A comparative study of pulsed Nd:YAG and CO2 laser effect on aortic valves

Laser angioplasty is a promising new technology, which sometimes offers the surgeon an alternative tool to conventional therapy. One of the main prerequisites of using powerful pulsed lasers in angioplasty is the optimum choice of the irradiation parameters (the wavelength, the pulse shape and duration, the energy parameters). Infrared lasers have numerous applications in surgery. Among them the pulsed CO2 laser emitting at 10.6 microns and the pulsed Nd:YAG laser emitting at 1.064 microns are the most widely used, since the delivery of laser energy in short pulses of high peak pulse power limits distant thermal effects. The CO2 laser wavelength is greatly absorbed by tissue water, while the Nd:YAG laser wavelength is poorly absorbed by water or other tissue chromophores, affecting deeper the tissue. The CO2 laser incises effectively the tissue, but presents inadequate coagulation, while the Nd:YAG laser seems to present better coagulation properties. In this work, a comparative study of pulsed Nd:YAG and CO2 lasers in ablating cardiovascular tissue, is presented. The irradiation regime of the two lasers is determined, for the specific tissue and/or pathology. Also the depth of thermally induced coagulation is measured. The results are presented according to the efficacy of each laser for incision and/or coagulation.