High-bandwidth energy source for improved transmission through optical fibers for intravascular lithotripsy.

Abstract

The catheter system 100 includes a light guide 122A and a light source 124. The light guide 122A is configured to selectively receive light energy. The light source 124 generates light energy. The light source 124 is in optical communication with the light guide 122A. The light source can include (i) a seed source 260 that outputs light energy, (ii) a preamplifier 262 that receives light energy from the seed source 260, the preamplifier 262 being in optical communication with the seed source 260, and (iii) an amplifier 264 that receives light energy from the preamplifier 262, the amplifier 264 being in optical communication with the preamplifier 262 and the light guide 122A.

Description

[Technical field]

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 273,065, entitled "HIGH BANDWIDTH ENERGY SOURCE FOR IMPROVED TRANSMISSION THROUGH OPTICAL FIBER FOR INTRAVASCULAR LITHOTRIPSY," filed October 28, 2021, and U.S. Patent Application No. 17 / 970,359, entitled "HIGH BANDWIDTH ENERGY SOURCE FOR IMPROVED TRANSMISSION THROUGH OPTICAL FIBER FOR INTRAVASCULAR LITHOTRIPSY," filed October 20, 2022. To the extent permitted, the contents of U.S. Provisional Patent Application No. 63 / 273,065 and U.S. Patent Application No. 17 / 970,359 are incorporated herein by reference in their entireties. [Background technology]

[0002] Vascular lesions within the body's blood vessels can be associated with an increased risk of major adverse events, such as myocardial infarction, embolism, deep vein thrombosis, and stroke. Severe vascular lesions can be difficult for physicians to treat and achieve patency in a clinical setting. Vascular lesions can be treated using interventions such as medical therapy, balloon angioplasty, atherectomy, stenting, and vascular graft bypass, to name a few. Such interventions may not always be ideal or may require subsequent treatment to address the lesion.

[0003] The use of optical fiber delivery of laser pulses to generate plasma-induced mechanical impulses on the lesion is one way to treat vascular lesions by spallation. Shaping the time morphology of the optical pulses allows the peak power of the pulse to be reduced below the damage threshold of the optical fiber and still transmit the full energy to generate the mechanical impulse. This increases the amount of energy that can be delivered within a set time interval while at the same time minimizing the peak laser intensity and remaining below the damage threshold of the optical fiber. However, nonlinear optical processes in the bulk optical fiber can still inhibit energy transmission through the fiber. Thus, nonlinear optical processes can limit the peak energy delivered and the device's ability to spall the lesion.

[0004] One of the main problems encountered by using optical energy pulses to generate plasma-driven acoustic bubbles is coupling enough energy into the input end (proximal end) of an optical fiber or other optical guide to produce an effective therapeutic effect at the output end (distal end) of the optical fiber. Damage to the optical guides transmitting the optical energy pulses within the body has been a significant challenge in the development of this technology. The factors involved are the laser-induced damage threshold (LIDT) of the optical guide interface and the bulk threshold of the medium itself. The LIDT of bulk fused silica is 1866 J / cm at 1064 nm for a 12 ns pulse. -2 . The LIDT of a surface can be 10 times lower than this value. The quality and cleanliness of the surface finish greatly affect this figure. The damage threshold of a light guide surface is much lower than that of the bulk material, so failure usually manifests as damage at the light guide input (proximal) end. The amount of energy transmitted through a light guide is limited by the peak intensity of the pulse at the proximal face. This limitation has been primarily addressed by stretching the energy pulse width in time. This reduces the peak power and surface irradiance while maintaining the overall energy.

[0005] Furthermore, recent experiments have shown that for pulses with an approximately Gaussian time form, the peak pressure generated by an optical pulse is proportional to the peak intensity of the pulse. This means that, although shorter pulses are limited to a lower total energy by the damage threshold of the transmission medium, they can generate similar pressure waves as longer pulses using significantly less total optical energy. As a result, pressure waves of sufficient energy can be generated to disrupt calcified lesions while remaining well below the damage threshold of the optical guide.

[0006] Even when the peak power at the light guide surface is reduced using the technique of pulse stretching, the peak power remains high enough to induce Stimulated Brillouin Scattering (SBS) in the light guide material itself. SBS is a nonlinear process that can occur in optical media at relatively low input power levels. When the Brillouin threshold is reached, SBS manifests by generating backward propagating Stokes waves that carry most of the input power. The interaction of the input photons with the moving refractive index changes in the material generates backscattered phonons, or Stokes waves. This process removes energy from the input beam. The backward propagating waves then create regions of periodic curvature change that act like a Bragg grating. This causes more of the forward beam to be scattered backwards. This nonlinear process causes an exponential decrease in the total transmitted energy as the input power is gradually increased. The nonlinear process essentially suppresses the total energy transmitted as more energy is added.

[0007] Input optical frequency linewidth Δv p is narrow compared to the frequency linewidth of the Brillouin scattering, the unsaturated Brillouin gain coefficient G at wavelength λ B0 is given by the following equation:

number

number

[0008] This means that one way to reduce the effects of SBS is to reduce the Δv p This directly shows that the

[0009] Linewidth (optical bandwidth) is a measure of spectral purity (monochromaticity). Pulsed solid-state lasers with short cavity lengths typically feature narrow linewidths, on the order of tens of kilohertz to hundreds of megahertz. It is also useful to consider this in terms of the coherence length, given by

number

[0010] This range of linewidths corresponds to coherence lengths from several thousand meters to 2 m. This is the range in which the laser light can interfere with itself and contribute to SBS. The 135 MHz Brillouin frequency linewidth in silica corresponds to a coherence length of about 70 cm. In order to reduce the Brillouin gain coefficient to a point where SBS does not affect the light transmission through the fiber, the linewidth needs to be an order of magnitude larger than the fundamental Brillouin frequency linewidth. This would be 13 GHz to 30 GHz, which corresponds to a coherence length of about 7 mm to 3 mm. Other energy sources can have bandwidths in the range of 50 pm to 69 pm, which corresponds to 13.25 GHz to 18.25 GHz at 1064 nm. Summary of the Invention

[0011] The present invention is directed to a catheter system for treating a treatment site within or adjacent to a blood vessel wall or heart valve. In various embodiments, the catheter system includes a light guide and a light source. The light guide is configured to selectively receive light energy. The light source generates light energy. The light source is in optical communication with the light guide. The light source can include (i) a seed source that outputs light energy, (ii) a preamplifier that receives light energy from the seed source, the preamplifier in optical communication with the seed source, and (iii) an amplifier that receives light energy from the preamplifier, the amplifier in optical communication with the preamplifier and the light guide.

[0012] In some embodiments, the catheter system further includes a seed controller that controls the seed source.

[0013] In certain embodiments, the catheter system further includes an optical element configured to direct light energy into the light guide.

[0014] In various embodiments, the seed source includes one of a diode laser, a programmable semiconductor laser, a gated fiber optic laser, and a low power solid state laser.

[0015] In some embodiments, the seed source, preamplifier, and amplifier are free-space combined within the light source.

[0016] In certain embodiments, the seed source is optically coupled to the preamplifier by a first coupling light guide, and the preamplifier is optically coupled to the amplifier by a second coupling light guide.

[0017] In various embodiments, the preamplifier includes one of a fiber optic laser, a solid state laser, a flash lamp, and a diode-pumped neodymium-doped yttrium aluminum garnet rod.

[0018] In some embodiments, the amplifier includes one of a high gain stage configured to have high energy output capability, a fiber optic laser, a diode-pumped solid-state laser, and a flash lamp.

[0019] In certain embodiments, the amplifier includes a gain medium including one of (i) a neodymium-doped yttrium aluminum garnet rod, (ii) a neodymium-doped yttrium aluminum garnet slab, (iii) a neodymium-doped glass, and (iv) an erbium-doped yttrium lithium fluoride, the gain medium optically coupled to one of a laser diode stack and a flash lamp.

[0020] In various embodiments, the light source includes a collimator that collimates the light energy output by the preamplifier, the collimator being in optical communication with the preamplifier and the amplifier.

[0021] The present invention is also directed to a catheter system for treating a treatment site within or adjacent to a blood vessel wall or heart valve. In various embodiments, the catheter system includes a light guide and a light source. The light guide is configured to selectively receive light energy. The light source generates light energy. The light source is in optical communication with the light guide. The light source can include (i) a seed source that outputs light energy, (ii) a linewidth modifier that modifies a linewidth of the light energy output by the seed source, (iii) a preamplifier that receives the light energy from the linewidth modifier, the preamplifier in optical communication with the linewidth modifier, (iv) a collimator that collimates the light energy output by the preamplifier, the collimator in optical communication with the preamplifier, and (v) an amplifier that receives the light energy from the preamplifier, the amplifier in optical communication with the collimator and the light guide.

[0022] In some embodiments, the seed source includes a modulated distributed feedback laser.

[0023] In a specific embodiment, the seed source includes multiple modulated distributed feedback lasers.

[0024] In various embodiments, a plurality of modulated distributed feedback lasers are configured with seed offsets at center wavelengths above and below the amplifier wavelength of the amplifier.

[0025] In some embodiments, the seed source is optically coupled to the linewidth modifier by a first coupling light guide.

[0026] In certain embodiments, the seed pulse shape of the seed source is controlled at least in part by directly modulating the seed source.

[0027] In various embodiments, the seed pulse shape of the seed source is controlled at least in part by an acousto-optic modulator.

[0028] In some embodiments, the seed source includes a diode configured to have high spatial coherence and low temporal coherence.

[0029] In a particular embodiment, the diode is a superluminescent diode.

[0030] In various embodiments, the linewidth modifier is a band-limiting filter.

[0031] In some embodiments, the linewidth modifier is a fiber optic Bragg grating.

[0032] In certain embodiments, the seed source and linewidth modifier work in conjunction to (i) increase a seed linewidth of the seed source, (ii) improve the amplification of light energy, and (iii) minimize stimulated Brillouin scattering within the light guide.

[0033] The present invention is further directed to a catheter system for treating a treatment site within or adjacent to a blood vessel wall or heart valve. In various embodiments, the catheter system includes a light guide and a light source. The light guide is configured to selectively receive light energy. The light source generates light energy. The light source is in optical communication with the light guide. The light source can include (i) a seed source that outputs light energy, and (ii) an amplifier that receives the light energy from the seed source, the amplifier in optical communication with the seed source and the light guide.

[0034] The present invention is also directed to a method for treating a treatment site within a blood vessel wall or a heart valve, or adjacent to a blood vessel wall or a heart valve, comprising providing and / or using any of the catheter systems shown and / or described herein.

[0035] This Summary is an overview of some of the teachings of the present application and is not intended to be an exclusive or exhaustive treatment of the subject matter. Further details are found in the detailed description and the appended claims. Other aspects will become apparent to those skilled in the art upon reading and understanding the following detailed description and viewing the drawings that form a part of it, each of which should not be taken in a limiting sense. The scope of the present specification is defined by the appended claims and their legal equivalents.

[0036] The novel features of the present invention, as well as the invention itself, both as to its structure and its operation, can best be understood from the accompanying drawings in conjunction with the accompanying description, in which like reference numerals refer to like parts, and in which: [Brief description of the drawings]

[0037] [Figure 1] 1 is a simplified schematic diagram of one embodiment of a portion of a catheter system having features of the present invention. [Diagram 2] FIG. 13 is a simplified schematic diagram of another embodiment of a portion of a catheter system. [Diagram 3] FIG. 13 is a simplified schematic diagram of yet another embodiment of a portion of a catheter system. [Figure 4] FIG. 13 is a simplified schematic diagram of yet another embodiment of a portion of a catheter system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0038] While the embodiments are susceptible to various modifications and alternative forms, details thereof have been shown by way of example and drawings and will be described in detail. It is to be understood, however, that the scope of the specification is not limited to the particular embodiments described. On the contrary, the intention is to cover modifications, equivalents, and alternatives falling within the spirit and scope of the specification.

[0039] Treatment of vascular lesions (also referred to herein as "treatment sites") can reduce major adverse events or deaths in affected subjects. As referred to herein, major adverse events can occur anywhere in the body due to the presence of vascular lesions. Major adverse events can include, but are not limited to, major adverse events in the heart, major adverse events in the peripheral or central vasculature, major adverse events in the brain, major adverse events in muscle tissue, or major adverse events in any of the internal organs.

[0040] As used herein, the terms "intravascular lesion," "vascular lesion," and "treatment site" are used interchangeably unless otherwise noted. Intravascular lesion and / or vascular lesion may be referred to herein simply as "lesion." Also, as used herein, the terms "focused location" and "focused spot" are used interchangeably unless otherwise noted and may refer to any location where light energy is focused to a diameter smaller than the initial diameter of the light source.

[0041] Those skilled in the art will realize that the following detailed description of the invention is illustrative only and is not intended to be in any way limiting. Other embodiments of the invention will themselves readily suggest themselves to such skilled artisans having the benefit of this disclosure. Reference will now be made in detail to embodiments of the invention as illustrated in the accompanying drawings.

[0042] For purposes of clarity, not all of the specific features of the embodiments described herein are shown and described. Of course, it will be recognized that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developer's particular goals, such as adhering to application-related and business-related constraints, and that these particular goals will vary from implementation to implementation and developer to developer. Moreover, it will be recognized that such a development effort may be complex and time-consuming, but would nevertheless be a routine undertaking of engineering for those of ordinary skill in the art having the benefit of this disclosure.

[0043] The catheter system disclosed herein may include many different configurations. Referring now to FIG. 1, a schematic cross-sectional view of a catheter system 100 according to various embodiments is shown. The catheter system 100 is adapted to apply pressure waves to induce fragmentation at one or more treatment sites within or adjacent to a vessel wall of a blood vessel or on or adjacent to a heart valve within a patient. In the embodiment shown in FIG. 1, the catheter system 100 may include one or more of a catheter 102, a light guide bundle 122 including one or more light guides 122A (some embodiments described herein include at least a first light guide and a second light guide), a handle assembly 128, a source manifold 136, a fluid pump 138, and a system console 101. The system console 101 includes one or more of a multiplexer 123, a light source 124, a power source 125, a system controller 126, a graphic user interface 127 (sometimes referred to herein as a "graphic user interface"), and a light analyzer assembly 142. Alternatively, the catheter system 100 may include more or fewer components than those specifically shown and described with respect to FIG.

[0044] It will be appreciated that the catheter system 100 is generally described herein as including a light guide bundle 122 including one or more light guides 122A and a light source 124. In some alternative embodiments, the catheter system 100 can include energy guide bundles including different types of energy guides and / or different types of energy sources.

[0045] In various examples, the catheter 102 is configured to navigate to a treatment site 106 within or adjacent to a vascular wall 108A of a blood vessel 108 in a body 107 of a patient 109. The treatment site 106 may include one or more vascular lesions 106A, such as, for example, a calcified vascular lesion. Additionally or alternatively, the treatment site 106 may include a vascular lesion 106A, such as a fibrous vascular lesion. Further alternatively, in some embodiments, the catheter 102 may be used at a treatment site 106 within or adjacent to a heart valve in the body 107 of the patient 109.

[0046] The catheter 102 may include an inflatable balloon 104 (sometimes referred to herein simply as a "balloon"), a catheter shaft 110, and a guidewire 112. The balloon 104 may be coupled to the catheter shaft 110. The balloon 104 may include a balloon proximal end 104P and a balloon distal end 104D. The catheter shaft 110 may extend from a proximal portion 114 of the catheter system 100 to a distal portion 116 of the catheter system 100. The catheter shaft 110 may include a longitudinal axis 144. The catheter shaft 110 may also include a guidewire lumen 118 configured to travel over the guidewire 112. As utilized herein, the guidewire lumen 118 defines a conduit through which the guidewire 112 extends. The catheter shaft 110 may further include an inflation lumen (not shown) and / or various other lumens for various other purposes. In some embodiments, the catheter 102 can have a distal end opening 120 to accommodate and track the guidewire 112 over the guidewire 112 as the catheter 102 is moved and positioned at or near the treatment site 106. In some embodiments, the balloon proximal end 104P can be coupled to the catheter shaft 110 and the balloon distal end 104D can be coupled to the guidewire lumen 118.

[0047] The balloon 104 includes a balloon wall 130 that defines a balloon interior 146. The balloon 104 can be selectively inflated with a balloon fluid 132 to expand from a contracted state suitable for advancing the catheter 102 through the patient's vasculature to an inflated state (as shown in FIG. 1 ) suitable for securing the catheter 102 in place relative to the treatment site 106. Stated differently, when the balloon 104 is in the inflated state, the balloon wall 130 of the balloon 104 is configured to be positioned substantially adjacent to the treatment site 106. While FIG. 1 illustrates that the balloon wall 130 of the balloon 104 is shown spaced apart from the treatment site 106 of the blood vessel 108 when in the inflated state, it will be appreciated that this is done solely for ease of illustration. It will be appreciated that the balloon wall 130 of the balloon 104 will typically be substantially immediately adjacent and / or abutting the treatment site 106 when the balloon 104 is in the inflated state.

[0048] Balloons 104 suitable for use in the catheter system 100 include those that, when in a deflated state, can pass through the vasculature of a patient 109. In some embodiments, the balloon 104 is made from silicone. In other embodiments, the balloon 104 can be made from polydimethylsiloxane (PDMS), polyurethane, a polymer such as PEBAX™ material, nylon, or any other suitable material.

[0049] Balloon 104 can have any suitable diameter (when inflated). In various embodiments, balloon 104 can have a diameter (when inflated) ranging from less than 1 millimeter (mm) to 25 mm. In some embodiments, balloon 104 can have a diameter (when inflated) ranging from at least 1.5 mm to 14 mm. In some embodiments, balloon 104 can have a diameter (when inflated) ranging from at least 2 mm to 5 mm.

[0050] In some embodiments, the balloon 104 can have a length ranging from at least 3 mm to 300 mm. More particularly, in some embodiments, the balloon 104 can have a length ranging from at least 8 mm to 200 mm. It is recognized that a balloon 104 having a relatively long length can be positioned adjacent a larger treatment site 106 and thus can be used to impart pressure waves onto a larger vascular lesion 106A or multiple vascular lesions 106A and induce fragmentation at a precise location within the treatment site 106. It is further recognized that a longer balloon 104 can also be positioned adjacent multiple treatment sites 106 at any one given time.

[0051] The balloon 104 may be inflated to an inflation pressure of approximately 1 atmosphere (atm) to 70 atm. In some embodiments, the balloon 104 may be inflated to an inflation pressure of at least 20 atm to 60 atm. In other embodiments, the balloon 104 may be inflated to an inflation pressure of at least 6 atm to 20 atm. In yet other embodiments, the balloon 104 may be inflated to an inflation pressure of at least 3 atm to 20 atm. In yet other embodiments, the balloon 104 may be inflated to an inflation pressure of at least 2 atm to 10 atm.

[0052] The balloon 104 may have a variety of shapes, including, but not limited to, a conical, a square, a rectangular, a spherical, a conical / square, a conical / spherical, an expanded spherical, an elliptical, a tapered, a bone, a stepped diameter, an offset, or a conical offset. In some embodiments, the balloon 104 may include a drug eluting coating or a drug eluting stent structure. The drug eluting coating or drug eluting stent may include one or more therapeutic agents, including anti-inflammatory agents, anti-tumor agents, anti-angiogenic agents, and the like.

[0053] The balloon fluid 132 may be a liquid or a gas. Some examples of balloon fluids 132 suitable for use may include, but are not limited to, one or more of water, saline, contrast, a gas such as fluorocarbon, perfluorocarbon, carbon dioxide, or any other suitable balloon fluid 132. In some embodiments, the balloon fluid 132 may be used as a base inflation fluid. In some embodiments, the balloon fluid 132 may include a mixture of saline and contrast in a volume ratio of approximately 50:50. In other embodiments, the balloon fluid 132 may include a mixture of saline and contrast in a volume ratio of approximately 25:75. In still other embodiments, the balloon fluid 132 may include a mixture of saline and contrast in a volume ratio of approximately 75:25. However, it is understood that any suitable ratio of saline and contrast may be used. The balloon fluid 132 may be adjusted based on composition, viscosity, etc., such that the speed of travel of the pressure wave is approximately appropriately manipulated. In certain embodiments, the balloon fluid 132 suitable for use herein is biocompatible. The volume of the balloon fluid 132 can be adjusted depending on the light source 124 selected and the type of balloon fluid 132 used.

[0054] In some embodiments, the imaging agent used in the imaging medium may include, but is not limited to, an iodine-based imaging agent, such as an ionic or non-ionic iodine-based imaging agent. Some non-limiting examples of ionic iodine-based imaging agents include diatrizoate, metrizoate, iothalamate, and ioxaglate. Some non-limiting examples of non-ionic iodine-based imaging agents include iopamidol, iohexol, ioxilan, iopromide, iodixanol, and ioversol. In other embodiments, non-iodine-based imaging agents may be used. Suitable non-iodine-containing imaging agents may include gadolinium(III)-based imaging agents. Suitable fluorocarbon and perfluorocarbon agents may include, but are not limited to, chemicals such as perfluorocarbon dodecafluoropentane (DDFP, C5F12).

[0055] The balloon fluid 132 may include those containing absorbers capable of selectively absorbing light in the ultraviolet (e.g., at least 10 nanometers (nm) to 400 nm), visible (e.g., at least 400 nm to 780 nm), or near infrared (e.g., at least 780 nm to 2.5 μm) regions of the electromagnetic spectrum. Suitable absorbers may include those having an absorption maximum along a spectrum of at least 10 nm to 2.5 μm. Alternatively, the balloon fluid 132 may include those containing absorbers capable of selectively absorbing light in the mid-infrared (e.g., at least 2.5 μm to 15 μm) or far-infrared (e.g., at least 15 μm to 1 mm) regions of the electromagnetic spectrum. In various embodiments, the absorbers may have an absorption maximum that matches the emission maximum of a laser used in the catheter system 100. As non-limiting examples, the various lasers described herein may include a neodymium:yttrium aluminum garnet (Nd:YAG-emission maximum=1064 nm) laser, a holmium:YAG (Ho:YAG-emission maximum=2.1 μm) laser, or an erbium:YAG (Er:YAG-emission maximum=2.94 μm) laser. In some embodiments, the absorber may be water soluble. In other embodiments, the absorber is not water soluble. In some embodiments, the absorber used in the balloon fluid 132 may be tailored to match the peak emission of the light source 124. Various light sources 124 having emission wavelengths of at least 10 nanometers to 1 millimeter are discussed elsewhere herein.

[0056] The catheter shaft 110 of the catheter 102 can be coupled to one or more light guides 122A of the light guide bundle 122 in optical communication with the light source 124. The light guides 122A can be disposed along the catheter shaft 110 and within the balloon 104. Each of the light guides 122A can have a guide distal end 122D at any suitable longitudinal position relative to the length of the balloon 104. In some embodiments, each light guide 122A can be an optical fiber and the light source 124 can be a laser. The light source 124 can be in optical communication with the light guide 122A at the proximal portion 114 of the catheter system 100. More specifically, the light source 124 can be in optical communication with the light guide 122A selectively, simultaneously, sequentially, and / or in any desired combination, sequence, and / or pattern, depending on the presence and operation of the handle assembly 128.

[0057] In some embodiments, the catheter shaft 110 can be coupled to multiple light guides 122A, such as a first light guide, a second light guide, a third light guide, etc., which can be positioned at any suitable location about the guidewire lumen 118 and / or the catheter shaft 110. For example, in certain non-exclusive embodiments, two light guides 122A can be spaced apart by approximately 180 degrees around the circumference of the guidewire lumen 118 and / or the catheter shaft 110, three light guides 122A can be spaced apart by approximately 120 degrees around the circumference of the guidewire lumen 118 and / or the catheter shaft 110, or four light guides 122A can be spaced apart by approximately 90 degrees around the circumference of the guidewire lumen 118 and / or the catheter shaft 110. Further alternatively, the multiple light guides 122A need not be evenly spaced from one another around the circumference of the guidewire lumen 118 and / or catheter shaft 110. More specifically, the light guides 122A can be either evenly or unevenly spaced around the guidewire lumen 118 and / or catheter shaft 110 to achieve a desired effect at a desired location.

[0058] The catheter system 100 and / or the light guide bundle 122 may include any number of light guides 122A in optical communication with the light source 124 at the proximal portion 114 and in optical communication with the balloon fluid 132 within the balloon interior 146 of the balloon 104 at the distal portion 116. For example, in some embodiments, the catheter system 100 and / or the light guide bundle 122 may include from one light guide 122A to five light guides 122A. In other embodiments, the catheter system 100 and / or the light guide bundle 122 may include from five light guides 122A to fifteen light guides 122A. In yet other embodiments, the catheter system 100 and / or the light guide bundle 122 may include from ten light guides 122A to thirty light guides 122A. Or, in still other embodiments, the catheter system 100 and / or the light guide bundle 122 may include more than thirty light guides 122A.

[0059] The light guide 122A may have any suitable design to generate plasma and / or pressure waves in the balloon fluid 132 within the balloon interior 146. In certain embodiments, the light guide 122A may include an optical fiber or a flexible light pipe. The light guide 122A may be thin and flexible, allowing for the transmission of optical signals with little loss of strength. The light guide 122A may include a core surrounded by a cladding. In some embodiments, the core may be a cylindrical core or a partially cylindrical core. The core and cladding of the light guide 122A may be formed from one or more materials, including, but not limited to, one or more types of glass, silica, or one or more polymers. The light guide 122A may also include a protective coating, such as a polymer. It is recognized that the refractive index of the core is greater than the refractive index of the cladding.

[0060] Each light guide 122A can guide light energy along its length from a proximal guide end 122P to a distal guide end 122D having at least one optical window (not shown), positioned within the balloon interior 146.

[0061] In various embodiments, the guide distal end 122D can further include and / or incorporate a distal light receiver 122R that allows light energy to travel back into and through the light guide 122A from the guide distal end 122D to the guide proximal end 122P. Stated another way, the light energy can travel in a first direction 121F along the light guide 122A, generally from the guide proximal end 122P toward the guide distal end 122D of the light guide 122A. At least a portion of the light energy can also travel in a second direction 121S along the light guide 122A that is substantially opposite the first direction 121F, i.e., from the guide distal end 122D toward the guide proximal end 122P of the light guide 122A. Furthermore, as described in more detail below, after being passed back through the light guide 122A (in the second direction 121S), the light energy emitted from the guide proximal end 122P is separated and then optically detected, inspected, and / or analyzed using the light analyzer assembly 142.

[0062] The light guide 122A can take on many configurations around and / or relative to the catheter shaft 110 of the catheter 102. In some embodiments, the light guide 122A can extend parallel to the longitudinal axis 144 of the catheter shaft 110. In some embodiments, the light guide 122A can be physically coupled to the catheter shaft 110. In other embodiments, the light guide 122A can be disposed along the length of the outer diameter of the catheter shaft 110. In still other embodiments, the light guide 122A can be disposed within one or more light guide lumens within the catheter shaft 110.

[0063] The optical guides 122A may also be positioned at any suitable location around the circumference of the guidewire lumen 118 and / or catheter shaft 110, and the guide distal ends 122D of each of the optical guides 122A may be positioned at any suitable longitudinal location relative to the length of the balloon 104 and / or relative to the length of the guidewire lumen 118 to more effectively and precisely deliver pressure waves for the purpose of destroying the vascular lesion 106A at the treatment site 106.

[0064] In certain embodiments, the light guide 122A can include one or more opto-acoustic transducers 154, and each opto-acoustic transducer 154 can be in optical communication with the light guide 122A in which it is disposed. In some embodiments, the opto-acoustic transducers 154 can be in optical communication with the distal guide end 122D of the light guide 122A. Further, in such embodiments, the opto-acoustic transducers 154 can have a shape that corresponds to and / or matches the distal guide end 122D of the light guide 122A.

[0065] The photoacoustic transducer 154 is configured to convert light energy into sound waves at or near the distal guide end 122D of the light guide 122A. The direction of the sound waves can be adjusted by changing the angle of the distal guide end 122D of the light guide 122A.

[0066] In certain embodiments, the opto-acoustic transducer 154 disposed at the guide distal end 122D of the light guide 122A can have the same shape as the guide distal end 122D of the light guide 122A. For example, in certain non-exclusive embodiments, the opto-acoustic transducer 154 and / or the guide distal end 122D can have a conical shape, a convex shape, a concave shape, a bulbous shape, a square shape, a stepped shape, a semicircular shape, an oval shape, etc. The light guide 122A can further include additional opto-acoustic transducers 154 disposed along one or more sides of the length of the light guide 122A.

[0067] In some embodiments, the light guide 122A can further include one or more diverting features or "diverters" (not shown in FIG. 1 ) within the light guide 122A that are configured to direct light out of the light guide 122A toward a side that may be located at or near the distal guide end 122D of the light guide 122A and toward the balloon wall 130. The diverting features can include any system feature that redirects light energy from the light guide 122A away from its axial flow path toward a side of the light guide 122A. Additionally, the light guides 122A can each include one or more optical windows disposed along a longitudinal or circumferential surface of each light guide 122A and in optical communication with the diverting features. Stated another way, the redirecting mechanism can be configured to direct optical energy of the light guide 122A towards a side surface at or near the guide distal end 122D, the side surface being in optical communication with the optical window. The optical window can include a portion of the light guide 122A that allows optical energy to exit the light guide 122A from within the light guide 122A, such as a portion of the light guide 122A that does not have cladding material on or around the light guide 122A.

[0068] Examples of redirecting mechanisms suitable for use include reflective elements, refractive elements, and fiber diffusers. Redirecting mechanisms suitable for focusing the optical energy away from the tip of the light guide 122A can include, but are not limited to, those with convex surfaces, gradient-index (GRIN) lenses, and mirror focus lenses. Upon contact with the redirecting mechanism, the optical energy is redirected within the light guide 122A to one or more of the plasma generator 133 and the opto-acoustic transducer 154, which is in optical communication with the side of the light guide 122A. As described, the opto-acoustic transducer 154 then converts the optical energy into acoustic waves that propagate away from the side of the light guide 122A.

[0069] The source manifold 136 may be positioned at or near the proximal portion 114 of the catheter system 100. The source manifold 136 may include one or more proximal end openings that may receive one or more light guides 122A of the light guide bundle 122, the guidewire 112, and / or an inflation conduit 140 that is coupled in fluid communication with a fluid pump 138. The catheter system 100 may also optionally include a fluid pump 138 configured to inflate the balloon 104 with balloon fluid 132.

[0070] As noted above, in the embodiment shown in FIG. 1, the multiplexer 123 includes one or more of the light source 124, the power source 125, the system controller 126, and the GUI 127. Alternatively, the multiplexer 123 may include more or fewer components than those specifically shown in FIG. 1. For example, in certain non-exclusive alternative embodiments, the multiplexer 123 may be designed without the GUI 127. Further alternatively, one or more of the light source 124, the power source 125, the system controller 126, and the GUI 127 may be provided in the catheter system 100 without a specific need for a multiplexer 123.

[0071] In some embodiments, the multiplexer 123 can include a two-channel splitter design. The light guide bundle 122 can include a manual positioning mechanism that is mounted on an optical breadboard and / or platen. This design allows linear position adjustment and tilting of the array by rotating about the light guide 122A axis (not shown in FIG. 1) of one of the channels. In other embodiments, the adjustment method can include at least two adjustment steps: 1) aligning the planar position of the guide beam 124B in channel 1, and 2) adjusting the light guide bundle 122 to achieve the best alignment in channel 10.

[0072] 1, in certain embodiments, at least a portion of the optical analyzer assembly 142 can be positioned within the multiplexer 123. Alternatively, various components of the optical analyzer assembly 142, or the entire optical analyzer assembly 142, can be positioned outside or remote from the multiplexer 123.

[0073] As shown, the multiplexer 123 and components included therewith are operatively coupled to the catheter 102, the light guide bundle 122, and the remainder of the catheter system 100. For example, in some embodiments, as shown in FIG. 1, the multiplexer 123 can include a console connection aperture 148 (which may also be referred to generically as a "socket"), whereby the light guide bundle 122 is mechanically coupled to the multiplexer 123. In such embodiments, the light guide bundle 122 can include a guide coupling housing 150 (which may also be referred to generically as a "ferrule") that receives a portion of each of the light guides 122A, e.g., the guide proximal end 122P. The guide coupling housing 150 is configured to be selectively retained in the console connection aperture 148 to provide a mechanical coupling between the light guide bundle 122 and the multiplexer 123.

[0074] The light guide bundle 122 may also include a guide bundler 152 (or "shell") that packs each of the individual light guides 122A closer together, allowing the light guides 122A and / or the light guide bundle 122 to be in a more compact configuration as they extend with the catheter 102 into the blood vessel 108 during use of the catheter system 100. In some embodiments, the light guides 122A leading to the plasma generator 133 may be packed into a light guide bundle 122 that includes a linear block with an array of precision holes that form a multi-channel ferrule. In other embodiments, the light guide bundle 122 may include a mechanical connector array or block connector that packs the single ferrules into one of: (i) a linear array; (ii) a circular pattern; and (iii) a hexagonal pattern.

[0075] The light source 124 can be selectively and / or alternatively coupled in optical communication with each of the light guides 122A in the light guide bundle 122, i.e., to the guide proximal end 122P of each of the light guides 122A. In particular, the light source 124 is configured to generate optical energy in the form of a source beam 124A, e.g., a pulsed source beam, which can be selectively and / or alternatively directed and received as an individual guide beam 124B to each of the light guides 122A in the light guide bundle 122. The optical element 147 can selectively and / or alternatively direct the guide beam 124B to the light guides 122A in the light guide bundle 122 and / or the multiplexer 123. The optical element 147 can include a lens, a focusing lens, a coupling lens, and / or a reflector. Alternatively, the catheter system 100 can include two or more light sources 124. For example, in one non-exclusive alternative embodiment, the catheter system 100 can include a separate light source 124 for each light guide 122A in the light guide bundle 122. The light sources 124 can be operated at low energy.

[0076] The light source 124 can have any suitable design. In certain embodiments, the light source 124 can be configured to provide sub-millisecond pulses of light energy from the light source 124, which are focused to a small spot for coupling the light source 124 to the proximal guide end 122P of the light guide 122A. Such pulses of light energy are then directed and / or guided along the light guide 122A to a location within the balloon interior 146 of the balloon 104, thereby inducing plasma formation (sometimes referred to herein as a "plasma flash") in the balloon fluid 132 within the balloon interior 146 of the balloon 104, for example, via a plasma generator 133, which may be located at the distal guide end 122D of the light guide 122A. In particular, light emitted at the distal guide end 122D of the light guide 122A energizes the plasma generator 133 to form plasma within the balloon fluid 132 within the balloon interior 146. The plasma formation causes rapid bubble formation imparting pressure waves to the treatment site 106. An exemplary plasma-induced bubble 134 is shown in FIG.

[0077] When plasma first forms in the balloon fluid 132 within the balloon interior 146, the plasma emits a broad spectrum of electromagnetic radiation. This can be seen as a broad spectrum flash detectable by the naked eye. A portion of the light emitted from the plasma bubble 134 is transmitted to the distal receiver 122R at the distal guide end 122D of the light guide 122A and returned to the proximal guide end 122P where it can be separated, detected and analyzed by use of the light analyzer assembly 142. The intensity and timing of the visible light pulses relative to the plasma generating pulses provide an indication of the functioning of the plasma generator 133, its energy output and its functional state. Visible light flashes can occur at other locations in the light guide 122A if the light guide 122A is damaged or broken. Such other visible light flashes are also coupled into the light guide 122A and returned to the proximal guide end 122P. The intensity and timing of these other light pulses provide an indication of damage or failure of the light guide 122A or the plasma generator 133. In such circumstances, the optical analyzer assembly 142 may include a safety shutdown system that may be selectively activated to stop operation of the catheter system 100.

[0078] The configuration of the plasma generator 133 and / or the distal receiver 122R may further enable, in certain embodiments, coupling ambient light originating outside of the catheter 102 into the distal guide end 122D of the light guide 122A. In one embodiment, the light analyzer assembly 142 monitors the returning ambient light energy traversing the light guide 122A from the distal guide end 122D to the proximal guide end 122P. In such a situation, if any ambient light energy is present and detected by the light analyzer assembly 142, this is an indication that the catheter 102 is located outside the body 107 of the patient 109 and accordingly the light analyzer assembly 142 may be configured to lock out the light source 124. Notably, in such a situation, the safety stop system 283 of the light analyzer assembly 142 may be selectively actuated to stop operation of the catheter system 100.

[0079] In various non-exclusive alternative embodiments, sub-millisecond pulses of light energy from light source 124 can be delivered to treatment site 106 at frequencies between about 1 Hertz (Hz) and 5000 Hz, between about 30 Hz and 1000 Hz, between about 10 Hz and 100 Hz, or between about 1 Hz and 30 Hz. Alternatively, sub-millisecond pulses of light energy can be delivered to treatment site 106 at frequencies that can be greater than 5000 Hz or less than 1 Hz, or at any other suitable range of frequencies.

[0080] It will be appreciated that while light source 124 is typically utilized to provide pulses of light energy, light source 124 may still be described as providing a single source beam 124A, i.e., a single pulsed source beam.

[0081] Light sources 124 suitable for use can include various types of light sources, including lasers, seed sources, and lamps. For example, in certain non-exclusive examples, light source 124 can be an infrared laser that emits light energy in the form of pulses of infrared light. Alternatively, as noted above, light sources 124 referred to herein can include any suitable type of energy source.

[0082] Suitable lasers can include short pulse lasers on the sub-millisecond time scale. In some embodiments, the light source 124 can include a laser on the nanosecond (ns) time scale. The laser can also include short pulse lasers on the picosecond (ps), femtosecond (fs), and microsecond (us) time scale. It is recognized that there are many combinations of laser wavelengths, pulse widths, and energy levels that can be employed to achieve a plasma within the balloon fluid 132 of the catheter 102. In various non-exclusive alternative embodiments, the pulse widths can include those falling within a range including at least 10 ns to 3000 ns, at least 20 ns to 100 ns, or at least 1 ns to 500 ns. Alternatively, any other suitable pulse width range can be used.

[0083] Exemplary nanosecond lasers can include those in the UV to IR spectrum, spanning wavelengths from approximately 10 nanometers (nm) to 1 millimeter (mm). In some embodiments, the light source 124 suitable for use in the catheter system 100 can include those capable of generating light at wavelengths of at least 750 nm to 2000 nm. In other embodiments, the light source 124 can include those capable of generating light at wavelengths of at least 700 nm to 3000 nm. In still other embodiments, the light source 124 can include those capable of generating light at wavelengths of at least 100 nm to 10 micrometers (μm). The nanosecond laser can include those having a repetition rate of up to 200 kHz. In some embodiments, the laser can include a Q-switched Thulium:Yttrium Aluminum Garnet (Tm:YAG) laser. In other embodiments, the laser can include a neodymium:yttrium aluminum garnet (Nd:YAG) laser, a holmium:yttrium aluminum garnet (Ho:YAG) laser, an erbium:yttrium aluminum garnet (Er:YAG) laser, an excimer laser, a helium-neon laser, a carbon dioxide laser, and a doped pulsed fiber laser. In yet another embodiment, the light source 124 can include a SLED having a bandwidth in the range of 13.25 GHz to 18.25 GHz at 1064 nm.

[0084] The catheter system 100 can generate pressure waves having a maximum pressure in the range of at least 1 megapascal (MPa) to 100 MPa. The maximum pressure generated by a particular catheter system 100 depends on the light source 124, the absorbing material, the bubble expansion, the propagation medium, the balloon material, and other factors. In various non-exclusive alternative embodiments, the catheter system 100 can generate pressure waves having a maximum pressure in the range of at least approximately 2 MPa to 50 MPa, at least approximately 2 MPa to 30 MPa, or at least approximately 15 MPa to 25 MPa.

[0085] The pressure waves can be applied to the treatment site 106 from a distance extending radially from the light guide 122A within a range of at least about 0.1 millimeters (mm) to more than about 25 mm when the catheter 102 is positioned at the treatment site 106. In various non-exclusive alternative embodiments, the pressure waves can be applied to the treatment site 106 from a distance extending radially from the light guide 122A within a range of at least about 10 mm to 20 mm, at least about 1 mm to 10 mm, at least about 1.5 mm to 4 mm, or at least about 0.1 mm to 10 mm when the catheter 102 is positioned at the treatment site 106. In other embodiments, the pressure waves can be applied to the treatment site 106 from another suitable distance different from the above ranges. In some embodiments, the pressure waves can be applied to the treatment site 106 from a distance of at least about 0.1 mm to 10 mm and in a range of at least about 2 MPa to 30 MPa. In some embodiments, the pressure waves can be applied to the treatment site 106 from a distance of at least about 0.1 mm to 10 mm and in a range of at least about 2 MPa to 25 MPa. Further alternatively, other suitable pressure ranges and distances may be used.

[0086] The power source 125 is electrically coupled to each of the light source 124, the system controller 126, the GUI 127, the handle assembly 128, and the optical analyzer assembly 142 and is configured to provide the necessary power. The power source 125 may have any suitable design for such purpose.

[0087] The system controller 126 is electrically coupled to the power source 125 and receives power from the power source 125. Additionally, the system controller 126 is coupled to each of the light source 124, the GUI 127, and the optical analyzer assembly 142 and configured to control the operation of each. The system controller 126 may include one or more processors or circuits to control the operation of at least the light source 124, the GUI 127, and the optical analyzer assembly 142. For example, the system controller 126 may control the light source 124 to generate pulses of optical energy as desired and / or at any desired firing rate. Additionally, the system controller 126 may control and / or operate in conjunction with the optical analyzer assembly 142 to effectively provide continuous real-time monitoring of the performance, reliability, safety, and proper use of the catheter system 100.

[0088] The system controller 126 may be further configured to control the operation of other components of the catheter system 100, such as positioning of the catheter 102 adjacent the treatment site 106, inflation of the balloon 104 with balloon fluid 132, etc. Additionally or alternatively, the catheter system 100 may include one or more additional controllers, which may be positioned in any suitable manner to control various operations of the catheter system 100. For example, in certain embodiments, the additional controllers and / or portions of the system controller 126 may be positioned within and / or incorporated into the handle assembly 128.

[0089] The GUI 127 is accessible by a user or operator of the catheter system 100. Additionally, the GUI 127 is electrically connected to the system controller 126. With such a design, the GUI 127 can be used by the user or operator to ensure that the catheter system 100 is effectively utilized to apply pressure to the treatment site 106 to induce fracturing. The GUI 127 can provide the user or operator with information that can be used before, during, and after use of the catheter system 100. In one embodiment, the GUI 127 can provide the user or operator with static visual data and / or information. Additionally or alternatively, the GUI 127 can provide the user or operator with dynamic visual data and / or information, such as video data or any other data that changes over time during use of the catheter system 100. In various embodiments, the GUI 127 can include one or more colors, different sizes, different brightness, etc., that can alert the user or operator. Additionally or alternatively, the GUI 127 can provide the user or operator with audio data or information. The details of the GUI 127 may vary depending on the design requirements of the catheter system 100 or the particular needs, specifications, and / or desires of a user or operator.

[0090] 1, the handle assembly 128 may be positioned at or near the proximal portion 114 of the catheter system 100 and / or near the source manifold 136. In this embodiment, the handle assembly 128 is coupled to the balloon 104 and positioned spaced apart from the balloon 104. Alternatively, the handle assembly 128 may be positioned in another suitable location.

[0091] The handle assembly 128 is manipulated and used by a user or operator to operate, position, and control the catheter 102. The design and specific features of the handle assembly 128 can be varied to suit the design requirements of the catheter system 100. In the embodiment shown in FIG. 1, the handle assembly 128 is separate from, but in electrical and / or fluid communication with, one or more of the system controller 126, the light source 124, the fluid pump 138, the GUI 127, and the optical analyzer assembly 142. In some embodiments, the handle assembly 128 can integrate and / or include at least a portion of the system controller 126 within the handle assembly 128. For example, as shown, in certain such embodiments, the handle assembly 128 can include circuitry (not shown in FIG. 1) that can form at least a portion of the system controller 126. In some embodiments, the circuitry can receive electrical signals or data from the optical analyzer assembly 142. Additionally or in the alternative, the circuitry may transmit such electrical signals or provide data to the system controller 126 .

[0092] In one embodiment, the circuitry may include a printed circuit board (not shown) having one or more integrated circuits or any other suitable circuitry. In alternative embodiments, the circuitry may be omitted or may be included within the system controller 126, which in various embodiments may be located outside the handle assembly 128, for example, within the multiplexer 123. It is understood that the handle assembly 128 may include fewer or additional components than those specifically shown and described herein.

[0093] As with all embodiments shown and described herein, various features may be omitted from the drawings for purposes of clarity and ease of understanding. Additionally, the drawings may include certain features that can be omitted without departing from the spirit and scope of the present invention.

[0094] 2 is a simplified schematic diagram of another embodiment of a portion of a catheter system 200. FIG. 2 illustrates a non-limiting and non-exclusive example of a master oscillator and power amplifier (MOPA) configuration of the light source 224. In some such embodiments, the MOPA configuration allows a low-power master oscillator to seed a power amplifier with suitable pulses for amplification. If the pulse energy is low enough that the amplifier gain does not drop significantly during the pulse, the time form of the system's output will approximately match the output of the seed laser.

[0095] The MOPA configuration also minimizes nonlinear optical processes and allows for a significant increase in the linewidth of the light source 224 while maintaining adequate optical energy transmission through the light guide 222A. This configuration provides techniques and methods for significantly increasing the linewidth of the energy output by the light source 224 by enabling transmission through a small diameter light guide 222A with minimal loss.

[0096] As shown in Figure 2, the catheter system 200 may include a light guide 222A, a light source 224, a power source 225, a plasma generator 233, and optical elements 247. These components may be substantially similar in shape, arrangement, and / or function to those previously described with respect to the catheter system 100 shown in Figure 1. The catheter system 200 may further include a seed controller 258, a seed source 260, a preamplifier 262, and an amplifier 264.

[0097] The seed controller 258 controls the operation and / or functionality of the seed source 260. For example, the seed controller 258 may control the output of energy from the seed source 260. The seed controller 258 may control the wavelength, center wavelength, seed pulse shape, frequency, and / or any suitable characteristics of the energy output by the seed source 260. The seed controller 258 may directly modulate the seed source 260. The design and specific features of the seed controller 258 may be varied to suit the design requirements of the catheter system 200 and / or the seed source 260.

[0098] The seed controller 258 may include one or more processors, microprocessors, and / or circuitry for controlling the operation of at least the seed source 260. The seed controller 258 may include a printed circuit board having one or more integrated circuits, acousto-optic modulators, or any other suitable circuitry. In alternative embodiments, the seed controller 258 may be omitted or may be included in the system controller 126 (shown in FIG. 1 ), and in various embodiments may be located outside the light source 124, for example, in the multiplexer 123. It is understood that the seed controller 258 may include fewer or additional components than those specifically shown and described herein.

[0099] The seed source 260 outputs optical energy. The seed source 260 may be in optical communication with the light guide 222A, the optical element 247, the preamplifier 262, and the amplifier 264. The seed source 260 may be free space coupled within the light source 224 with the preamplifier 262 and the amplifier 264. The seed source 260 may be configured to have a seed offset at a center wavelength above and below the amplifier wavelength of the amplifier 264. The seed source 260 may be configured to have a seed pulse shape that is controlled at least in part by (i) directly modulating the seed source 260 or (ii) by an acousto-optic modulator (which may be included within the seed controller 258).

[0100] The seed source 260 can have a seed linewidth that is intrinsic to the seed source. The seed source 260 can be programmable such that the seed linewidth is adjustable to suit the design requirements of the catheter system 200 and / or the seed source 260. In various embodiments, the seed source 260 can operate at a low threshold to lengthen the seed pulse shape. The seed linewidth of the seed source 260 can be tuned such that the seed center wavelength and the seed overall linewidth substantially match the preamplifier center wavelength of the preamplifier 262 and / or the amplifier center wavelength of the amplifier 264. By substantially matching the linewidth and / or center wavelength, the energy conversion of the optical energy is improved.

[0101] The design and specific features of the seed source 260 can be varied to suit the design requirements of the catheter system 200, the light source 224, the light guide 222A, the optical element 247, the preamplifier 262, and / or the amplifier 264. The seed source 260 can include diodes, superluminescent diodes, diode lasers, programmable semiconductor lasers, gated fiber optic lasers, low power solid state lasers, and / or modulated distributed feedback lasers. It is understood that the seed source 260 can include fewer or additional components than those specifically shown and described herein.

[0102] The preamplifier 262 receives and amplifies the optical energy from the seed source 260. In various embodiments, the preamplifier 262 can be in optical communication with the light guide 222A, the optical element 247, the seed source 260, and / or the amplifier 264. The preamplifier 262 can be powered by the power source 225. The design and specific features of the preamplifier 262 can be varied to suit the design requirements of the catheter system 200, the light source 224, the light guide 222A, the optical element 247, the seed source 260, and / or the amplifier 264.

[0103] The preamplifier 262 may include a fiber optic laser, a solid-state laser, a flash lamp, and / or a diode-pumped neodymium-doped yttrium aluminum garnet rod. It is understood that the preamplifier 262 may include fewer or additional components than those specifically shown and described herein. In some embodiments, the preamplifier 262 may be omitted entirely from the light source 224, depending on the output energy of the seed source 260 and the design requirements of the catheter system 200, the light source 224, the light guide 222A, the optical element 247, and / or the amplifier 264. In other embodiments, the light source 224 may include multiple preamplifiers 262.

[0104] The amplifier 264 receives and amplifies the optical energy from the seed source 260 and / or the preamplifier 262. In various embodiments, the amplifier 264 can be in optical communication with the light guide 222A, the optical element 247, the seed source 260, and / or the preamplifier 262. The amplifier 264 can be powered by the power source 225. The design and specific features of the amplifier 264 can be varied to suit the design requirements of the catheter system 200, the light source 224, the light guide 222A, the optical element 247, the seed source 260, and / or the preamplifier 262.

[0105] The amplifier 264 may include a high gain stage, an optical fiber laser, a diode-pumped solid-state laser, a gain medium, and / or a flashlamp configured to have high energy output capabilities. The gain medium may include (i) a neodymium-doped yttrium aluminum garnet rod, (ii) a neodymium-doped yttrium aluminum garnet slab, (iii) a neodymium-doped glass, and / or (iv) an erbium-doped yttrium lithium fluoride. The gain medium may be optically coupled (e.g., within the amplifier 264) to one of a laser diode stack and a flashlamp. It is understood that the amplifier 264 may include fewer or additional components than those specifically shown and described herein. The amplifier 264 may have a variety of amplifier bandwidths. In some embodiments, the amplifier bandwidth may vary from 1 MHz to 1000 GHz. In other embodiments, the amplifier bandwidth may be less than 1 MHz or greater than 1000 GHz.

[0106] The amplifier 264 may include a solid-state high power amplifier that omits a tuning cavity. The solid-state high power amplifier may be driven to amplify optical energy up to a gain medium linewidth of the gain medium. In some embodiments, when the gain medium includes neodymium doped yttrium aluminum garnet, the gain medium linewidth is about 0.7 nm. In other embodiments, the optical energy solid-state high power amplifier may be driven to amplify optical energy up to a gain medium linewidth greater than 0.7 nm or less than 0.7 nm.

[0107] In some embodiments, the amplifier 264 may be omitted entirely from the light source 224, depending on the output energy of the seed source 260 and the design requirements of the catheter system 200, the light source 224, the light guide 222A, the optical element 247, and / or the preamplifier 262. In other embodiments, the light source 224 may include multiple amplifiers 264.

[0108] 3 is a simplified schematic diagram of yet another embodiment of a portion of a catheter system 300. As shown in FIG. 3, the catheter system 300 can include a light guide 322A, a light source 324, a power source 325, a plasma generator 333, optical elements 347, a seed controller 358, a seed source 360, a preamplifier 362, and an amplifier 364. These components can be substantially similar in shape, arrangement, and / or function to those previously described with respect to the catheter system 300 shown in FIGS. 1-2. In certain embodiments, the catheter system 300 can further include a plurality of coupled light guides 322C and a collimator 366.

[0109] A combined light guide 322C can optically couple various components of the light source 324. For example, as shown in FIG. 3, a combined light guide 322C can optically couple a seed source 360 ​​to a preamplifier 362, and another combined light guide 322C can optically couple the preamplifier 362 to a collimator 366.

[0110] The coupling methods of the various components within the light source 324 may be mixed depending on (i) the design requirements of the catheter system 300 and / or the light source, and (ii) the energy output of the seed source 360, the preamplifier 362, and the amplifier 364. For example, free space coupling and coupling light guides 322C, respectively, may be utilized within the light source 324 (e.g., as shown in FIG. 3).

[0111] The design and specific configuration of the coupled light guide 322C can be varied to suit the design requirements of the catheter system 300, the light source 324, the light guide 322A, the optical element 347, the seed source 360, the preamplifier 362, the amplifier 364, and / or the collimator 366. The coupled light guide 322C can be a fiber optic cable.

[0112] The collimator 366 can collimate the optical energy output by the seed source 360, the preamplifier 362, and / or the amplifier 364. The collimator 366 can be in optical communication with the light guide 322A, the optical element 347, the seed source 360, the preamplifier 362, and / or the amplifier 364. The design and specific features of the collimator 366 can be varied to suit the design requirements of the catheter system 300, the light source 324, the light guide 322A, the optical element 347, the seed source 360, the preamplifier 362, and / or the amplifier 364. It is understood that the collimator 366 can include fewer or additional components than those specifically shown and described herein.

[0113] 4 is a simplified schematic diagram of yet another embodiment of a portion of a catheter system 400. As shown in FIG. 4, the catheter system 400 can include a light guide 422A, a plurality of coupled light guides 422C, a light source 424, a power source 425, a plasma generator 433, optical elements 447, a seed controller 458, a seed source 460, a preamplifier 462, an amplifier 464, and a collimator 466. These components can be substantially similar in shape, arrangement, and / or function to those previously described with respect to the catheter system 400 shown in FIGS. 1-3. In certain embodiments, the catheter system 400 can further include a line width modifier 468.

[0114] Linewidth modifier 468 modifies the linewidth of the optical energy output by seed source 460. In various embodiments, linewidth modifier 468 can be in optical communication with light guide 422A, optical element 447, seed source 460, preamplifier 462, and / or amplifier 464. Linewidth modifier 468 and seed source 460 can operate in conjunction to (i) increase the seed linewidth of seed source 460, (ii) improve amplification of optical energy, and (iii) minimize stimulated Brillouin scattering (SBS) within light guide 422A.

[0115] The design and specific features of the linewidth modifier 468 can be varied to suit the design requirements of the catheter system 400, the light guide 422A, the light source 424, the optical element 447, the seed source 460, the preamplifier 462, and / or the amplifier 464. The linewidth modifier 468 can include, by way of non-limiting and non-exclusive examples, a band-limiting filter, and / or a fiber optic Bragg grating. It is understood that the linewidth modifier 468 can include fewer or additional components than those specifically shown and described herein.

[0116] laser Lasers suitable for use herein can include various types of lasers, including lasers and lamps. Suitable lasers can include short pulse lasers on the sub-millisecond timescale. In some embodiments, the lasers can include nanosecond (ns) timescale lasers. Lasers can also include short pulse lasers on the picosecond (ps), femtosecond (fs), and microsecond (us) timescales. It is recognized that there are many combinations of laser wavelengths, pulse widths, and energy levels that can be employed to achieve plasma within the balloon fluid of the catheters shown and / or described herein. In various embodiments, the pulse widths can include those that fall within a range of at least 10 ns to 200 ns inclusive. In some embodiments, the pulse widths can include those that fall within a range of at least 20 ns to 100 ns inclusive. In other embodiments, the pulse widths can include those that fall within a range of at least 1 ns to 5000 ns inclusive.

[0117] Exemplary nanosecond lasers can include those in the UV to IR spectrum, spanning wavelengths from about 10 nanometers to 1 millimeter. In some embodiments, lasers suitable for use in the catheter systems herein can include those capable of generating light at wavelengths of at least 750 nm to 2000 nm. In some embodiments, the lasers can include those capable of generating light at wavelengths of at least 700 nm to 3000 nm. In some embodiments, the lasers can include those capable of generating light at wavelengths of at least 100 nm to 10 micrometers (μm). Nanosecond lasers can include those having repetition rates of up to 200 kHz. In some embodiments, the lasers can include Q-switched Thulium:Yttrium Aluminum Garnet (Tm:YAG) lasers. In some embodiments, the laser can include neodymium:yttrium aluminum garnet (Nd:YAG), holmium:yttrium aluminum garnet (Ho:YAG), erbium:yttrium aluminum garnet (Er:YAG), excimer lasers, helium-neon lasers, carbon dioxide lasers, and doped pulsed fiber lasers.

[0118] Pressure Waves The catheter systems shown and / or described herein are capable of generating pressure waves having maximum pressures in the range of at least 1 Megapascal (MPa) to 100 MPa. The maximum pressure generated by a particular catheter system depends on the laser, the absorbing material, the bubble expansion, the propagation medium, the balloon material, and other factors. Such factors include the following:

[0119] (i) Pulse energy may be the primary factor determining the size of the bubbles generated and their ability to disrupt calcified lesions. Clinical efficacy is directly linked to the mechanical energy, not the acoustic shock wave that precedes the mechanical bubble. The energies have an inverse cubic relationship:

number

[0120] (ii) Pulse width and envelope shape play a minor role: these factors affect the overall conversion efficiency and the amplitude of the acoustic shock wave that precedes the mechanical bubble.

[0121] (iii) The conversion efficiency is improved by delivering more energy, i.e., more energy within the region where the plasma occurs on the relaxation timescale of the phenomenon. By packing more optical energy into the plasma before bubbles start to form, the conversion efficiency and peak acoustic energy are increased.

[0122] (iv) Stretching the optical energy pulse in time is an effective way to reduce the surface irradiance below the damage threshold of the light guide material while preserving the total energy in the pulse, thereby maximizing the bubble size.

[0123] In some embodiments, the catheters shown and / or described herein are capable of generating pressure waves having a maximum pressure in the range of at least 2 MPa to 50 MPa. In other embodiments, the catheters shown and / or described herein are capable of generating pressure waves having a maximum pressure in the range of at least 2 MPa to 30 MPa. In yet other embodiments, the catheters shown and / or described herein are capable of generating pressure waves having a maximum pressure in the range of at least 15 MPa to 25 MPa. In some embodiments, the catheters shown and / or described herein can generate pressure waves having peak pressures greater than or equal to 1 MPa, 2 MPa, 3 MPa, 4 MPa, 5 MPa, 6 MPa, 7 MPa, 8 MPa, 9 MPa, 10 MPa, 11 MPa, 12 MPa, 13 MPa, 14 MPa, 15 MPa, 16 MPa, 17 MPa, 18 MPa, 19 MPa, 20 MPa, 21 MPa, 22 MPa, 23 MPa, 24 MPa, or 25 MPa, 26 MPa, 27 MPa, 28 MPa, 29 MPa, 30 MPa, 31 MPa, 32 MPa, 33 MPa, 34 MPa, 35 MPa, 36 MPa, 37 MPa, 38 MPa, 39 MPa, 40 MPa, 41 MPa, 42 MPa, 43 MPa, 44 MPa, 45 MPa, 46 MPa, 47 MPa, 48 MPa, 49 MPa, or 50 MPa. The catheters shown and / or described herein can generate pressure waves having operating pressures or maximum pressures that fall within a range, and any of the numerical values ​​above can serve as the lower or upper limits of a range, so long as the lower limit of the range is less than the upper limit of the range.

[0124] The therapeutic treatment can be applied via a fatigue mechanism or a brute force mechanism. For a fatigue mechanism, the operating pressure can be at least about 0.5 MPa to 2 MPa, or about 1 MPa. For a brute force mechanism, the operating pressure can be at least about 20 MPa to 30 MPa, or about 25 MPa. Pressures at the extreme ends of these two ranges can be applied to the treatment site using a combination of the fatigue and brute force mechanisms.

[0125] The pressure waves described herein can be applied to the treatment site from a distance ranging from at least 0.01 millimeters (mm) to 25 mm extending radially from the longitudinal axis of the catheter disposed at the treatment site. In some embodiments, the pressure waves can be applied to the treatment site from a distance ranging from at least 1 mm to 20 mm extending radially from the longitudinal axis of the catheter disposed at the treatment site. In other embodiments, the pressure waves can be applied to the treatment site from a distance ranging from at least 0.1 mm to 10 mm extending radially from the longitudinal axis of the catheter disposed at the treatment site. In still other embodiments, the pressure waves can be applied to the treatment site from a distance ranging from at least 1.5 mm to 4 mm extending radially from the longitudinal axis of the catheter disposed at the treatment site. In some embodiments, the pressure waves can be applied to the treatment site from a range of at least 2 MPa to 30 MPa at a distance of 0.1 mm to 10 mm. In some embodiments, the pressure waves can be applied to the treatment site from a range of at least 2 MPa to 25 MPa at a distance of 0.1 mm to 10 mm. In some embodiments, pressure waves can be applied to the treatment site from a distance greater than or equal to 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, or 0.9 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, or 10 mm, or can be an amount falling within or outside of any of the above ranges.

[0126] By shaping the time morphology of the optical pulse so that it has a fast rise time and minimal overshoot (ideally approaching a square wave), the efficiency for generating pressure waves can be improved and the amount of energy that can be delivered in a given time interval can be increased while simultaneously reducing the peak laser intensity to remain below the damage threshold of the optical fiber.

[0127] The present technology is also directed to methods for treating treatment sites within or adjacent to a vessel wall, such methods utilizing the devices disclosed herein.

[0128] It should be noted that, as used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the content and / or context clearly dictates otherwise. It should also be noted that the term "or" is generally used in its sense including "and / or" unless the content or context clearly dictates otherwise.

[0129] It should also be noted that, as used herein and in the appended claims, the phrase "configured" describes a system, apparatus, or other structure that is constructed or arranged to perform a particular task or adopt a particular structure. The phrase "configured" may be used interchangeably with other similar phrases, such as arranged and configured, constructed and arranged, constructed, manufactured and arranged, etc.

[0130] As used in this specification, the recitation of numerical ranges by endpoints is intended to include all numbers subsumed within that range, including the endpoints (e.g., 2 to 8 includes 2, 2.1, 2.8, 5.3, 7, 8, etc.).

[0131] It will be appreciated that the figures shown and described are not necessarily drawn to scale, and that they are provided for ease of reference and understanding, and for the relative positioning of structures.

[0132] The headings used herein are provided for consistency with suggestions under 37 CFR 1.77 or to provide organizational guidance. These headings are not to be considered as limiting or characterizing the invention(s) set forth in any claim that may be issued from this disclosure. As an example, a description of a technology in the "Background" is not an admission that the technology is prior art to any invention(s) in this disclosure. Neither the "Summary" nor the "Abstract" are to be considered as features of the invention(s) set forth in the claims to be issued.

[0133] The embodiments described herein are not intended to be exhaustive or to limit the invention to the precise forms disclosed in the following detailed description. Rather, the embodiments are chosen and described so that those skilled in the art can appreciate and understand the principles and practices. As such, aspects have been described with reference to various specific preferred embodiments and techniques. However, it should be understood that many variations and modifications may be made while remaining within the spirit and scope of the present description.

[0134] Although several different embodiments of the catheter system have been shown and described herein, it will be understood that one or more features of any one embodiment may be combined with one or more features of one or more other embodiments so long as such combinations meet the intent of the invention.

[0135] While several exemplary aspects and embodiments of the catheter system have been described above, those skilled in the art will recognize certain modifications, permutations, additions and subcombinations thereof, and therefore, the following appended claims and the claims set forth below are intended to be construed to include all such modifications, permutations, additions and subcombinations as fall within their true spirit and scope, and are not intended to be limitations to the details of construction or design shown herein.

Claims

1. 1. A catheter system for treating a treatment site within a blood vessel wall or a heart valve, or adjacent to a blood vessel wall or a heart valve, comprising: a light guide configured to selectively receive light energy; a light source that generates the optical energy, the light source being in optical communication with the light guide, the light source including: (i) a seed source that outputs the optical energy; (ii) a preamplifier that receives the optical energy from the seed source, the preamplifier being in optical communication with the seed source; and (iii) an amplifier that receives the optical energy from the preamplifier, the amplifier being in optical communication with the preamplifier and the light guide.

2. The catheter system of claim 1 , further comprising a seed controller that controls the seed source.

3. The catheter system of claim 1 or 2, further comprising an optical element configured to direct the light energy into the light guide.

4. 3. The catheter system of claim 1, wherein the seed source comprises one of a diode laser, a programmable semiconductor laser, a gated fiber optic laser, and a low-power solid-state laser.

5. The catheter system of claim 1 or 2, wherein the seed source, the preamplifier, and the amplifier are free-space coupled within the light source.

6. 3. The catheter system of claim 1, wherein the seed source is optically coupled to the preamplifier by a first coupling light guide, and the preamplifier is optically coupled to the amplifier by a second coupling light guide.

7. 3. The catheter system of claim 1, wherein the preamplifier comprises one of a fiber optic laser, a solid-state laser, a flashlamp, and a diode-pumped neodymium-doped yttrium aluminum garnet rod.

8. 3. The catheter system of claim 1, wherein the amplifier comprises one of a high gain stage configured for high energy output capability, a fiber optic laser, a diode-pumped solid-state laser, and a flashlamp.

9. 3. The catheter system of claim 1, wherein the amplifier includes a gain medium comprising one of (i) a neodymium-doped yttrium aluminum garnet rod, (ii) a neodymium-doped yttrium aluminum garnet slab, (iii) a neodymium-doped glass, and (iv) an erbium-doped yttrium lithium fluoride, and the gain medium is optically coupled to one of a laser diode stack and a flashlamp.

10. 3. The catheter system of claim 1, wherein the light source includes a collimator that collimates the light energy output by the preamplifier, the collimator being in optical communication with the preamplifier and the amplifier.

11. 1. A catheter system for treating a treatment site within a blood vessel wall or a heart valve, or adjacent to a blood vessel wall or a heart valve, comprising: a light guide configured to selectively receive light energy; a light source that generates the optical energy, the light source being in optical communication with the light guide, and including: (i) a seed source that outputs the optical energy; (ii) a linewidth modifier that modifies a linewidth of the optical energy output by the seed source; (iii) a preamplifier that receives the optical energy from the linewidth modifier, the preamplifier being in optical communication with the linewidth modifier; (iv) a collimator that collimates the optical energy output by the preamplifier, the collimator being in optical communication with the preamplifier; and (v) an amplifier that receives the optical energy from the preamplifier, the amplifier being in optical communication with the collimator and the light guide.

12. 12. The catheter system of claim 11, wherein the seed source comprises a modulated distributed feedback laser.

13. 13. The catheter system of claim 11 or 12, wherein the seed source comprises a plurality of modulated distributed feedback lasers.

14. 1. A catheter system for treating a treatment site within a blood vessel wall or a heart valve, or adjacent to a blood vessel wall or a heart valve, comprising: a light guide configured to selectively receive light energy; a light source for generating light energy, the light source being in optical communication with the light guide, the light source including: (i) a seed source that outputs light energy; and (ii) an amplifier that receives the light energy from the seed source, the amplifier being in optical communication with the seed source and the light guide.

15. a seed controller for controlling the seed source; an optical element configured to direct the light energy into the light guide; The catheter system of claim 14 further comprising:

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