Restenosis Following Laser Angioplasty

Approximately ten years ago, our laboratory initiated work evaluating the use of the laser as a tool for altering vascular tissue biology to reduce the restenosis rate [1]. The attention of laser technology, however, was directed at a device to obtain immediate lumen enlargement by removing plaque [2–5]. Early limitations of laser applications in the cardiovascular system were primarily related to arterial perforation due to optical fiber stiffness and uncontrolled energy delivery [6–9]. As with balloon angioplasty, the use of a guidewire was adapted effectively to maintain coaxiality of the optical fibers within the vessel (Fig. 1) [10]. Thus, most devices currently available are capable of removing plaque and creating a lumen equivalent to the diameter of the catheter device. In addition, numerous studies have been done to evaluate the effects of various laser wavelengths and delivery modes on arterial tissue. The primary focus was on the use of continuous wave vs. pulsed laser systems. The optimum combination of laser wave-lengths and modes for laser angioplasty has been hotly debated. This resulted in the sense that thermal devices were passe and pulsed lasers were the only way to do laser angioplasty. In fact, most studies have demonstrated that there are more similarities than differences among the various laser systems with regard to tissue responses [1, 11, 12]. This chapter will focus primarily on the immediate and chronic tissue effects in the arterial system following laser angioplasty.