Patent Application
20240225734
Coronary and peripheral artery calcification (CPAC) complicates percutaneous coronary intervention (PCI) by reducing vessel compliance, interfering with device delivery, impairing balloon expansion, and potentially providing uneven drug distribution in the arterial wall. Further, CPAC causes damage to the drug-eluting polymer, thus resulting in more treatment failures. Decreased vessel compliance also reduces the ability of implanted stents to expand, causing stent failure through under expansion sometimes resulting in complications such as stent thrombosis and restenosis. Calcium localization (superficial or deep), distribution (focal, circumferential or longitudinal extension) and thickness also adversely impacts procedural time and success. CPAC has been an independent predictor of lower survival rate post PCI and is strongly correlated to major adverse cardiovascular events (MACE) after PCI.
Solutions which are currently used clinically to increase vessel compliance and deal with excessive calcium include high pressure balloon inflation, and calcium scoring with cutting balloons. However, these approaches are often unsuccessful because of inability to completely cut calcium, and only applicable to superficial calcium. Coronary atherectomy with both rotational atherectomy systems (e.g., Rotablator™) and orbital atherectomy are suited for removing luminal superficial calcium. However, these approaches do not address deeper calcium and therefore do not always increase vessel compliance sufficiently to assure full stent expansion. These techniques are also technically complex, time consuming and can introduce increased risk since they send cut debris into the micro-circulation which can result in myocardial infarction during the procedure from no-reflow. Thus, dealing with the calcium burden of atherosclerosis in a safe and efficacious manner is a major clinical challenge for interventional cardiologists.
Intravascular lithotripsy (IVL) techniques have been developed using electrical wires, electrodes, and electricity inside a balloon catheter. The electric current discharge creates a vapor bubble formation which during collapse (micro-cavitation) generating sonic pressure waves that travel through soft vascular tissue and can selectively fracture calcium in the vessel wall. The high difference in density and mechanical sonic wave impedance properties between calcium and soft tissue allows the sonic pressure to fracture calcium while leaving soft tissue intact. However, the use of electrical current discharge limits the amount of delivered energy available and the ability to control spatially and temporally the delivery of energy to vaporize the fluid and induce calcium fracture. The electrical current discharge approaches also result in large voltage spikes that can pace the left ventricle with each delivered electric pulse, which is not ideal. There have been multiple cases reported of ventricular fibrillation, and case reports of atrial fibrillation/flutter because the delivered shocks are not timed with the endogenous pacemaker of the heart. Also, the size of the electrodes and wires limit miniaturization of the device. As a result, electric IVL devices are often larger in diameter than the residual lumen of many calcified lesions. As a result, there are many instances where rotational or orbital atherectomy are used simply to deliver the electric IVL device across the calcified lesion. The current electrical current discharge IVL devices are 12 mm in length while most coronary arteries are 100 mm in length. Development of longer balloons for electric IVL would require the addition of more wires and electrodes, further increasing the diameter of the device. Accordingly, systems and methods are desired that overcome these and other limitations associated with existing electrical IVL systems and methods.
An urgent need is recognized for the ability to effectively fracture intravascular calcium for treatment of patient conditions, including atherosclerosis and other coronary diseases. Similarly, a need to decalcify heart valves, and the aorta is also recognized. A catheter apparatus is described herein for vascular insertion that employs diode laser sources that can be coupled into small diameter optical fibers to generate cavitation bubbles in a biocompatible fluid that upon collapse generates shock waves that can propagate into the walls of an artery. The optical fibers can be comprised of polymer and/or glass—unlike catheters that use near infrared light that are constructed of a glass material. An important element of our catheter apparatus is the diode laser/biocompatible fluid combination that allows the generation of large pressure-amplitude shock waves (50 atm or more). Indocyanine green is an FDA-approved biocompatible fluid that absorbs strongly at diode laser emission wavelengths (e.g., 700 nm-1000 nm). This particular diode laser/biocompatible fluid combination provides numerous practical advantages. First, the radiant brightness of diode laser sources in the 700 nm-1000 nm spectral range allows the delivery of large pulse energies into small diameter optical fibers (100-400 um) that can be positioned inside arteries with a small lumen diameter. Second, the large pulse energy propagating down the optical fiber does not generate any non-specific electrical/magnetic fields that can interfere with cardiac function. Third, diode lasers that emit light in the 700 nm-1000 nm spectral range can propagate through polymer optical fibers and allow more design flexibility for optical emission elements in the catheter. Fourth, diode laser sources that emit in the 700 nm-1000 nm spectral range can be directly electric-current pulsed to provide light emission allowing precise temporal control over the light emission time and pulse duration. Fifth, because ICG can absorb in the 700-1000 nm spectral range diode laser sources allow incorporation of numerous emission wavelengths that can be coupled into a small diameter optical fiber with multiple optical emission emitting elements. Moreover, the multiple optical emission elements can be each selected for a specific diode laser emitter(s) that can be controlled by electric-current pulsing the appropriate diode emission element(s). More specifically, we disclose specific diode laser emission wavelengths, pulse durations, and formulations of ICG (concentrations and compositions) that when combined together unexpectedly generate large amplitude shock waves that can fracture calcium in the walls of coronary arteries.
Although near infrared pulsed lasers have been applied for decades to generate shock waves in saline due to cavitation bubble generation and/or collapse, these lasers are typically expensive, bulky and can generate shock waves with limited pressure magnitude. Diode laser sources can provide a number of practical advantages in numerous medical therapeutic systems. Diode lasers provide photons at high economic value—the economic cost per radiant watt is less than competing sources and has been decreasing exponentially over the last few decades and is expected to continue decreasing in the future. Generation of shock waves for fracturing calcium in arteries using diode laser sources can provide a number of important advantages. First, the radiant brightness of diode laser sources allows the delivery of large pulse energies into small diameter (100 um-1000 um) optical fibers that can be positioned inside arteries with a small lumen diameter. Second, the large pulse energy propagating down the optical fiber does not generate any non-specific electrical/magnetic fields that can interfere with cardiac function. More specifically, the electric fields associated with large pulse energies are confined to the optical fiber and do not extend outside the catheter and thus do not interfere with surrounding tissues such as the heart. Third, diode lasers emit light that can propagate through polymer and/or glass optical fibers and allow more design flexibility for optical emission elements. Fourth, diode laser sources can be directly electric-current pulsed to provide light emission allowing precise temporal control over the light emission time and pulse duration. Precise temporal control over the light emission allows control over the generation/collapse of generated cavitation bubbles and the corresponding shock wave pressure magnitudes and direction of travel. Fifth, diode laser sources allow selection of numerous emission wavelengths that can be matched to the specific absorption profiles of candidate biocompatible fluids and directed to one of multiple optical emission emitting elements in the fiber catheter that can be selected by electric-current pulsing the appropriate diode emission element.
Previously an apparatus that uses a diode laser source to generate shock waves in a biocompatible fluid and propagate into a biological tissue had not been realized. The biocompatible fluid must be safe when injected into a human coronary artery. Preferably, the biocompatible fluid is already approved by a regulatory agency (e.g., US Food and Drug Agency) for injection into coronary arteries. In previous work, the primary biocompatible fluid contemplated for generating shock waves inside an artery is saline. In existing electrical-source embodiments for generating shock waves, saline is the biocompatible fluid contemplated. In existing light-source embodiments for generating shock waves in arteries, near infrared laser sources that emit in the 1.9-2.1 um spectral range and are strongly absorbed by water have been applied. The use of near infrared laser sources to generate shock waves has a number of limitations. For example, if multiple shock wave emitters are desired, a multiplexing approach is employed where light from one laser source is sequentially spatio-temporally multiplexed into multiple optical fibers. What is needed is a device that can employ economic diode laser sources that can be coupled into a small diameter optical fiber catheter and a biocompatible fluid that when a short pulse of light is injected into the biocompatible fluid a cavitation bubble is generated and collapses creating a shock wave.
Exemplary embodiments of the present disclosure include an apparatus comprising a diode laser light source and an optical fiber, where the optical fiber comprises: a polymer optical core; a cladding surrounding the polymer optical core; and a laser light emission element. In certain embodiments the laser light emission element is a first laser light emission element in a plurality of laser light emission elements. In particular embodiments each of the plurality of laser light emission element is configured to emit light at an equivalent wavelength range. In some embodiments each of the plurality of laser light emission elements is configured to emit light at equivalent power.
In specific embodiments a first laser light emission element of the plurality of laser light emission elements is configured to emit light at a first wavelength range, a second laser light emission element of the plurality of laser light emission elements is configured to emit light at a second wavelength range, and the first wavelength range is different than the second wavelength range. In certain embodiments an optical grating within the optical fiber comprises the plurality of laser light emission elements. In particular embodiments the plurality of laser light emission elements emit light radially from the optical fiber. In some embodiments the plurality of laser light emission elements is configured as a line of scattering centers along the polymer optical core of the optical fiber. In specific embodiments the plurality of laser light emission elements is configured as scattering centers located at positions offset from the polymer optical core and placed at equivalent angles near the cladding. In certain embodiments the plurality of laser light emission elements is configured as one or more photonic crystal lattices comprising a plurality of scatting centers in the polymer optical core.
In particular embodiments the plurality of laser light emission elements comprises N number of laser light emission elements, and wherein laser light emission elements are positioned radially around the optical fiber such that there are 360/N degrees between each laser light emission element in the plurality of laser light emission element. In some embodiments the plurality of laser light emission elements emit light radially 360 degrees around the optical fiber. In specific embodiments the diode laser light source is configured to emit laser light at a wavelength between approximately 690 nanometers (nm) and 900 nm. In certain embodiments the diode laser light source can provide a pulse of light between 50 nanoseconds and 150 microseconds. In particular embodiments radiant power propagating in the optical fiber is between 100 watts (W) and 100 kilowatts (kW). In some embodiments the polymer optical core comprises poly(methyl methacrylate) (PMMA), polydimethylsiloxane (PDMS), polyacrylamide (PAM) or a transparent amorphous fluoropolymer. In specific embodiments the polymer optical core comprises a transparent thermoplastic. In certain embodiments the transparent thermoplastic is poly(methyl methacrylate). In particular embodiments the polymer optical core comprises a silicon-based organic polymer. In some embodiments the silicon-based organic polymer is polydimethylsiloxane. In specific embodiments the polymer optical core comprises a transparent amorphous fluoropolymer. In certain embodiments the polymer optical core comprises a synthetic polymer.
Particular embodiments further comprise an expandable member. In some embodiments the expandable member comprises a lumen configured to receive the optical fiber. In specific embodiments the expandable member contains a fluid. In certain embodiments the fluid surrounds the optical fiber and wherein the fluid absorbs light emitted by the diode laser light source. In particular embodiments the fluid comprises indocyanine green (ICG). In some embodiments the fluid comprises a solvent, and in specific embodiments the concentration of the ICG to the solvent is between 5 milligrams/milliliter (mg/ml) and 25 mg/ml. In certain embodiments the solvent comprises water, saline or dextrose.
Particular embodiments further comprise a control system configured to control an operational parameter of the diode laser light source. In some embodiments the operational parameter is a pulse duration, a wavelength frequency, multiple varying wavelength frequencies, or a wavelength amplitude of the diode laser light source. In specific embodiments the control system is configured to provide a first laser light emission and a second laser light emission from the diode laser light source. In certain embodiments the first laser light emission is configured to generate a bubble in the fluid in the expandable member. In particular embodiments the control system is configured to provide the second laser light emission from the diode laser light source when the bubble in the fluid in the expandable member collapses.
In specific embodiments the optical fiber comprises an imaging element, and in certain embodiments the imaging element is configured to provide intravascular ultrasound (IVUS) or optical coherence tomography (OCT) imaging data. In certain embodiments the diode laser light source is a first diode laser light source in a plurality of diode laser light sources, and the optical fiber is a first optical fiber in a plurality of optical fibers. In particular embodiments each diode laser light source in the plurality of diode laser light sources is coupled to a separate optical fiber in the plurality of optical fibers. In some embodiments an optical fiber in the plurality of optical fibers comprises a conical distal end.
In specific embodiments the plurality of optical fibers are coupled via a tapered fiber coupler. In certain embodiments the plurality of optical fibers are coupled via a side-coupling region. In particular embodiments the plurality of optical fibers are coupled via sleeve coupling elements and at least one of the plurality of optical fibers comprises an angled polished end coated with a dielectric reflector.
Exemplary embodiments include an apparatus comprising: a diode laser light source and an optical fiber, where the optical fiber comprises: an optical core; a cladding surrounding the polymer optical core; and a plurality of laser light emission elements, where the laser light emission elements are configured as emission centers in the optical core. In particular embodiments the plurality of laser light emission elements is configured as a line of scattering centers along the optical core of the optical fiber. In some embodiments the plurality of laser light emission elements is configured as scattering centers located at positions offset from the optical core and placed at equivalent angles near the cladding. In specific embodiments the plurality of laser light emission elements is configured as one or more photonic crystal lattices comprising a plurality of scatting centers in the optical core. In certain embodiments the optical core is a polymer optical core, and in particular embodiments the optical core is a glass optical core.
In specific embodiments the diode laser light source is a first diode laser light source in a plurality of diode laser light sources, and the optical fiber is a first optical fiber in a plurality of optical fibers. In particular embodiments each diode laser light source in the plurality of diode laser light sources is coupled to a separate optical fiber in the plurality of optical fibers. In some embodiments an optical fiber in the plurality of optical fibers comprises a conical distal end.
In specific embodiments the plurality of optical fibers are coupled via a tapered fiber coupler. In certain embodiments the plurality of optical fibers are coupled via a side-coupling region. In particular embodiments the plurality of optical fibers are coupled via sleeve coupling elements and at least one of the plurality of optical fibers comprises an angled polished end coated with a dielectric reflector.
Exemplary embodiments include a method of fracturing calcium in an artery, where the method comprises: inserting an optical fiber into an artery, where the optical fiber is coupled to a diode laser light source, and the optical fiber comprises a polymer optical core, a cladding surrounding the polymer optical core, and a laser light emission element; inserting an expandable member into the artery; expanding the expandable member via a fluid in the expandable member; emitting electromagnetic energy from the laser light emission element, where the electromagnetic energy generates a pressure wave in the fluid contained within the expandable member; and fracturing the calcium in the artery via the pressure wave in the fluid.
In certain embodiments the laser light emission element is a first laser light emission element in a plurality of laser light emission elements. In particular embodiments each of the plurality of laser light emission elements is configured to emit light at an equivalent wavelength range. In some embodiments each of the plurality of laser light emission elements is configured to emit light at equivalent power. In certain embodiments a first laser light emission element of the plurality of laser light emission elements is configured to emit light at a first wavelength range; a second laser light emission element of the plurality of laser light emission elements is configured to emit light at a second wavelength range; and the first wavelength range is different than the second wavelength range. In particular embodiments a grating structure within the optical fiber comprises an element of each laser light emission element. In some embodiments the plurality of laser light emission elements emits light radially from the optical fiber. In specific embodiments the plurality of laser light emission elements comprises N number of laser light emission elements, and wherein laser light emission elements are positioned radially around the optical fiber such that there are 360/N degrees between each laser light emission element in the plurality of laser light emission element.
In certain embodiments the plurality of laser light emission elements emits light radially 360 degrees around the optical fiber. In particular embodiments the diode laser light source is configured to emit laser light at a wavelength between approximately 690 nanometers (nm) and 900 nm. In some embodiments the diode laser light source can provide a pulse of light between 50 nanoseconds and 150 microseconds. In specific embodiments radiant power propagating in the optical fiber is between 100 watts (W) and 100 kilowatts (kW). In particular embodiments the polymer optical core comprises a synthetic polymer. In some embodiments the polymer optical core comprises poly(methyl methacrylate) (PMMA), polydimethylsiloxane (PDMS), polyacrylamide (PAM) or a transparent amorphous fluoropolymer. In specific embodiments the polymer optical core comprises a transparent thermoplastic. In certain embodiments the transparent thermoplastic is poly(methyl methacrylate). In particular embodiments, the optical fiber has a high numerical aperture (NA) so that for a required etendue (or optical throughput) the diameter of the fiber is less. The use of high NA fibers allows the device diameter to be reduced and provides advantages for navigating highly stenotic arteries.
In particular embodiments the polymer optical core comprises a silicon-based organic polymer, and in some embodiments the silicon-based organic polymer is polydimethylsiloxane. In specific embodiments the polymer optical core comprises a transparent amorphous fluoropolymer. In certain embodiments of the method, the fluid comprises indocyanine green (ICG). In particular embodiments the fluid comprises a solvent, and in some embodiments the concentration of the ICG to the solvent is between 5 milligrams/milliliter (mg/ml) and 25 mg/ml. In specific embodiments the solvent comprises water, saline or dextrose.
In certain embodiments the expandable member comprises a lumen, and the optical fiber extends through the lumen of the expandable member. In particular embodiments of the method the optical fiber comprises an imaging element. In some embodiments the imaging element is configured to provide intravascular ultrasound (IVUS) or optical coherence tomography (OCT) imaging. In specific embodiments the imaging element provides imaging data while: inserting the optical fiber into the artery; inserting the expandable member into the artery; expanding the expandable member via a fluid in the expandable member; emitting electromagnetic energy from the laser light emission element; or fracturing the calcium in the artery via the pressure wave in the fluid. In certain embodiments the imaging element provides imaging data after fracturing the calcium in the artery via the pressure wave in the fluid.
In the following disclosure, the term “coupled” is defined as connected, although not necessarily directly, and not necessarily mechanically.
The use of the word “a” or “an” when used in conjunction with the term “comprising” in the claims and/or the specification may mean “one,” but it is also consistent with the meaning of “one or more” or “at least one.” The terms “about” and “approximately” mean, in general, the stated value plus or minus 5%. The use of the term “or” in the claims is used to mean “and/or” unless explicitly indicated to refer to alternatives only or the alternative are mutually exclusive, although the disclosure supports a definition that refers to only alternatives and “and/or.”
The terms “comprise” (and any form of comprise, such as “comprises” and “comprising”), “have” (and any form of have, such as “has” and “having”), “include” (and any form of include, such as “includes” and “including”) and “contain” (and any form of contain, such as “contains” and “containing”) are open-ended linking verbs. As a result, a method or device that “comprises,” “has,” “includes” or “contains” one or more steps or elements, possesses those one or more steps or elements, but is not limited to possessing only those one or more elements. Likewise, a step of a method or an element of a device that “comprises,” “has,” “includes” or “contains” one or more features, possesses those one or more features, but is not limited to possessing only those one or more features. Furthermore, a device or structure that is configured in a certain way is configured in at least that way, but may also be configured in ways that are not listed.
Other objects, features and advantages of the present invention will become apparent from the following detailed description. It should be understood, however, that the detailed description and the specific examples, while indicating specific embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will be apparent to those skilled in the art from this detailed description.
The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.
The following drawings form part of the present specification and are included to further demonstrate certain aspects of the present disclosure. The invention may be better understood by reference to one of these drawings in combination with the detailed description of specific embodiments presented herein.
Exemplary embodiments of the present disclosure include apparatus and methods for fracturing arterial calcium, including for example calcium in a coronary artery. Referring initially to
In
In
In the embodiment shown in
In the embodiment shown in
As shown in
In particular embodiments elements of apparatus 100 are specifically selected to increase the ability to create fractures 280 in calcium 270 with reduced power requirements from diode laser light source 110 and reduced manufacturing costs for apparatus 100. For example, the laser light source 110 and fluid 320 can each be selected to maximize the amount of energy provided by ultrasonic waves 340 while minimizing the power requirements from diode laser light source 110. In particular embodiments, the operational parameters of laser light source 110 (e.g. the wavelength, pulse duration, etc. of electromagnetic energy 170) and the concentration of ICG in fluid 320 can be selected to optimize the efficiency of apparatus 100 (e.g. the ability to create fractures 280 in calcium 270 for a given power requirement of laser light source 110).
Furthermore, in particular embodiments optical fiber 120 may be formed from fibers with significantly lower costs than glass fibers. In specific embodiments, optical fiber 120 may be formed from fiber material that costs approximately $0.10 per meter, significantly reducing the manufacturing costs for apparatus 100.
A close-up view of one embodiment of distal end 129 is shown in the partial section schematic view of
Exemplary embodiments of the present disclosure may comprise emission elements 150 of one or more configurations.
In the embodiment shown in
In exemplary embodiments of the present disclosure, directing light from the optical fiber into the surrounding biocompatible absorbing fluid is accomplished using one or more emission elements configured as optical emitter(s) embedded into the optical fiber. Exemplary embodiments of optical emitter elements comprise a patterned refractive index gradient within the fiber-core guiding structure of the optical fiber. In particular embodiments, the function of the optical emitter elements is to couple to and direct light out of the fiber-core guiding structure and into the surrounding biocompatible absorbing fluid. The patterned refractive index gradient embedded within the fiber-core guiding structure can be of multiple forms and may comprise one or more of: (1) reflective surface; (2) refractive surface; (3) scattering center; (4) dielectric grating; (5) waveguide within the core; and/or (6) photonic crystal lattice.
In particular embodiments, the refractive index of selected regions in the core of an optical fiber can be modified (increased or decreased) by directing focused radiation into the core of the optical fiber to create a scattering center. The scattering center can have higher or lower refractive index compared to the surrounding core in specific embodiments. Referring now to
In the embodiment shown in
In particular embodiments, a photonic crystal lattice can be written into the core region of the optical fiber. Referring now to
In addition, the absorbing biocompatible fluid in the expandable member can be configured to efficiently fracture calcium with respect to the electromagnetic energy provided. As molar concentration of ICG increases in solution, the absorption coefficient also increases. However, this increase is not linear. Hence, if 1× concentration is 1 cm−1, 100× is not necessarily 100 cm−1. This is because of an “aggregation” effect of cyanine dyes. Cyanine dyes, including ICG, tend to aggregate at high concentration in aqueous solutions, which can reduce the absorption coefficient.
A lower aggregation implies lower power needed to generate the same pressure. While dimethyl sulfoxide (DMSO) can be used to avoid aggregation in ex vivo applications, it is not biocompatible. Accordingly exemplary embodiments of the present disclosure can comprise other techniques, including for example, dissolving the dye in liposome-type nano droplets. In addition, exemplary embodiments of the present disclosure can utilize dextrose, plasma, albumin and/or water in the solution to increase the absorption coefficient.
Data from one particular embodiment is shown in
As previously noted, the contents of fluid 320 can be optimized efficiently fracture calcium with respect to the electromagnetic energy provided. In
Another factor for consideration when determining a desired ICG formulation is the extent to which ICG precipitates out of solution.
Exemplary embodiments of the present disclosure may also be configured to provide sequential electromagnetic energy (e.g. laser light) emissions specifically time to maximize the ability of a pressure wave created in a fluid to fracture calcium in an artery. For example, certain embodiments can be configured to generate a first electromagnetic energy emission that generates a vapor bubble in a fluid (e.g. ICG), where the vapor bubble initially expands and then collapses. Particular embodiments can be configured to also generate a second electromagnetic energy emission that is emitted at approximately the same time as the bubble generated from the first electromagnetic energy emission collapses. By timing the emission of the second electromagnetic energy pulse to occur when the vapor bubble from the first electromagnetic energy emission is collapsing, a larger pressure pulse can be created and the ability to fracture calcium in an artery or other environment can be enhanced.
Referring now to
The data for the single pulse was collected initially to determine the delay between the laser pulse and the vapor bubble collapse. The single pulse data was collected five times to determine an average delay between the laser pulse and the vapor bubble collapse and the amplitude of the shockwave pressure. The dual pulse data was collected by firing a second laser pulse at the average time delay observed in the single pulse between the laser pulse and the vapor bubble collapse. The data recorded for the 10 μs laser pulse is shown in
Particular embodiments of the present disclosure may also comprise a plurality of optical fibers, where each optical fiber is coupled to a separate diode laser. Such embodiments can provide increased flexibility with the operational parameters of the laser light emissions from the diode lasers. For example, the use of multiple separate optical fibers each coupled to an individual diode laser can allow a user to have increased spatio-temporal control by emitting light from the separate diode laser/optical fiber units in a manner that may not be possible with a single laser (or multiple lasers) coupled to a single optical fiber.
Several considerations are made in the configuration of a diode laser IVL catheter incorporating multiple optical fibers. A diode laser emitter provides a specified radiance (W/(sr area)) or Watts per unit Etendue. A laser IVL catheter specification requires a number of emitters, and each emitter in a laser IVL catheter needs to provide some minimum radiant power density (Watts/Area) to generate a shockwave. For example, for 5 mg/ml ICG a typical minimum radiant power density of approximately 2 kW/mm2 is needed for shockwave generation. One challenge with laser IVL catheter design centers on the distribution of source radiance (W/Etendue) provided by diode laser emitters into catheter emitters. The optical etendue (capacity to carry light) of a fiber is proportional to the product of the core-area and solid angle (NA2).
IVL catheter design considerations include compatibility with existing guidewire (e.g. 0.014″ wire/350 μm) and minimizing the overall catheter diameter. For a laser IVL catheter, the diameter of each optical fiber contributes to the overall diameter of the laser IVL catheter. Accordingly, the use of small core diameter/high numerical aperture (NA) optical fibers provides a number of important advantages. For example, the small core diameter allows satisfying the overall design diameter constraint of the laser IVL catheter. In addition, fibers with a small core diameter provide increased radiant exitance (W/Area) at the fiber tip. Furthermore, fibers with high NA's increase the etendue of the fiber, and for a given diode laser emitter allow more efficient coupling of diode laser radiant emission into the fiber and allow coupling of more wattage into each fiber.
The use of a separate optical fiber for each diode laser can also reduce or eliminate the need for passive splitters/combiners (e.g. used to split or combine light paths from one or more laser sources). A block diagram of a system utilizing multiple diode lasers combined into a single fiber and then split into different fibers for each emitter is shown in
Referring now to
As shown in
Referring now to
In certain embodiments, optical fibers 501-507 can be configured to direct laser light emissions through aperture in outer coil 511 as described in previous embodiments (e.g. through an aperture via a GRIN lens or the configuration of the optical fiber as shown in
Certain embodiments of the present disclosure may comprise a tapered fiber coupler configured for use in an IVL catheter. Referring now to
Particular embodiments of the present disclosure may also comprise one or more side-coupled fibers in which an evanescent field in a primary fiber couples into one or more emitter fibers. Referring now to
Specific embodiments of the present disclosure may also comprise optical fibers with inline reflectors comprising dielectric films. Referring now to
All of the apparatus, systems and/or methods disclosed and claimed herein can be made and executed without undue experimentation in light of the present disclosure. While the apparatus, systems and methods of this invention have been described in terms of particular embodiments, it will be apparent to those of skill in the art that variations may be applied to the devices, systems and/or methods in the steps or in the sequence of steps of the method described herein without departing from the concept, spirit and scope of the invention. All such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the spirit, scope and concept of the invention as defined by the appended claims.
The contents of the following references are incorporated by reference herein:
This application claims benefit of priority to U.S. Provisional Patent Application No. 63/479,123 filed Jan. 9, 2023, the entire contents of which is hereby incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 63479123 | Jan 2023 | US |
