Intravascular lithotripsy

Abstract

The medical device may include a elongate body having a distal elongate body portion and a central longitudinal axis. The medical device may include a balloon disposed along the distal elongate body portion. The balloon may be configured to receive a fluid for inflating the balloon such that an outer balloon surface contacts a calcified lesion within a patient's vasculature. The medical device may include one or more pressure wave emitters disposed along the central longitudinal axis of the elongate body. The one or more pressure wave emitters may be configured to propagate at least one pressure wave through a fluid to fragment the calcified lesion. The at least one pressure wave emitter may include an optical fiber configured to transmit laser energy into the balloon. The laser energy may be configured to generate cavitation bubbles within the fluid.

Description

Technical Field

[0001] (Cross - Reference to Related Applications) The entire content of U.S. Provisional Patent Application No. 63 / 347,981, filed on June 1, 2022, entitled "INTRAVASCULAR LITHOTRIPSY", is incorporated herein by reference. The entire content of U.S. Provisional Patent Application No. 63 / 381,487, filed on October 28, 2022, entitled "INTRAVASCULAR LITHOTRIPSY", is incorporated herein by reference. The entire content of U.S. Provisional Patent Application No. 63 / 482,547, filed on January 31, 2023, entitled "INTRAVASCULAR LITHOTRIPSY", is incorporated herein by reference.

[0002] This disclosure relates to the treatment of calcified plaque lesions within a patient's vasculature.

Background Art

[0003] During intravascular lithotripsy (IVL) procedures, clinicians use catheters configured to break down calcified plaque lesions within a patient's vasculature. Some such methods involve the generation and rapid collapse of cavitation bubbles to produce shockwaves that cause this calcification breakdown.

Summary of the Invention

[0004] This disclosure describes systems and techniques for generating and inducing energy to create cavitation bubbles for the fragmentation and / or collapse of calcified lesions within a patient's vasculature. For illustrative purposes, the techniques herein are described primarily with respect to laser - based systems and their respective uses, such as coronary vascular applications. However, it should be understood that the techniques described herein are equally applicable to similar systems based on other forms of energy, such as electrically - based systems, and to their respective uses, such as peripheral treatment applications, except as explicitly described otherwise below.

[0005] In some examples, a medical device (see, e.g., medical device 12 as shown in FIG. 1) includes a elongate body (see, e.g., elongate body 302 as shown in FIG. 3) having a distal elongate body portion (see, e.g., distal elongate body portion 306 as shown in FIG. 3) and a central longitudinal axis (see, e.g., central longitudinal axis 308 as shown in FIG. 3). According to some examples, the medical device includes a balloon (see, e.g., balloon 204 as shown in FIG. 2) disposed along the distal elongate body portion, the balloon having an inner balloon surface (see, e.g., inner balloon surface 702 as shown in FIG. 7A) and an outer balloon surface (see, e.g., outer balloon surface 704 as shown in FIG. 7B), and being configured to receive a fluid (see, e.g., fluid 212 as shown in FIG. 2) to inflate the balloon such that the outer balloon surface contacts a calcified lesion (see, e.g., calcified lesion 50 as shown in FIG. 1) within a vasculature of a patient (see, e.g., patient 20 as shown in FIG. 1). The medical device may include one or more pressure wave emitters (see, e.g., pressure wave emitter 206 as shown in FIG. 2) disposed along the central longitudinal axis of the elongate body within the balloon, the one or more pressure wave emitters being configured to propagate at least one pressure wave through the fluid to fragment the calcified lesion. In some examples, at least one of the pressure wave emitters includes an optical fiber (see, e.g., optical fiber 802 as shown in FIG. 8) configured to transmit laser energy into the balloon. According to some examples, the laser energy is configured to generate cavitation bubbles within the fluid upon contact with the fluid to generate at least one pressure wave.

[0006] The foregoing features and other features and advantages of the present invention will be apparent from the following more specific description of the preferred embodiments of the invention, the accompanying drawings, and the claims.

Brief Description of the Drawings

[0007] These and other features, aspects, and advantages will be described below with reference to the drawings, which are intended to illustrate and not to limit the invention. In the drawings, like reference numerals consistently denote corresponding features throughout the similar embodiments.

[0008]

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[0009] Specific examples are disclosed below, but the subject matter of the present invention extends beyond the specifically disclosed examples to their alternatives and / or their uses and modifications and equivalents. Accordingly, the claims appended hereto are not limited by any of the specific examples described below. For example, in any method or process disclosed herein, the acts or operations of that method or process may be performed in any suitable order and are not necessarily limited to the specific disclosed order. The various operations may be described as a plurality of individual operations in a way that helps to understand the specific examples, but the order of description should not be construed as meaning that these operations are order-dependent. Further, the structures, systems, and / or devices described herein may be embodied as integrated or individualized components.

[0010] For purposes of comparing the various examples, specific aspects and advantages of these examples are described. Not all such aspects or advantages are necessarily achieved by a particular example. Thus, for example, the various examples may be implemented in a way that achieves or optimizes one advantage or group of advantages taught herein without necessarily achieving other aspects or advantages taught or proposed herein.

[0011] During an intravascular lithotripsy (IVL) procedure, a clinician uses the formation and subsequent collapse of cavitation bubbles to generate high-energy pressure waves to break up calcified plaque lesions within a patient's vascular system. A typical IVL procedure involves the generation of shock waves through an electrode emitter or an electrode pair. In such a system, the cross-profile can be large and the manufacturing can become increasingly complex.

[0012] Moreover, conventional IVL catheters lack the ability to finely control the directionality of the delivered energy. Using an optical fiber to generate cavitation bubbles can help correct these drawbacks of prior art devices, increase the delivered power, enhance the effectiveness of treatment, improve the consistency of energy delivery, improve the durability of the entire IVL catheter, reduce complexity, and reduce manufacturing costs.

[0013] The present disclosure describes systems and techniques for generating and directing high-energy intravascular pressure waves for fragmentation and / or disruption of calcified lesions within a patient's vasculature. For purposes of explanation, the techniques herein are described primarily with respect to optical (e.g., laser)-based systems and their respective applications such as coronary vascular applications. However, it is understood that the techniques described herein are equally applicable to similar systems based on other forms of energy, such as electrical-based systems, and to their respective applications, such as peripheral treatment applications, except as explicitly described otherwise below. Further, throughout this specification, the treatment site is described as including calcified lesions, but it is understood that the present disclosure is also capable of treating restenotic lesions.

[0014] The systems described herein generally include an energy source, an IVL catheter having a distal IVL device, and an optical fiber. In some examples, the system includes an interventional balloon. During a lesion disruption procedure, a clinician advances the interventional balloon into a target treatment site within a patient's vasculature and may inflate the balloon with an inflation fluid, such as a saline / contrast mixture, until the balloon contacts at least a portion of the local vessel wall. The saline / contrast mixture is understood to have a viscosity suitable for generating cavitation bubbles upon introduction of electrical or optical energy. Since the saline / contrast mixture is often mixed during treatment, the ratio of saline to contrast can vary. Nevertheless, laser-based energy delivery may be relatively insensitive to these variations. The clinician then activates the energy generator to generate cavitation bubbles within the catheter's fluid-filled balloon and propagate high-energy pressure waves through the balloon and the calcified lesion. A second pressure wave may also occur due to the collapse of subsequent liquid cavitation, further destabilizing the internal structure of the lesion.

[0015] In examples that do not include an interventional balloon, a saline / contrast mixture is released into the patient's vasculature near the treatment site to displace the blood in the local area. Once this saline / contrast mixture has at least partially displaced the blood in this area, the clinician activates the energy generator to cause the catheter to generate cavitation bubbles in the area of the saline / contrast mixture and propagate high-energy pressure waves through this area to the calcified lesion.

[0016] Regardless of the presence or absence of an interventional balloon, additional examples include introducing a photosensitizer into the saline / contrast mixture. This photosensitizer may provide a target for the energy source to aim at and may enable more detailed control over where cavitation bubbles form within the interventional balloon and / or the saline / contrast mixture that has displaced the local area's blood.

[0017] As used herein, "superheating" means heating a liquid above its boiling point without evaporating it under pressure. In some examples, the devices disclosed in this application do not superheat the fluid within the balloon to form cavitation bubbles. In alternative examples, the devices of the present disclosure superheat the fluid within the balloon to form these cavitation bubbles.

[0018] FIG. 1 shows a schematic view of an intravascular lithotripsy (IVL) system 10 as it might appear inserted within a patient's vasculature. The IVL system 10 may include a medical device 12, perhaps an interventional balloon, as shown in subsequent figures. During a lesion ablation procedure, a clinician may advance the medical device through an access point 14 within the patient 20, such as the femoral artery or the common femoral artery, as shown in FIG. 1. Other access points may include the radial artery, tibial artery, pedal artery, axillary artery, peroneal artery, and the like. The medical device 12 may then be advanced through the patient's vasculature until it reaches a blood vessel 30 that includes a treatment region 40. In the case of IVL, the treatment region may include a calcified lesion 50. FIGS. 2A and 2B show close-up views of two examples of an IVL system positioned within or adjacent to a treatment region 40 that includes a calcified lesion 50.

[0019] Figure 2A shows a schematic view of a medical device 12 within a treatment region 40 that includes a calcified lesion 50 within a blood vessel 30. In this example, the medical device 12 includes a balloon 204. During an IVL procedure, a clinician may expand the balloon 204 to physically contact at least a portion of the calcified lesion 50 within the treatment region 40 and the wall of the blood vessel 30. This expansion of the balloon 204 may include the use of a saline / contrast agent fluid mixture that propagates a pressure wave or “shock wave” when heated by a laser. This saline / contrast agent fluid solution may be in any percentage ratio since no distinguishable differences have been observed during testing. Any saline / contrast agent fluid solution may be used, but since saline is not visible under fluoroscopic guidance and thus does not show the operator the expansion or problems associated with the expansion, it is desirable to include at least a small percentage of a contrast agent fluid in the solution. As discussed in FIGS. 10A - 10B, a specific wavelength of laser energy can heat the saline / contrast agent fluid mixture without assistance (FIG. 10A). However, other wavelengths may have low absorbability in the saline / contrast agent fluid mixture and may require a target block to heat and generate a pressure wave.

[0020] Also shown in FIG. 2A is a central lumen 208 located within an elongate body (302 below). Along the elongate body 302, there is a pressure wave emitter 206. As shown in FIGS. 2A and 2B, five pressure wave emitters (206a, 206b, 206c, 206d, and 206e) are present within the medical device 12. FIGS. 2A and 2B show five pressure wave emitters 206, but the emitter 206 array of the medical device 12 may include anywhere from a minimum of one individual emitter unit 206 to the maximum number of emitter units 206 that can reasonably fit within the balloon 204. Also note that the individual emitter unit 206 is also referred to as 206 throughout the present disclosure (e.g., with respect to the emitter unit 206 as a whole).

[0021] FIG. 2B shows a schematic view of the medical device 12 adjacent to the treatment region 40 including the calcified lesion 50 within the blood vessel 30. The medical device 12, balloon 204, and pressure wave emitter 206 may be the same as those described in FIG. 2A. However, the central lumen 208 of the elongate body 302 in FIG. 2B is shown to deploy or inject fluid 212 into the treatment region 40. This fluid 212 can move the blood within the treatment region 40 before inserting the medical device 12 into the treatment region 40, facilitate the expansion of the balloon 204, and enhance the effect of the IVL treatment.

[0022] FIG. 3 is a diagram showing the IVL system 10. As shown in FIG. 3, the IVL system 10 may include at least an energy generator 310 and an elongate body 302 removably coupled to the energy generator 310 via an electrical connector 312 or the like. The elongate body 302 may include a medical device 12 disposed at the distal elongate body portion 306. In some examples, the elongate body 302 is configured to navigate the tortuous vasculature of the patient 20 towards the target treatment site 40, e.g., the calcified plaque lesion 50 within the blood vessel 30.

[0023] The term "elongate body" is used throughout this specification, and it is understood that the elongate body can refer to a catheter such as an IVL catheter. Further, although the connector 312 is described as an electrical connector 312 in the description of FIG. 3, it is understood that the connector 312 may be an optical connector 312. In fact, in some embodiments, the IVL system 10 does not require an electrical connector 312. In these embodiments, a treatment button may be present on the console and there may be no electrical interrogation of the catheter itself. The electrical connector 312 is not necessary in all examples, but an optical connector 312 is required to provide laser energy to the catheter.

[0024] As shown in FIG. 3, the medical device 12 can include a fluid-expandable interventional balloon 204 and an array of pressure wave emitters 206 disposed within the balloon 204 (shown but not labeled due to size constraints). The emitter 206 array can include one or more individual emitter units 206. For example, the interventional balloon 204, or a distal elongate body portion 306 passing therethrough, may define a central longitudinal axis 308, and the emitter units 206 may be longitudinally disposed along the central longitudinal axis 308.

[0025] Each emitter unit 206 is configured to receive energy from an energy generator 310 and use the received energy to generate high-energy pressure waves that are transmitted across the treatment site through the balloon 204. As will be described in further detail below, the energy generator 310 may generate and transmit energy in the form of electrical energy, light energy, or a combination thereof. For example, the emitter unit 206 may use the received energy to generate cavitation bubbles 1404 within the fluid within the balloon 204 and propagate one or more high-energy pressure waves radially outward through the balloon and the calcified lesion.

[0026] Although not in all cases, in some cases, a secondary set of high-energy pressure waves can follow from the collapse of the fluid cavitation bubbles 1404 (as shown in FIG. 14) and further destabilize the internal structure of the calcified plaque lesion. In some examples, one or more of the emitters 206 can include a light-based emitter 206 configured to receive a high-energy light (e.g., optical) signal from the generator 310 via, for example, one or more optical fibers 802 (as shown in FIG. 8) and direct the optical signal to trigger initial cavitation. Additionally, one or more of the emitters 206 can also include an electrically-based emitter 206 configured to receive electrical energy from the generator 310 via, for example, one or more conductive wires and generate a spark between a pair of electrodes to thereby trigger initial cavitation.

[0027] According to some examples, the cooling mechanism functions in parallel with the energy generator 310. However, the flash lamp system may supply energy to the optical fiber 802 without requiring the cooling mechanism. Further, the diode system may be used as an alternative to the flash lamp system that does not require a cooling mechanism.

[0028] FIG. 4 shows an embodiment that appears to use the IVL system 10 of FIG. 3. Optionally, a medical post may be provided to facilitate movement of the IVL system 10 between rooms. The power supply 402 may be disposed near the base of the medical post and coupled to a power cord 408 to receive power from wall power or the generator 310 and an umbilical cord to be electrically coupled to the console 404. As shown in FIG. 4, the console 404 enables a user, such as a clinician, to operate the IVL system 10. The elongate body 302 may receive energy from the power supply 402 and be coupled to the console 404 via a power cable to transmit energy to the emitter 206 within the IVL balloon 204. There may be a separate line dedicated to inflating the IVL balloon 204.

[0029] According to some examples, a detection line 406 exists. The detection line 406 may provide several ways to provide feedback regarding the integrity of the individual components within the IVL balloon 204. For example, a safety pressure sensor may be provided. If a rapid pressure drop is detected, a failure such as a rupture of the IVL balloon 204 may have occurred. This suggests to the clinician that the procedure should be stopped and the IVL balloon 204 should be immediately and safely retrieved from the patient's vasculature. According to some examples, when a pressure sensor within the IVL balloon 204 detects a balloon 204 rupture, the energy release through the elongate body 302 may be immediately stopped. It is understood that the term "stop" may be used to issue an error code to the operator for a manual shutdown or an automatic system shutdown.

[0030] Furthermore, the pressure sensor may be located anywhere within the pressure path, where the pressure path defines a path that begins at the generator and ends at the balloon 204. In some examples, the pressure sensor may be located within the generator 310. According to some examples, the pressure sensor may be located within a hub that is an intermediate component connecting the elongate body 302 to the generator 310 (in an example including another generator 310). The pressure sensor may be located within the elongate body 302. In some examples, as described in the previous paragraph, it is the IVL balloon 204. The pressure sensor may be located outside of these separate components (generator 310, hub, elongate body 302), but within the pressure path.

[0031] Furthermore, in some examples, the pressure sensor may be located anywhere within the IVL system 10, including outside of the aforementioned pressure path. This may include a separate device outside of the medical device 12, such as a part of a hub connector or an inflation device attached to the hub connector. This inflation device may be adjacent to, but outside of, the guide wire lumen 208. The pressure sensor may be part of such an inflation device or attached to such an inflation device.

[0032] Furthermore, a fiber interrogation mechanism may be present. According to some examples, the purpose of the fiber interrogation mechanism is to sense or detect whether at least one of the optical fibers, or the optical fiber 802 (see FIG. 8), is damaged or otherwise cut. This may be achieved by reflecting at least a portion of the energy back to the optical fiber 802 when a pulse is emitted, and the disruption of this return pulse indicates to the clinician that something is wrong, so the IVL balloon 204 needs to be retrieved and the problem corrected.

[0033] FIG. 5 shows a block diagram of a laser energy source system 502 according to several examples. As can be seen from the dotted line surrounding most of the components, the laser energy source system 502 includes an energy source. Power, such as power from a wall indicated by the arrow through 120V(IN), can be supplied to a power supply 402 within the energy source. The power supply 402 supplies power to a flash lamp power supply 504 and a central processing unit (CPU) 518. The flash lamp power supply 504 may be controlled by the CPU 518.

[0034] The CPU 518 includes a user interface, and the user interface may include other user communication means such as tactile buttons and switches, or a touch screen. A power-on switch 516 is shown electronically communicating with the CPU 518, and a push button 520 for resetting (reset) the CPU 518 and starting treatment (treatment) when the elongate body 302 is in a predetermined position is also shown. The CPU 518 also controls the lamp 514 (ON (on), RDY (ready), E (emitting light), and F (fault)). The ON lamp 514 indicates that the system 502 is on. The RDY lamp 514 indicates that the system 502 is connected and ready to activate laser energy. The E lamp 514 indicates that the laser energy is currently active. The F lamp 514 indicates that a fault has occurred and the system 502 needs to be reset. In the IVL system 10 including a safety function such as the safety pressure sensor as described above, the CPU 518 receives this feedback from the pressure sensor 522, and the pressure sensor 522 is disposed within the IVL balloon 204 and thus exists outside the energy source.

[0035] The flash lamp power supply 504 includes a lamp lead 506 that electrically couples the flash lamp power supply 504 to the laser head 508. The laser head 508 communicates electronically with the CPU 518 and is directed at a shutter 510 that is controlled. The shutter 510 is an additional safety device that prevents premature emission of the laser through the elongate body 302. The shutter 510 is commanded by the CPU 518 immediately before triggering the flash lamp, and the flash lamp starts the laser energy. In the case of a laser source such as an excimer laser, the triggering of the shutter 510 may be a high voltage switch and not necessarily the flash lamp. The shutter 510 separates the laser head 508 from the optical fiber 802 as indicated by the fiber out 512. The optical fiber 802 then travels the length of the elongate body 302 to the treatment site. In the IVL system 10 including a safety function such as the fiber interrogation mechanism described above, the CPU 518 receives feedback from the optical fiber 802 via the fiber interrogation mechanism 524 as shown. Since the fiber interrogation mechanism can operate from any location along the fiber line (a break at any location on the line can be detected at other locations on the line as long as the detection is made before the break), the fiber interrogation mechanism 524 is shown to be conveniently located within the energy source.

[0036] FIG. 6 shows a side view of an exemplary elongate body 302 that includes an IVL balloon 204 in the distal elongate body portion 306 and a connector 312 for coupling the elongate body 302 to the generator 310. In some examples, the elongate body 302 includes an inner shaft and an outer shaft surrounding the inner shaft. The inner shaft may include a guide wire lumen 208, or another type of lumen 208, depending on the needs of the clinician.

[0037] According to FIG. 6, an IVL balloon 204 may be present. The IVL balloon 204 may be inflated with a saline / contrast agent fluid mixture when the elongate body 302 is advanced to the treatment site. There is at least one emitter within the IVL balloon 204. As described above, a single emitter 206 may be present (as described in FIGS. 14A, 14B, 16A, and 16B), or multiple emitters 206 may be present (as shown in detail in FIGS. 18A, 18B, and 18C).

[0038] According to some examples, a single emitter such as an optical fiber may be scored to create multiple locations for emitting light or signals for the laser, causing a single optical fiber 802 to function as multiple emitters 206. Such embodiments will be discussed in more detail in FIGS. 14A and 14B.

[0039] At the proximal elongate body portion 304, the connection point between the elongate body 302 and the generator 310 can be seen. This connection point may occur by directly coupling the elongate body 302 to the generator 310 or by means of an adapter suitable for coupling one end to the elongate body 302 and the opposite end to the generator 310. In an example where multiple fibers 802 are utilized as emitters 206 at this proximal elongate body portion 304, a fiber bundle may be present. This fiber bundle is in optical communication with the generator 310 or optically coupled to the generator 310 to supply laser energy to the optical fibers 802, and this laser energy is emitted into the fluid-filled IVL balloon 204.

[0040] As previously disclosed, in some examples, the IVL balloon 204 may not be present and is not necessary on the elongate body 302. In these embodiments, the inner shaft may include a lumen 208 configured to deliver a saline / contrast agent fluid mixture to the treatment region of the vasculature. Introducing this saline / contrast agent fluid mixture can displace the local blood in this vasculature, and thus the energy emitted by the optical fiber 802 can generate cavitation bubbles 1404 without the need for an external structure such as the IVL balloon 204.

[0041] Figures 7A and 7B show two cross-sectional views of the medical device 12 of FIG. 6. Specifically, FIG. 7A shows the balloon 204 having a metallization coating 706 on the inner balloon surface 702, and FIG. 7B shows the balloon 204 having a metallization coating 706 on the outer balloon surface 704. Both FIGS. 7A and 7B also show the elongate body 302 and the central lumen 208. The radii and ratios of each feature are exaggerated to simplify the representation of each independent structure in the drawing.

[0042] The metallization coating 706 may be configured to increase the damage threshold of the balloon 204 to laser energy. That is, since the metallization coating 706 is present on either the inner balloon surface 702 or the outer balloon surface 704, the resistance to perforation and collapse of the balloon 204 due to excessive laser energy may increase. The metallization coating 706 may provide additional safety in the event of balloon 204 failure or shrinkage. This metallization coating 706 may prevent the optical fiber (802 below) from contacting or penetrating the balloon 204. Without additional safety means, if the balloon perforates during treatment, fragments of the balloon may be left inadvertently in place, and they may move through the patient's vasculature. Further, this additional measure may facilitate the prevention of unwanted balloon shrinkage.

[0043] This metallization coating 706 may be made of aluminum, nickel, chromium, gold, alloys, dielectric reflective coatings, etc. This list of metallization coatings 706 is not exhaustive, and it is understood that equivalent metallization coatings 706 not described herein may also be used. The metallization coating 706 may be deposited in a very thin layer. These layers may be only a few microns thick, making the metallization coating 706 substantially transparent and achieving the advantages described herein while minimizing changes to the thickness of the balloon 204 as much as possible.

[0044] In both FIGS. 7A and 7B, the metallization coating does not significantly change compliance or other balloon characteristics. The additional thickness added to the balloon 204 may depend on whether the metallization coating 706 is on the inner balloon surface 702 or the outer balloon surface 704. For example, in FIG. 7A, the metallization coating 706 may be folded, which may increase the thickness of the balloon 204 by up to twice. In FIG. 7B, an additional layer may be disposed outside the metallization coating 706 on the outer balloon surface 704 to prevent particle movement. This may suggest increasing the thickness of the balloon 204 by up to six times.

[0045] FIG. 8 shows a perspective view of the IVL balloon 204 and an inset showing the position of the distal fiber end (hereinafter 1402) of the optical fiber 802 by the elongate body 302 of FIG. 6. In this example and the following examples, any existing optical fiber 802 functions as the pressure wave emitter 206 as detailed in the previous figures. According to the example of FIG. 8, the protective sleeve can accommodate the inner shaft and / or any current lumen 208 and protect these surfaces from energy release from the distal fiber end 1402 of the optical fiber 802. Although not shown in the figure, the optical fiber 802 may include a toe or blunt feature at its end portion to prevent accidental perforation of the balloon 204 by the optical fiber 802. It is understood that such a toe or blunt feature does not prevent the passage of laser energy from the distal fiber end 1402.

[0046] FIGS. 9A and 9B show perspective views of a portion of the elongate body 302 at the distal fiber ends 1402 of two optical fibers 802 according to some examples. At least one optical fiber 802 may terminate at least partially adjacent to the target 902. In the context of short wavelength radiation such as a Nd:YAG laser, the target 902 provides a safety feature and may be a component in the formation of the cavitation bubble 1404.

[0047] As far as safety is concerned, the higher energy provided by the Nd:YAG laser can potentially progress into the patient's vasculature if left uninterrupted after causing cavitation. In such a situation, at a sufficiently high energy level, this can be harmful to the patient. The target 902 can prevent energy from exceeding the boundaries of the IVL balloon 204 and / or the effective treatment area in situations where the IVL balloon 204 is not provided.

[0048] Regarding the formation of the cavitation bubble 1404, the target 902 can receive the energy emitted by the optical fiber 802 and start heating. When the target 902 is further heated, the cavitation bubble 1404 can be formed on the target 902. In this scenario, the wavelength of the laser is not absorbed by or not intended to be absorbed by the saline / contrast agent mixture. This is because all of the energy is delivered to the target 902, and subsequent heating of the surrounding saline / contrast agent mixture can promote the generation of superheated cavitation bubbles 1404 on the surface of the target 902.

[0049] Figures 10A, 10B, 10C, and 10D show diagrams of a medical device 12 having an IVL balloon 204 with the distal fiber end 1402 of the optical fiber 802 held in a predetermined position by a fiber positioner 1002 and directed toward a target 902.

[0050] Figure 10A shows a side view of the medical device 12 without a target. In this example, the wavelength of the energy from the laser is such that the saline / contrast agent fluid mixture is heated by the laser itself and propagates cavitation bubbles without the need for additional components in the form of a target. In Figures 10B - 10D, various other wavelengths of laser energy may be used since the saline / contrast agent fluid mixture is not the intended recipient of the energy. The reason is that the target 902 is used to receive and overheat the laser energy, heating the surrounding saline / contrast agent fluid mixture in turn and subsequently causing the propagation of cavitation bubbles.

[0051] FIG. 10B shows a side view of the target 902a as a trapezoid, with the flat side facing the distal fiber end 1402. FIG. 10C shows a side view of the target 902b as an elongated octagon, where an inclined or sloped surface can be within the path of the optical signal. FIG. 10D shows an example of a target 902c having a surface facing the fiber, and the surface has a slope or is inclined with respect to the angle of travel of the laser energy. This inclined surface enables the cavitation bubble 1404 to be emitted substantially perpendicular to the angle of travel of the laser energy and towards the calcified lesion.

[0052] In the elongate body 302 of FIGS. 10A, 10B, 10C, and 10D, the optical fiber 802 is locked in place by the fiber positioner 1002. This fiber positioner 1002 can ensure that the relationship between the optical fiber 802 and the target 902 is consistent both in terms of the distance from each other and in terms of the distance of the distal fiber end 1402 from the central lumen 208.

[0053] According to some examples, the fiber may be repositioned within the balloon 204 so that the clinician may adjust the distance to the target 902. As described in other figures, this ability to reposition the optical fiber 802 is independent of the target 902 present within the elongate body 302. The slide mechanism may be included in a handle or control interface coupled to the optical fiber 802, thereby enabling axial movement and control of the optical fiber 802. If the clinician wishes to independently control each optical fiber 802 present within the elongate body 302, separate slide mechanisms may be included. If only a single optical fiber 802 is present within the elongate body 302, only a single slide mechanism may be required. The fiber positioner is shown and described in FIGS. 11A, 11B, 11C, and 11D.

[0054] Figures 11A, 11B, 11C, and 11D show profile diagrams of three possible configurations of a fiber positioner for holding an optical fiber in a predetermined position, as shown in Figures 10A - 10D. Specifically, Figure 11A shows a marker band 1102 having a top component fiber positioner 1002a that holds the optical fiber 802 and has a chamfered portion at an end where the tip of the optical fiber is disposed without contact. Such a fiber positioner 1002 may be injection molded or extruded.

[0055] Figure 11B shows the fiber positioner 1002 of Figure 11A, but without the marker band 1102. This fiber positioner 1002b may also be extruded or injection molded, but since there is no marker band 1102, the fiber positioner 1002b may be attached to a pre - manufactured marker band 1102 or another component using an adhesive or the like. The fiber positioner 1002b has a radially shaped bottom surface to enable attachment to a circular mechanism such as the elongate body 302, the marker band 1102, or another component.

[0056] Figure 11C shows another example of a fiber positioner 1002c. This fiber positioner 1002c is simpler in structure than those of Figures 11A and 11B because it does not include a plurality of openings or a radial bottom. This fiber positioner 1002c may be held in a predetermined position with respect to the elongate body 302, or may include laser - cut slits in its flare portion to enable crimping to the elongate body 302, the marker band 1102, or another component. Additional embodiments include attaching the fiber positioner 1102c to an internal mechanism (i.e., the elongate body 302, the marker band 1102, etc.) via an ultraviolet (UV) adhesive, heat shrinkage, or a swaged marker band. It is understood that these attachment embodiments may be used with the fiber positioner 1002b of Figure 11B. These attachment embodiments are not necessary in the case of the fiber positioner 1002a of Figure 11A because the fiber positioner 1002a and the marker band 1102 are molded together in such an example.

[0057] Figure 11D shows another example of the fiber positioner 1002 shown as the marker band 1102b. In this example, there are two marker bands 1102, namely, an inner marker band 1102a around the guide wire lumen 208 and an outer marker band 1102b surrounding the inner marker band 1102a and any current optical fiber 802. In this way, the inner marker band 1102a separates the optical fiber 802 from the guide wire lumen 208 by a predetermined distance, and the outer marker band 1102b maintains the optical fiber 802 in a predetermined position.

[0058] A flare similar to the shroud shown and described in FIG. 13 below is not present in FIGS. 11A-11D, but may be present in any of FIGS. 11A-11D. This flare may act as a safety feature and facilitate preventing laser energy from contacting either the surface of the balloon or the guide wire lumen.

[0059] FIG. 12 shows, according to some examples, a view of two optical fibers 802 represented as optical fiber 802a and optical fiber 802b traversing the elongate body 302 along the guide wire lumen 208 and terminating inside the IVL balloon 204. As seen in FIG. 12, the optical fiber 802a shown above the guide wire lumen 208 shows an angled distal tip. According to some examples, this angled distal tip has an angle greater than 114 degrees with respect to the longitudinal axis of the guide wire lumen 208. In other words, if the distal fiber end 1402 moves substantially parallel to the vasculature through which it moves, the distal tip may have an angle greater than 24 degrees with respect to a plane perpendicular to the longitudinal axis of the lumen 208. This angled distal tip helps avoid laser energy colliding with the outer surface of the guide wire lumen 208. This can improve the safety of the guide wire lumen 208 and ensure that all laser energy is delivered to the target 902, or both.

[0060] As seen in the optical fiber 802b below the guide wire lumen 208, the optical fiber 802b may terminate radially outwards from the center below the guide wire lumen 208. Similar to the angled distal tip, this radially outwards terminating optical fiber 802b helps to avoid the laser energy impinging on the outer surface of the guide wire lumen 208. The distance at which the optical fiber 802b is presented radially outwards from the guide wire lumen 208 depends on the diameter of the optical fiber and the location where the optical fiber 802b is allowed to start bending. If the bend of the optical fiber 802b is large, a larger balloon 204 may be required, which can be a problem in smaller diameter vasculature.

[0061] FIG. 13 shows a profile view of a shroud 1302 for protecting the balloon 204 from the optical fiber 802. The shroud 1302 may be joined to a skirt made of cloth, polymer, or other flexible material and may be a laser cut nitinol structure. The skirt may expand when the balloon 204 expands. The nitinol structure includes teeth with curved ends to provide a smooth contact point with the balloon 204 and may prevent accidental perforation of the balloon 204. The skirt may also expand using a different mechanism within the handle proximate to the elongate body 302.

[0062] As used in the examples of FIGS. 11A, 11B, 11C, and 11D, the shroud 1302 may be used to protect the balloon 204 from the tip of the optical fiber 802 and prevent accidental perforation of the balloon 204. The shroud 1302 may also be used with any fiber positioner 1002.

[0063] The solid portion of the shroud 1302 is crimped or potted onto the optical fiber 802, and the optical fiber 802 may extend to a point just inside the portion of the shroud 1302 where the skirt begins. This allows the nitinol structure ("arm") and skirt to collapse around and beyond the tip of the optical fiber 802. The shroud 1302 is shown as a 180-degree structure, but it is understood that the shroud 1302 may exhibit any amount of circumferential coverage between 0 degrees (no cover) and 360 degrees (full circumferential cover).

[0064] Figures 14A and 14B show perspective views of a single optical fiber 802 moving along the elongate body 302 and an elongate cavitation bubble 1404 formed at the distal fiber end 1402. Specifically, FIG. 14A shows the distal elongate body portion 306, and FIG. 14B shows a close-up view of the distal fiber end 1402 of the optical fiber.

[0065] Although an elongate cavitation bubble 1404 is shown in FIGS. 14A and 14B, in some examples, smaller cavitation bubbles 1404 may be formed. In either case, the single optical fiber 802 may move the length of the elongate body 302 and terminate near the distal elongate body portion 306. In examples that include the IVL balloon 204, the optical fiber 802 may terminate within the IVL balloon 204. When a small cavitation bubble 1404 is used, the distal fiber end 1402 may be positioned at least partially concentric with the treatment site. Here, the cavitation bubble 1404 is formed by generating energy along the optical fiber and then directing the energy. This energy is emitted from the distal fiber end 1402 and then interacts with the saline / contrast agent fluid mixture to form a cavitation bubble. When this cavitation bubble 1404 collapses, a shock wave is propelled radially from the collapse point, colliding with or penetrating the treatment site and damaging the current calcification.

[0066] In the case of an elongated cavitation bubble as shown in FIGS. 14A and 14B, the process is very similar. However, the difference lies in the pulse width and frequency generated to produce the Moses effect. The Moses effect is a propagating cavitation bubble. When cavitation bubble 1404 is formed, subsequent laser energy travels through the formed cavitation bubble, enabling the deposition of laser energy at the distal end of cavitation bubble 1404, i.e., the end of cavitation bubble 1404 farthest from the distal fiber end 1402. Since cavitation bubble 1404 continues to propagate and collapse over the length of the treatment site (an area of saline / contrast agent fluid mixture such as a portion of the vasculature where blood has moved or up to the length of IVL balloon 204), it becomes possible to treat lesions longer than a single cavitation bubble.

[0067] Target 902 as described in FIGS. 9B, 10B, 10C, and 10D is likely not used with the elongate body 302 that implements the Moses effect. This is because the distance over which cavitation bubble 1404 can propagate is significantly limited. In some examples, an energy source with a longer wavelength, such as Ho:YAG or CTH:Yag, may be utilized.

[0068] FIG. 15 shows a cross-sectional view of the elongated body 302 and the optical fiber 802 of FIGS. 14A and 14B. As seen in FIG. 15, the optical fiber 802 includes a core 1502 and a cladding 1504. The cladding 1504 prevents laser energy from exiting the optical fiber 802 from the core 1502. Although not shown in FIG. 15, scores within the cladding 1504 are shown and described in FIGS. 16A-18C, which enable laser energy to be prematurely emitted from the optical fiber 802 to the distal fiber end 1402. In some examples, such as the examples of FIGS. 14A, 14B, and 15, the system may prevent this laser energy from prematurely exiting the optical fiber 802. Although not shown, in some examples, the core may also be scored slightly. Similar to FIGS. 7A and 7B above, the radii and ratios of each feature are exaggerated to simplify the representation of each independent structure in the drawings.

[0069] FIGS. 16A and 16B show perspective views of a single optical fiber 802 moving along an elongated body 302 having a score 1602 cut into the optical fiber. Specifically, FIG. 16A shows the distal elongated body portion 306, and FIG. 16B shows a close-up view of two scores 1602 within the optical fiber 802. Both FIGS. 16A and 16B show a cavitation bubble 1404 starting at the score 1602 of the optical fiber 802.

[0070] As shown in FIGS. 16A and 16B, each score 1602 indicates an energy exit point. This can effectively convert a single optical fiber 802 into a multi-emitter laser fiber. In these examples, the energy is reflected within the optical fiber 802 until it finds a natural termination point where it can be emitted, such as at each of the scores 1602. As shown in FIG. 16B, the energy may be emitted through the opening of the distal fiber end 1402 in addition to the score 1602.

[0071] Similar to the example of the single optical fiber 802 in FIGS. 14A and 14B, when energy is released from the score, the energy reacts with the saline / contrast agent fluid mixture to generate cavitation bubbles. These cavitation bubbles 1404 then collapse, generating shock waves that impact or penetrate the treatment area, damaging the current calcification. Similar to the Moses effect described above, when multiple scores 1602 are present, multiple cavitation bubbles 1404 are generated across the treatment area, increasing the length of the applicable treatment.

[0072] As shown in FIG. 16B, the distal fiber end 1402 may be used as an exit point, similar to the example shown in FIGS. 14A and 14B. This distal fiber end 1402 can function similarly to the distal fiber end 1402 of the single optical fiber 802 in that cavitation bubbles 1404 can be formed here. Depending on the generator settings such as pulse width and frequency, the Moses effect may be utilized at this distal fiber end 1402.

[0073] FIG. 16A shows five scores 1602, and FIG. 16B shows the two most distal scores 1602. There may be only one score, or multiple scores (e.g., in an example including the IVL balloon 204, scores 1602 that fit within the IVL balloon 204) may be present.

[0074] FIG. 17 shows a cross-sectional view of the elongate body and the optical fiber of FIGS. 16A and 16B. Similar to FIG. 15, the optical fiber 802 includes a core 1502 and a cladding 1504. The cladding prevents laser energy from exiting the optical fiber 802 from the core 1502 at undesirable locations. Different from FIG. 15, the cladding 1504 is shown to include a score 1602 in FIG. 17. The score 1602, illustrated and described in FIGS. 16A and 16B and described later in FIGS. 18A, 18B, and 18C, enables laser energy to exit the optical fiber 802 in front of the distal fiber end 1402. This early emission enables the formation of a plurality of cavitation bubbles 1404 along the body of the optical fiber 802, increasing the effective treatment length along the calcified lesion 50 in the treatment region 40. Similar to FIGS. 7A, 7B, and 15, the radii and ratios of each feature are exaggerated to simplify the representation of each independent structure in the drawing.

[0075] FIGS. 18A, 18B, and 18C show various perspective views of an embodiment of a plurality of optical fibers 802 of the elongate body 302. In each of FIGS. 18A-18C, the termination point at each distal fiber end 1402 of the optical fiber 802 of the present invention indicates the start of a cavitation bubble.

[0076] According to the elongate body 302 of FIGS. 18A-18C, each optical fiber 802 operates in the same manner as the elongate body 302 of FIGS. 14A and 14B. Energy is transmitted from the generator 310 through each optical fiber. When energy is emitted from each distal fiber end 1402a, 1402b, 1402c, and 1402d, the energy may interact with the saline / contrast agent fluid mixture, as shown, to generate cavitation bubbles 1404. When the cavitation bubbles 1404 collapse, shock waves are propelled substantially radially from each point of collapse, strike and penetrate the treatment site, and damage existing calcifications. Since there are a plurality of optical fibers 802 and the distal fiber ends 1402 are arranged longitudinally spaced from each other, a plurality of cavitation bubbles 1404 are formed along the length of the treatment region, so that the size of treatable lesions can be enlarged.

[0077] By controlling the pulse width and frequency of the supplied energy, the operator may achieve the Moses effect from each optical fiber 802. However, the advantage of achieving this using a plurality of laser emitters 206 is that it may not be more effective than using a single laser emitter since the plurality of laser emitters 206 already achieve the goal of extending the treatment region.

[0078] Depending on the energy source used, one target 902 or a plurality of targets 902 may be applied to the distal elongate body portion 306 to absorb the energy provided by the optical fiber 802. Similar to the exemplary targets 902 of FIGS. 9B, 10B, 10C, and 10D, the target 902 may be heated by absorbing this energy. As the target 902 continues to heat, cavitation bubbles 1404 may form on the target 902 as a result of the target heating the surrounding saline / contrast agent solution. In this case, the wavelength of the energy may not be intended to be directly absorbed by the saline / contrast agent fluid mixture. All of the energy may be delivered into the target 902, and the heat generated by the saline / contrast agent fluid mixture may absorb this heat, facilitating the generation of superheated cavitation bubbles 1404 on the surface of the target 902.

[0079] Although not shown in FIGS. 18A-18C, the optical fiber 802 may be fixed in place by the fiber positioner 1002. This fiber positioner 1002 may ensure that the relationship between each distal fiber end 1402 and the associated target 902 remains consistent, similar to the distance by which each optical fiber 802 is offset from the central lumen 208.

[0080] Each of FIGS. 18A-18C shows five optical fibers 802. The optical fibers 802 may be present only one (as shown in FIGS. 14A and 14B), may be present in multiple numbers that can fit within the IVL balloon 204 (in embodiments including the IVL balloon 204), or may be present in multiple numbers that can fit within the vasculature being treated.

[0081] The exemplary elongate body 302 of FIGS. 18A-18C shows optical fibers 802 surrounding the central lumen 208, and the distal fiber ends 1402 terminate at different points along the central lumen 208. For example, the optical fibers 802 may be further spaced apart from each other, or the optical fibers 802 may be arranged symmetrically around the central lumen 208. Any configuration may be utilized.

[0082] Although cross-sectional views of FIGS. 18A-18C are not shown, it is understood that the cross-sectional views may appear similar to the cross-sectional view without a score in FIG. 15 or the cross-sectional view having a score 1602 in FIG. 17. In either case, the only change is the number of optical fibers 802 surrounding the elongate body 302.

[0083] In all of FIGS. 14A-18C, it is understood that the cavitation bubbles 1404 formed by the means disclosed herein are considered to radiate outwardly from substantially the center of the elongate body 302, even though each optical fiber 802 is spaced apart at a short radius. The central lumen 208 does not interfere with the cavitation bubbles 1404 in any meaningful way. As such, it is understood that each provided cavitation bubble 1404 radiates to cover the vessel wall completely or nearly completely 360 degrees. In an example where the central lumen 208 creates some shadow, the cavitation bubbles 1404 still radiate to cover the vessel wall 360 degrees, but there may be some variation in the magnitude of the bubble intensity around this perimeter.

[0084] FIGS. 19A-19H show side views of various distal fiber ends 1402 of the optical fibers 802 that may be provided on the elongate body 302. In examples of distal fiber ends 1402 (such as FIGS. 19A, 19C, 19D, 19E, 19H, etc.) intended to collect light or optical signals, the shape of the fiber tip at the distal fiber end 1402 may improve the ability of the aforementioned fiber interrogation mechanism 524. By using these various fiber tips to increase the probability that light or optical signals reflected by the optical fiber 802 are captured by the distal fiber end 1402, the likelihood of false negatives for problems related to the fiber, such as disconnection, not being reported is increased. Accordingly, the clinician will not prematurely remove the elongate body 302 due to false data reporting problems related to the optical fiber.

[0085] In the example of the distal fiber end 1402 (FIGS. 19B, 19C, 19D, 19F, and 19G) intended to emit light or laser energy in a specific direction, depending on the shape of the fiber tip at the distal fiber end 1402, it is possible to direct the laser emission directionally, redirect the laser without bending the optical fiber, or facilitate the narrowing or widening of the light beam or optical signal, thereby affecting the amount of energy delivered to the point.

[0086] Notably, the examples shown in FIGS. 19C and 19D can facilitate both the emission of light or optical signals from the laser and the collection of light or optical signals from the laser. The fiber tip has functionality that improves both of these operations, and thus can support both the delivery means of the laser and the safety in the form of sensing the reflected laser according to the user's needs.

[0087] FIG. 19A shows a distal fiber end 1402 including a frustum 1902 (increasing in radius dimension) according to some examples. The frustum 1902 may increase the laser spot size and decrease the power density at the interface between the distal fiber end 1402 and the saline / contrast agent fluid mixture or target 902. FIG. 19B shows a distal fiber end 1402 having a taper 1904 (decreasing in radius dimension). The taper 1904 profile may decrease the laser spot size and increase the fluence or energy density of the laser.

[0088] FIG. 19C shows an optical fiber 802 having a distal fiber end 1402 including a convex lens 1906. The convex lens 1906 may increase the collection of light or optical signals from the laser while reducing divergence. FIG. 19D shows a distal fiber end 1402 including a concave lens 1908 according to some examples. The concave lens 1908 may increase the divergence of the laser light or optical signal.

[0089] FIG. 19E shows an optical fiber 802 having a distal fiber end 1402 that includes a spherical ball lens 1910. The spherical ball lens 1910 may increase the potential light collection angle by the optical fiber. FIG. 19F shows a distal fiber end 1402 that includes a diffuser type chip 1912. The diffuser type chip 1912 may enable complete peripheral illumination through all sides of the distal fiber end 1402.

[0090] FIG. 19G shows an optical fiber 802 in which the distal fiber end 1402 includes a side fire chip 1914. The angle of the side fire chip 1914 deflects the laser at least partially with respect to the angle of the elongate body 302 across the vasculature. This deflection may be at any angle, including a substantially perpendicular angle or a 180-degree deflection of the laser. FIG. 19H shows a distal fiber end 1402 that includes an angled end 1916. The angled end 1916 may reduce back reflection when collecting light or laser energy.

[0091] In any of FIGS. 19A - 19H where the IVL balloon 204 is present on the elongate body 302, the polished distal fiber end 1402 terminates within the IVL balloon 204. The polished distal fiber end 1402 may be cleaved, shaped, or flame polished. In all embodiments including the balloon 204, the rough edges of the distal fiber end 1402 are undesirable because they can cause wear on the inner wall of the balloon 204 and potentially reduce the life of the balloon 204. However, it is understood that the distal fiber end 1402 need not be polished in any way without affecting the overall capabilities of the IVL system 10.

[0092] Any energy source suitable for supplying energy via the optical fiber 802 to generate cavitation bubbles, either through interaction with a saline / contrast agent mixture or with the target 902, may be used with any of the IVL systems 10 and features shown in FIGS. 1-19H. Some examples include the use of laser media such as Nd:YAG (neodymium-doped: yttrium aluminum garnet), Ho:YAG (holmium), or CTH:YAG (chromium, thulium, holmium). Laser media with short wavelengths, such as Nd:YAG (about 3124 nanometers for Nd:YAG), can benefit from using the target 902 described in FIGS. 9B, 10B, 10C, and 10D. Laser media with longer wavelengths, such as CTH:YAG (about 2.1 microns in the case of CTH:YAG), can benefit from the IVL system 10 in which cavitation bubbles 1404 are formed by interaction with a saline / contrast agent mixture. Additionally, different types of pumped lasers may be used with any of the IVL systems 10 and features shown in FIGS. 1-19H, such as discharge-pumped excimer lasers or flashlamp-pumped lasers.

[0093] The lasers provided have wavelengths in the range of 308 nanometers to 2.1 microns (examples include 308 nanometer excimer lasers and 355 nanometer triple Nd:YAG lasers), but any suitable wavelength may be used. The pulse width may be "long" (about 300 - 600 microseconds) or short (less than 100 nanoseconds). The pulse repetition rate may be about 1 - 2 Hertz (Hz), but any pulse repetition rate may be used. The diameter of the optical fiber 802 includes 150 micrometers, 175 micrometers, and 200 micrometers. Again, any functional diameter of the optical fiber 802 may be used. The energy levels provided may be, for example, between 40 and 1500 millijoules (mJ).

[0094] FIG. 20 shows a flowchart illustrating a method for generating cavitation bubbles within a balloon catheter. In some examples, the method includes providing a medical device (at step 2000) in accordance with the description and figures herein. The medical device may be the medical devices shown and described in FIGS. 1 - 19H, or any combination of these examples. According to some examples, the method includes placing a balloon (at step 2002) within a patient's vasculature adjacent to a calcified lesion. The balloon may surround or partially surround the distal end of the catheter.

[0095] The method includes inflating the balloon (at step 2004) using a fluid. This inflation can serve multiple purposes. For example, inflating the balloon with the fluid may bring the balloon into contact with the calcified lesion within the treatment area. Further, the fluid used to inflate the balloon can function as a receptacle for input energy from a laser source, if a laser source is provided. In this case, the fluid may be a saline / contrast agent fluid mixture of any ratio of composition. In some examples, the method includes transmitting laser energy (at step 2006) via an optical fiber. This laser energy is delivered through the catheter towards the distal end of the catheter. The laser energy is intended to heat a target, which may be a physical target (as described in step 2008b) or the fluid within the balloon (as described in step 2008a).

[0096] According to some examples, the method includes heating a fluid (at step 2008a). Laser energy is absorbed by the fluid, such as a saline / contrast agent mixture, and then the absorbed energy heats the fluid. The method may include generating cavitation bubbles (at step 2010). As a result of the fluid being heated, cavitation bubbles may form and then collapse. This cavitation bubble may generate a high-energy pressure wave, which can be utilized to break up calcified lesions within the treatment area.

[0097] Alternatively, in some examples, the method includes heating a target (at step 2008b). In this case, this physical target may act as a receptacle for the laser energy. When the target is heated, the target gives its heat to the surrounding fluid, so the surrounding fluid can be heated as well. According to some examples, the method includes generating cavitation bubbles (at step 2010). In a manner similar to that described above, as a result of the fluid being heated, cavitation bubbles may form and then collapse. Again, this cavitation bubble may then generate a high-energy pressure wave, which can be utilized to break up calcified lesions within the treatment area.

[0098] FIG. 21 shows a flowchart illustrating a method of generating cavitation bubbles within a blood vessel. In some examples, the method includes providing a medical device (at step 2100) according to the description and figures herein. Again, the medical device may be the medical device shown and described in FIGS. 1-19H, or any combination of these examples. According to some examples, the method includes transmitting fluid through a central lumen (at step 2102). The provided fluid may be used to inflate a balloon, if present, as described in FIG. 20. The provided fluid may be used as a receptacle for energy coming from a laser source, if a laser source is provided. In this case, the fluid may be a saline / contrast agent fluid mixture of any ratio of composition.

[0099] The method may include discharging fluid into a treatment region (at step 2104) through a distal elongate portion of the central lumen. In this case, no balloon is present and instead the fluid is injected directly into the patient's vasculature. In some examples, the method includes moving blood within the treatment region (at step 2106). This movement of blood improves the contact between the fluid and the walls of the treatment region and enables more effective disruption of existing calcified lesions by pressure waves released from collapsing cavitation bubbles. By removing blood from the treatment region, the fluid may fill all or a substantial portion of the treatment region.

[0100] According to some examples, the method includes transmitting laser energy through an optical fiber (at step 2108). This laser energy may be delivered through a catheter towards the distal end of the catheter. In some examples, the laser energy is intended to heat a target, which may be a physical target (as described in step 2108b) or the fluid within a balloon (as described in step 2108a).

[0101] The method may include heating a fluid (at step 2110a). The laser energy may be absorbed by a fluid such as a saline / contrast agent mixture, and then the absorbed energy heats the fluid. In some examples, the method may include generating cavitation bubbles (at step 2112). As a result of the fluid being heated, cavitation bubbles may form and then collapse. This cavitation bubble may generate a high-energy pressure wave, which can be utilized to break up calcified lesions within the treatment area.

[0102] Alternatively, according to some examples, the method includes heating a target (at step 2110b). In this case, this physical target may act as a receptacle for the laser energy. When the target is heated, the target gives its heat to the surrounding fluid, so the surrounding fluid can be heated as well. The method may include generating cavitation bubbles (at step 2112). Similar to the above, as a result of the fluid being heated, cavitation bubbles may form and then collapse. This cavitation bubble may generate a high-energy pressure wave, which can be utilized to break up calcified lesions within the treatment area.

[0103] The present disclosure includes a medical device 12 that includes an elongate body 302 having a distal elongate body portion 306 and a central longitudinal axis 308. According to some examples, the medical device 12 includes a balloon 204 disposed along the distal elongate body portion 306, the balloon 12 having an inner balloon surface 702 and an outer balloon surface 704, and being configured to receive a fluid 212 to inflate the balloon 204 such that the outer balloon surface 704 contacts a calcified lesion 50 within the vasculature of a patient 20. The medical device 12 may include one or more pressure wave emitters 206 disposed along the central longitudinal axis 308 of the elongate body 302 within the balloon 204, the one or more pressure wave emitters 206 being configured to propagate at least one pressure wave through the fluid 212 to fragment the calcified lesion 50. In some examples, at least one of the pressure wave emitters 206 includes an optical fiber 802 configured to transmit laser energy into the balloon 204. According to some examples, the laser energy is configured to generate cavitation bubbles 1404 within the fluid 212 upon contact with the fluid 212 to generate at least one pressure wave.

[0104] The optical fiber 802 may terminate near the distal elongate body portion 306. In some examples, the medical device 12 further includes a laser energy generator 310 configured to selectively pulse the laser energy. According to some examples, the pulsed laser energy is configured to produce a Moses effect.

[0105] The medical device 12 further includes a plurality of optical fibers 802, each optical fiber 802 being configured to transmit laser energy and terminating at a distal fiber end 1402 at different distances along the distal elongate body portion 306. In some examples, the laser energy is emitted from the distal fiber end 1402.

[0106] According to some examples, the optical fiber 802 includes a core and a cladding. In some examples, the cladding is disposed around the core, and laser energy is emitted from the core through a score disposed within the cladding. The medical device 12 may further include a plurality of optical fibers 802 disposed around the distal elongate body portion 306.

[0107] In some examples, the laser energy is configured to have a wavelength between about 1900 nanometers (nm) and 2100 nm. According to some examples, the wavelength is about 2000 nm. The isotopes of the doping element may cause a slight spread in the wavelength, and the doping concentration in the crystal may similarly shift the wavelength slightly. For this reason, the "about" used herein with "wavelength" is intended to mean plus or minus 30 nm. In some examples, the wavelength is between 1970 nm and 2030 nm. In examples where a CTH:YAG laser is used, the wavelength may be selected from the group consisting of 1970 nm, 2030 nm, 2080 nm, 2091 nm, 2097 nm, and 2121 nm. In examples where a Ho:YAG laser is used, the wavelength may be about 2100 nm.

[0108] In some examples, the laser energy is configured to have an energy between about 40 mJ and about 1500 mJ. According to some examples, the laser energy has a pulse width between about 10 nanoseconds and about 600 microseconds. The laser energy may have a pulse repetition rate between about 1 Hz and about 2 Hz.

[0109] In some examples, the medical device 12 further includes a Nd-YAG laser configured to provide laser energy. According to some examples, the medical device 12 further includes a holmium laser selected from the group consisting of Ho:YAG and CTH:YAG, and the holmium laser is configured to provide laser energy. The medical device 12 may further include an excimer laser configured to provide laser energy.

[0110] In some examples, the medical device 12 further includes a pressure sensor 522 configured to detect a rupture within the balloon 204, and the pressure sensor 522 is configured to stop the laser energy when detecting a balloon rupture. This detection may also occur due to a loss of pressure at a specific threshold. According to some examples, the medical device 12 further includes a fiber interrogation mechanism 524 configured to detect a break in the optical fiber 802.

[0111] The medical device 12 may further include a target 902 disposed distal to the optical fiber 802. In some examples, at least one of the pressure wave emitters 206 includes an optical fiber 802 configured to transmit laser energy to the balloon 204 and impinge on the target 902. According to some examples, the target 902 is configured to heat up when impinged by laser energy, and the heat from the target 902 is configured to heat a fluid 212 that causes the emission of a pressure wave. The medical device 12 may further include an optical fiber 802 having a distal fiber end 1402 and a fiber positioner 1002 that maintains a fixed distance between the distal fiber end 1402 and the target 902 such that the laser energy transmitted to the balloon 204 impinges on the target 902.

[0112] In some examples, the medical device 12 defines a central lumen 208 that extends through the elongate body 302, and the central lumen 208 has a proximal lumen end and a distal lumen end opposite the proximal lumen end. In some examples, the central lumen 208 is configured to transmit a fluid 212 to replace the blood within a treatment region 40 adjacent to a calcified lesion 50 within the vasculature of the patient 20.

[0113] According to some examples, the balloon surface selected from the group consisting of the inner balloon surface 702, the outer balloon surface 704, and combinations thereof further includes a metallization coating 706 configured to increase the damage threshold of the balloon 204.

[0114] None of the steps described in this specification are essential or indispensable. Any step can be adjusted or modified. Other steps or additional steps can also be used. Any part of the steps, processes, structures, and / or devices disclosed or illustrated in one embodiment, flowchart, or example in this specification can be combined with, or used in place of, any other part of the steps, processes, structures, and / or devices disclosed or illustrated in a different embodiment, flowchart, or example. The embodiments and examples provided in this specification are distinct from each other and are not intended to be separated.

[0115] The headings and subheadings of the sections provided in this specification are non-limiting. The headings and subheadings of the sections do not represent or limit the full scope of the embodiments described in the sections to which the headings and subheadings pertain. For example, a section titled "Topic 1" may include embodiments not related to Topic 1, and the embodiments described in other sections may be applicable to, or combined with, the embodiments described within the "Topic 1" section.

[0116] The various features and processes described above may be used independently of each other or combined in various ways. All possible combinations and sub - combinations are intended to fall within the scope of this disclosure. Further, certain methods, events, states, or process blocks may be omitted in some implementations. Also, the methods, steps, and processes described herein are not limited to a particular sequence, and the blocks, steps, or states associated therewith can also be executed in other suitable sequences. For example, the described tasks or events may be executed in an order other than the specifically disclosed order. Multiple steps may be combined into a single block or state. Exemplary tasks or events may be executed serially, in parallel, or in some other way. Tasks or events may be added to or removed from the disclosed exemplary embodiments. The exemplary systems and components described herein may be configured differently from those described. For example, elements may be added, removed, or reconfigured compared to the disclosed exemplary embodiments.

[0117] The conditional language used in this specification, such as "can", "is possible", "may", "may be", "for example", etc., generally conveys that a particular embodiment includes a particular feature, element, and / or step, but other embodiments do not include the particular feature, element, and / or step, unless otherwise specified or understood in a different way within the context in which it is used. Therefore, such conditional language is generally not intended to mean that a feature, element, and / or step is required for one or more embodiments, or that one or more embodiments necessarily include logic for determining whether these features, elements, and / or steps are included in a particular embodiment or should be performed in a particular embodiment, regardless of the presence or absence of the creator's input or prompt. Terms such as "comprise", "include", "have", etc. are synonymous and are used in an inclusive, open-ended manner and do not exclude additional elements, features, acts, operations, etc. Also, the term "or" is used in its inclusive sense (not in its exclusive sense), so, for example, when used to connect a list of elements, the term "or" means one, some, or all of the elements in the list. Connective language such as the phrase "at least one of X, Y, Z" is understood in the context in which it is generally used to convey that an item, term, etc. is any of X, Y, or Z, unless otherwise specified. Therefore, such connective language is generally not intended to mean that a particular embodiment requires the presence of at least one of X, at least one of Y, and at least one of Z, respectively.

[0118] The term "and / or" means that "and" applies to some embodiments and "or" applies to some embodiments. Thus, A, B, and / or C can be replaced with A, B, and C written in one sentence and A, B, or C written in another sentence. A, B, and / or C means that some embodiments can include A and B, some embodiments can include A and C, some embodiments can include B and C, some embodiments can include only A, some embodiments can include only B, and some embodiments can include A, B, and C. The term "and / or" is used to avoid unnecessary redundancy.

Description of Reference Numerals

[0119] 10: Intravascular lithotripsy (IVL) system 12: Medical device 14: Access point 20: Patient 30: Blood vessel 40: Treatment area 50: Calcified lesion 204: Balloon 206: Pressure wave emitter 206a: Pressure wave emitter 206b: Pressure wave emitter 206c: Pressure wave emitter 206d: Pressure wave emitter 206e: Pressure wave emitter 208: Central lumen 212: Fluid 302: Elongated body 304: Proximal elongated body portion 306: Distal elongated body portion 308: Central longitudinal axis 310: Generator 312: Connector 402: Power supply 404: Console 406: Detection line 408: Power cord 502: Laser energy source system 504: Flash lamp power supply 506: Lamp lead 508: Laser head 510: Shutter 512: Fiber out 514: Lamp 516: Power on 518: Central processing unit (CPU) 520: Button 522: Pressure sensor 524: Fiber inquiry mechanism 702: Inner balloon surface 704: Outer balloon surface 706: Metallization coating 802: Optical fiber 802a: Optical fiber 802b: Optical fiber 902: Target 902a: Target 902b: Target 902c: Target 1002: Fiber positioner 1002a: Fiber positioner 1002b: Fiber positioner 1002c: Fiber positioner 1102: Marker band 1102a: Marker band 1102b: Marker band 1302: Shroud 1402: Distal fiber end 1404: Cavitation bubble 1502: Core 1504: Cladding 1602: Score 1902: Frustum 1904: Taper 1906: Convex lens 1908: Concave lens 1910: Spherical ball lens 1912: Diffuser type chip 1914: Side fire chip 1916: Tapered end

Claims

1. A medical device, comprising a elongate body having a distal elongate body portion and a central longitudinal axis, a balloon disposed along said distal elongate body portion, having an inner balloon surface and an outer balloon surface, and configured to receive a fluid for inflating said balloon such that said outer balloon surface contacts a calcified lesion within a patient's vasculature, one or more pressure wave emitters disposed along said central longitudinal axis of said elongate body within said balloon, and configured to transmit at least one pressure wave through said fluid to fragment said calcified lesion, and at least one of said pressure wave emitters comprises an optical fiber configured to transmit laser energy into said balloon, said laser energy being configured to generate cavitation bubbles within said fluid upon contact with said fluid to generate said at least one pressure wave, a medical device.

2. said optical fiber terminating near said distal elongate body portion, the medical device according to claim 1.

3. further comprising a laser energy generator, said laser energy generator being configured to selectively pulse said laser energy, the medical device according to claim 2.

4. said pulsed laser energy being configured to generate a Moses effect, the medical device according to claim 3.

5. further comprising a plurality of optical fibers, each optical fiber being configured to transmit laser energy and terminating at a distal fiber end at a different distance along said distal elongate body portion, said laser energy being emitted from said distal fiber ends, the medical device according to claim 1.

6. The medical device according to claim 1, wherein the laser energy is configured to have a wavelength between about 2000 nm and 2200 nm.

7. The medical device according to claim 6, wherein the wavelength is about 2100 nm.

8. The medical device according to claim 1, wherein the optical fiber comprises a core and a cladding, the cladding is disposed around the core, and the laser energy is emitted from the core through a score disposed in the cladding.

9. The medical device according to claim 1, further comprising a plurality of optical fibers disposed around the distal elongate body portion.

10. The medical device according to claim 1, wherein the laser energy is configured to have an energy between about 40 mJ and about 1500 mJ.

11. The medical device according to claim 1, wherein the laser energy has a pulse width between about 10 nanoseconds and about 600 microseconds.

12. The medical device according to claim 1, wherein the laser energy has a pulse repetition rate between about 1 Hz and about 2 Hz.

13. The medical device according to claim 1, further comprising a Nd - YAG laser configured to provide the laser energy.

14. The medical device according to claim 1, further comprising a holmium laser selected from the group consisting of Ho:YAG and CTH:YAG, the holmium laser being configured to provide the laser energy.

15. The medical device according to claim 1, further comprising an excimer laser configured to provide the laser energy.

16. The medical device according to claim 1, further comprising a pressure sensor configured to detect a rupture within the balloon, wherein the pressure sensor is configured to stop the laser energy when detecting a balloon rupture.

17. The medical device according to claim 1, further comprising a fiber interrogation mechanism configured to detect damage to the optical fiber.

18. The medical device further comprises a target disposed distally of the optical fiber, The optical fiber includes a distal fiber end and a fiber positioner that keeps the distance between the distal fiber end and the target constant so that the laser energy transmitted into the balloon impinges on the target. The optical fiber is configured to transmit laser energy into the balloon to impinge on the target. The target is configured to heat when impinged by the laser energy. The medical device according to claim 1, wherein the heat from the target is configured to heat a fluid that causes the release of the pressure wave.

19. The elongate body defines a central lumen extending therethrough, the central lumen having a proximal lumen end and a distal lumen end opposite the proximal lumen end, the central lumen configured to transmit fluid to displace blood within a treatment region adjacent to a calcified lesion within a patient's vascular system. The medical device according to claim 1.

20. The balloon surface selected from the group consisting of the inner balloon surface, the outer balloon surface, and combinations thereof further includes a metallization coating configured to increase the damage threshold of the balloon. The medical device according to claim 1.

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