Abstract 12155: Detecting Peripheral Arterial Stenosis and Monitoring Atherosclerosis Severity

Abstract

Background: The AHA guidelines recommend measuring the Ankle-Brachial Index (ABI) for assessing the severity of atherosclerosis. There is also an unmet need for early detection of peripheral artery stenosis to reduce morbidity and tissue loss. However, the sensitivity of ABI in detecting arterial stenosis is limited in the presence of arterial stiffening (arteriosclerosis), especially in diabetic and elderly patients, since arteriosclerosis yields fictitious higher ABI. We hypothesize that non-invasive quantification of the peripheral perfusion dynamics, instead of a single pressure point, can improve the diagnosis and differentiate between focal stenosis and general arteriosclerosis. Methods: Impedance plethysmography (IPG) were measured from the calf of patients that underwent peripheral revascularization, before and shortly after the interventions. The characteristic perfusion dynamics curves were derived from the cardiac complexes of the IPG that were recorded over at least 3 minutes. Successful interventions were defined according to the guidelines as a post-operational ABI increase of at least 0.15. Results: Twenty-four patients (60.9±9.3 years old, 16 (66.6 %) diabetics) that underwent above-knee revascularization were analyzed. The perfusion upstroke consisted of two characteristic phases: an initial slow phase followed by a fast vigorous rise. Improvement in the perfusion after the revascularization appeared only in the initial slow duration, denoted as the ‘Perfusion Deficit Index` (PDI). Of those, 15 (62%) had a successful intervention and the PDI decreased from 115±48 ms to 22±10 ms (p<0.0001) while the ABI increased from 0.53±0.26 to 0.94±0.22. In 9 limbs (37%) with unsuccessful interventions, there were no significant changes in PDI and ABI (from 143±31 ms to 117±40 ms and from 0.38±0.11 to 0.48±0.11, respectively). There was no significant change in the pulse transit time (p=0.19), a well-known index of arteriosclerosis, before and after the interventions. Conclusions: The PDI is a novel sensitive index for detection of focal arterial stenosis and it is independent of the severity of arteriosclerosis. This simple to use method can be used for monitoring atherosclerosis severity.