Using maximal systolic acceleration to diagnose and assess the severity of peripheral artery disease in a flow model study

Background: Because of the presence of medial calcific sclerosis, both ankle-branchial index and toe pressure measures can yield misleading results when attempting to diagnose peripheral artery disease (PAD). A new ultrasound parameter, maximal systolic acceleration (ACC_max), can be an accurate tool for diagnosing PAD, including in diabetic patients. However, it has not been evaluated thoroughly. The aim of this study was to assess the feasibility of using ACC_max to diagnose and assess the severity of PAD.

Methods: The human circulatory system was simulated using an in vitro circulatory system driven by a pulsatile pneumatic pump. Arterial stenosis of various degrees (50%, 70%, 80%, and 90%) was simulated in order to investigate the change in several ultrasound parameters (including ACC_max), as well as the intraluminal mean arterial pressure gradient. In a separate set of measurements, interobserver variability was measured using two investigators who were unaware of the degree of stenosis.

Results: ACC_max significantly decreased (P < .001), and the pressure gradient increased (P < .001) as the degree of stenosis increased. Moreover, we found a strong correlation between ACC_max and the pressure gradient (R² = 0.937). Finally, interobserver variability with respect to ACC_max was extremely low, with an intraclass correlation coefficient of 0.99.

Conclusions: The results of this flow model study suggest that ACC_max can be a valid, noninvasive tool for diagnosing PAD. Moreover, our finding that ACC_max decreases as the severity of stenosis increases, together with the strong correlation between ACC_max and the pressure gradient, suggests that ACC_max may be useful as an alternative diagnostic tool for assessing the severity of PAD. These promising in vitro data warrant further study in a clinical setting.