Effects of surrounding tissue on the sound spectrum of arterial bruits in vivo

Abstract

Turblent flow dlatal to arterial atenoaes produces brults with a cbaracterlstic sound spectrum, analysis of which has permitted accurate noo-lnraslve assessment of the residual tomen diameter of the stenosis in the case of the human carotid artery. In contrast, Investigators working with In vitro elastic models of arteries or with excised vessels hare reported finding mainly resonant spectra of bruits recorded distal to stenoses. We hare studied the effects of turbulent flow on the sound spectrum produced at the arterial wall and the influence of surrounding tissue on this spectrum. Aortic, carotid, and femoral steooses were produced in dogs by external banding of the arteries with Smm wide Teflon bands. Recordings of bruits made directly on the vessel wall had a sound spectrum made up of 2 components, one due to turbulent flow, and the second to a superimposed resonant spectrum from arterial wall vlbratlon. This was true of 3 kinds of vessels studied. The effects of surrounding tissue on the sound spectrum of arterial bruits was shown by comparing the spectra of bruits recorded directly on the vessel wall, on the freshly closed wound and on the healed wound. The sound properties of the artery in situ are very different from those of exposed or excised vessels or elastic tubes. Although intravascular turbulence may be accurately appreciated at the skin surface, arterial wall resonance in the intact animal is extensively damped by the normal coopliog of the artery to its surrounding tissue. © 1980 American Heart Association, Inc.