Intravascular lithotripsy device and system with spark monitoring feedback

Abstract

An intravascular lithotripsy catheter system for use in delivering energy waves and forces to a thrombus or lesion in a blood vessel, the catheter system comprising: a catheter extending from a proximal end to a distal end, the catheter having a saline delivery lumen opening from the distal end of the catheter for creating a controlled volume or bolus of saline at a distal region of the catheter; at least one electrode pair disposed within the distal region of the controlled volume, the at least one electrode pair connectable to a high-voltage pulse generator for generating a spark across the electrode pair when inflated with saline solution; and an optical fiber extending distally from the proximal end of the catheter to a position within the balloon for observing an optical phenomenon within the balloon when the optical phenomenon generates detectable light. Preferably, the optical fiber is connected to an optical sensor at the proximal end of the catheter. Methods of using such a catheter system are also contemplated.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to and benefit of U.S. Provisional Application No. 63 / 434,912, filed December 22, 2022, and entitled "INTRAVASCULAR LITHOTRIPSY DEVICES AND SYSTEMS HAVING SPARK MONITORING FEEDBACK."

[0002] The present invention is directed to a catheter system for treating vascular thrombi or calcified lesions, etc., utilizing energy waves generated by electrodes in a conductive fluid medium. [Background technology]

[0003] Angioplasty balloon catheter systems are commonly used to inflate the balloon to apply physical force to calcified lesions in blood vessels, pushing the calcifications back into the vessel wall. Some such calcified lesions and thrombi are not effectively disrupted by the use of angioplasty balloons.

[0004] Recently, catheter systems have been developed that include a balloon similar to angioplasty balloons filled with a conductive liquid medium, such as saline solution, for inflation at the location of the lesion or thrombus. These catheter systems include one or more pairs of electrodes operatively positioned in the conductive liquid medium. The electrodes are pulsed with high-voltage direct current, and with each pulse, a spark jumps across the gap between the two electrodes. The spark within the conductive medium generates an energy wave that propagates through the liquid medium, causing the balloon to exert a physical force against the lesion or thrombus. The energy propagation also includes the generation of microbubbles, which also promote the physical force. Such devices are known to deliver energy waves that act against the lesion or thrombus with the goal of disrupting calcifications or clots.

[0005] Current catheter systems include treatment sequences that include a maximum number of consecutive pulses followed by a minimum delay time and a hard maximum total number of pulses associated with the particular catheter. One such product is shown below.

[0006] [Table 1]

[0007] If the treatment is not complete after the maximum total number of pulses per catheter, the physician must replace the catheter, with unwanted cost, delay, and inconvenience.

[0008] Intravascular lithotripsy (IVL) devices are available in several calcification patterns. Disposable IVL balloon devices are available in different designs and sizes for peripheral or coronary indications. All designs utilize a reusable power source, such as an IVL generator. One reusable DC generator consists of the following specifications:

[0009] [Table 2]

[0010] One such disposable device consists of a 0.014-inch guidewire-compatible fluid-filled balloon angioplasty catheter with two lithotripsy emitters integrated into the shaft of a 12-mm-long balloon segment. After inflating the fluid-filled balloon (e.g., with 50 / 50 saline contrast) to approximately 4 atmospheres, an electrical pulse is delivered to the emitters, which generate high-voltage sparks to deliver the treatment. Sound waves are generated, causing calcium to break down. Summary of the Invention

[0011] In one aspect, the present invention is directed to an intravascular lithotripsy catheter system for use in applying energy waves and forces to a thrombus or lesion in a blood vessel. The catheter system includes a catheter extending from a proximal end to a distal end, the catheter having a saline delivery lumen opening from the distal end of the catheter for creating a controlled volume or bolus of saline at a distal region of the catheter, at least one electrode pair disposed within the distal region of the controlled volume, the at least one electrode pair connectable to a high-voltage pulse generator for generating a spark across the electrode pair when inflated with saline solution, and an optical fiber extending distally from the proximal end of the catheter to a position within the balloon for observing an optical phenomenon within the balloon when the optical phenomenon generates detectable light. Preferably, the optical fiber is connected to an optical sensor at the proximal end of the catheter.

[0012] The catheter system may further include a balloon near the distal end of the catheter operatively connected to the saline delivery lumen and inflatable by delivery of a controlled volume of saline. Preferably, the optical sensor includes a photodiode. In one embodiment, an optical fiber having a distal tip directed toward the gap of the electrode pair terminates within the controlled volume of saline.

[0013] The optical fiber preferably includes a cladding layer, and in one embodiment, the distal end is polished to receive detectable light from the optical phenomenon. It is contemplated that multiple optical fibers may be provided, each of which may be connected to an optical sensor. Additionally, multiple electrode pairs are also contemplated, and multiple optical fibers may be directed to multiple electrode pairs.

[0014] In another embodiment, the optical fiber can be modified along its length to provide multiple fiber sides that can receive optical energy back to one or more optical sensors at multiple locations along its length. Such an arrangement can be achieved with or without multiple electrode pairs. Such an arrangement can further comprise a Bragg grating distal to the multiple fiber sides to reflect optical energy at selected wavelengths proximally to one or more optical sensors.

[0015] In another aspect of the present invention, a method using an intravascular lithotripsy catheter system can be used to apply energy waves and forces to a thrombus or lesion within a blood vessel. The catheter system includes a catheter extending from a proximal end to a distal end, the catheter having a saline delivery lumen open from the distal end of the catheter, at least one electrode pair provided in a distal region, the at least one electrode pair connectable to a high-voltage pulse generator, which generates a spark across the electrode pair when inflated with saline solution; and an optical fiber extending distally from the proximal end of the catheter, the optical fiber connected to an optical sensor at the proximal end of the catheter, for observing an optical phenomenon when detectable light is generated by the optical phenomenon. The method includes creating a controlled volume or bolus of saline at the distal region of the catheter by delivering saline into the saline delivery lumen, generating a spark across the electrode pair within the controlled volume of saline, and detecting the detectable light from the optical phenomenon with the optical sensor at the proximal end of the optical fiber by an optical fiber also positioned within the controlled volume of saline.

[0016] Such a method can include inflating the balloon by delivering a controlled volume of saline, with the electrode pair and optical fiber also positioned within the balloon. The optical sensor can include a photodiode that detects light at a selected wavelength.

[0017] In such methods, the detecting step can be performed by an end of an optical fiber terminating in a controlled volume of saline solution with a distal tip directed toward the gap between the electrode pairs. The optical fiber can include a cladding layer, and the distal end can be polished to receive detectable light from the optical phenomenon. Alternatively, the detecting step can be performed by an optical fiber modified along its length to provide multiple fiber sides capable of receiving optical energy back to one or more optical sensors at multiple locations along its length. In such methods, a Bragg grating can be positioned distal to the multiple fiber sides, and the method can include reflecting optical energy at selected wavelengths proximally to one or more optical sensors. When there are multiple electrode pairs, the method can include receiving optical energy from multiple electrode pairs at multiple fiber sides. In another alternative, multiple electrode pairs can be provided, and the method can include receiving optical energy from multiple electrode pairs by multiple optical fibers directed to the multiple electrode pairs.

[0018] The method can detect an optical phenomenon involving a precursor discharge of light emitted from an electrode of an electrode pair prior to the generation of a spark. Alternatively, the method can detect an optical phenomenon involving the collapse of one or more microbubbles within a controlled volume of saline solution, the collapse of the microbubbles producing light emitted as a result of sonoluminescence. [Brief explanation of the drawings]

[0019] [Figure 1] 1 illustrates a system for providing intravascular lithotripsy according to one aspect of the present invention. [Figure 2] 1 shows a balloon inflated within a blood vessel for providing intravascular lithotripsy according to one aspect of the present invention. [Figure 3] 1 illustrates a schematic of one embodiment of the present invention for sensing light generated in the gap between a pair of electrodes, with an optical fiber threaded through an IVL balloon. [Figure 4]10A and 10B schematically illustrate another embodiment of the present invention for sensing light generated at multiple locations within an IVL balloon. [Figure 5] 10A and 10B schematically illustrate yet another embodiment of the present invention including a light reflecting structure disposed distal to the sensor portion of the optical fiber. [Figure 6] 1 illustrates features of a particular IVL catheter, detailing the working length of such an IVL catheter, the energy profile of the IVL catheter, and the provision of an optimized overlap zone within such an IVL catheter design. DETAILED DESCRIPTION OF THE INVENTION

[0020] The present invention is directed to IVL devices of the type that include electrodes or lithotripsy emitters that generate acoustic waves by arcing between electrode components, but can also include devices that generate acoustic energy within the balloon via a laser energy source. Examples of such laser systems are described in U.S. Patent Nos. 11,058,492 and 11,717,139, the entire contents of which are incorporated by reference. Examples of electrically guided systems are described in U.S. Patent Nos. 8,728,091, 9,642,673, and 10,850,078, and published U.S. patent application Ser. No. 2022-0054194, the entire contents of which are incorporated by reference.

[0021] Referring to the figures, FIGS. 1 and 2 show a system 10 according to the present invention. The system comprises a power source 12 (in the form of a generator, but alternatively in the form of a laser system), a treatment delivery controller 15, and a handle 14 having a catheter 20 with two lithotripsy emitters 22 (shown in the form of a pair of arc-discharge electrodes, but alternatively may be optical or laser emitters), and a fluid-filled balloon 24. Optional marker bands B may also be provided. The catheter 20 preferably includes a central tube 26 defining a guidewire lumen 27 through which a guidewire G passes for delivery of the balloon 24 to a desired location along the guidewire G. A sheath 28 surrounds the central tube 26 and defines a delivery lumen 29 through which saline can be controllably delivered for inflation of the balloon 24. The lumen 29 provides a concentric space around the central tube 26 through which electrode wires (not shown) can extend from the controller 15 to the emitters 22, among other components according to the present invention and described below. Sheath 28 is connected at its proximal end to hub 17. Hub 17 may include any number of ports to allow electrode wires to pass through lumens 27 or 29 along with saline for inflation, guidewires G, and any number of other components, as needed.

[0022] The balloon 24 can be in a deflated position to more easily pass through the patient's blood vessels to reach the site of calcification. In use, the balloon 24 is inflated to a pressure typical for angioplasty procedures (e.g., 4 atmospheres) and treatment is administered via the implementation control unit 15.

[0023] 2 shows the balloon 24 inflated to a treatment delivery state, in which the lithotripsy emitter 22 can be "fired" to disrupt vascular calcification C. An optional indicator band B may be provided for visualization and proper positioning using known imaging techniques. The balloon 24 is inflated to typical angioplasty pressures (e.g., 4 atmospheres) and the treatment is delivered. The balloon 24 can spontaneously expand during or immediately after delivery of the treatment to clear the vessel for blood flow.

[0024] The controller 15 is used to generate one or a series of voltage pulses according to a treatment scheme. A high-voltage pulse is provided to one of the emitters 22, which are comprised of a pair of spaced-apart electrodes, and, according to the illustrated embodiment, is then sequentially provided to a second emitter, also comprised of a pair of spaced-apart electrodes. The high-voltage pulse is passed sequentially within the balloon 24, generating a spark across the first electrode pair and then across the second electrode pair. The somewhat conductive saline solution in the balloon 24 generates a high-voltage spark across each electrode pair, creating an energy wave that propagates within the balloon toward the vascular calcification.

[0025] Any sparks generated within the balloon 24 placed within a patient's blood vessel will also generate visible or detectable light events. Such light events can be detected at wavelengths other than those of visible light. It is further understood that a visible or detectable light precursor discharge can emanate from the ground-connected electrode of any electrode pair when a high-voltage pulse is initiated at the hot electrode pair prior to the actual spark event. Such a precursor discharge is similar to that seen from a conductive object prior to a lightning strike. The present invention aims to monitor these visible or detectable light events as feedback to the controlled generation of high-voltage sparks. Understanding the timing of such precursor discharges and actual sparks occurring at one or more electrode pairs after generation of the high-voltage pulse may lead to design changes to electrode pairs and other components for propagating the energy wave within the balloon. The present invention aims to better predict the timing of spark generation relative to the delivery of a high-voltage pulse by sensing any optical phenomenon that can predict when an actual spark will occur. Determining the timing delay of the precursor discharge relative to the high-voltage pulse and visualizing the resulting spark also allows the system to accurately measure the appropriate timing to ensure the current and electrode gap are performing sufficiently within treatment specifications.

[0026] It is also contemplated that catheters without balloons may be utilized in accordance with the present invention. Such catheters preferably include a lumen 29 that delivers saline to a controlled volume containing one or more emitters 22. Such a controlled volume may be created by the anatomy of the patient's blood vessels in conjunction with the distal end of the catheter in the region of the emitters. Saline may be delivered to fill such a controlled volume or may flow into and out of such a controlled volume at a controlled rate, creating a bolus of controlled fluid environment. Partial balloons are also contemplated, from which a flow of saline may seep out of the open distal end of the partial balloon. Such partial or open balloon designs may be useful in forward-facing electrode systems, such as those disclosed in pending U.S. Provisional Patent Application No. 63 / 416,231, filed October 14, 2022, the entire contents of which are incorporated herein by reference. In the case of a catheter 20 having a balloon 24, a controlled volume is provided within the volume of the balloon 24. Having a direct pulse to feedback system in an uncontrolled environment was key to verifying that the proper environment was set up (fluid bolus / flow) to allow for proper dielectric breakdown of the fluid and subsequent bubble formation and collapse.

[0027] As also shown in FIG. 2 , an optical fiber 30 preferably extends through the lumen 29 to a desired point within the balloon 24 for the purpose of sensing the occurrence of any optical events within the balloon 24 (e.g., which may include a light precursor or spark). The optical fiber can also detect non-optical events, such as when a spark is expected but not generated. Such occurrences are described in more detail below. The proximal end of the optical fiber 30 is preferably optically coupled to a photodetector, which preferably provides an amplified signal of the sensed light. Optical fibers are commonly known as including an optical core through which light can propagate, surrounded by a cladding layer. The cladding layer may be further surrounded by a protective layer. For example, light generated by a spark or precursor may travel along the optical core and be detected by a photodetector, such as a photodiode. Direct detection of the occurrence of a spark or precursor through visible or detectable light observed (via the optical fiber) can improve the lifespan of the IVL device by varying the power consumption of each spark and optimizing the spark by its intensity. It is contemplated that shortening the intensity and duration of the spark may benefit the lifespan of the IVL device and reduce the detrimental effects of heat generated by the spark. Additionally, understanding spark strength and timing relative to the high voltage pulse can improve control and responsiveness.

[0028] For example, if a current high-voltage pulse monitorable according to the present invention occurs without a subsequent light-emitting event (either a leading discharge, full spark, or arc), diagnostic factors such as current rise, total current loss / supply from the storage mechanism, and / or user prompts can be used to diagnose the system prior to the subsequent discharge. In products where multiple serial electrodes are ignited / activated by a single high-voltage pulse generator, the discharge versus current from a single electrode can be monitored to verify that the total discharge versus discharge properly represents a complete and proper discharge and treatment delivery. The medium within the controlled fluid environment, either closed or open, also provides system diagnostic information regarding the wavelengths of light produced at different stages (e.g., sodium arc (saline or saline / contrast) versus hydrogen arc (water) versus arc representing generation in uncharacterized blood).

[0029] An additional optional use of the optical fiber 30 and optical sensor is the detection of microbubbles in the saline solution of the balloon 24, which may disrupt the generation of a single shock wave that causes bubble collapse. It is understood that microbubbles are generated by a high-voltage spark, the resulting energy wave, and electrolysis of the fluid within the balloon. It is also understood that such microbubbles can be disrupted by applying a certain amount of energy to microbubbles suspended in the solution. Sonoluminescence is a phenomenon in which the collapse of such microbubbles can generate both detectable light and sound waves. In a situation of interest, a first pulse can generate an energy wave, generating microbubbles in the saline solution within the balloon 24. In addition to monitoring and reacting to the light emitted during spark activation, fluid in a controlled volume can also be actively monitored by providing a light source of a controlled wavelength from an optical fiber and capturing the absorption / reflection of the medium in a controlled environment. For example, if the fluid contains bubbles or microbubbles, the absorption / reflection and wavelength will be affected, indicating an uncontrolled environment requiring intervention.

[0030] Subsequent pulses can generate another energy wave and microbubbles, but can also cause the collapse of microbubbles in the saline solution from the previous pulse. Such events can generate other detectable light that can be detected by the optical fiber 30 during electrode activation and / or at the end of activation and before the next activation. Such light generated from microbubble collapse can be detectable at a different wavelength than the spark-detectable light, for example. Optical filters can be used to understand the light emitted at specific wavelengths and to detect the optical phenomenon being detected. For example, sodium ion excitation in saline solution can result from the emission of light at a wavelength of 589 nm (yellow-orange). Detection of light at this wavelength is characteristic of a spark and allows for adjustments to the spark generation and / or the fluid environment surrounding the electrode (e.g., adjusting the percentage of saline in the fluid).

[0031] In one embodiment of the present invention, the end of the optical fiber can be positioned near or adjacent to the electrode pair, with the polished distal end of the optical fiber facing the electrode pair. Figure 3 shows a schematic diagram of an arrangement in which the optical fiber 130 can be threaded to a location within the balloon 124. Also positioned within the balloon, as previously described, are a pair of electrodes 122 and 123, defining a gap 125 between the nearest ends of the electrodes 122 and 123. The electrode 122 can be connected to the hot side of the high-voltage pulse generator 12 by an electrical wire threaded into the balloon 124, and the other electrode can be electrically connected by a wire also threaded into the balloon 124 and connected to the ground side of the generator. As previously described, application of a high-voltage pulse can generate a spark in the gap 125 within the balloon 124.

[0032] Optical fiber 130 preferably has a highly polished end 131 that is preferably placed adjacent to gap 125 and directed toward gap 125 to sense each generated spark and / or precursor discharge, or any other detectable optical event as a light generation. The zigzag line between electrodes 122 and 123 in Figure 3 indicates a spark generated within gap 125. The proximal end of the optical fiber can be connected to a light sensor, such as a photodiode 132.

[0033] It is contemplated that multiple optical fibers may be threaded through electrode pairs 122-123 to observe gap 125 from multiple different vantage points, allowing for pass-through monitoring of the light source and subsequent interruption of the light. Such multiple vantage points may be from different distances and / or angles. For example, as shown in FIG. 3, the distal end of an optical fiber may be located to sense and monitor the spark generated within gap 125, while another distal end of the optical fiber may be directed toward the ground electrode end to sense and monitor that end for the generation of a leading discharge before the spark occurs. Other variations are contemplated, such as using multiple optical fibers in a single spark gap to increase the data associated with each spark and / or leading discharge, for example, by directing light from the proximal end of each optical fiber to a different optical sensor equipped with a filter for a different wavelength of light.

[0034] 4 illustrates the provision of a single optical fiber 230 capable of sensing and transmitting light from multiple locations to a light sensor, such as a photodiode 232. Multiple electrode pairs are shown schematically connected in series and spaced apart within a balloon 224. Thus, a high voltage pulse sequentially generates sparks from a first electrode pair, including electrodes 222 and 223, and then a second electrode pair, including electrodes 226 and 228. These electrode pairs are electrically connected to the high voltage generator 12 as previously described, supplying hot electrode side 222, ground side 223, and electrodes 226 and 228, connected in series with current flowing through sequential gaps 225 and 227 between the electrode pairs.

[0035] Optical fiber 230 is threaded into and through balloon 224, passing near each gap 225 and 227. Rather than directing or pointing the end of the optical fiber into the gap, the optical fiber can be modified at each gap 225 and 227 (or more) to receive light and return it to photodiode 232. Specifically, portions of the optical fiber's cladding can be removed at predetermined locations to correlate with gaps 225 and 227. In this manner, this is one side of the optical fiber that collects light energy from multiple locations. The cladding and / or any protective layers can be etched, polished, or otherwise controllably removed at predetermined locations to receive light generated within the optical fiber's core. Such received light propagates along the optical fiber to photodiode 232 as described above. Sequential sensing of light from successive sparks can be monitored in this manner.

[0036] It is contemplated that such a side-sensing approach can also be utilized for single gap monitoring. Similarly, such multiple fiber side modifications can be used to sense light at multiple locations from a single gap. As previously described, one sensor area of ​​the fiber can view the lead discharge at the ground end of electrode 223 or 228, while another sensor area of ​​the fiber can view the gap, and therefore the spark. Optical fiber 230 can be threaded to view the same or different areas of the electrode gap from different angles. Each of these aspects also applies to optical fibers threaded near multiple gaps, as shown in FIG. 4. This side-sensing approach can also be utilized to sense multiple locations, multiple electrodes, along a single fiber. This reduces the bulk and complexity of feeding multiple fibers into a single catheter / system.

[0037] FIG. 5 schematically illustrates another embodiment of the present invention, providing an optical fiber 330 with a lateral sensor region as described above and shown in FIG. 4 . The optical fiber 330 can be threaded past and near a gap 325 formed between electrodes 322 and 323 and provided in balloon 324. For example, in any arrangement with fiber lateral sensing by removing a portion of the fiber cladding at one or more predetermined regions along the fiber side, light can enter the fiber core and be transmitted or propagated proximate to a photodiode 332 as an optical sensor. However, light also transmits or propagates within the fiber core toward the distal end of the optical fiber 330. Therefore, it is further contemplated to provide a reflector distal to the lateral sensor location to increase the light transmitted to the photodiode 332.

[0038] Reflectors within optical fibers are well known and can be wavelength-specific. A Bragg grating 340 can be provided within a short segment of optical fiber 330 to reflect light at a selected wavelength. Figure 5 shows light being transmitted proximally and distally to a Bragg grating that reflects the light back proximally. Light other than the selected wavelength is transmitted distally. The desired wavelength is controlled by periodic variations in the refractive index of the fiber core. The desired wavelength can then be aligned with a photodiode 332 to provide cleaner, more intense data. Multiple such Bragg gratings 340 configured to reflect different wavelengths of light can be provided along the distal portion of optical fiber 330. Other optical filters can be provided proximal to the light sensing location. In this regard, for example, a light-generating precursor discharge may have a greater light intensity at one wavelength, while a spark may have a greater light intensity at another wavelength. Alternatively, it may be desirable to analyze the generated light at multiple wavelengths for different aspects of the generated light. Additionally, it may be beneficial to reflect light at wavelengths associated with the leading discharge to increase the signal-to-noise ratio at the detector, while at the same time allowing a portion of the high intensity light associated with the spark to travel distally and be absorbed rather than reaching the detector and causing disturbances or damage to sensitive electronic components.

[0039] It should be noted that the above light from either the pre-discharge or the spark includes visible light, however, detectable light other than visible light can be sensed and monitored by a photodetector based on the desired light range to be monitored.

[0040] As discussed above, it is contemplated that multiple photodiodes or other optical sensors can receive optical data transmitted from optical sensing at the end or side regions of the optical fiber. For example, multiple photodiodes can receive sensed light from one or more optical splitters located at the proximal end of the optical fiber, and the photodiodes can respond cumulatively to the optical data or to different sides (wavelengths) of the transmitted light. Multiple optical fibers with side optical sensing and / or fiber ends can also be provided for redundancy. That is, a spark event can cause residue buildup from successive pulses that prevents proper optical signal detection. A redundant optical fiber can be positioned at a different perspective or angle than another optical fiber. Such multiple optical fibers can be connected to the same or multiple such optical detectors. For example, if one optical fiber senses an optical phenomenon but another optical fiber does not, the other optical fiber may be damaged or covered with residue.

[0041] It is also contemplated that such optical fibers may be useful in detecting spark leakage or pulse discharges to the patient. For example, if a high voltage pulse is generated and a spark is detected, but no current is sensed at the ground electrode of the electrode pair, the spark must be grounding elsewhere, such as the patient. A current sensor somewhere along the ground wire side of the electrode pair would indicate the absence of ground current. [Explanation of symbols]

[0042] 10 Systems 12 Power supply 14 Handle 15 Treatment implementation control unit 17. Hub 20 catheter 22 Crushed Stone Emitter 24 fluid-filled balloons 26 Central Tube 27 Guidewire lumen 28 Sheath 29 delivery lumens 30 Optical Fiber 122 electrodes 123 Electrode 124 Balloon 125 Gap 130 Optical Fiber 132 Photodiode 133 Highly Polished Edge 222 Electrode 223 Electrode 224 Balloon 225 Gap 226 Electrode 227 Gap 228 Electrode 230 Optical Fiber 232 Photodiode 322 Electrode 323 Electrode 324 Balloon 325 Gap 330 Optical Fiber 332 Photodiode 340 Bragg diffraction grating B Marker band, indicator band C Vascular calcification G Guidewire

Claims

1. 1. An intravascular lithotripsy catheter system for use in applying energy waves and forces to a thrombus or lesion in a blood vessel, comprising: a catheter extending from a proximal end to a distal end, the catheter having a saline delivery lumen opening from the distal end of the catheter for creating a controlled volume or bolus of saline at a distal region of the catheter, at least one electrode pair disposed within the distal region of the controlled volume, the at least one electrode pair connectable to a high voltage pulse generator for generating a spark across the electrode pair when inflated with saline solution; an optical fiber extending distally from the proximal end of the catheter to a location within the controlled volume of saline for observing an optical phenomenon within the controlled volume of saline when the optical phenomenon produces detectable light, the optical fiber being connected to an optical sensor at the proximal end of the catheter; A catheter system comprising:

2. The catheter system of claim 1 , further comprising a balloon near the distal end of the catheter operatively connected to the saline delivery lumen and inflatable by delivery of the controlled volume of saline.

3. The catheter system of claim 2 , wherein the optical sensor includes a photodiode.

4. The catheter system of claim 1 , wherein the optical fiber having a distal tip directed toward the gap of the electrode pair terminates within the controlled volume of saline.

5. The catheter system of claim 4 , wherein the optical fiber includes a cladding layer and the distal end is polished to receive the detectable light from the optical phenomenon.

6. 10. The catheter system of claim 9, comprising a plurality of optical fibers, each optical fiber connected to an optical sensor.

7. The catheter system of claim 6 , further comprising a plurality of electrode pairs, and wherein the plurality of optical fibers are directed toward the plurality of electrode pairs.

8. 10. The catheter system of claim 1, further comprising a plurality of electrode pairs, wherein the optical fiber is modified along its length to provide a plurality of optical fiber sides capable of receiving optical energy returned to one or more optical sensors at a plurality of locations along its length.

9. 10. The catheter system of claim 8, further comprising a Bragg grating distal to the plurality of fiber sides for reflecting optical energy at selected wavelengths proximally to the one or more optical sensors.

10. 1. A method of using an intravascular lithotripsy catheter system to deliver an energy wave and force to a thrombus or lesion in a blood vessel, the catheter system comprising: a catheter extending from a proximal end to a distal end, the catheter having a saline delivery lumen opening from the distal end of the catheter, at least one electrode pair provided in a distal region, the at least one electrode pair connectable to a high voltage pulse generator that generates a spark across the electrode pair when inflated with saline solution; and an optical fiber extending distally from the proximal end of the catheter to observe an optical phenomenon when the optical phenomenon generates detectable light, the optical fiber being connected to an optical sensor at the proximal end of the catheter, the optical fiber creating a controlled volume or bolus of saline at a distal region of the catheter by delivering saline into the saline delivery lumen; generating a spark, and therefore an optical phenomenon, across the electrode pair within the controlled volume of saline; detecting detectable light from the optical phenomenon by the optical fiber disposed within the controlled volume of saline with an optical sensor at a proximal end of the optical fiber; A method comprising:

11. 11. The method of claim 10, wherein the catheter further includes a balloon near the distal end of the catheter that is operatively connected to the saline delivery lumen, the method including inflating the balloon by delivering the controlled volume of saline.

12. The method of claim 10 , wherein the light sensor comprises a photodiode that detects light at a selected wavelength.

13. 11. The method of claim 10, wherein the detecting step is performed by an end of the optical fiber terminating in the controlled volume of saline with a distal tip directed toward the gap of the electrode pair.

14. The method of claim 10 , wherein the detecting step is performed by the optical fiber including a cladding layer and the distal end being polished to receive the detectable light from the optical phenomenon.

15. 11. The method of claim 10, wherein the detecting step is performed by the optical fiber being modified along a length thereof to provide a plurality of optical fiber sides capable of receiving optical energy returned to one or more optical sensors at a plurality of locations along the length of the optical fiber.

16. 16. The method of claim 15, wherein the optical fiber further comprises a Bragg grating distal to the plurality of fiber sides, the method comprising reflecting optical energy at a selected wavelength proximally to the one or more optical sensors.

17. 17. The method of claim 16, wherein the catheter includes a plurality of electrode pairs, the method including receiving optical energy from the plurality of electrode pairs on the sides of the plurality of fibers.

18. 11. The method of claim 10, wherein the catheter includes a plurality of electrode pairs, the method including receiving optical energy from the plurality of electrode pairs by a plurality of optical fibers directed at the plurality of electrode pairs.

19. The method of claim 10 , wherein the optical phenomenon comprises a precursor discharge of light emitted from an electrode of the electrode pair before the generation of a spark.

20. 11. The method of claim 10, wherein the optical phenomenon comprises the collapse of one or more microbubbles within the controlled volume of saline, the collapse of the microbubbles producing light emitted as a result of sonoluminescence.

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