Electromagnetic field focusing probe (EFFP)--a new angioplasty tool.

An electromagnetic field focusing probe (EFFP) consists of a radiofrequency generator, solenoidal coil, and a hand-held or catheter probe. The probe is operated in the near field (distance within one wave length of an electromagnetic field source) of a coil, which induces eddy current in a biological tissue. The induced eddy current is converged maximally at the tip of the probe upon contact of the tip with the tissue. The probe produces very high temperatures depending on the wattage selected. In this study, the EFFP was used to evaporate atheromatous plaques in human cadaver abdominal aorta specimens, which were then studied histologically. Gas produced by this technique was analyzed and the volume found to be related to power delivered, but in such small amounts as to be of no embolic significance. While temperature varied with wattage and time of application, it was maximal at the probe tip and easily controlled, resulting in clean obliteration of plaque.