Dynamic Peripheral Vascular Sonography: A Novel Technique

Abstract

The effects of exercise on circulation have been well documented in numerous published research studies using pulsed-wave Doppler. Spectral Doppler demonstration of these effects, however, has been restricted to comparisons of flow before exercise and after exercise. The very nature of the Doppler effect has limited the analysis of peripheral vascular flow to immobile structures, eliminating any extraneous movement. Could spectral Doppler be used to evaluate the hemodynamic effects of repetitive limb movement as it occurred? This was the question posed by a team of researchers investigating the hemodynamic effects of the repetitive motion created during use of the Treadwell®. The novel technique of pulsed-wave Doppler investigation during repetitive limb movement was employed to investigate and demonstrate these hemodynamic changes. Blood flow velocity was measured in the superficial femoral artery (SFA) and femoral vein (FV) to determine the hemodynamic changes occurring during repetitive, active-assisted motion in the most distal part of the lower extremity. Spectral Doppler analysis conducted during repetitive flexion and extension of the ankles demonstrated an initial increase in venous outflow, followed by an increase in arterial flow velocity into the lower extremity. As muscle activity continued, pulsed-wave Doppler demonstrated and documented a conversion from the typical high-resistance flow pattern in the SFA at rest to a low-resistance flow pattern, typically seen immediately following exercise.