Abstract 537: Marked Attenuation of Age-Related Increases in Aortic Pulse Wave Velocity in Critical Lower Limb Ischemia

Abstract

Although an increased aortic pulse wave velocity (PWV) may be employed to predict cardiovascular risk, the extent to which this may be limited by decreases in PWV in peripheral arterial disease (PAD) is uncertain. Applanation tonometry (SphygmoCor software) and vascular B-mode ultrasound were employed to assess carotid-femoral PWV and carotid intima-media thickness (IMT) respectively in 1030 randomly selected healthy adults, and in 217 patients with chronic critical lower limb ischemia (CLI). Patients with CLI had a marked attenuation of age-related increases in aortic PWV (slope of the multivariate adjusted age-log PWV relationship: CLI group=0.23±0.07, Controls=0.54±0.03, p<0.0001 for comparison of slopes) and multivariate adjusted aortic PWV (m/sec)(CLI group=4.48±0.20, Controls=6.77±0.08, p<0.0001). As compared to the community sample carotid IMT was greater in patients with CLI (p<0.0001). Carotid IMT was correlated with aortic PWV in the community sample (r=0.50, p<0.0001), but not in patients with CLI (r=0.06, p=0.37). In a multivariate model with both carotid IMT and aortic PWV in the same model, both an increased IMT (standardized β-coefficient=0.18±0.04, p<0.0001) and a reduced PWV (standardized β-coefficient=-0.23±0.03, p<0.0001) were independently associated with CLI. In conclusion, a marked decline in age-related increases in aortic PWV occurs in CLI and a reduced aortic PWV is associated with CLI independent of the extent of atherosclerosis, as indexed by carotid IMT. Thus, the presence of PAD may limit the sensitivity of the use of an increased aortic PWV as a risk predictor and a decrease in aortic PWV may herald the onset of advanced PAD.