Abstract: A fiber-optic waveguide, used for ablating lesions in blood vessels, is mounted within and guided by a catheter having multiple lumens extending therethrough and parallel to each other. The waveguide fits within at least one lumen and a guidewire, previously inserted in a blood vessel, extends through another lumen. The distal end of the waveguide can have a short section of larger diameter fiber fused to it to cause a laser beam transmitted through the fiber to expand as it emerges from the waveguide to provide a larger ablation area. The waveguide may also be connected to an energy source by means of an energy coupler.

Abstract: A deflectable guidewire for a catheter includes a core extending from the proximal end of the guidewire toward the distal end thereof; a hollow sheath for encasing the core; the hollow core including a deflecting region at the distal end of the guidewire, the deflecting region having a first side and a second side, the first side being on an opposite side of a plane extending axially through the hollow means than the second side; the first side of the deflecting region being able to be compressed a greater distance than the second side of the deflecting region; the core being fixed to the hollow sheath at the distal side of the deflecting region; and a control handle mounted at the proximal end of the core and the hollow sheath for applying tension to the core with respect to the hollow sheath so that the tension causes the first side of the deflecting region to compress a greater amount than the second side, thus deflecting the deflecting region.

Abstract: A catheter having an axis extending between a proximal end and an opposing distal end includes a plurality of optical fibers arranged to spiral in a first direction to form a circumferential layer around the axis. Rotation of the catheter in the first direction tends to expand the layer while rotation of the catheter in a second opposite direction tends to contract the circumferential layer. An outer jacket limits the expansion of the circumferential layer while an inner core limits the contraction of the circumferential layer to increase torquability of the catheter. The stranded fibers equalize bending stresses to maintain a circular cross-sectional configuration, increase flexibility and a reduced diameter for the catheter.

Abstract: A laser head comprising a tube having a wall with the configuration of a hollow cylinder. A first ring flange extends radially generally outwardly of the tube wall at one end and is connected to the tube by a single continuous weld. A second plate flange is disposed at the same end and extends generally axially of the first flange. The first flange is coupled to the second flange and sandwiches a metal gasket therebetween to form a pressure seal. An electrode assembly is mounted to the second plate flange and at least one high voltage discharge feed extends through the wall of the tube to energize the electrode assembly. The tube is formed of a homogeneous metal that is free of any surface plating and is less reactive with Halogen gas than pure aluminum. In an associated method, the interior surface of the tube is polished to reduce the surface area and inhibit the entrapment of water vapor.

Abstract: Apparatus for optically controlling the output energy of a pulsed laser source comprising a laser producing a plurality of laser pulses in a laser beam. An optical attenuator is disposed in the laser beam to attenuate the energy in the laser beam to provide an attenuated laser beam, and a pick-off is provided for sensing the energy in the attenuated laser beam. A controller is coupled to the pick-off for controlling the optical attenuator to vary the energy in the attenuated laser beam to thereby vary the output fluence from the apparatus.

Abstract: A fiber-optic waveguide, used for ablating lesions in blood vessels, is mounted within and guided by a catheter having multiple lumens extending therethrough and parallel to each other. The waveguide fits within at least one lumen and a guidewire, previously inserted in a blood vessel, extends through another lumen. The distal end of the waveguide can have a short section of larger diameter fiber fused to it to cause a laser beam transmitted through said fiber to expand as it emerges from the waveguide to provide a larger ablation area. The waveguide may also be connected to an energy source by means of an energy coupler. One or more balloons may be mounted to the distal end of the catheter in order to facilitate positioning the waveguide.

Abstract: A fiber-optic instrument, used for ablating lesions in blood vessels, is mounted to and guided by a sleeve having two lumens extending therethrough and parallel to each other. The instrument fits within one lumen and a guidewire, previously inserted in a blood vessel, extends through the other lumen. The sleeve and instrument are advanced along the guidewire within the blood vessel. An inflatable balloon may be provided at the distal end of a fiber optic instrument for retaining saline in order to displace opaque blood that would otherwise surround the distal end of the instrument.

Abstract: An interventional therapeutic apparatus is described which includes a probe in the form of a transmission line such as coaxial cable. The probe is adapted to pass through the interior of a body cavity such as a blood vessel and includes an inductive load such as a ferrite bead at the remote end of the cable. Radio frequency energy is applied to the cable and converted into heat by a ferrite bead. As a result of the heat conversion by the ferrite bead, the remote end of the coaxial cable is heated to a sufficient temperature to provide the effect desired, for example to melt or otherwise remove plaque deposits in blood vessels.

Abstract: The transmittance of high peak energy ultraviolet laser light that is conducted within a silica fiber-optic waveguide is increased by doping the silica with a material that functions to repair inherent structural defects in the silica. Preferred materials include one or both of an OH.sup.- radical and fluorine. The silica is synthetic silica that is substantially free of metallic impurities. The cladding for the waveguide is made of an organic material rather than glass.

Abstract: The density of the energy that is conducted within a fiber-optic waveguide is increased by means of an energy coupler at the input end of the optical fiber. This energy coupler comprises a fused or ground lens at the input end of a silica-based fiber. A second lens, preferably a plano-convex lens, focusses a large collimated laser beam to a point source. The lens at the end of the fiber is located at a distance greater than the focal length of the second lens, so as to receive light from the point source and couple it into the fiber.