Ultrasound Angioplasty: Experimental Studies

Abstract

It has been 30 years since Lane and Minot demonstrated that ultrasound energy could be used to ablate atherosclerotic plaque [1]. However, an additional 20 years passed before there was another published report on the use of ultrasound for atherosclerotic plaque disruption [2,3]. In the mid-1980s, there was intense investigation to develop methods to resolve the limitations of balloon angioplasty, that is, complete obstructions; multi-segment, multivessel disease; and restenosis. Consequently, several new techniques were developed and investigated, including hot tip thermal catheters, directional atherectomy catheters, high-speed rotational devices, and a number of laser systems. The applications of therapeutic medical and surgical ultrasound include the treatment of dental plaque, renal and ureteral calculi, calcific cardiac valves, neoplasms, and emulsification of lenses with cataracts [4–6]. These uses demonstrated that ultrasound was effective in disrupting hard or rigid tissues, and relatively atraumatic to adjacent normal tissues. Based on these reported uses of ultrasound, we began investigating the efficiency and safety of using catheter-delivered ultrasound energy to ablate atherosclerotic plaque [2,7–13]. This chapter reviews our in vitro and in vivo studies using high-intensity, low-frequency ultrasound for plaque ablation.