Catheter for laser angiosurgery

A method of removing a biological obstruction by radiant energy comprising:

• providing a catheter having waveguide means for guiding said radiant energy from a source thereof, said catheter having a distally located emission aperture for emission of said radiant energy in a beam propagating along the beam axis;
• forming said beam into a geometrically expanding pattern in which the energy distribution around said beam axis is substantially uniform whereby the energy density of said beam along said beam axis when applied to said obstruction decreases both exponentially and geometrically in a distally extending direction;
• the energy density in a working region of the beam within a first isothermal zone being sufficient to effect removal of the material forming the obstruction when said material is located in said region, the portion of the beam extending distally of said working region having insufficient energy density to effect said removal;
• said working region defining cross-sectional dimensions large enough to enable the catheter to be passed therethrough, the working region having an axially extending depth not substantially greater than about the cross-sectional dimension of the catheter;
• whereby when said beam of energy is applied to the biological material said radiant energy will be effective to remove said material to a depth no greater than about the axial depth of said working region, thereby limiting said removal to a layer approximating the axial depth of said working region, and minimizing perforation of tissue located distal or radial to the isothermal boundary of said working region.

A catheter for recanalizing an obstructed lumen by selectively removing sequential layers of biological obstructing material by radiant energy comprising:

• an elongate catheter body containing a flexible optical conductor;
• the proximal end of the catheter having means to enable said radiant energy to enter the flexible optical conductor;
• the distal end of the catheter having an emission aperture from which a beam of said radiant energy may be emitted, said emission aperture having a cross-sectional dimension which substantially corresponds to that of the distal end of the catheter;
• said catheter and emission aperture being constructed and arranged to shape the radiant energy beam emitted from the emission aperture to define an unfocused beam having a working region in which the density of energy is sufficient to cause said removal, and so that the portion of the beam extending distal to the working region has insufficient energy density to cause said removal;
• and
• the cross-sectional dimensions of the beam in the working region being no smaller than about the diameter of the distal end of the catheter thereby to enable the catheter to be passed through a recanalized hole formed by said working region, the axial depth of the working region being not substantially greater than the cross-sectional dimension of the distal end of the catheter.

A method of removing a biological obstruction by radiant energy comprising:

• providing a catheter having waveguide means for guiding said radiant energy from a source thereof, said catheter having a distally located emission aperture for emission of said radiant energy in a pattern propagating along an axis;
• forming said emitted radiant energy into a geometrically expanding pattern in which the energy distribution around said axis is substantially uniform whereby the energy density of said emitted energy along said axis when applied to said obstruction decreases both exponentially and geometrically in a distally extending direction;
• the energy density in a working region of the emitted energy within a first isothermal zone being sufficient to effect removal of the material forming the obstruction when said material is located in said region, the portion of the emitted energy extending distally of said working region having insufficient energy density to effect said removal;
• said working region defining cross-section dimensions large enough to enable the catheter to be passed therethrough, the working region having an axially extending depth not substantially greater than about the cross-sectional dimension of the catheter;
• whereby when said emitted energy is applied to the biological material said radiant energy will be effective to remove said material to a depth no greater than about the axial depth of said working region, thereby limiting said removal to a layer approximating the axial depth of said working region, and minimizing perforation of tissue located distal or radial to the isothermal boundary of said working region.

A catheter for recanalizing an obstructed lumen by selectively removing sequential layers of biological obstructing material by radiant energy comprising:

• an elongate catheter body containing a flexible optical conductor;
• the proximal end of the catheter having means to enable said radiant energy to enter the flexible optical conductor;
• the distal end of the catheter having an emission aperture from which said radiant energy may be emitted, said emission aperture having a cross-sectional dimension which substantially corresponds to that of the distal end of the catheter;
• said catheter and emission aperture being constructed and arranged to shape the radiant energy emitted from the emission aperture to define an unfocused pattern having a working region in which the density of energy is sufficient to cause said removal, and so that the portion of the emitted energy extending distal to the working region has insufficient energy density to cause said removal, and
• the cross-sectional dimensions of the emitted energy in the working region being no smaller than about the diameter of the distal end of the catheter thereby to enable the catheter to be passed through a recanalized hole formed by said working region, the axial depth of the working region being not substantially greater than the cross-sectional dimension of the distal end of the catheter.

A method of removing occluding material from within a lumen comprising:

• providing a catheter having a cross-sectional area and a light transmitting optical waveguide that is optically coupled at a distal end of the waveguide to an output surface of the catheter, the output surface having a cross-sectional area corresponding substantially to the cross-sectional area of the catheter;
• inserting the catheter into a lumen to locate the output surface in proximity to the occluding material;
• and
• directing controlled radiation through the waveguide to cause emission of the radiation from the output surface, the radiation emitted from the waveguide being divergent and sufficient to cause removal of the occluding material to form a hole therein of predetermined depth, the hole having a cross-sectional area corresponding substantially to the cross-sectional area of the catheter such that the catheter can be advanced into the hole.

A method of performing laser angiosurgery within an artery or vein of a patient comprising:

• providing a fiber optic probe having a cross-sectional area and a light transmitting optical fiber that is optically coupled at a distal end of the fiber to a light transmitting distal output surface, the output surface having a cross-sectional area corresponding substantially to the cross-sectional area of the probe;
• inserting the fiber optic probe into an artery to locate the distal surface in proximity to the occluding material within the artery;
• and
• directing laser radiation through the fiber to cause simultaneous emission of the radiation from substantially the entire distal surface, the radiation emitted from the fiber being divergent and sufficient to cause removal of the occluding material to form a hole therein of predetermined depth, the hole having a cross-sectional area corresponding substantially to the cross-sectional area of the fiber optic probe such that the probe can be advanced into the hole.

A method of performing laser angiosurgery within an artery or vein of a patient comprising:

• providing a fiber optical probe having a cross-sectional area and a light transmitting optical fiber that is optically coupled at a distal end of the fiber to a light transmitting distal output surface, the output surface having a cross-sectional area corresponding substantially to the cross-sectional area of the probe;
• inserting the fiber optic probe into an artery to locate the distal surface in contact with the occluding material within the artery;
• directing laser radiation through the fiber to cause emission of the radiation from substantially the entire distal surface, the radiation emitted from the fiber being divergent and sufficient to cause removal of the occluding material to form hole therein of predetermined depth, the hole having a cross-sectional area corresponding substantially to the cross-sectional area of the fiber optic probe;
• advancing the probe into the hole such that the probe is in contact with additional occluding material;
• directing additional laser radiation onto the additional occluding material to cause emission of the radiation from substantially the entire distal output surface, the radiation being divergent and sufficient to cause removal of the additional occluding material to form a deeper hole therein of predetermined depth, the hole having a cross-sectional area corresponding substantially to the cross-sectional area of the fiber optic probe;
• and
• repeating the advancing and directed radiation steps until the occluding material has been penetrated.