Arterial Flow Enhancement by Impulse Compression

Abstract

Preliminary observations of rapid relief of ischemic rest pain following appli cation of a foot impulse compression device prompted this study to quantify its immediate effects. Blood flow was calculated by means of a duplex ultrasound imager interfaced with a Doppler spectrum analyzer. Twelve normal subjects and 10 patients with peripheral vascular disease (mean Doppler ankle/brachial systolic pressure index = 0.62 (range 0.33-0.74) were studied. Mean resting blood flow ( SD) was not significantly different in the two groups: 55.6 24.0 in normal subjects and 48.3 29.8 in the arteriopaths (p = > 0.1). During five minutes of pump application in a 45-degree foot-down position, mean popliteal blood flow increased by 93% in normal subjects (p < 0.0001) and 84 % in peripheral vascular patients (p < 0.03); there was no change in the opposite limb. In 5 normal subjects a "placebo" device produced no significant change in flow (p >0.1). In 4 patients with vascular disease lying supine, impulse pumping produced no significant increase in popliteal blood flow. It is suggested that the hyperemic effect may be explained by the liberation of endothelial-derived relaxing factor (EDRF), a powerful relaxant of vascular smooth muscle, produced in response to sudden pressure changes (hemodynamic shear-stress) within the venous system.