High intensity ultrasound increases distensibility of calcific atherosclerotic arteries

To assess the effect of high intensity ultrasound energy on atherosclerotic arteries, the pressure-volume relation of stenoses in 14 atherosclerotic human cadaver arteries was measured before and after intraarterial application of ultrasound energy. The pressure-volume relation was measured by inflating a 3-mm angioplasty balloon within each artery with use of a syringe equipped with pressure and volume transducers. To minimize potential effects of balloon inflations on compliance, balloon inflation pressure was set at less than or equal to 3 atm before ultrasound application. Ultrasound energy was applied by using a titanium wire probe at a frequency of 20 kHz for 2 min. After exposure to ultrasound, arterial distensibility (measured as volume at 1 atm of balloon pressure) increased by a mean value of 82 +/- 60 microliters. These data suggest that ultrasound energy probably increases the pliability of atherosclerotic lesions by interrupting calcified plaque. This effect may enhance in vivo distensibility and render calcified atherosclerotic lesions more amenable to balloon angioplasty.