[Attempt at in vitro decalcification of aortic valves using various types of lasers]

The effects of three types of laser were studied in vitro on calcified aortic valves removed in the course of valve replacement. These were: 1) argon laser; 2) Nd-YAG laser with a long (1 ms) impulse, and 3) Nd-YAG laser with a short (10 ns) impulse. With the first two types of laser, lesions of carbonization and fragments detached from the areas treated were observed. With the 10 ns ND-YAG laser, a mean energy of 100 mj per shot excavated the calcified valves by drilling holes that were 0.5 to 1.5 mm in diameter and had clear-cut non carbonized borders. No residue was found during the procedure: the substance was simply vaporized. The splitting of several calcareous nodules on a valve made it more pliable. If it were possible to transfer this high peak energy onto a flexible optic fibre, the aortic valves could be decalcified by interventional catheterization.