 4,802 participants 70-89 years were included to examine the association between PAD and AAD, and 4,224 participants were included to examine the association between AS and AAD. The anterior-posterior (AP) diameter of the AA was quantified by b-mode ultrasound at the proximal, mid-, and distal locations. The ankle-brachial index (ABI) and pulse wave velocity (PWV) were used to evaluate PAD and AS (central and peripheral), respectively. Heart-carotid (hc) and carotid-femoral (cf) PWV were used to quantify central AS, and femoral-ankle (fa) PWV was used to measure peripheral AS. ABI and PWV measurements were performed using an automated non-invasive waveform analyzer. Results: Sixty percent of examinees were women, ~22% were black, and the mean age was 75.3±5.1 years. The mean AP diameters and confidence intervals (CIs) for proximal, mid-, and distal diameters were; 1.95±0.32cm, 1.81±0.33cm, and 1.70±0.35cm, respectively. The mean value and CI for the lowest ABI of the right and left leg was 1.10±0.14. The mean values and CIs for hcPWV, cfPWV, right faPWV, and left faPWV were 1,132.8±344.5cm/s, 1,159.5±302.7cm/s, 1,099.2±180.8cm/s, and 1,067.8±174.8cm/s, respectively. A U-shaped association between ABI and AAD was observed at all three levels of the AA. A positive, linear association between hcPWV was observed at all the levels of the aorta as the only measure of AS exhibiting a consistent and statistically significant association with AAD. Conclusions: In older adults AAD is associated with PAD and with central AS. Although statistically significant, these associations are of small magnitude and have little practical applicability as indicators of AA dilatation.Doctor of Philosoph