Ultrasound system and method with improved occlusion engagement during crossing and atherectomy procedures - Patent Application 20070122997

Abstract

The ultrasonic system includes an ultrasonic device having an ultrasonic transducer and a core wire having a proximal end coupled to the ultrasonic transducer and a distal end portion terminating at a distal tip. An ultrasonic energy source is electrically connected to the ultrasonic transducer. The ultrasonic energy source includes an ultrasonic signal generator circuit, a modulator circuit, and a controller. The ultrasonic signal generator circuit generates an ultrasonic electrical signal. The modulator circuit amplitude-modulates the ultrasonic electrical signal with a macromotion electrical signal to generate a modulated ultrasonic electrical signal. The controller executes program instructions to select between an engagement mode and a transverse mode, where in the engagement mode, a first ultrasonic electrical signal is provided from the ultrasonic energy source to the ultrasonic transducer, and in the transverse mode, a modulated ultrasonic electrical signal is provided from the ultrasonic energy source to the ultrasonic transducer.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] None

[0002] The present invention relates to ultrasound systems and methods, and more particularly to ultrasound systems and methods with improved occlusion engagement during crossing and atherectomy procedures. [Background technology]

[0002]

[0003] Surgical procedures, such as crossing or atherectomy, are used to restore patency and blood flow lost due to one or more intravascular occlusions. A crossing procedure is a procedure in which an opening is created through an intravascular occlusion. An atherectomy procedure may involve crossing, but also attempts to disrupt and remove the intravascular occlusion. An ultrasound system with an ultrasound catheter may be used in performing crossing and atherectomy procedures.

[0003]

[0004] The intravascular occlusion may be in the form of a calcified vascular occlusion having rigid proximal and distal end caps. During an ultrasound crossing or atherectomy procedure, the distal tip of the ultrasound catheter engages the proximal end cap of the calcified vascular occlusion. However, due to the rigidity of the proximal end cap of the calcified vascular occlusion, the distal tip of the ultrasound catheter may be unintentionally repelled by the proximal end cap and take a subintimal path of migration into the sidewall of the vasculature.

[0004]

[0005] What is needed in the art is a system and method for more securely engaging and anchoring the distal tip of an ultrasound catheter into the proximal end cap of an intravascular occlusion at the beginning of a crossing or atherectomy procedure so as to reduce the likelihood of the distal tip of the ultrasound catheter taking an unintended subintimal path. Other applications of ultrasound catheters outside the human body are also contemplated. Summary of the Invention [Problem to be solved by the invention]

[0005]

[0006] The present invention provides a system and method for more securely engaging and anchoring the distal tip of an ultrasound catheter into the proximal end cap at the beginning of a crossing or atherectomy procedure to reduce the likelihood of the distal tip of the ultrasound catheter taking an unintended subintimal path. Other applications of ultrasound catheters outside the human body are also contemplated. [Means for solving the problem]

[0006]

[0007] In one aspect, the present invention relates to an ultrasonic system including an ultrasonic device having an ultrasonic transducer and a core wire having a proximal end and a distal end portion terminating at a distal tip. The proximal end is coupled to the ultrasonic transducer. An ultrasonic energy source is electrically connected to the ultrasonic transducer. The ultrasonic energy source includes an ultrasonic signal generator circuit, a modulator circuit, and a controller. The ultrasonic signal generator circuit is configured to generate a first ultrasonic electrical signal having a first ultrasonic frequency. The modulator circuit is configured to amplitude modulate the first ultrasonic electrical signal with a macromotion electrical signal to generate a modulated ultrasonic electrical signal. The macromotion electrical signal has a frequency at least 350 times less than the first ultrasonic frequency of the first ultrasonic electrical signal. The controller is communicatively coupled to the ultrasonic energy source. The controller executes program instructions to select between an engagement mode and a transverse mode, where in the engagement mode a first ultrasonic electrical signal is supplied from the ultrasonic energy source to the ultrasonic transducer, and in the transverse mode a modulated ultrasonic electrical signal is supplied from the ultrasonic energy source to the ultrasonic transducer.

[0007]

[0008] The invention in another form is a method of operating an ultrasound catheter coupled to an ultrasound energy source, the ultrasound catheter having a core wire coupled to an ultrasound transducer, the ultrasound transducer coupled to the ultrasound energy source, the method including the steps of providing an engagement mode in which the ultrasound energy source generates an ultrasonic electrical signal having a first frequency, the ultrasonic electrical signal being supplied to the ultrasound transducer to establish a continuous wave at an ultrasonic vibration frequency in a distal end portion of the core wire, the continuous wave resulting in a vibratory motion of the distal end portion of the core wire having substantially only longitudinal (i.e., longitudinal) vibrational motion. providing a transverse mode, wherein the ultrasonic electrical signal is amplitude modulated with a macro-motion electrical signal having a second frequency at least 350 times less than the first frequency to establish a modulated continuous wave at the distal end portion of the core wire at a modulated ultrasonic vibration frequency, the modulated continuous wave resulting in a vibratory motion of the distal end portion of the core wire having a combination of longitudinal and transverse vibratory motion; operating the ultrasound catheter in the engagement mode for a first time; and operating the ultrasound catheter in the transverse mode for a second time following the first time in the engagement mode.

[0008]

[0009] In yet another form, the invention is directed to a method of operating an ultrasound catheter coupled to an ultrasound energy source, the ultrasound catheter having a core wire coupled to an ultrasound transducer, the ultrasound transducer coupled to an ultrasound energy source, the method including the steps of: providing an engagement mode in which the ultrasound energy source generates an ultrasound electrical signal having an ultrasound frequency, the engagement mode being achieved by adjusting an output energy level of the ultrasound energy source to a first output energy level to achieve substantially only longitudinal vibrational motion of a distal end portion of the core wire; providing a transverse mode in which the output energy level of the ultrasound energy source is increased from the first output energy level to a second output energy level higher than the first output energy level to achieve a combination of longitudinal vibrational motion of the distal end portion of the core wire and transverse vibrational motion of the distal end portion of the core wire; operating the ultrasound catheter in the engagement mode for a first time; and operating the ultrasound catheter in the transverse mode for a second time following the first time in the engagement mode.

[0009]

[0010] An advantage of the present invention is that in the engagement mode, the distal tip of the ultrasound catheter more securely engages and anchors within the proximal end cap of the intravascular occlusion at the beginning of the crossing or atherectomy procedure, reducing the likelihood of the distal tip of the ultrasound catheter taking an unintended subintimal path of travel when the system transitions to the transverse mode.

[0010]

[0011] The above and other features and advantages of the present invention, as well as the manner in which they are achieved, will become more apparent and the present invention will be better understood by referring to the following description of embodiments of the present invention in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0011] [Figure 1]

[0012] 1 is a diagrammatic representation of an ultrasound system according to one embodiment of the present invention for performing a crossover and atherectomy procedure. [Figure 2]

[0013] FIG. 2 is a block diagram of a portion of the ultrasound system of FIG. 1 in accordance with one embodiment of the present invention. [Figure 3]

[0014] 1 is a graph depicting the output energy level of an ultrasonic energy source versus time through engagement and transverse modes. DETAILED DESCRIPTION OF THE INVENTION

[0012]

[0015] Corresponding reference characters indicate corresponding parts throughout the several views. The examples set forth herein illustrate at least one embodiment of the present invention, and such examples are not to be construed as in any way limiting the scope of the invention.

[0013]

[0016] Referring now to the drawings, and more particularly to FIG. 1, an ultrasound system 10 according to one embodiment of the present invention for performing crossover and atherectomy procedures is shown.

[0017] The ultrasound system 10 may include a console 12 and an ultrasound device 14. The ultrasound device 14 includes a handpiece 16 and an ultrasound catheter 18. The ultrasound catheter 18 is removably attached to the handpiece 16.

[0014]

[0018] The console 12 includes a user interface 20, a controller 22, and an ultrasonic energy source 24. The console 12 may include multiple components within a single housing unit or within separate housing units. Optionally, the console 12 may also include a foot switch 26 and / or a saline syringe 28.

[0015]

[0019] In this embodiment, the handpiece 16 includes a housing body 16-1 and an ultrasonic transducer 16-2 housed within the housing body 16-1. The housing body 16-1 has an external shape and size that facilitates grasping by the surgeon during a transverse or atherectomy procedure.

[0016]

[0020] The ultrasonic transducer 16-2 may be, for example, a piezoelectric transducer. The ultrasonic transducer 16-2 of the handpiece 16 is electrically connected to the ultrasonic energy source 24 by an electrical cable 32 and is configured to receive and convert ultrasonic electrical signals generated by the ultrasonic energy source 24 into ultrasonic vibration energy, which may be in a frequency range corresponding to the frequency range of the ultrasonic electrical signals.

[0017]

[0021] In this embodiment, the ultrasound catheter 18 includes a housing 34 , a sheath 36 , and a core wire 38 .

[0022] Housing 34 includes a Y-connector 34-1 that provides access to an irrigation lumen (not shown) of sheath 36. Y-connector 34-1 is connected to saline syringe 28, for example, by flexible hose 30. In this embodiment, housing 34 further includes a telescoping mechanism 40, such as a slide, that is connected to sheath 36.

[0018]

[0023] The sheath 36 is an elongated, flexible tube, such as a polymer tube. The sheath 36 includes a proximal end 36-1, a distal end 36-2, and a sheath lumen 36-3. In this embodiment, the sheath lumen 36-3 is an elongated lumen extending longitudinally within the sheath 36 from the proximal end 36-1 to the distal end 36-2 and may be formed as a central lumen relative to the diameter of the sheath 36. The proximal end 36-1 of the sheath 36 is connected to the housing 34, and more particularly, to the telescoping mechanism 40 in this embodiment.

[0019]

[0024] Core wire 38 is an elongated, flexible metal wire, such as Nitinol, located in and extending longitudinally within sheath lumen 36-3 of sheath 36. In this embodiment, core wire 38 may have a length greater than 60 centimeters (cm), and in some embodiments, a length of 100-200 cm. Core wire 38 has a proximal end 38-1, a distal tip 38-2, and a distal end portion 38-3.

[0020]

[0025] The proximal end 38-1 of the core wire 38 is operatively connected to the ultrasonic transducer 16-2, for example, by an acoustic connector, to receive vibrational energy from the ultrasonic transducer 16-2 to effect vibrational motion of the core wire 38. According to the present invention, the vibrational motion of the core wire 38 can be longitudinal or a combination of longitudinal and transverse vibrations, depending on the mode of operation.

[0021]

[0026] For example, if the frequency of the ultrasonic electrical signal generated by the ultrasonic energy source 24 and supplied to the ultrasonic transducer 16-2 is 20 kHz, the vibration frequency of the longitudinal vibration of the distal end portion 38-3 of the core wire 38 may correspondingly be 20 kHz, and when the ultrasonic electrical signal is amplitude modulated by a low frequency modulation signal, for example, 1 Hz to 50 Hz, transverse vibration occurs simultaneously with the longitudinal vibration in the distal end portion 38-3 of the core wire 38.

[0022]

[0027] Distal tip 38-2 of core wire 38 may be, for example, a blunt, rounded tip, e.g., a blunt tip. In practice, core wire 38 is advanced into a vessel of the vasculature having a vascular occlusion, and distal tip 38-2 of core wire 38 engages the vascular occlusion.

[0023]

[0028] The distal end portion 38-3 extends proximally from the distal tip 38-2, where the distal end portion 38-3 terminates distally. In this embodiment, the distal end portion 38-3 can have a reduced diameter portion proximal to and spaced from the distal tip 38-2.

[0024]

[0029] In this embodiment, the telescoping mechanism 40 of the housing 34 is configured to retract the sheath 36 from a first fully extended position of the sheath 36 (as shown in FIG. 1 ), in which the distal end portion 38-3 of the core wire 38 extends distally from the distal end 36-2 of the sheath 36, e.g., 5 cm to 8 cm, to a fully retracted position of the sheath 36, in which the core wire 38 is disposed entirely within the sheath lumen 36-3 of the sheath 36. However, it is contemplated that the core wire 38 may alternatively be slidably moved relative to the sheath 36 so as to fully extend the core wire 38 to expose the distal end portion 38-3 of the core wire 38 distally from the distal end 36-2 of the sheath 36, and so as to fully retract the core wire 38 to cover the distal end portion 38-3 of the core wire 38 with the sheath 36.

[0025]

[0030] The footswitch 26 is connected to the controller 22 by an electrical cable 26-1. The footswitch 26 may provide auxiliary input signals to the controller 22 that the controller 22 may use to activate and deactivate system components, such as the ultrasonic energy source 24 and / or the saline syringe 28 of the ultrasound system 10.

[0026]

[0031] The saline syringe 28 is connected to the controller 22 by an electrical cable 28-1. As depicted in FIG. 1 , the saline syringe 28 is in fluid communication with the ultrasound catheter 18 by a flexible hose 30. The saline syringe 28 may selectively deliver sterile saline to the ultrasound catheter 18, which may be used to irrigate the anatomical region undergoing the endovascular occlusion revision procedure and / or to cool the moving components of the ultrasound catheter 18, such as the core wire 38.

[0027]

[0032] Referring also to FIG. 2 , the user interface 20 is connected to the controller 22 by an electrical cable 20-1, e.g., a multi-wire cable or USB, to provide an electrical and communication interconnection. Alternatively, the user interface 20 may be communicatively coupled to the controller 22 via a wireless link, e.g., Bluetooth. The user interface 20 may include, for example, a touchscreen display 20-2 (see FIG. 1 ) and associated input and output processing circuitry. The touchscreen display 20-2 may include, for example, a liquid crystal display (LCD) or a light-emitting diode (LED) display. Alternatively, the user interface 20 may be in the form of a laptop computer or tablet. The user interface 20 is configured to generate control signals based on user input received by the touchscreen display 20-2. For example, a user may operate the touchscreen display 20-2 of the user interface 20 to provide control signals to the controller 22 to start and / or end operation of the ultrasonic energy source 24 and to selectively start or stop the saline syringe 28.

[0028]

[0033] 2, the controller 22 is electrically connected to and communicatively coupled to each of the user interface 20 and the ultrasonic energy source 24. The controller 22 includes a processor circuit 42, an interface circuit 44, and an electronic memory circuit 46.

[0029]

[0034] Processor circuitry 42 may include one or more programmable microprocessors and associated circuitry such as input / output interfaces, clocks, buffers, memory, etc. Processor circuitry 42 may be programmed, for example, through software or firmware stored in memory circuitry 46, to execute program instructions to process received input data and to generate and transmit output data.

[0030]

[0035] The interface circuitry 44 includes input and output circuitry to facilitate electrical connection and data transfer with the user interface 20 and the ultrasonic energy source 24 .

[0036] The memory circuit 46 is a non-transitory electronic memory having multiple data storage locations, as is well known in the art. The memory circuit 46 may include one or more of a volatile memory circuit, such as a random access memory (RAM), and a non-volatile memory circuit, such as a read-only memory (ROM), an electronically erasable programmable ROM (EEPROM), a NOR flash memory, or a NAND flash memory. The memory circuit 46 may be used, for example, to store program instructions to be executed by the processor circuit 42.

[0031]

[0037] Controller 22 executes program instructions to process signals received from touchscreen display 20-2 (see FIG. 1) of user interface 20 and to provide output control signals C1, C2, and C3 (see FIG. 2) to ultrasonic energy source 24 to control the operation of ultrasonic energy source 24.

[0032]

[0038] The ultrasonic energy source 24 is connected to the controller 22 by an electrical cable 48. The electrical cable 48 includes electrical conductors 48-1, 48-2, and 48-3, each configured to carry a respective output control signal C1, C2, and C3. The ultrasonic energy source 24 includes an ultrasonic signal generator circuit 50, a modulator circuit 52, and an electrically actuated selector circuit 54, e.g., an electronic switch circuit. Each of the circuits 50, 52, 54 may be implemented as an electrical / electronic component circuit, although it is contemplated that one or more of the circuits may alternatively be implemented in software / firmware.

[0033]

[0039] The ultrasonic signal generator circuit 50 is configured to generate an ultrasonic electrical signal S1, e.g., a high frequency current, within a frequency range of 20 kHz to 150 kHz. More preferably, for example, the frequency of the ultrasonic electrical signal S1 may be within a range of 20 kHz to 40 kHz. In some applications, the ultrasonic frequency of the ultrasonic electrical signal S1 may be 20 kHz, or may be initially 20 kHz.

[0034]

[0040] Modulator circuit 52 is an amplitude modulation circuit configured to receive ultrasonic electrical signal S1 and amplitude modulate ultrasonic electrical signal S1 with macro-motion electrical signal S2 to generate modulated ultrasonic electrical signal S3. Macro-motion electrical signal S2 is a low-frequency modulated signal, defined herein as an electrical signal having a frequency at least 350 times less than the frequency of ultrasonic electrical signal S1. For example, the frequency of macro-motion electrical signal S2 can be in the range of 1 Hz to 50 Hz.

[0035]

[0041] The selector circuit 54 is operated by the controller 22 to select one of the ultrasonic electrical signal S1 and the modulated ultrasonic electrical signal S3 as the excitation signal ES to be supplied to the ultrasonic transducer 16-2.

[0036]

[0042] In accordance with one aspect of the present invention, ultrasound system 10 performs a crossover or atherectomy procedure by automatically progressing through an engagement mode to a transverse mode. In particular, controller 22 executes program instructions to select between the engagement mode and the transverse mode, which selection is accomplished by operation of selector circuit 54, such that in the engagement mode, an ultrasonic electrical signal S1 is provided from ultrasonic energy source 24 to ultrasonic transducer 16-2, and in the transverse mode, a modulated ultrasonic electrical signal S3 is provided from ultrasonic energy source 24 to ultrasonic transducer 16-2.

[0037]

[0043] The engagement mode is used to initially engage and anchor the distal tip 38-2 of the core wire 38 into the proximal end cap of a vascular occlusion, such as a calcified vascular occlusion, based on ultrasonic electrical signal S1 excitation of the ultrasonic transducer 16-2. In this context, the term "anchoring" means that the distal tip 38-2 of the core wire 38 penetrates into the proximal end cap, restricting lateral movement of the distal tip 38-2, but the distal tip 38-2 is not necessarily attached to the proximal end cap of the blood vessel. The proximal end cap of a calcified vascular occlusion typically has an irregular shape but may have a globally or locally convex or concave surface. Thus, anchoring is particularly useful for preventing subintimal migration of the distal tip 38-2 when the proximal end cap has a convex shape. Therefore, by anchoring the distal tip 38-2 of the core wire 38 within the proximal end cap of the calcified vascular occlusion, the distal tip 38-2 of the core wire 38 has a higher likelihood of remaining in the true lumen of the vessel during the occlusion crossing or atherectomy procedure without progressing subintima.

[0038]

[0044] For example, in the engagement mode, an ultrasonic electrical signal S1 is generated at an ultrasonic frequency, e.g., 20 kHz, and the ultrasonic electrical signal S1 is supplied to the ultrasonic transducer 16-2. The power of the ultrasonic electrical signal S1 supplied to the ultrasonic transducer 16-2 is selected, for example, by the controller 22, to establish a continuous wave at an ultrasonic vibration frequency in the distal end portion 38-3 of the core wire 38. Based on the ultrasonic electrical signal S1 excitation of the ultrasonic transducer 16-2, the continuous wave causes vibrational motion of the distal end portion 38-3 and distal tip 38-2 of the core wire 38, which has substantially only longitudinal vibrational motion, so as to anchor the distal tip 38-2 of the core wire 38 into the proximal end cap of the calcified vascular occlusion. In this embodiment, the longitudinal vibrational motion of the distal end portion 38-3 of the core wire 38 is in the range of 20 microns to 40 microns.

[0039]

[0045] As used herein, the term "substantially only longitudinal vibratory motion" refers to longitudinal vibratory motion with essentially no concurrent transverse vibratory motion. The term "essentially no concurrent transverse vibratory motion" refers to transverse vibratory motion of less than 1 micron anywhere along distal end portion 38-3 of core wire 38.

[0040]

[0046] The transverse mode follows the engagement mode. The transverse mode is used to more aggressively penetrate into and disrupt the vascular lesion based on the modulated ultrasonic electrical signal S3 excitation of the ultrasonic transducer 16-2 such that the distal end portion 38-3 of the core wire 38 is under the influence of a combination of longitudinal and transverse vibrational motions while remaining anchored within the calcified vascular occlusion until crossing and / or disruption of the vascular occlusion is complete. In this embodiment, the longitudinal vibrational motion of the distal end portion 38-3 of the core wire 38 is in the range of 20 microns to 40 microns, and the transverse vibrational motion of the distal end portion 38-3 of the core wire 38 is in the range of 3 microns to 10 microns.

[0041]

[0047] For example, in the transverse mode, an ultrasonic electrical signal S1 having an ultrasonic frequency of, for example, 20 kHz is amplitude-modulated with a macro-motion electrical signal S2 having a non-ultrasonic frequency at least 350 times lower than the ultrasonic frequency of the ultrasonic electrical signal S1 to generate a modulated ultrasonic electrical signal S3. The frequency of the macro-motion electrical signal S2 may be, for example, in the range of 1 Hz to 50 Hz, or more specifically, in the range of 5 Hz to 15 Hz. The amplitude-modulated ultrasonic electrical signal S3 is supplied to the ultrasonic transducer 16-2, which establishes a modulated continuous wave at the modulated ultrasonic vibration frequency in the distal end portion 38-3 of the core wire 38. The modulated continuous wave, based on the excitation of the modulated ultrasonic electrical signal S3 by the ultrasonic transducer 16-2, results in a vibrational motion of the distal end portion 38-3 (including the distal tip 38-2) of the core wire 38 having a combination of longitudinal and transverse vibrational motions that is transmitted to the calcified vascular occlusion. In this embodiment, the longitudinal vibrational motion of distal end portion 38-3 of core wire 38 is in the range of 20 microns to 40 microns, and the transverse vibrational motion of distal end portion 38-3 of core wire 38 is in the range of 3 microns to 10 microns.

[0042]

[0048] 3, during operation, the controller 22 executes program instructions to cause the ultrasound system 10 to operate in engagement mode for a first time (t0-t1), and then in transverse mode for a second time (t1-t3) following the first time (t0-t1) in the engagement mode. The first time (t0-t1) begins at time t0, when the distal tip 38-2 of the distal end portion 38-3 of the corewire 38 contacts the proximal end cap of a calcified vascular occlusion within a blood vessel, and an excitation signal ES(S1) is delivered to the ultrasound transducer 16-2. During the first time (t0-t1), the distal tip 38-2 of the corewire 38 penetrates the proximal end cap of the calcified vascular occlusion, anchoring the distal end portion 38-3 of the corewire 38 within the calcified vascular occlusion.

[0043]

[0049] For example, the first time (t0-t1) may be 1-3 seconds and may vary within that range based on factors such as the expected stiffness / density of the proximal end cap of the vascular occlusion. In some procedures, a first time (t0-t1) of 1.75 seconds may be selected as the initial setting. The second time (t1-t3) required for the distal tip 38-2 of the core wire 38 to exit the distal end cap of the vascular occlusion is variable based on factors such as the length and density of the vascular occlusion and whether the procedure is a crossover procedure or an atherectomy procedure. In an atherectomy procedure, the distal tip 38-3 of the core wire 38 disrupts the calcified vascular occlusion.

[0044]

[0050] The transition from engagement mode to transverse mode may occur as a smooth increase in the output energy level, i.e., power, current, and / or voltage, of the ultrasonic energy source 24 during the transverse mode time period (t1-t2), i.e., at the completion of engagement mode.

[0045]

[0051] For example, in the engagement mode, the controller 22 executes the program instructions to adjust the output energy level (e.g., amplitude or frequency of the ultrasonic electrical signal S1) of the ultrasonic energy source ultrasonic signal generator circuit 50 to a first output energy level OEL1 to achieve substantially only longitudinal vibratory motion of the distal end portion 38-3 of the core wire 38, i.e., substantially no transverse vibratory motion of the distal end portion 38-3 of the core wire 38. The longitudinal vibratory motion of the distal end portion 38-3 of the core wire 38 continues at the first output energy level OEL1 for a first time (t0-t1) to anchor the distal tip 38-2 of the core wire 38 within the proximal end cap of the vascular occlusion.

[0046]

[0052] In the transverse mode, the controller 22 may execute program instructions such that the amplitude of the macro-motion electrical signal S2, which amplitude-modulates the ultrasonic electrical signal S1, is increased according to a ramp (i.e., gradient) profile during a time period (t1-t2), such that the output energy level of the modulated ultrasonic electrical signal S3 of the ultrasonic energy source 24 gradually increases from a first output energy level OEL1 to a second output energy level OEL2 according to the ramp profile. The ramp profile is constrained (i.e., bounded) by the first output energy level OEL1 and the second output energy level OEL2. It is contemplated that the ramp profile may be linear or, alternatively, curvilinear, such as parabolic, exponential, or "S"-shaped.

[0047]

[0053] In the transverse mode, the amount of transverse vibratory motion of the distal end portion 38-3 of the core wire 38 increases as the output energy level increases for a time period (t1-t2). The combination of longitudinal and transverse vibratory motion of the distal end portion 38-3 of the core wire 38 continues at a second output energy level OEL2 for the remainder (t2-t3) of the second time period (t1-t3).

[0048]

[0054] Stated differently, in this embodiment, the output energy level of the ultrasonic energy source 24 is increased from a first output energy level OEL1 to a second output energy level OEL2 (higher than the first output energy level) by introducing a macro-motion electrical signal S2, i.e., by amplitude modulation of the ultrasonic electrical signal S1 by the macro-motion electrical signal S2, and the amplitude of the macro-motion electrical signal S2 can be increased according to a ramp profile over a time period (t1-t2) so as to smoothly increase the amount of lateral vibrational motion of the distal end portion 38-3 of the core wire 38.

[0049]

[0055] While the present embodiment depicted in Figures 1 and 2 shows the distal end portion 38-3 of the core wire 38 extending from the distal end 36-2 of the sheath 36, it should be understood that the present invention may be practiced in ultrasound catheter configurations in which the distal end portion 38-3 is contained completely or partially within the sheath 36 and / or with the distal end portion 38-3 connected to the distal end 36-2 of the sheath 36, as is the case, for example, with Crosser® brand ultrasound catheters available from BD / CR Bard, Inc.

[0050]

[0056] The following items also relate to the present invention:

[0057] In one aspect, the present invention relates to an ultrasonic system. The ultrasonic system may include an ultrasonic device having an ultrasonic transducer and a core wire having a proximal end and a distal end portion terminating at a distal tip, the proximal end being coupled to the ultrasonic transducer. An ultrasonic energy source may be electrically connected to the ultrasonic transducer. The ultrasonic energy source may include an ultrasonic signal generator circuit and a modulator circuit. The ultrasonic signal generator circuit may be configured to generate a first ultrasonic electrical signal having a first ultrasonic frequency. The modulator circuit may be configured to amplitude modulate the first ultrasonic electrical signal, optionally with a macromotion electrical signal, to generate a modulated ultrasonic electrical signal. The macromotion electrical signal may have a frequency at least 350 times less than the ultrasonic frequency of the first ultrasonic electrical signal. A controller may be communicatively coupled to the ultrasonic energy source. The controller may be configured to execute program instructions to select between an engagement mode and a transverse mode, wherein in the engagement mode a first ultrasonic electrical signal is supplied from the ultrasonic energy source to the ultrasonic transducer, and in the transverse mode a modulated ultrasonic electrical signal is supplied from the ultrasonic energy source to the ultrasonic transducer.

[0051]

[0058] In any of the embodiments, the ultrasound system may include a sheath having a sheath lumen, the corewire being positioned in and extending longitudinally within the sheath lumen of the sheath.

[0059] In some embodiments, a distal end portion of the core wire may extend from the distal end of the sheath.

[0052]

[0060] In any of the embodiments, in the engagement mode, the ultrasonic system can be controlled by the controller such that the ultrasonic transducer establishes a continuous wave at an ultrasonic vibration frequency in the distal end portion of the core wire, the continuous wave resulting in a vibrational motion of the distal end portion of the core wire having substantially only longitudinal vibrational motion.

[0053]

[0061] In any of the embodiments, in transverse mode, the ultrasonic system can be controlled by a controller such that the ultrasonic transducer establishes a modulated continuous wave that results in vibratory motion of the distal end portion of the core wire having both longitudinal and transverse vibratory motion, where the longitudinal vibratory motion can be in the range of 20 microns to 40 microns and the transverse vibratory motion can be in the range of 3 microns to 10 microns.

[0054]

[0062] In any of the embodiments, the frequency of the first ultrasonic electrical signal may be in the range of 20 kHz to 40 kHz, and the frequency of the macro-motion electrical signal may be in the range of 1 Hz to 50 Hz.

[0055]

[0063] In any of the embodiments, the controller may be configured to execute program instructions to operate in the engagement mode for a first time period and to operate in the lateral mode for a second time period following the first time period in the engagement mode.

[0056]

[0064] In any of the embodiments, the ultrasonic energy source may be configured such that an output energy level of the ultrasonic energy source may be increased from a first output energy level to a second output energy level higher than the first output energy level by introduction of a macromotion electrical signal.

[0057]

[0065] In any of the embodiments, the ultrasonic energy source may be configured such that the amount of transverse vibratory motion increases as the output energy level increases, and the transition from the first output energy level to the second output energy level may follow a ramp profile.

[0058]

[0066] In any of the embodiments, the amplitude of the macro-motion electrical signal may increase according to the gradient profile.

[0067] In another aspect, the present invention relates to a method of operating an ultrasound catheter coupled to an ultrasound energy source, the ultrasound catheter having a core wire coupled to an ultrasound transducer, the ultrasound transducer being coupled to an ultrasound energy source, optionally an ultrasound system of any of the preceding paragraphs

[0057] to

[0066] . The method may include providing an engagement mode in which an ultrasonic energy source generates an ultrasonic electrical signal having a first frequency, the ultrasonic electrical signal being supplied to an ultrasonic transducer to establish a continuous wave at the distal end portion of the core wire at an ultrasonic vibration frequency, the continuous wave resulting in vibratory motion of the distal end portion of the core wire having substantially only longitudinal vibration motion; providing a transverse mode in which the ultrasonic electrical signal is optionally amplitude-modulated with a macromotion electrical signal having a second frequency at least 350 times less than the first frequency to establish a modulated continuous wave at the distal end portion of the core wire at the modulated ultrasonic vibration frequency, the modulated continuous wave resulting in vibratory motion of the distal end portion of the core wire having a combination of longitudinal and transverse vibration motion; operating the ultrasonic catheter in the engagement mode for a first time; and operating the ultrasonic catheter in the transverse mode for a second time following the first time in the engagement mode.

[0059]

[0068] In any of the embodiments, the first frequency of the ultrasonic electrical signal may be in the range of 20 kHz to 40 kHz, and the second frequency of the macro-motion electrical signal may be in the range of 1 Hz to 50 Hz.

[0060]

[0069] In some embodiments, the first frequency of the ultrasonic electrical signal may be 20 kHz and the second frequency of the macro-motion electrical signal may be in the range of 5 Hz to 15 Hz.

[0061]

[0070] In any of the embodiments, in the engagement mode, the longitudinal oscillatory motion may be in the range of 20 microns to 40 microns, and the transverse oscillatory motion is less than 1 micron.

[0071] In any of the embodiments, in the transverse mode, the longitudinal oscillatory motion may be in the range of 20 microns to 40 microns, and the transverse oscillatory motion may be in the range of 3 microns to 10 microns.

[0062]

[0072] In any of the embodiments, the first time period may be between 1 second and 3 seconds.

[0073] In any of the embodiments, the first time period may begin when the distal tip of the distal end portion of the core wire contacts the proximal end cap of a calcified vascular occlusion within a blood vessel and an excitation signal is delivered to the ultrasound transducer.

[0063]

[0074] In any of the embodiments, during a first time period, the distal tip of the corewire can penetrate the calcified vascular occlusion.

[0075] In any of the embodiments, during the second time period, the distal end portion of the corewire can disrupt the calcified vascular occlusion.

[0064]

[0076] In some embodiments, the amplitude of the macro-motion electrical signal may increase according to the gradient profile.

[0077] In another aspect, the present invention relates to a method of operating an ultrasound catheter, optionally the ultrasound system of any of the preceding paragraphs

[0057] to

[0066] , coupled to an ultrasound energy source, the ultrasound catheter having a core wire coupled to an ultrasound transducer, the ultrasound transducer coupled to the ultrasound energy source. The method may include providing an engagement mode in which the ultrasound energy source generates an ultrasonic electrical signal having an ultrasonic frequency, the engagement mode being achieved by adjusting an output energy level of the ultrasound energy source to a first output energy level to achieve substantially only longitudinal vibrational motion of the distal end portion of the core wire, providing a transverse mode in which the output energy level of the ultrasound energy source is increased from the first output energy level to a second output energy level higher than the first output energy level to achieve a combination of longitudinal vibrational motion of the distal end portion of the core wire and transverse vibrational motion of the distal end portion of the core wire, operating the ultrasound catheter in the engagement mode for a first time period, and operating the ultrasound catheter in the transverse mode for a second time period subsequent to the first time period in the engagement mode.

[0065]

[0078] In any of the embodiments, in the transverse mode, the output energy level of the ultrasonic energy source is increased from a first output energy level to a second output energy level, optionally by amplitude modulating the ultrasonic electrical signal with a macro-motion electrical signal, the macro-motion electrical signal having a frequency at least 350 times less than the ultrasonic frequency of the ultrasonic electrical signal.

[0066]

[0079] In any of the embodiments, in the transverse mode, the amount of transverse oscillatory motion increases as the output energy level increases, and the transition from the first output energy level to the second output energy level may follow a ramp profile.

[0067]

[0080] In some embodiments, the amplitude of the macro-motion electrical signal may be increased according to a gradient profile.

[0081] In some embodiments, the amplitude of the macro-motion electrical signal may be increased according to a ramp profile to increase the output energy level of the ultrasonic energy source from a first output energy level to a second output energy level.

[0068]

[0082] In some embodiments, the method may include continuing longitudinal oscillatory motion of the distal end portion of the core wire at a first output energy level for a first time period to anchor the distal tip of the core wire within the proximal end cap of the occlusion; increasing the output energy level according to a predetermined ramp profile for a second time period to effect a combination of longitudinal and lateral oscillatory motion of the distal end portion of the core wire, wherein the amount of lateral oscillatory motion increases as the output energy level increases and the ramp profile is constrained to the first output energy level and a second output energy level; and continuing the combination of longitudinal and lateral oscillatory motion of the distal end portion of the core wire at the second output energy level for the remainder of the second time period, wherein the second time period may be variable.

[0069]

[0083] In any of the embodiments, the first time period may be in the range of 1.0 to 3.0 seconds.

[0084] In some embodiments, the first period of time may be 1.75 seconds.

[0070]

[0085] As used herein, "substantially," "generally," and other words of degree are relative modifiers intended to indicate acceptable variation from the characteristic so modified. For example, unless otherwise specified, the term "substantially" covers something that approaches or approximates such physical or functional characteristic that it modifies. Also, as used herein, a range designated "X to Y" includes the X and Y boundaries of the range.

[0071]

[0086] While the present invention has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.

Claims

1. an ultrasonic device having an ultrasonic transducer and a core wire having a proximal end and a distal end portion terminating in a distal tip, the proximal end being coupled to the ultrasonic transducer; an ultrasonic energy source electrically connected to the ultrasonic transducer, an ultrasonic signal generator circuit configured to generate a first ultrasonic electrical signal having a first ultrasonic frequency; and a modulator circuit configured to amplitude modulate the first ultrasonic electrical signal with a macro-motion electrical signal to generate a modulated ultrasonic electrical signal, the macro-motion electrical signal having a frequency at least 350 times less than the first ultrasonic frequency of the first ultrasonic electrical signal, and the amplitude of the macro-motion electrical signal being increased according to a ramp profile to cause modulation of the first ultrasonic electrical signal; an ultrasonic energy source, a controller communicatively coupled to the ultrasonic energy source, the controller configured to execute program instructions to select between an engagement mode and a transverse mode, wherein in the engagement mode, the first ultrasonic electrical signal is provided from the ultrasonic energy source to the ultrasonic transducer, and in the transverse mode, the modulated ultrasonic electrical signal is provided from the ultrasonic energy source to the ultrasonic transducer; and An ultrasound system comprising:

2. 10. The ultrasound system of claim 1, comprising a sheath having a sheath lumen, the core wire positioned in and extending longitudinally within the sheath lumen of the sheath.

3. The ultrasound system of claim 2 , wherein the distal end portion of the core wire extends from the distal end of the sheath.

4. 4. The ultrasonic system of claim 1, wherein in the engagement mode, the ultrasonic transducer establishes a continuous wave at an ultrasonic vibration frequency in the distal end portion of the core wire, the continuous wave resulting in a vibrational motion of the distal end portion of the core wire having substantially only longitudinal vibrational motion.

5. 4. The ultrasound system of claim 1, wherein in the transverse mode, the ultrasound transducer establishes a modulated continuous wave that produces vibratory motion of the distal end portion of the core wire having both longitudinal and transverse vibratory motion, the longitudinal vibratory motion being in a range of 20 microns to 40 microns and the transverse vibratory motion being in a range of 3 microns to 10 microns.

6. 4. The ultrasound system of claim 1, wherein the frequency of the first ultrasound electrical signal is in the range of 20 kHz to 40 kHz and the frequency of the macro-motion electrical signal is in the range of 1 Hz to 50 Hz.

7. 4. The ultrasound system of claim 1, wherein the controller executes program instructions to operate in the engagement mode for a first time period and to operate in the transverse mode for a second time period subsequent to the first time period in the engagement mode.

8. 4. The ultrasound system of claim 1, wherein an output energy level of the ultrasound energy source is increased from a first output energy level to a second output energy level higher than the first output energy level upon introduction of the macro-motion electrical signal.

9. 10. The ultrasound system of claim 8, wherein an amount of lateral oscillatory motion increases as the output energy level increases, and the transition from the first output energy level to the second output energy level follows a ramp profile.

10. 1. A method of operating an ultrasound catheter coupled to an ultrasound energy source, the ultrasound catheter having a core wire coupled to an ultrasound transducer, the ultrasound transducer being coupled to the ultrasound energy source, the method comprising: providing an engagement mode in which the ultrasonic energy source generates an ultrasonic electrical signal having a first frequency, the ultrasonic electrical signal being supplied to the ultrasonic transducer to establish a continuous wave at an ultrasonic vibration frequency in the distal end portion of the core wire, the continuous wave resulting in a vibratory motion of the distal end portion of the core wire having substantially only longitudinal vibrational motion; providing a transverse mode in which the ultrasonic energy source amplitude-modulates the ultrasonic electrical signal with a macro-motion electrical signal, the ultrasonic electrical signal being amplitude-modulated by increasing the amplitude of the macro-motion electrical signal according to a ramp profile with the macro-motion electrical signal having a second frequency at least 350 times less than the first frequency to establish a modulated continuous wave at the distal end portion of the core wire at a modulated ultrasonic vibration frequency, the modulated continuous wave resulting in a vibratory motion of the distal end portion of the core wire having a combination of longitudinal and transverse vibratory motion; the ultrasonic energy source operating the ultrasound catheter in the engagement mode for a first time period; the ultrasonic energy source operating the ultrasound catheter in the transverse mode for a second time period subsequent to the first time period in the engagement mode; A method comprising:

11. 11. The method of claim 10, wherein the first frequency of the ultrasonic electrical signal is in a range of 20 kHz to 40 kHz, and the second frequency of the macro-motion electrical signal is in a range of 1 Hz to 50 Hz.

12. 11. The method of claim 10, wherein the first frequency of the ultrasonic electrical signal is 20 kHz and the second frequency of the macro-motion electrical signal is in the range of 5 Hz to 15 Hz.

13. 13. The method of any one of claims 10 to 12, wherein in the engagement mode, the longitudinal oscillatory motion is in the range of 20 microns to 40 microns and the transverse oscillatory motion is less than 1 micron.

14. 13. The method of any one of claims 10 to 12, wherein in the transverse mode, the longitudinal oscillatory motion is in the range of 20 microns to 40 microns and the transverse oscillatory motion is in the range of 3 microns to 10 microns.

15. The method of any one of claims 10 to 12, wherein the first time period is between 1 second and 3 seconds.

16. 13. The method of claim 10, wherein the first time period begins when an excitation signal is delivered to the ultrasound transducer.

17. 1. A method of operating an ultrasound catheter coupled to an ultrasound energy source, the ultrasound catheter having a core wire coupled to an ultrasound transducer, the ultrasound transducer being coupled to the ultrasound energy source, the method comprising: providing an engagement mode in which the ultrasonic energy source generates ultrasonic electrical signals having ultrasonic frequencies, the engagement mode being achieved by adjusting an output energy level of the ultrasonic energy source to a first output energy level to achieve substantially only longitudinal vibrational motion of the distal end portion of the core wire; providing the ultrasonic energy source with a transverse mode, the transverse mode being achieved by increasing the output energy level of the ultrasonic energy source from the first output energy level to a second output energy level higher than the first output energy level to achieve a combination of longitudinal vibrational motion of the distal end portion of the core wire and transverse vibrational motion of the distal end portion of the core wire, wherein in the transverse mode, the output energy level of the ultrasonic energy source is increased from the first output energy level to the second output energy level by amplitude modulating the ultrasonic electrical signal with a macro-motion electrical signal by increasing the amplitude of the macro-motion electrical signal according to a ramp profile, the macro-motion electrical signal having a frequency at least 350 times less than the ultrasonic frequency of the ultrasonic electrical signal; the ultrasonic energy source operating the ultrasound catheter in the engagement mode for a first time period; the ultrasonic energy source operating the ultrasound catheter in the transverse mode for a second time period subsequent to the first time period in the engagement mode; A method comprising:

18. 18. The method of claim 17, wherein in the transverse mode, an amount of transverse vibratory motion increases as the output energy level increases, and the transition from the first output energy level to the second output energy level follows a ramp profile.

19. continuing the longitudinal oscillatory motion of the distal end portion of the core wire at the first output energy level for the first time period; increasing the output energy level according to a predetermined ramp profile for the second time period to effect the combination of longitudinal and lateral vibratory motion of the distal end portion of the core wire, wherein an amount of lateral vibratory motion increases as the output energy level increases, and wherein the ramp profile is constrained by the first output energy level and the second output energy level; continuing the combination of longitudinal and transverse vibrational motion of the distal end portion of the core wire at the second output energy level for the remainder of the second time period, the second time period being a variable time period; 18. The method of claim 17, comprising:

20. 20. The method of claim 19, wherein the first time period is in the range of 1.0 to 3.0 seconds.

21. 20. The method of claim 19, wherein the first time period is 1.75 seconds.

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