Poststenotic dilatation: arterial wall mechanics in response to vibration

A study of the relationship between the mechanical response of human iliac arteries subjected to sinusoidally varying dynamic pressures superimposed on a static pressure of 100 mm Hg (1mm Hg = 133 N/m2) and the development of arterial dilatation, with particular reference to poststenotic dilatation has been conducted. In 13 experiments, optical measurements of the amplitude of vessel wall movements in response to dynamic pressures of amplitude 5 mm Hg peak to peak indicated the presence of at least one, and at most four resonance peaks for frequencies in the mean range 0-100 Hz. Four specimens were vibrated at resonance and four at frequencies 15 Hz higher than resonance, in response to a dynamic pressure of 5 mm Hg peak to peak for 3 h. All specimens exhibited some dilatation, the average percentage increase in diameter being in the range 0.22 to 0.42% per hour. In four additional experiments, the dynamic pressure was doubled at constant frequency. This resulted in an increased amplitude of vibration and additional dilatation at an increased rate. It is concluded that the dynamic stresses present in the vessel influence the rate of dilatation.