Laser heated cautery cap with transparent substrate

Abstract

A laser heated cautery cap assembly includes a catheter assembly adapted to be introduced into a lumen, such as an arterial opening. The catheter assembly includes at least one optical fiber connected to a laser light source adapted to produce short output bursts. A cautery cap at the catheter distal end includes a transparent substrate member disposed to receive the laser energy from the optical fiber(s). The substrate member preferably is formed of a crystalline solid having a smooth, curved outer surface, with a central guidewire bore extending therethrough. One end of the bore is provided with a tapering counterbore, and the opposite end of the substrate member is an input surface disposed to receive laser energy from the optical fiber. A nose piece includes a central guidewire bore coaxial with the substrate member bore, the nose piece including a tapered proximal end dimensioned to fit within the counterbore of the substrate. The substrate counterbore and bore surfaces, and major portions of the curved outer surface are coated with a highly reflective material, and another portion of the outer surface is coated with a material which absorbs the laser energy and is heated thereby. The input surface of the substrate receives laser illumination from the optical fiber(s) and conducts it to the counterbore surface, which reflects the light internally to the absorptive coating portion. Thus a portion of the cap structure is heated, while the nose piece and the remainder of the substrate surface remains relatively cool.