Abstract: An uncured or partially cured, collagen-based material is delivered to a selected site in a blood vessel and is crosslinked in the blood vessel by laser energy or other suitable energy to form an endovascular stent. The collagen-based material can be delivered to the blood vessel as a coating on an inflatable balloon mounted on the distal end of a catheter. The collagen-based material can also be delivered to the blood vessel in liquid form and forced through a porous balloon to form a tubular configuration. The collagen-based material is preferably crosslinked by laser radiation carried through an optical fiber to a diffusing tip located within the balloon. In another embodiment, an endovascular stent is formed by rolling a flexible sheet of biologically-compatible material onto an outside surface of an inflatable balloon.

Abstract: Apparatus and methods for laser fusion of biological structures are disclosed employing a laser for delivery of a beam of laser radiation to an anastomotic site, together with a reflectance sensor for measuring light reflected from the site and a controller for monitoring changes in the reflectance of the light of the site and controlling the laser in response to the reflectance changes. In one embodiment, the laser radiation is delivered through a hand-held instrument via an optical fiber. The instrument can also include one or more additional fibers for the delivery of illumination light (which can be broadband or white light or radiation from a laser diode) which is reflected and monitored by the reflectance sensor. Reflectance changes during the course of the fusion operation at one or more wavelengths can be monitored (or compared) to provide an indication of the degree of tissue crosslinking and determine when an optimal state of fusion has occurred.

Abstract: A diffusion tip coupled to the end of an optical fiber for directing laser energy outwardly in a cylindrical or other desired radiation pattern. The diffusion tip includes a core, a cladding around the core and a jacket around the cladding. The cladding has an index of refraction that is lower than that of the core and has a thickness selected to transmit a portion of the laser radiation that is carried through the optical fiber so that laser radiation penetrates through the cladding and the jacket over the length of the diffusion tip. The thickness of the cladding is about the same as or slightly less than the penetration depth of the evanescent field in the cladding. The cladding can be tapered along the length of the diffusion tip to provide a uniform radiation pattern. The diffusion tip is particularly useful in a laser balloon catheter utilized in coronary angioplasty.

Abstract: A hot tip device, typically used for melting and plowing through stenotic deposits in a coronary artery, is provided with optical diagnostic capabilities. The device includes an elongated, flexible member, a filter glass heating element attached to the distal end of the flexible member and an optical fiber extending through the flexible member and optically coupled to the heating element. The filter glass heating element absorbs a first range of wavelengths for heating and passes a second range of wavelengths for irradiating the artery through the filter glass heating element. In a preferred embodiment, the flexible member is a steerable guidewire, and the filter glass heating element is heated by infrared radiation. Ultraviolet or visible radiation is used to stimulate fluorescence from deposits in the artery.

Abstract: Laser energy produced by a laser operating in the mid-infrared region (approximately 2 micrometers) is delivered by an optical fiber in a catheter to a surgical site for biological tissue removal and repair. Disclosed laser sources which have an output wavelength in this region include: Holmium-doped Yttrium Aluminum Garnet (Ho:YAG), Holmium-doped Yttrium Lithium Fluoride (Ho:YLF), Erbium-doped YAG, Erbium-doped YLF and Thulium-doped YAG. For tissue removal, the lasers are operated with relatively long pulses at energy levels of approximately 1 joule per pulse. For tissue repair, the lasers are operated in a continuous wave mode at low power. Laser output energy is applied to a silica-based optical fiber which has been specially purified to reduce the hydroxyl-ion concentration to a low level. The catheter may be comprised of a single optical fiber or a plurality of optical fibers arranged to give overlapping output patterns for large area coverage.

Abstract: A method for closing and sealing a puncture at a puncture site in an artery located beneath the skin after a catheter is removed from the puncture. The method includes the steps of applying pressure directly to the artery at the puncture site, and applying laser energy directly to the artery at the puncture site while pressure is applied. The laser energy is sufficient to thermally weld the artery at the puncture site. Preferably, the step of applying pressure directly to the artery includes the steps of advancing a tube having an inflatable balloon at its distal end through the overlying tissue to the punction site, and inflating the balloon. Laser energy is carried thorugh an optical fiber to the balloon and is directed through the wall of the balloon to the puncture site.

Abstract: Laser energy produced by a laser operating in the mid-infrared region (approximately 2 micrometers) is delivered by an optical fiber in a catheter to a surgical site for biological tissue removal and repair. Disclosed laser sources which have an output wavelength in this region include: Holmium-doped Yttrium Aluminum Garnet (Ho:YAG), Holmium-doped Yttrium Lithium Fluoride (Ho:YLF), Holmium-doped Yttrium-Scandium-Gadolinium=Garnet (HO:YSGG), Erbium-doped YAG, Erbium-doped YLF and Thulium-doped YAG. Laser output energy is applied to a silica-based optical fiber which has been specially purified to reduce the hydroxyl-ion concentration to a low level. The catheter may be comprised of a single optical fiber or a plurality of optical fibers arranged to give overlapping output patterns for large area coverage. In a preferred application for the removal of atheroscleotic plaque, a Holmium-doped laser operating in the wavelength range of from about 1.9 to about 2.1 micrometers is preferred.

Abstract: A laser balloon catheter intended primarily for coronary angioplasty includes a flexible tube having an inflatable balloon secured to its distal end, a central shaft within the balloon for carrying a guide wire, an optical fiber for carrying laser radiation through the flexible tube into the balloon, and a tip assembly in the balloon for directing laser radiation outwardly through a major portion of the balloon surface while limiting shadowing by the central shaft. The tip assembly preferably includes a tip portion of the optical fiber contained within a transparent, heat-formable tube and formed into a spiral shape around the central shaft by the heat-formable tube. The optical fiber tip portion is tapered so that it directs laser radiation outwardly over its length. Deuterium oxide is preferably used for inflation of the balloon because of its very low attenuation of laser radiation in the wavelength range of interest.

Abstract: A laser catheter for insertion in a body passage and for treatment of a relatively inaccessible location with laser radiation in a preselected first wavelength range, typically in the mid-infrared band, that is outside the transmission passband of silica optical fibers. The laser catheter includes an elongated flexible tube, an optical fiber for carrying optical pumping laser radiation in a second wavelength range through the flexible tube, and a laser attached to the flexible tube at or near the distal end thereof and responsive to optical pumping laser radiation in the second wavelength range for generating output laser radiation in the first wavelength range. The laser can comprise a cylindrical laser crystal attached to the distal end of the flexible tube and having laser mirrors on opposite end faces thereof. The laser crystal can be a suitable host material doped with a rare earth ion selected to produce the desired output wavelength.

Abstract: A catheter having optical fibers for delivering laser energy to a blood vessel to remove obstructions in the blood vessel is adapted to be guided controllably and selectively by a guide wire to the site to be treated. The catheter includes a central lumen which is open at the distal end of the catheter and which receives the guide wire so that the catheter may be advanced over the guide wire. A relatively few number of optical fibers are contained within and extend longitudinally of the catheter wall. The distal tip of the catheter is provided with a cylindrical optically transparent end cap and means are provided to securely mount the distal ends of the optical fibers with respect to the end cap so that the light emitted from the ends of the fibers passes through the cylindrical wall of the end cap and is emitted at the distal emissions face of the end cap.

Abstract: A catheter for delivering radiant energy, such as a laser beam, is used in a technique to controllably apply the radiant energy in a patient's body, such as in a blood vessel. The radiant energy is applied in a manner which erodes biological material and may be used to drill through vascular obstructions. The catheter emits the radiant energy from its distal end in a pattern which defines a relatively small working region in which the energy density level is sufficiently high to remove the biological material. The energy distribution is substantially uniform across the beam. Distally beyond the working region, the energy density of the beam decays sharply so that biological material beyond the working region is not removed.