Treatment of ischemia

Abstract

An intravascular device for passing an obstruction in a blood vessel comprises an elongated intravascular wire and a coupling. In use, the coupling transmits ultrasonic energy from an ultrasonic energy source along the wire to an active tip at the distal end of the wire. The coupling is arranged to couple the source to the wire at any one of a plurality of discrete operating positions along the length of the wire for the transmission of ultrasonic energy to the active tip.

Description

Background Art

[0001] Ischemia is an inadequate blood supply to an organ of the body. In atherosclerotic blood vessels, ischemia occurs because the blood vessel is blocked by an obstruction, either caused by a lesion in the vessel wall, an atherosclerotic plaque, or an embolus from another source. An atherosclerotic plaque is composed of a material whose structure gradually hardens over time.

[0002] By partially or completely occluding a vessel, the blockage restricts blood flow to tissues distal to the blockage, leading to cell death and rapid deterioration of tissue health.

[0003] The preferred modality for treating such blockages is minimally invasive endovascular angioplasty. In these procedures, small diameter therapeutic devices are introduced into the vasculature and navigated through the lumen of veins and arteries to the blockage and deployed at the site of the lesion to restore patency. These procedures, which revascularize occlusions in coronary and peripheral arteries in the treatment of chronic atherosclerotic plaques, can also be used to treat acute embolic occlusions, thrombi, or occlusive blood clots.

[0004] The anatomical structures in which these procedures are performed include, but are not limited to, the coronary arteries, neurovascular and peripheral arteries serving the lower extremities. Different anatomical structures are associated with different lesions. Lesions found in various peripheral vessels present different types of challenges to lesions found in the coronary arteries. The iliac, femoral, popliteal and subpopliteal arteries have varying degrees of tortuosity, often significantly smaller than the coronary arteries or neurovasculature. However, these arteries are prone to extensive calcification, which poses a serious obstacle to successful endovascular procedures.

[0005] In endovascular procedures, arteries are selected and recruited for gaining access to the vasculature. The selection is based on the ability of the artery to accommodate passage of the intended diagnostic or therapeutic device to the target site and the extent to which it can minimize tissue and patient trauma.

[0006] In peripheral arterial revascularization procedures, the femoral, popliteal, and pedal arteries are typically accessed through a surgical incision and puncture, which is often referred to in medical terms as the Seldinger technique. Once accessed, a guide wire and introducer sheath are inserted into the vessel and secured at the site. The sheath serves as a port for the introduction, withdrawal, and replacement of the device and minimizes abrasion to the arterial tissue. A guide catheter and guidewire are then introduced into the artery to provide further protection and assist in navigating the device to the target site.

[0007] The guidewire is carefully pushed along the lumen of the vessel to avoid any trauma to the vessel wall and navigated to the site of the obstruction. In a successful procedure, the guidewire is then pushed across or through the obstruction and remains in place to act as a guide through which diagnostic or therapeutic devices (such as balloon catheters and stents) are tracked to the site of the occlusion. Guidewires are used in other minimally invasive procedures to introduce other devices and instruments into blood vessels or other cavities of the body to enable examination, diagnosis, and different types of treatment.

[0008] In the case of balloon angioplasty, after a balloon catheter is introduced into the blood vessel over a guidewire and navigated to the site of occlusion, the balloon is then inflated, thereby destroying or crushing the occlusive material and restoring blood flow. Sometimes, a stent is placed over the area of ​​the flattened lesion to act as a support frame to maintain the patency of the blood vessel.

[0009] Visualization of the progress of guidewires and other diagnostic and therapeutic devices being advanced through anatomical structures is often accomplished by X-ray or duplex ultrasound. MRI is becoming more common in other anatomical structures.

[0010] Other medical procedures that utilize the aforementioned guidewires include gastrointestinal, urological, and gynecological procedures, all of which require passage through an obstruction to facilitate the passage of larger and often more cumbersome devices to the lesion or other target tissue distal to the lesion within the body.

[0011] Guidewires are key to therapeutic interventions and are made of different materials, most typically stainless steel and NiTi (Nitinol), with many different designs. Their manufacture involves changing the microstructural morphology of the material, such as by cold working the material while it is formed into a wire, and then machining the wire into different dimensional designs to achieve the desired properties. As an example, a specific taper can be machined into the length of the wire to produce a differential degree of flexibility along the length of the wire. The wire will therefore have sufficient flexibility at its distal end to conform to the shape of the vessel, and have the strength to transmit forces to the tip ("tip strength") or force through a lesion.

[0012] The construction of these devices typically includes a thin coil that can extend over the entire length of the wire or a discrete segment, most typically the distal segment. These coils help transmit forces over the tapered segment and increase the force that can be transmitted through the entire length of the wire. They also allow the wire to easily conform to the shape of the vessel and track through the tortuous anatomy that may be encountered, particularly in the coronary and neurovascular anatomy.

[0013] Make wire available within the outer diameter range associated with the anatomical structure they are treating. Wires with a diameter of about 0.010 inches (about 0.25mm) are generally used for neurovascular systems, while wires with an outer diameter of 0.014 inches to 0.018 inches (about 0.36mm to about 0.46mm) are generally used for coronary applications. These 0.014 inches and 0.018 inches (about 0.36mm and about 0.46mm) wires are also used for many peripheral vascular systems, generally for popliteal foot and tibial anatomical structures. When entering and treating sick larger diameters and straighter blood vessels (such as iliac vessels, aortic vessels and thoracic vessels), wires with a typical outer diameter of 0.035 inches (about 0.89mm) can be used. Wires with outer diameters of 0.016 inches (about 0.4 mm) and 0.018 inches (about 0.46 mm) are common in accessing the femoral, popliteal, and infrapopliteal vessels.

[0014] The length of wires used in intravascular procedures also varies according to the distance at which they are thought to be likely to operate. As an example, wires that are typically 750 mm up to 900 mm in length are used for many peripheral applications where they may be introduced into the femoral anatomy or popliteal anatomy, or need to be tracked to and through the obstruction in the ipsilateral iliofemoral and subpopliteal arteries. The length of wires used in contralateral and coronary applications tends to be about 1200 mm, 1500 mm, or 1700 mm. In practice, wires that can be tracked contralaterally may be longer, with a length of about 2000 mm to 2250 mm or 2500 mm.

[0015] These conventional intravascular wires are passive in that they do not transmit any energy other than that applied by the clinician. They have different configurations and designs to facilitate access and passage through lesions in different anatomical structures and for use with different devices. However, in many cases, the occlusion is too challenging for conventional wires to pass through.

[0016] In the case of peripheral arteries, these blockages are often too severely morbid and composed of material that is too stubborn to allow the passage of a wire and in these cases, the endovascular procedure takes significantly more time to perform or often requires more devices to cross the lesion or many times the lesion is simply abandoned.

[0017] In more than 50% of peripheral arterial cases, particularly in the popliteal, tibial, and peroneal arteries, the vessel is completely occluded by the lesion; in approximately 30% of cases, the target lesion is heavily calcified. These calcified lesions are actually composed of rigid, inelastic segments that typically extend to a length of 3 to 5 cm within extensive diffuse lesions that average approximately 20 cm in length or even longer. Selecting treatment for these lesions requires knowledge of their length and composition, which is not easily obtained from conventional imaging.

[0018] If the guidewire cannot pass through a lesion in a blood vessel, the potential success of the procedure is significantly affected. The failure of the guidewire to pass through a lesion in a blood vessel prevents preferred subsequent procedures, such as balloon angioplasty and stenting, and limits the ability to treat the patient.

[0019] Occlusions in the distal popliteal vessels or the anterior, posterior, and peroneal arteries result in an ischemic response to wounds and trauma, leading to refractory ulceration of wounds and incisions and other damage to tissue. This anticipated response makes surgical intervention less attractive, facilitating the need for endovascular solutions to chronic total occlusions (CTOs).

[0020] The result that conventional wire designs are often unable to cross refractory lesions has led to the development of advanced minimally invasive endovascular surgical techniques over the past two decades that employ conventional guidewires and balloons. These procedures are technically challenging and require considerable skill and training as well as specialized devices created to enable them to be completed more efficiently. Techniques such as the subintimal and retrograde approaches have been developed, and reentry devices have emerged to assist with the procedure.

[0021] Subintimal techniques bypass lesions by tunneling new pathways along the intima, around the media over the length of the lesion, and reentering the vessel distally. These pathways are created with balloon dilatation and stenting to maintain their patency. Reentry devices have been developed to facilitate these procedures.

[0022] Retrograde techniques utilize a softer distal cap of occlusion, which is easier to traverse than the calcified proximal cap encountered in the antegrade (femoral) approach. In these retrograde techniques, access is gained through vessels distal to the lesion in the foot or ankle in the case of peripheral disease; or through side branch (usually septal) vessels in the coronary anatomy. These procedures are more complex; they require greater skill and take longer to complete.

[0023] In the peripheral subiliac protocol, time is spent attempting a conventional (antegrade) approach and escalating through the wire in further antegrade attempts and then to a retrograde approach to cross the lesion.

[0024] In resource-limited healthcare systems, growing demands have made adoption of these life-saving and limb-saving endovascular technologies problematic for the clinical community. They arguably provide the best patient outcomes, consume fewer hospital and community care resources, and provide better financial outcomes for healthcare systems. However, widespread awareness of these outcomes, limited hospital and clinical resources, and the significant level of clinical training and practice required for current technologies have limited adoption.

[0025] Conventional intravascular guidewires are passive mechanical devices with no active components. They operate by being pushed, pulled, and twisted at their proximal ends to navigate to the site of the blockage, and then pushed through or around the blockage. Their design balances surface properties, stiffness, and flexibility to optimize the way they navigate and act when delivering therapy. These passive wires do not work as expected for guidewires, or are limited when attempting to pass through near-occlusive or fully occluded blockages that may also be significantly calcified. Technical Field

[0026] Extensive methods using ultrasonic vibrations transmitted via small diameter catheters and assemblies have been established in the past and recent prior art, as exemplified by US 3433226. US 5971949 describes the transmission of ultrasonic energy via waveguides of varying configurations and tip geometries. US 5427118 describes an ultrasonic guidewire system, but does not discuss in detail the proximal geometry of the wire or how it facilitates subsequent installation via a through-the-wire approach.

[0027] Many current single transducer systems are not ultrasound activated guidewires, but ultrasound activated catheters that contain wire members to agitate and ablate material. US 6855123 and US 4979939 describe such systems. These catheters themselves require a separate passive guidewire to help them navigate, and therefore, they are tools that facilitate the passage of a single guidewire through an obstruction. US9629643 shows a system that has a range of distal tip configurations, but all require a separate guidewire for entry.

[0028] These devices are intended to deliver an alternative method of revascularization and are described as atherectomy devices. They have not been found to cross lesions to facilitate delivery of the device to achieve revascularization with conventional PTA and PTCA treatment devices.

[0029] These ultrasound devices and recanalization wire devices are associated in the art with claims that they enhance clinical atherectomy procedures. They enhance revascularization and provide or enable atherectomy by removing lesion-forming plaque to reduce the volume of the lesion.

[0030] Many prior art disclosures suggest a reduced likelihood of vascular dissection as a result of the atraumatic manipulation of such devices on soft compliant tissue. Some facilitate movement of wires through the vasculature without reliance on hydrophobic or hydrophilic coatings.

[0031] There is also repeated mention in the art of how the vibration of ultrasonic intravascular devices can reduce the likelihood of vasospasm, an adverse event that can occur during any angioplasty procedure using conventional devices. This therapeutic benefit is believed to result from the vibratory effect of the wire massaging the tissue, see US 5324255.

[0032] Early researchers of these revascularization devices reported in the open literature how their efficacy was affected by contact with tissue, and they explained how these revascularization devices increased the power in the system to overcome losses by manually adjusting the voltage in a step-wise manner to overcome the losses. This suggests that some method of overcoming the effects of losses, such as changing the voltage to increase the amplitude or changing the frequency, is needed.

[0033] In later and current designs, ultrasonic generator systems have become large units, scaled to generate and control pulse waves. Although today's electronic devices make it possible to package such systems in smaller forms, the cost of miniaturization is not conducive to this. In addition, practical considerations mean that known systems usually include separate elements. For example, many systems are designed to contain the signal generator in a unit separate from the transducer, and some are mounted on large trolley units that occupy significant space in clinical environments. US 6450975, US 2008 / 0228111 and US 9282984 all describe such systems.

[0034] In the prior art, many systems describe semi-automatic control of amplitude by monitoring current through a feedback loop. This provides a method of modulating voltage to achieve maximum tip displacement through the device's channel through the vasculature and tunneling through the lesion. These systems do not directly relate this modulation to tip displacement and tunneling or to the composition or characteristics of the lesion.

[0035] US 6577042 to Angiosonic describes modulation of the output amplitude by current in an algorithm that interrogates the transducer current over a small range of frequencies. This maintains the power at a constant level and also monitors the current and voltage over a small range of frequencies to detect failure of the sonotrode, activation components, and to confirm the optimized output frequency.

[0036] WO 2018 / 002887 to Soundbite describes a different approach where multiple transducers or wave focusing are used to generate a concentrated waveform. This again results in the need for a large physical unit. The unit builds the output ultrasound wave by coordinating the sound waves generated by the transducers in the device, by taking at least two different component waves and combining them in a waveguide to form the desired output wave. These approaches all require extensive data acquisition and computer systems to implement the solution.

[0037] The method of coupling the mechanical waveguide or transmission member to the horn is critical, and many connection methods are disclosed. US 4572184 discloses a method using a screw connector, where the wire is held in the screw. In addition to the internal connection mechanism, there are many patents associated with design features to allow the user to interact with these mechanisms, such as US 6508781, US 5971949, US 5417672 and US 9433433.

[0038] Constraints in the lateral direction have also been proposed to optimize the way the wire will migrate through the vessel. The literature has also proposed providing strain relief at the transmission junction.

[0039] The nature of the wire has been proposed with respect to its form or shape, with solid wires such as disclosed in US 6589253 being the most common, although there are also proposals for hollow constructions such as in US 4538622. Modification of the wire by tapering has been proposed to drive distal tip displacement, as well as to optimize resonance along the length of the wire. The composition of the material is also critical in terms of type and combination, and composite material construction, such as disclosed in US 8500658 and US 5397301, respectively.

[0040] Ultrasound activated catheter and wire systems have been considered in the past as a method of atherectomy and preparation of blood vessels for angioplasty treatment. Some products were commercially available in the past, some products are still available on the market, and some new systems have recently been launched. These various types of catheters are mentioned below.

[0041] These catheter and wire systems typically include a) an ultrasonic generator that converts mains electricity into an ultrasonic waveform defined by its voltage amplitude and frequency; b) an ultrasonic transducer, and typically an amplifying horn, that converts electrical energy into high-frequency mechanical vibrations defined by vibration frequency and amplitude; and c) a small diameter waveguide coupled to the horn that transmits the mechanical vibrations to the distal tip of the wire. This causes the distal tip of the wire to vibrate at the desired amplitude and frequency with the goal of ablating material and ultimately promoting revascularization or recanalization of vessels and anatomical structures throughout the body.

[0042] Tissue and material near the distal tip are affected by the ultrasonic movement of the tip and its direct mechanical wear, ablation, and a combination of cavitation from pressure wave components and acoustic streaming that remove ablated material from the area surrounding the tip. Summary of the invention

[0043] The present invention is a disruptive advancement over conventional intravascular guidewire designs and existing activated guidewire and catheter systems, in which mechanical vibrations are transmitted via the wire to the distal tip.

[0044] Various aspects of the inventive concept are expressed in the appended claims.

[0045] An ultrasound system is disclosed that induces vibrations in a customized intravascular surgical wire device, interrogates and applies artificial intelligence and / or intelligent electronics to feedback in the system for optimizing the performance of the device in navigating to and through an intravascular occlusion and characterizing the intravascular occlusion.

[0046] The present invention provides a device that is designed to rapidly penetrate and traverse any occlusion of any composition in any artery or other blood vessel. The device can be used in a standalone procedure to achieve revascularization and restore blood flow in foot applications or other situations. However, the device is most advantageously used to facilitate the subsequent delivery of intravascular diagnostic and therapeutic devices to achieve and assist in the revascularization of a vessel.

[0047] The goals of ultrasound active guidewire devices are to 1) cross complex and calcified vascular occlusions, either as a stand-alone procedure, or as an active or passive guidewire, and 2) provide a conduit to enable passage of ancillary devices to achieve vascular revascularization and stenting.

[0048] In the literature, in patents and in products entering the market, the concepts of either wires or ultrasound activated systems position and clamp the proximal end of the device.

[0049] Embodiments of the invention provide for transmission or activation to be performed at intervals anywhere along the length of the wire. This allows the activation device to be moved along the length of the wire or left at a specific location, such as near an activation port, and the wire moved in and out of the device to prepare for passage through the treatment device.

[0050] In one sense, the present invention resides in a system that includes three interconnected components, namely: a) a compact housing and components that serve as an ultrasound source and connector; b) an active traversing wire assembly for accessing the anatomical system and transmitting energy to the active distal tip; and c) a signal acquisition, processing and communication chipset. The compact housing unit has an ultrasound generator; an ultrasound transducer, a horn and a control unit, which are collectively housed in a portable compact housing unit that is designed to be connected via a coupling unit that excites the intravascular traversing wire and monitors and modulates the excitation of the system in order to achieve traversal and characterization of intravascular occlusions. The onboard signal acquisition and processing chipset can acquire and control the excitation of the signal generator and provide communication of the output from the system to its user and / or an external data acquisition system.

[0051] The present invention resides in a device that advantageously ultrasonically activates an intravascular crossing wire along its entire length. When separated from the activation unit via the disassembly device of the present invention, the crossing wire has a nominal outer diameter that enables the wire to be used as a primary crossing device. The activation unit can be coupled to and separated from the wire and coupled at intervals along the length of the wire. When separated, the activation unit also facilitates the passage of therapeutic devices, such as atherectomy vessel preparation devices, angioplasty catheters and stents, through the wire to reach the occlusion site.

[0052] The controller can monitor the frequency and amplitude of the current and voltage and the measurement of the frequency and amplitude of the incident waveform, the reflected waveform and the standing wave waveform, and the distal tip displacement can be estimated from this. The modulation of these variables can be monitored as the wire passes through the anatomical structure and through different types of occlusions (including calcified chronic total occlusions). Determining the duration or length of calcified and non-calcified lesions and calcified segments is key to some aspects of the present invention.

[0053] The signal used to drive the ultrasound generator can be pulsed or varied to reduce heating and optimize analysis and matching of shifts in resonant frequency. Pulsing of the voltage over a small frequency range can activate the traversal wire. A digital signal processor unit can interrogate the measurements taken, provide feedback and interpret and compare the relative contributions of losses caused by anatomical tortuosity when navigating to the site and losses caused by traversing the occlusion.

[0054] For each standard wire type, a specific algorithm can be employed to estimate the diameter depicted by the deflection of the distal tip when excited at different levels of frequency and power and device configurations under procedure-related conditions. The algorithm can estimate the diameter along the length of the tunneling segment through the occlusion.

[0055] The system of the present invention can process data obtained from the measurements, which indicates when the ultrasound waves are generated, when the ultrasound waves pass through the transmission member, and when the conversion of resonant vibration occurs, when the reflected waveform is attenuated by the transmission member, when the ultrasound waves pass through the vasculature and when they pass through the occlusion. This data is processed or operated by the on-board algorithm to perform operations that convert the raw data into procedure-related outputs.

[0056] With the modulation of the transmitted signal monitored and analyzed, the system of the present invention can adjust the energy losses in the system by voltage control, possibly automatically, to increase the power in the system and compensate for the energy losses encountered in the wire as it passes through the vasculature to the occlusion. The system can distinguish these losses from the additional losses of the wire as it passes through the occlusion, and can compensate for the latter losses to maintain displacement at the distal tip.

[0057] Numerical operations may be performed on the measured parameters and variables to determine the rate of change of these measurements relative to each other and other parameters. The system of the present invention may numerically compare and interpret the differences between these calculated values ​​from the active system and a set of prescribed values ​​in order to characterize the nature of the substance occluding the vessel. Optionally, the energy may be manually controlled by an override controller that enables the user to increase the power in the system and, therefore, the energy level driving the waveguide. This method of providing a manual pulse override by adjusting the current or voltage may be used to immediately or preemptively address sudden losses in the system due to unexpected events or disturbances to the wire.

[0058] The output may be presented visually on a small display, or via tactile or audio hardware (such as a haptic interface) located on a device accessible and visible to the user.

[0059] Optionally, the active traversing wire assembly may be used in a passive mode without ultrasound activation, or the wire may be mechanically coupled to an ultrasonic transducer and acoustic horn in the housing unit to transmit ultrasonic vibrations, and then the wire may be detached from the housing unit to return it to the configuration for a subsequent procedure.

[0060] The active wire assembly can be connected by means for connecting the active wire assembly to the acoustic horn and compact housing unit in a manner that allows for efficient transmission of ultrasonic vibrations to the wire assembly. The proximal tip can be optimized in geometry for easy positioning, loading, and interference fit into the coupling connector to facilitate rapid loading and unloading and accurate, reliable transmission of energy through the wire.

[0061] The proximal end of the wire can be processed into a form that allows it to be positioned into the acoustic horn and engage with it in direct contact. Once the wire is in this position, the secondary mechanism can clamp or lock into a position that cooperates with the circumferential surface of the locking unit, so that the wire remains in place until the mechanism is released.

[0062] Custom active cross-wire assemblies can be provided with systems having integrated locating bosses that allow the components to be positioned in or out of the coupling for a procedure. A device can be provided for quickly separating an ultrasound activated intravascular wire from an acoustic horn by a mechanism that cuts the wire in a precisely controlled manner to allow the remainder of the device to be used as a delivery wire for a subsequent procedure. The bosses can perform either or both of the functions of coupling and cutting or breaking the wire.

[0063] Custom active wire assemblies may have features that optimize radiopacity under high frequency deflection, placed at regular intervals along the length of the assembly, and visible under duplex imaging. Such features may be processed and / or may include marker bands such as gold or platinum. Ultrasound as well as X-rays may be used to estimate the occlusion length during the procedure.

[0064] The distal tip edge of the crossing wire may be rounded and polished to limit the potential for trauma to tissue, and may be manufactured from a scratch-resistant material optimized for passing through lesions.

[0065] The custom traversing wires of the present invention may have a formable or shaped distal tip for manipulation and radiopacity for visibility to provide more effective tracking to and through a target lesion and to facilitate access to side branches.

[0066] The crossing wire is made of a resilient, fracture-resistant material, such as ASTM Type I to IV low inclusion density Nitinol wire, selected based on optimized properties for different diameters and target anatomy.

[0067] The traversing wires may have lubricious hydrophilic and hydrophobic coatings and / or low friction sheaths to further minimize the adverse effects of micromotion and minimize the possibility of condensation.

[0068] The controller may handle all measurements of the converted transmit and receive waveforms. The user interface may communicate the performance and progress of the track as it advances through any obstructions, and provide feedback via visual, audio, or tactile means (such as haptics) regarding the characterization of the composition and length of the lesion.

[0069] The system of the present invention can enable data transfer between a device and another device or wireless or cloud services for analysis and storage.

[0070] An auxiliary device attached to the Luer fitting through which the wire passes can provide telemetry related to the movement of the wire through the vessel.

[0071] Automated drives can be used to carefully control the speed at which the wire is inserted and withdrawn from the vasculature to provide more precise feedback on the composition of the plaque as it passes through the length of the lesion. This provides a means to achieve more sophisticated characterization of the lesion and intravascular environment.

[0072] The acoustic horn and transducer assembly may have a hollow port through the full length of the assembly, with an internal wire connect / disconnect mechanism or a locking collet.

[0073] The system of the present invention may comprise three interconnected components, wherein the components of the ultrasound system are disassembled. For example, the generator may be separated from the compact unit.

[0074] The wire may be secured in a crimping sleeve that captures the wire over the length of the sleeve. The sleeve may be cylindrical or may preferably have a polygonal cross-section, such as a hexagonal or octagonal pattern, which collapses onto the wire in a uniform manner. The sleeve or other coupling structure such as a collet may be made, for example, of stainless steel or of aluminum.

[0075] The crimping segments can be applied under controlled force, and the wall thickness of the collapsing sleeve ensures that a uniform load is applied to the wire. Conveniently, the proximal end of the crimping sleeve may be threaded to screw into the transducer head. Alternatively, the wire may be secured in a crimping set screw that captures the wire at the proximal length.

[0076] structure

[0077] In a preferred embodiment, the system of the present invention comprises:

[0078] a) Signal power generator;

[0079] b) ultrasonic transducer;

[0080] c) Optional acoustic horn;

[0081] d) a transmission waveguide or traversing wire that transmits high frequency ultrasonic vibrations from a proximal end to its distal tip to ablate through non-compliant material of an occluded artery and is of a size convenient for standard diagnostic and therapeutic devices;

[0082] e) a coupling, which is an attachment mechanism that couples the transmission wire to the acoustic horn or directly to the transducer, which minimizes losses and enables accurate and reliable transmission of high frequency mechanical vibrations;

[0083] f) means for separating or removing the transmission member from the acoustic horn or transducer, which may or may not utilize an attachment method; and

[0084] g) Programmable circuitry including an integrated or onboard programmable digital signal processing chipset to process the monitored, transmitted and received / input signals via algorithms that interrogate the responses, compare the ultrasound feedback and contribution to the resonant frequency standing waves, estimate the size of the opening tunneled through the lesion by the activated tip, and modulate the power in the system via voltage amplitude and system frequency.

[0085] For the purposes of the following description, the system can be considered to consist of four major subcomponents and subsystems:

[0086] 1) A compact housing unit that may or may not be handheld to control the operation of the medical device and that houses all or some of the following components, namely, a signal generator, an ultrasonic transducer, an acoustic horn (although the horn may be part of the transducer assembly or may be omitted) and interface connection components, as well as data acquisition, processing and system control.

[0087] Different embodiments of the device system can be envisioned. In one embodiment, all components are gathered in a single unit. In another embodiment, the components are disassembled, wherein the generator is housed separately. In another embodiment, the transducer horn is separate. In another embodiment, the coupling is directly connected to the transducer stack.

[0088] 2) A coupling and detachment module that allows the connection of a pass-through wire to the ultrasonic transducer and / or horn assembly.

[0089] 3) A set, multiple sets or series of interchangeable flexible transmission member assemblies or crossing guidewires for minimally invasive percutaneous surgical recanalization of obstructed or partially obstructed anatomical passages.

[0090] 4) Integrated signal processing circuit board for data acquisition and processing and controlled activation of the system. In some embodiments, the processing board is capable of analog and / or digital signal analysis and power control of the device and incorporates a communication module. This enables wired and wireless connection of the device and its data to a wider data network and the Internet, and facilitates the development of smarter algorithms to manage the system.

[0091] operate

[0092] In general, the system operates as follows: a) a signal generator provides electrical energy to the transducer; b) a piezoelectric ultrasonic transducer converts the electrical energy into mechanical vibrations; c) these mechanical vibrations may be further amplified by an acoustic horn; d) a customized transmission member is coupled to the acoustic horn or to the transducer via a customized coupling method; e) ultrasonic vibrations are transmitted via the transmission member; f) the distal tip of the transmission member vibrates at a specified frequency and amplitude, with the ability to beneficially destroy diseased tissue or other material; and g) digital signal processing and control circuitry allows for semi-autonomous overall characterization of lesions, power control, and estimated size of openings in the system.

[0093] When the ultrasound system is activated, the emitted waves travel along the wire to its distal tip where they are reflected. The reverberations created in the wire at different transition points set up a series of secondary and tertiary reflections. These waves have the characteristics of different wire designs and features, and can be optimized to enhance the differences in their signal characteristics. These reflections are determined to consist of specific response patterns in the waveform at any time for a given input, and their changes are associated with disturbances or differences in the surrounding environment.

[0094] The amplitude of displacement along the wire at a particular frequency changes over the course of the procedure due to damping caused by contact with surrounding tissue during navigation to the lesion site or during contact with diseased non-compliant or calcified tissue in the lesion. Compensation for these losses is performed, for example, by increasing the voltage or current in the generator and then in the transducer. This is used to drive the amplification and / or attenuation of the primary ultrasonic energy. Reverberations in the system are similar to primary losses and are affected in a characteristic manner, which allows them to be used to traverse and excavate lesions and characterize the source and nature of the damping.

[0095] control

[0096] To achieve a constant vibration amplitude, the ultrasonic transducer is controlled by a suitable feedback controller. In the case of ultrasonic waveforms, phase feedback control and comparison can be performed by an electrical equivalent model, such as the Butterworth–van Dyke model.

[0097] Ultrasonic transducers can be controlled by the frequency and amplitude of the excitation voltage. In an embodiment of the present invention, the change of frequency affects the phase between voltage and current. Here, the amplitude of the excitation voltage controls the current and is proportional to the amplitude of the vibration in resonance. This allows the control algorithm to drive the frequency using only phase and amplitude.

[0098] In a preferred embodiment, the method is to use the resonant frequency as the operating point of control, in conjunction with an amplitude feedback controller to drive the system, with the operation managed using a custom programmed control algorithm unique to each wire type.

[0099] The advantages of a resonantly driven, low damping system are the low voltages and high effective power values ​​required. This technology is novel in the context of active guidewire systems. It also provides additional advantages in controlling the response of the Nitinol wire system to ultrasound activation.

[0100] Preferably, the wire is activated at a frequency of 40 kHz in order to advance to the lesion and also through the lesion. The amplitude of the signal is determined by the extent to which it is likely to find resonance in the system due to perturbations caused by contact in a tortuous pathway or contact with a lesion forming a complete occlusion or a thrombus or some embolic material. An activation frequency of 40 kHz has been found to be effective in producing a traversing / digging action at and around the distal end portion of the wire and helps drive the wire to and through the lesion.

[0101] An activation frequency of 40 kHz enables ultrasonic energy to be transmitted over functional working lengths of 750 mm or less to 2 m or longer (e.g., 1.5 m) for distal tip activation, with sufficient intensity to achieve resonance at a range of harmonics and with sufficient energy to achieve penetration as well as excavation.

[0102] Basing the system on an activation frequency of 40 kHz also enables the components to be compact enough so that they can be contained in a handheld device of compact size and convenient form. For example, using a 20 kHz system would require the mass and size (both length and diameter) of the transducer to be doubled.

[0103] The transducer can be designed to have a desired resonant frequency based on the material properties, geometry and prestress of the transducer. Broadly speaking, the higher the resonant frequency of the transducer, the smaller its size and overall dimensions. For example, a transducer and horn configuration operating at a frequency of 40kHz can be made handheld and compact. This allows the production of a handheld transducer that can be easily used with a wire. In particular, a small transducer can be easily moved along the wire by a single operator and can be easily stored or fixed at a specific location along the wire.

[0104] The concept of such a system has been established to achieve atherectomy and remove the lesion as an obstruction. Therefore, one function of the device described is to achieve this. However, the product platform proposes another function, which is to act as a guidewire to deliver treatment or therapeutic devices to the lesion site. By using ultrasound to temporarily transform the guidewire into an activated wire, the wire is passed through the lesion of any composition, which allows the wire to pass through lesions that cannot be passed except by roundabout techniques.

[0105] For a given transducer, within certain limits, it is possible to compensate for temperature effects and changing loading conditions in the Nitinol due to interaction with surrounding tissue during the procedure, which could potentially result in changes in resonant frequency and vibration amplitude.

[0106] Thus, embodiments of the device are disclosed in which, in the use of voltage and current, differential changes over time and length will be monitored using control and analysis through resonant frequency, and such interrogation and compensation will be used to characterize the properties of the intravascular anatomical structure.

[0107] algorithm

[0108] The comparison and analysis between the primary emission and tertiary feedback responses in the wires takes into account the variation in characteristic losses that are typical of the engagement of active components with different healthy and diseased tissue types. The analysis distinguishes between losses in vessels and losses associated with lesions, as well as between lesions of different composition, especially between calcified and non-calcified lesions.

[0109] The resistive loads encountered and recorded by the system vary as the active member passes through different anatomical structures. The analog signals are interrogated and conditioned by onboard digital signal processing (DSP), and the parametric outputs are processed by algorithms to characterize the response and define feedback and effect control.

[0110] The characteristic responses to the differential changes that occur in different media and during the passage or navigation of the intravascular wire through different anatomical structures are used to create different algorithms that are used to: 1) determine the source of loss in the system and compensate for this loss; 2) assess the tone of the arterial vessel; and 3) determine the composition details of the lesion. These algorithms provide automatic levels of compensation to the tip of the wire when it comes into contact with compliant, non-compliant and calcified materials, and in the latter, amplify the energy in the system to increase cavitation and primary lumen formation.

[0111] The algorithm can be customized according to the wire type. The range and rate of change filtered by the signal processing circuitry and the differential order of the change can be used by the algorithm to characterize the properties of the material the wire passes through. This can then be communicated to the physician when the procedure is performed to help define the treatment.

[0112] Performance improvements

[0113] Advantageously, the algorithm can be trained by benchmark in vitro and in vivo data. The latter is enabled by embodiments of the device having a communication mode that provides for data transfer to and from the device. Thus, the quality of operation and interpretation of the device can be improved over time by interpolating more data sets from additional protocols built on experience and evidence of use, which can be released into iterative generations of control algorithms for the product.

[0114] This onboard, local, and cloud-based algorithmic improvement improves the device’s design and operating interface. It also provides more detailed feedback to the physician using the device and facilitates customization of the device’s operation to accommodate different wire geometries and anatomies.

[0115] Connection and configuration

[0116] The ultrasonic generator, main housing, circuitry, and connection components remain outside the patient's body. Most of the length of the transmission member and any peripheral catheter components are the only parts of the system that need to enter the patient's body. The proximal segments of the transmission member and any peripheral catheter components remain external to facilitate connection to the main unit and the regulatory requirements for manipulation and control.

[0117] The first concept of the present invention is a detachable active traversing guidewire. In this way, the active traversing wire can be used as a guidewire for subsequent treatment after traversing. This involves a method of operation in which the traversing wire can be used in passive and active configurations. The traversing wire can be connected to or detached from the transducer housing at the point of care.

[0118] In a preferred method of operation, the intravascular traversing wire may initially be used in the anatomical passage in a passive mode without ultrasonic vibrations. While the wire remains in the anatomical passage, the proximal end of the traversing wire may then be connected to an acoustic horn / transducer assembly located in the housing as needed to excite or transmit ultrasonic vibrations via the wire acting as a transmission member, thereby causing vibrations at the distal tip to achieve traversal of the lesion.

[0119] After ultrasound activation, the pass-through wire may then be detached or separated from the acoustic horn located in the housing to return to a passive wire configuration to facilitate further subsequent placement or treatment, if desired.

[0120] The ultrasonic transducer, horn, coupling device, signal generator, power supply and control circuit can all be located in the same portable, lightweight, compact housing unit. In another embodiment, the signal generator is separate and connected to the compact housing unit containing the transducer and horn via a connector cable. In another embodiment, the entire system can be designed as a disposable device. In another embodiment, the ultrasonic transducer, horn, coupling device, generator and control circuit can all be located in the same portable, compact housing unit and connected to the power supply via a cable.

[0121] A customized transmission member or wire is disclosed that will act as an intravascular traversing guidewire, designed and customized to effectively transmit vibration energy over its length and achieve controlled ablation at its distal tip.

[0122] Also disclosed are various methods of mechanically coupling the transmission member to an acoustic horn or transducer located in the housing.The coupling arrangement used in reverse may also function as a decoupling arrangement.

[0123] It is also disclosed that the system may include a separate breakaway component to quickly remove the transmission member proximally from the entire system to facilitate its use as a tracking guidewire or positioning device.

[0124] The coupling and decoupling mechanism may be housed a) in the main housing in which the transducer and horn are housed, or b) as part of a proximal housing that is part of the transmission member assembly.

[0125] In another embodiment, the transmission member is pre-coupled to the acoustic horn located in the housing during the manufacturing stage.

[0126] The design of the coupling is optimized to achieve efficient transmission and to limit undesirable strains and acoustic transmission losses.

[0127] The connection method is designed to facilitate user interaction, connection, and visual / tactile feedback of connection status.

[0128] In one embodiment, the transmission member is a part of a custom wire assembly with a proximal housing, which includes a connection and separation arrangement and a wire support to minimize the loss in the energy delivery of the proximal segment of the transmission member. This custom assembly and proximal wire segment allow better guidewire control and entry during passive crossing. The design of the coupling mechanism is optimized for the transmission of acoustic ultrasonic energy from a transducer and / or an acoustic horn. The way the wire is engaged is important for achieving the desired transmission of the actuation force to the distal tip over the length of the waveguide.

[0129] The system delivers controlled levels of energy to the transmission component through a custom coupling to achieve minimal losses, and can guide initial deformation of the transmission component to minimize losses and unwanted loading of the transmission component.

[0130] The design of the transmission member or waveguide wire is optimized to control the transmission of the wave pattern through different anatomical structures to the distal tip and through different materials. The morphology of the materials used is important, and while they may appear as highly elastic isotropic material morphologies at the macroscopic level, they may have anisotropic microscopic morphological features that may delay the onset of crack initiation or inhibit crack progression.

[0131] To deliver destructive vibrations to the lesion site, the present invention contemplates a custom-made through-wire that resonates at the drive frequency of the system. This is achieved by understanding the material properties including the speed of sound and density in addition to the resonant properties of the elongated rod and numerical modeling.

[0132] The pass-through wire may be made from a single piece of drawn wire or may be constructed by joining segments together end to end.

[0133] Proximal features may be included to enhance the connection of the wire to the ultrasonic drive unit and reduce the risk of fatigue failure. Conversely, distal features may be included to enhance the performance of navigation and traversal, including optimizing the control and maneuverability of the wire for tracking through anatomical structures, and also increasing the opening profile achieved. In addition, a marker band may be included to provide visibility under fluoroscopy or x-ray. For example, a radiopaque marker may indicate the working length of the wire and the traversal tip.

[0134] More generally, the present invention allows for the introduction of specific features worked into the wire at the proximal and distal ends and throughout its length to enhance the ability of the wire to pass through a lesion, strengthen the wire, achieve greater control over the wire, and achieve coupling of the wire and efficient transmission of energy through the wire. The composition of the design varies with the materials used and the intended use.

[0135] The wire geometry and the materials used are optimized for different application applications. The wire is processed to minimize defects and optimize transmission over and through sections of the material length through tightly controlled tapers and keyed splines.

[0136] The material used in the exemplary embodiment is a nickel titanium (Nitinol) alloy. Specifically, in the case of Nitinol alloy, the size and number of inclusions are strictly controlled in order to limit the possibility of fracture.

[0137] The design of the distal tip and any geometric features utilize modern manufacturing methods and have optimized geometries to achieve different effects. As non-limiting examples, these effects include: limiting trauma to tissue; accelerating the waveguide through different anatomical structures; and limiting unwanted lateral deflection through different types of different lesions. Lesions can be of different lengths, diameters, or compositions, or be thrombotic or calcified in origin. The distal tip is also optimized to open or increase the diameter of the channel to provide a subsequent treatment device, if necessary.

[0138] The present invention may include a novel semi-automatic control system that can control or modulate the signal applied from the generator to the transducer and horn and therefore to the traversing wire. The control may be based on feedback from the wire-tissue interaction to control the signal transmitted to adjust for losses due to damping or increased resistance or to modulate the applied force.

[0139] Embodiments of the system include visual and tactile feedback indicators that can provide visual, audio, and / or tactile feedback to the user regarding the status of the device and the nature of the ablated tissue. Such feedback can also indicate the level of force that can be applied to achieve ablation and destruction of tissue and advancement of the wire.

[0140] The system may include a means to provide a manual override to help control the amplitude of the vibrations delivered to the distal tip. This allows the system to be controlled by a user operating the device during a procedure through controls and user input mechanisms located on the generator and transmission unit, or to be controlled autonomously.

[0141] The transmission link and controller unit may include a sensory feedback system and haptics that allow the user to sense the extent to which the wire has passed through the lesion.

[0142] In the device described herein, the frequency of the converter converting the mechanical signal is in a set short-range frequency sweep within a short-range frequency to accommodate the losses caused by the interaction and impact of different forces on the length of the wire. The speed of the microprocessor allows the device to handle small fluctuations in resonance in real time. Signal processing and analysis of the feedback ensures that the best mechanical feedback is achieved.

[0143] The device operates at a set frequency between 20kHz and 60kHz, preferably between 35kHz and 45kHz, more preferably between 37kHz and 43kHz and most preferably around 40kHz. The device also operates at a desired low power, for example in the range of 1W to 5W, to reduce the risk of vascular trauma or dissection. In addition to automatic control of the desired low power range, for example 1W to 5W, the output of the device can also be controlled to allow the user to amplify the power outside of this range and thereby compensate for unexpected interference and ensure fast and efficient crossing. Therefore, the device can also achieve maximum load at higher power levels (for example, up to 50W to 100W) to decisively cross challenging lesions and overcome attenuation or deflection of the tip.

[0144] Another objective goal of the procedure is to employ methods of interrogating the feedback signal to characterize the lesion that the wire is passing through and to collect data about the lesion being passed through, such as its length and composition, aspects that inform the physician of the manner in which the target lesion may be treated.

[0145] This data is also provided as feedback to the physician in tactile and / or visual or audio form on a display to allow the physician to operate the device. For example, in one embodiment, such feedback can allow the physician to monitor the traversal and assess the characteristics of the lesion using a simple backlit screen on a compact housing unit.

[0146] In another embodiment, where the user has access to a network, data from the procedure can be captured anonymously to protect patient confidentiality and transmitted from the device to a data storage and processing platform where the data can be analyzed in real time or at a later time.

[0147] Characteristics of the lesion may also be presented to the user for analysis and interpretation during the procedure.

[0148] In another embodiment, an accessory is used to record and measure the displacement of the wire as it traverses the vasculature, and the feedback is mapped against lesion composition to characterize lesion properties as a function of displacement through the lesion.

[0149] In another embodiment, the system is supported in a displacement drive that can propel the wire over a controlled distance to provide semi-automatic and robotic traversal of lesions and more accurate characterization of their composition and displacement.

[0150] In another embodiment, the active wire is supported in a sliding lock mechanism where the wire may run through the center of the transducer body, but there is a lock in the transducer, such as at its distal end, where transmission of energy is achieved.

[0151] In another mechanism, the activation unit may be traveled along the length of the wire and positioned at the desired point to lock and enable transmission via a sliding lock mechanism. BRIEF DESCRIPTION OF THE DRAWINGS

[0152] In order that the present invention may be more readily understood, reference will now be made, by way of example, to the accompanying drawings, in which:

[0153] Figure 1 is a schematic diagram of a system according to the present invention, comprising a compact housing unit;

[0154] Figure 2 yes Figure 1 a perspective view of the system shown;

[0155] Figure 3 is a schematic side view showing another embodiment in which the ultrasonic generator is housed in a separate unit;

[0156] Figure 4 It is a diagram of the analog and digital data flow in the system;

[0157] Figure 5 is a flow chart illustrating a preferred method of operation of the system;

[0158] Figure 6 is a diagram showing the operational functional flow of the system;

[0159] Figure 7is a flow chart showing the operation of the semi-autonomous intelligent control system of the present invention;

[0160] Figure 8a , Figure 8b and Figure 8c is a schematic side view showing the active wire assembly prior to being connected to the horn, then connected to the horn using an appropriate mechanical coupling method, and separated from the main housing and proximal assembly by a separation method;

[0161] Figure 9a , Figure 9b and Fig.9c is a cross-sectional view showing one embodiment of a connection method;

[0162] Fig.10 and Fig.11 is an enlarged partial cross-sectional view showing other embodiments of the linear push-twist connection method;

[0163] Fig.12 is an enlarged partial cross-sectional view showing another embodiment of a connection method using mechanical locking;

[0164] Fig.13 is an enlarged partial cross-sectional view showing an embodiment of a screw connection method using a radial release mechanism;

[0165] Fig.14 A coupling method having a proximal interlocking feature on a transmission member is shown;

[0166] Fig.15 is a perspective view of a wire release mechanism for breaking or cutting an active wire between opposing blades;

[0167] Fig.16 is a schematic diagram of a wire release mechanism that breaks or cuts an active wire between blades carried by gears actuated by rollers;

[0168] Fig.17 is a schematic diagram of a wire release mechanism that breaks or cuts an active wire between blades carried by linearly actuated gears;

[0169] Figures 18a to 18c is a schematic detailed side view illustrating a method of breaking an active wire;

[0170] Fig.19 is a cross-sectional side view of a proximal subassembly that can measure the displacement of an active wire as it traverses;

[0171] Fig. 20 is a schematic side view showing a housing unit supported by an automatic drive system;

[0172] Fig.21is a cross-sectional side view of an embodiment wherein the acoustic horn and transducer assembly has a hollow port through the full length of the assembly with an internal wire connect / disconnect mechanism or locking collet;

[0173] Fig. 22 is a cross-sectional side view of an embodiment in which the acoustic horn / transducer assembly of the activation unit has a hollow port through most of the body length of the assembly, but the wire exits the assembly through a side port, thereby enabling the activation unit to be locked along the wire by a mechanism in the transducer tip;

[0174] Figures 23a to 23c is a schematic side view of an acoustic horn / transducer assembly showing an alternative method for connecting active wires;

[0175] Figures 24a to 24c yes Figures 23a to 23c Schematic side view of a variation of the arrangement shown in , in which the active wire extends through the full length of the horn / transducer assembly;

[0176] Figures 25a to 25c yes Figures 23a to 23c Schematic side view of another variation of the arrangement shown in Fig.25d is a schematic perspective view thereof, wherein the active wire exits the horn / transducer assembly through a side port;

[0177] Figures 26a to 26c yes Figures 25a to 25c A schematic side view of a variation of the arrangement shown in Fig.26d is a schematic detail view thereof in which the active wire is laterally removable from the horn / transducer assembly in a direction transverse to the longitudinal axis of the active wire;

[0178] Figures 27a to 27c is a schematic side view showing a housing unit positioned at various longitudinal positions along a proximal portion of an active wire protruding from a patient's body;

[0179] Figure 28 to Figure 31 is an exploded perspective view of various clamp arrangements used to secure active wire to the horn / transducer assembly;

[0180] Fig.32a and Figure 32b yes Fig.30 an enlarged perspective view of the chuck shown;

[0181] Fig.33 is a schematic cross-sectional side view of an alternative chuck arrangement;

[0182] Fig.34a and Fig.34b is a schematic side view of another active wire of the present invention;

[0183] Fig.35 is a schematic side view of an active wire of the present invention;

[0184] Fig.36 is a perspective view of a variation of the present invention in which the active wire has an angularly offset distal end portion;

[0185] Fig.37 is similar to Fig.35 A schematic side view of an active wire having an angled offset distal end portion is shown;

[0186] Fig.38a and Figure 38b is a schematic side view of another active wire including a marker band of the present invention;

[0187] Fig.39 is a schematic side view of another active wire of the present invention;

[0188] Fig.40 and Fig.41 is a schematic side view of other active wires of the present invention, each having an enlarged bulbous distal tip; and

[0189] Figures 42a to 42c is a schematic side view showing the wire of the present invention being used initially as an active wire to pass through a lesion and then as a guidewire to deliver a subsequent device to the lesion. DETAILED DESCRIPTION

[0190] Figure 1 A schematic diagram comprising a compact housing unit 2. In this configuration, the compact housing unit 2 comprises an ultrasonic generator 4, an ultrasonic transducer 6 and an acoustic horn 8. The housing unit 2 is connected via a power cable 10 to an available power source.

[0191] Figure 1 Also shown is an active pass-through wire assembly 12 connectable to the housing unit 2. The active wire assembly 12 comprises a flexible transmission member in the form of a wire 14.

[0192] The proximal section of the active crossing wire assembly 12 includes an attachment module 16 and a detachment module 18, and provides one or more additional ports 20. Also shown is a distal section of the active crossing wire assembly 12, including an enlarged view of the distal tip 24 of the wire 14. Fig. 22 In this example, the distal tip 24 is bulbous.

[0193] When coupled and activated, the transducer 6 and wire 14 vibrate at the proximal end with sufficient amplitude to enable the distal end of the wire 14 to effect traversal of a lesion by energy transmitted along the wire 14 .

[0194] For example, the length of wire 14 may exceed 2m. For example, entering a lesion in or through the foot may involve wire 14 traveling a distance of typically 1200mm to 2000mm in the vascular system, depending on whether an ipsilateral approach or a contralateral approach is selected. In this regard, wire 14, which tapers to a fine line distally at its tip, can navigate to the foot artery and around the arch of the foot between the dorsal artery and the plantar artery. However, the present invention is not limited to foot or other peripheral applications and can be used, for example, in coronary applications, where the ability of wire 14 to navigate and dig into a tortuous small diameter artery is also beneficial.

[0195] Figure 2 Also shown are the compact housing unit 2 and the active pass-through wire assembly 12. Also shown are user input controls 26 and means for providing feedback to the user, here exemplified by a display 28.

[0196] The wire 14 may be coupled to the transducer 6 via the acoustic horn 8 or may alternatively be coupled directly to the transducer 6, in which case the acoustic horn 8 may be omitted. Figure 2 , the attachment module 16 can attach the wire 14 directly to the transducer 6 within the body of the housing unit 2, below the display 28 of the housing unit 2.

[0197] Figure 3 A variant is shown in which the ultrasonic transducer 6 and the acoustic horn 8 are integrated into the compact housing unit 2, while the ultrasonic generator and the circuit 4 are accommodated in a separate generator housing unit 30. In this case, the housing unit is connected to the generator housing unit via a connector cable 32.

[0198] Figure 4 The components and elements of the system and the data flow through the system, including communications, are shown. A controller within the housing unit controls the ultrasonic generator to produce a signal that is converted by the transducer into ultrasonic energy. The ultrasonic energy is fed via an optional acoustic horn to an active wire that navigates the vasculature and passes through an obstruction, such as a chronic total occlusion (CTO).

[0199] Feedback from the active wire is received by a feedback receiver, amplified by an amplifier and filtered by a series of bandpass filters, and then converted to digital to generate feedback data, which is sent to the processor. The controller preferably controls the wireless communication system, such as using a Wi-Fi network or Bluetooth connection, to receive data from the processor and transmit the data from the housing unit to a local storage device and / or the cloud. Figure 4 Also shown are means in the housing unit for providing feedback to the user, such as a display and / or a tactile feedback system as described above.

[0200] Next go to Figure 5, which shows that the system can be used in either passive or active mode. Initially, the active wire assembly is introduced into the artery and the distal tip of the wire is navigated to the target blockage, which may be calcified or diffuse. If the blockage can be traversed without ultrasound activation of the wire, the system is in passive mode and the blockage is traversed. Conversely, if the blockage cannot be traversed without ultrasound activation of the wire, the active wire assembly is connected to the housing unit and then ultrasound activated to achieve traversal.

[0201] Once the obstruction is crossed, the active wire assembly is disconnected from the housing unit. The wire is then ready for use as a guidewire to facilitate the introduction and navigation of subsequent therapeutic or diagnostic devices as needed.

[0202] Figure 6 The operation of the system is further outlined, as well as the procedures and decision points associated with the use of the system.

[0203] Figure 7 is a flow chart outlining the semi-autonomous control of the system. In practice, the system can collect data input by the user prior to operation, such as the expected lesion type and its anatomical location. This data can be coupled with real-time inputs, such as power requirements, as the active wire passes through the lesion.

[0204] The system can automatically sense changes in frequency and power and can use onboard algorithms to optimize the performance of the active wire. This information can be fed back to the user via tactile, visual or audio means (such as a display on the housing unit).

[0205] Variations in the magnitude of the input and control parameters of current, voltage and frequency, together with the characteristic capacitance of the converter, provide a matrix of measurements and controls that are used to determine the power required and characterize the lesion being traversed.

[0206] While the input is held constant, changes in the current are indicative of the absorbed strain energy or damping effect along the wire and particularly at the distal tip of the wire as it passes through the lesion at the sustained frequency of the system.

[0207] Monitoring the current allows interpretation of the wire's behavior, and modulation of the voltage allows amplification of power and recovery of frequency when the wire actuates to contact the surface and reduce deflection. This array of measurements over a small frequency range then allows for an overall characterization of the composition of the lesion, whether it is calcified, fibrous, or gelatinous throughout its length.

[0208] These interpolated characteristic components are not absolute properties of the lesion, but rather indicate its composition and consistency, such as: calcification, rigid compaction or decomposition; or compacted calcification particles vs. uncompacted fibrosis vs. hard or soft gel-like. These properties can indicate the nature and severity of the lesion and inform the clinician of the best treatment options to consider.

[0209] The system may also transmit this data via existing wireless or wired communication networks and receive optimized performance algorithms.

[0210] Figures 8a to 8c A method of attachment is shown in which the active pass-through wire assembly 12 and the compact housing unit 2 are not initially mechanically coupled together. Figure 8a As shown, the wire 14 can be used as a conventional guidewire in its passive mode, ie, without ultrasound activation.

[0211] Figure 8b 1 shows how the active passing wire assembly 12 can be mechanically coupled to the housing unit 2 if and when desired. In particular, engagement of the attachment module 16 with the distal end of the housing unit 2 enables alignment and mechanical coupling of the proximally protruding end portion of the wire 14 within the central hole 34 at the distal end of the acoustic horn 8. Once coupled in this manner, ultrasonic vibrations can be transmitted from the acoustic horn 8 along the wire 14 to pass through the lesion.

[0212] After crossing the lesion, Figure 8c The wire 14 is shown now separated from the acoustic horn 8 after operation of the separation module 18. Specifically, the opposing blades of the separation module 18 are brought together around the wire 14 to break or cut the wire 14. The compact housing unit 2 and the proximal segment of the active pass-through wire assembly 12 can now be removed from the wire 14, thus separating all other components from the wire 14.

[0213] Figures 9a to 9c An embodiment of the proximal segment of the active traversing wire assembly 12 is shown, particularly the attachment module 16. In this embodiment, the wire 14 is mechanically coupled 36 to a screw connector 38, which includes an enlarged head and an external thread extending toward the proximal side. The head of the screw connector 38 is clamped and engaged by a surrounding sleeve 40 having a longitudinal stepped shape. The narrower tubular distal end of the sleeve 40 provides strain relief around the wire 14.

[0214] The sleeve 40 and the head of the screw connector 38 are constrained to rotate together about the central longitudinal axis of the wire 14. For example, Fig.9c The cross-sectional view of shows that the head of the screw connector 38 can have various rotationally asymmetric outer shapes 42 that complement and interlock with the corresponding inner shape of the sleeve 40. However, relative axial movement between the sleeve 40 and the head of the screw connector 38 is possible.

[0215] The acoustic horn 8 is shown within the housing unit 2. The acoustic horn 8 comprises a central distal threaded hole 44 which is opposite and complementary to the external threads of the screw connector 38.

[0216] When Figure 9bWhen coupled as shown, the proximal segment of the active wire assembly 12 is axially pushed to the housing unit 2 via the snap-on connectors 46, 48. The snap-on connector 46 of the housing unit 2 is integral with an axially retractable tube 50, which is biased distally by a spring 52. The retraction of the tube 50 against the bias of the spring 52 allows the outer threads of the screw connector 38 to be screwed into the hole 44 of the acoustic horn 8 by turning the sleeve 40, which applies torque to the head of the screw connector 38. Once the threads of the screw connector 38 are fully engaged with the hole 44 of the acoustic horn 8, the sleeve 40 is released, and the spring 52 acting on the tube 50 then pushes the proximal segment of the active wire assembly 12, including the sleeve 40, away from the wire 14 and the acoustic horn 8.

[0217] Fig.10 Another embodiment of the screw connector is shown, wherein the spring mechanism 54 is located in the proximal section of the active wire assembly 12. The screw connector 38 and wire 14 are as previously shown. The active through-wire assembly 12 and the housing unit 2 are coupled via a snap-fit ​​structure 56. Fig.11 Shows Fig.10 A variation of the arrangement also includes a snap-fit ​​section 58 extending distally.

[0218] Fig.12 A screw connector 38 including a manual push-twist-pull slot entry and locking system 60 is shown, best understood here in a perspective detail view of the distal end of the housing unit 2. The proximal segment of the active through-wire assembly 12 includes an inwardly facing lug 62 that is initially aligned with an external slot 64 formed in the distal end of the housing unit 2. After the lug 62 travels proximally along the slot 64, the proximal segment of the active through-wire assembly 12 rotates about the central longitudinal axis of the wire 14. This aligns the lug 62 with a notch 66 formed in the distal end of the housing unit. As shown in FIG. Fig.12 As shown in the cross-sectional view of , the lug 62 engages with the notch 66 distally to lock the proximal segment of the active crossing wire assembly 12 to the distal end of the housing unit 2.

[0219] Fig.13 A radial connector gripping and releasing mechanism 68 is shown. The screw connector 38 is retained by a radial retainer 70, which is initially held in a radially inward position by an axially movable sleeve 72. The retainer 70 transmits torque from the sleeve 72 to the screw connector 38 to screw the outer threads of the screw connector 38 into the hole 44 of the acoustic horn 8. Once the screw connector 38 is fully engaged with the acoustic horn 8, sliding the sleeve 72 proximally over the distal segment of the housing unit 2 releases the radial retainer 70 to radially spring off the screw connector 38. This separates the wire 14 from the sleeve 72 and from the rest of the proximal segment of the active wire assembly 12.

[0220] Fig.14 A connection arrangement is shown in which the proximal end of the wire 14 has a series of geometric features, such as a circumferential ridge 74 that is embedded within and interlocked with a coupling connector 76. The coupling connector 76 has external threads at its proximal end that engage with the threaded hole 44 at the distal end of the acoustic horn 8.

[0221] Next go to Figures 15 to 17 , these figures show various convenient arrangements for disconnecting the wire 14 to release the wire 14 from the housing unit 2 after successful passage through a lesion.

[0222] Fig.15 The internal mechanism of the squeeze action wire breaking system 76 is shown. The surrounding housing is omitted for clarity. Here, the wire 14 supports a pair of sharp blades 78 that are opposed around the wire 14. The blades 78 are integral with a resilient lever 80 that clamps and cuts the wire 14 between the blades 78 when squeezed together.

[0223] Fig.16 and Fig.17 The blades 82 are shown attached to respective meshing gears 84, one on each side of the wire 14. Opposing rotations of the gears 84 bring the blades 82 together to clamp and cut the wire 14. Fig.16 In the embodiment, the gears 84 are rotated by the user rolling the exposed side of at least one of the gears 84, which in turn rotates the other gear. Fig.17 , the linear button mechanism 86 turns one of the gears when pressed, which in turn causes the other gear to rotate.

[0224] Figures 18a to 18c Another method of breaking the wire is shown. This involves creating a sharpness defect and applying a cyclic load that induces fatigue.

[0225] Fig.18a The wire 14 is shown in its original form with a smooth outer surface as it will be used to pass through a lesion. Fig.18b The wire 14 is shown after passing through a lesion, such as by scoring or incision 88 with a blade. The wire 14 will then break rapidly when vibrated with sufficient energy at an appropriate frequency by a transducer, such as Fig.18c This is due to crack 90 propagating through the diameter of wire 14 from transverse indentation or notch 88 which acts as a weakening or stress concentration point to initiate crack 90.

[0226] This failure mechanism is readily exploited for disassembly of coiled Nitinol wires by utilizing ultrasonic energy and the inherent toughness of Nitinol. Scoring the surface of the wire 14 creates a scratch defect that concentrates stress. Since the critical crack length of Nitinol is relatively low, ultrasonic loading at high amplitude will cause the wire 14 to break there by creating a complete plane strain surface failure.

[0227] Fig.19 A measuring accessory 92 is shown that can measure and display the distance that the wire 14 and proximal sheath 94 have traveled longitudinally relative to the housing 96 and front sheath 98. In this example, a linear scale is etched, printed, or molded into the proximal sheath 94. An accessory 92 such as this allows the distance that the distal tip of the wire 14 has traveled within the vasculature to be conveniently measured at the proximal end of the wire 14.

[0228] Fig. 20 A linear drive system 100 is shown that can support or otherwise hold the housing unit 2 and can longitudinally advance and retract the housing unit 2 as shown. To this end, the drive system 100 includes a drive mount 102 and a unit 104 that includes a motor, encoder, and force sensor unit. The drive system 100 facilitates autonomous or robotic insertion and navigation of the wire 14 through the vascular system and across the lesion.

[0229] Fig.21 The active wire 14 is shown passing through a threaded ultrasonic transducer and horn assembly 106. The locking collet 108 has a tapping segment that is screwed onto the threads to close a spring collet clamp 110. The spring collet clamp 110 clamps to the wire 14 over a long interface. This configuration allows the proximal end of the wire 14 to be fed through the acoustic horn / transducer assembly 106 and connected to the assembly 106 at any of a number of points along the length of the wire 14.

[0230] Fig. 22 Shows Fig.21 A variation of the arrangement of wherein the acoustic horn / transducer assembly 106 has a hollow port that passes through most but not all of the body length of the assembly 106. In this case, the wire 14 exits through the side port 112, allowing the activation unit to be locked at any of a number of points along the wire 14 by a mechanism in the distal tip of the assembly 106.

[0231] Figures 23a to 23c An arrangement is shown in which the proximal end of the wire 14 is received in the central distal hole 114 of the acoustic horn 8 within the housing 2. Fig.23a After the wire 14 is inserted into the hole 114 as shown, the twist lock mechanism 116 on the distal end of the housing 2 is rotated to lock the wire 14 to the acoustic horn 8, as shown in FIG. Figure 23bAs shown, the acoustic horn 8 can then feed ultrasonic energy into the wire 14. When the wire 14 is no longer required to be ultrasonically activated, the wire 14 can be unlocked from the acoustic horn 8 by reversing the twist lock mechanism 116 and can then be withdrawn longitudinally, as shown in FIG. Fig.23c shown.

[0232] Figures 24a to 26d Various additional concepts related to adjustable position activation are shown. They show additional arrangements in which an activation system including a housing 118 containing a transducer / horn 120 can slide and lock or "slide and stick" on the crossing wire 14 and thus be coupled to the crossing wire 14 at any location along the wire 14 outside the patient's body.

[0233] To this end, Figures 24a to 24c Show Figures 23a to 23c A variation of the arrangement shown in FIG. 1 is shown in FIG. 1 , in which the central hole 114 in the transducer / horn 120 extends longitudinally through the housing 118 and opens to the distal and proximal ends of the housing 118. Figure 24b As shown, this allows the wire 14 to extend through and protrude from both ends of the housing 118, thereby allowing the housing 118 to be longitudinally repositioned relative to the wire 14.

[0234] In this arrangement, the wire 14 is still Fig.23a The transducer / horn 120 is inserted longitudinally into the distal end thereof as shown and as Fig.23c 120. As shown, the wire 14 is longitudinally withdrawn from the distal end of the transducer / horn 120. Again, the twist lock mechanism 116 on the distal end of the housing 118 is rotated to lock the wire 14 to the transducer / horn 120, as shown. Figure 23b shown.

[0235] Figures 25a to 25d Wire 14 is shown as being able to emerge from housing 118 through openings other than central opening 122 at the proximal end of housing 118. In the example shown here, wire 14 exits transducer / horn 120 through lateral port 124 that communicates with the central distal opening of aperture 34. Laterally exiting portion of wire 126 extends from port 124 to exit housing 118 through a lateral opening aligned with port 124. Thus, wire 14 is deflected from the central longitudinal axis of transducer / horn 120 through an acute angle to exit transducer / horn 120 laterally.

[0236] As mentioned above, the wire 14 is Fig.23a As shown, the transducer / horn 120 is inserted longitudinally into the distal end thereof and as shown Fig.23c 120. As shown, the wire 14 is longitudinally withdrawn from the distal end of the transducer / horn 120. Again, the twist lock mechanism 116 on the distal end of the housing 118 is rotated to lock the wire 14 to the transducer / horn 120, as shown. Figure 23b shown.

[0237] exist Figures 25a to 25c In a further variation of the lateral outlet principle shown in , Figures 26a to 26d An arrangement is shown in which the wire 14 can be pulled laterally from (and optionally also inserted laterally into) a transducer / horn 120 within a housing 118. Fig.26d , the wire 14 is received in a longitudinal slot 130 that can be closed and opened by rotating the pivotable jaws 128 of the acoustic horn 118. When closed, the jaws 128 surround and engage the wire 14 to couple the wire 14 to the transducer / horn 120. When opened by relative angular motion about the central longitudinal axis, the jaws 128 release the wire 14 from the transducer / horn 120 to exit the transducer / horn 120 through the slot 130. The housing 118 has a corresponding slot 132 that allows the wire to exit the housing 118 laterally to release the wire 14.

[0238] exist Figures 24a to 26d In the illustrated embodiment, because the wire 14 is only required to be excited in the distal direction from the housing 118, the damping material in the housing 118 can prevent or damp the excitation of the portion of the wire 14 extending proximally from the housing 118. Damping can be achieved using a variety of materials, typically elastomeric, such as silicone seals or gaskets. More generally, unwanted excitation can be damped by contact between the wire 14 and the wall of the housing 118 around the side port of the housing 118.

[0239] Figures 27a to 27c The physician is shown to be able to disconnect and reconnect the housing 118 at any location along the outer proximal portion of the wire 14, thereby allowing the wire 14 to be loaded and unloaded as needed. Fig.27c As shown, the wire 14 may be marked along its length at regular or irregular intervals 133 that are characteristic of harmonics at an activation frequency of, for example, 40 kHz, such as λ / 2 and λ / 4.

[0240] The housing 118 can be released from the wire 14, repositioned at specific longitudinal intervals, and reconnected to the wire 14 multiple times as the wire 14 is fed in the forward or distal direction. Generally speaking, the housing 118 or the wire 14 can be moved relative to each other, allowing the physician to move the wire 14 to pass through a lesion or find a better position for the housing 118 to activate the wire 14 at that location. Removing the housing 118 from the wire 14 and then reconnecting it to the wire 14 allows other devices to be placed or left on the wire 14 and allows the wire 14 to not move during the procedure, which greatly enhances ease of use for the physician.

[0241] For example, the housing 118 may be placed over the wire 14 near where the wire 14 enters the introducer sheath 135 and the patient's body 137, as shown in FIG. Fig.27a shown. Figure 27b and Fig.27c Other locations where housing 118 may be coupled to wire 14 are shown. Figure 27b The housing is shown at an intermediate position between the guide sheath 135 and the proximal end of the wire 14, and Fig.27c The housing 118 is shown at a proximal position at or near the proximal end of the wire 14 .

[0242] Next go to Figures 28 to 33 , these figures show various connector concepts, the main goal of which is to achieve an excellent acoustic connection between the through wire and the rest of the system. In this regard, the transducer and the connection method must work in unison. In particular, the transducer with the connection interface component optionally including an acoustic horn is designed to resonate at the drive frequency of the system.

[0243] For example, the transducer may be constructed of grade 5 titanium or an aluminum alloy or steel alloy with a stepped configuration. The shape and size of the transducer is selected to achieve amplification gain while ensuring that the system remains close to its operating resonant frequency. Additionally, any modifications to the distal drive face of the transducer to accommodate the connector must be considered and accounted for with respect to the resonant response.

[0244] Fig.28 The transducer 134 is shown assembled with a bi-conical collet 136 and a cap screw 138. The cap screw 138 has an outer structure that is convenient for a user to grip and turn.

[0245] The wire 14 enters through a central hole 140 in the cap screw 138, which is opposite a countersunk base hole 142 in the distal face of the transducer 134. The wire 14 extends through the collet 136, which is interposed between the base hole 142 and the cap screw 138. The taper at the proximal end of the collet 136 is complementary to the countersunk base hole 142. The cap screw 138 similarly receives and is complementary to the taper at the distal end of the collet 136.

[0246] The collet 136 includes a first pair of slits 144 at its proximal end and a second pair of slits 146 at its distal end. Each pair of slits 144, 146 extends longitudinally over half the length of the collet 136. The slits 144, 146 of each pair are located in mutually orthogonal planes that intersect along the central longitudinal axis of the collet 136. The second pair of slits 146 are rotated 45° about the central longitudinal axis relative to the first pair of slits 144.

[0247] The torque applied to the cap screw 138 advances the cap screw 138 to longitudinally compress the collet 136. Thus, the tapered end causes and the slots 144, 146 allow the collet 136 to be radially compressed to clamp the wire 14. Advantageously, the collet 136 provides a substantially uniform load pattern based on a uniform radial reduction, and therefore provides uniform clamping of the wire 14, thereby improving energy transmission and fatigue life.

[0248] Fig.29 The transducer 148 is shown equipped with a single-taper externally threaded collet 150. The tapered proximal end of the collet 150 has a Fig.28 The collet 150 is provided with a similar orthogonal slit 152 of the collet 136. When torque is applied to the collet 150 to advance the collet 150 along the hole 154, the collet 150 anchors the wire 14 within the complementary threaded hole 154 in the distal end of the transducer 148. The complementary taper at the proximal base of the hole 154 then radially compresses the collet 150 to clamp the wire 14.

[0249] Fig.30 Show Fig.29 A variation of the arrangement is shown in which wire 14 extends from the distal end through the full length of transducer 148 to emerge from the proximal end.

[0250] Fig.31 , Fig.32a and Figure 32b A transducer 156 is shown with a bi-conical reverse locking wire release collet 158. The reverse locking system embodies the concept of mutual alignment and misalignment between a pair of longitudinally separated collet members 160, 162 that are rotatable relative to each other about a common central longitudinal axis. Fig.32a When misaligned as shown, the wire 14 is captured in the clamp 158. In contrast, when the longitudinal slots 164 in the clamp members 160, 162 are as shown in FIG. Figure 32b When aligned as shown, the wire 14 is disengaged from the collet 158 ​​to be able to exit the collet 158 ​​in a direction transverse to the central longitudinal axis of the collet 158 ​​.

[0251] Accordingly, the cap screw 166 and the transducer 156 include a slot 168 that can be used to Fig.26c 14 to release wire 14 for lateral removal from transducer 156 or for lateral insertion.

[0252] The principle here is that when the clamping torque is released and when the slots 164 in the components 160, 162 of the collet 158 ​​are aligned with each other and with the slots 168 in the cap screw 166 and transducer 156, the wire 14 can be released from the collet 158. This is achieved by anchoring the proximal component 162 of the collet 158 ​​to the transducer 156 and applying torque from the cap screw 166 to the distal component 160 of the collet 158 ​​when the cap screw 166 is turned to release the clamping force.

[0253] The proximal part 162 of the collet 158 ​​can be positioned, for example, onto the spline structure of the transducer 156 to align and lock it to prevent rotation. The distal part 160 of the collet 158 ​​can have small facets with which the cap screw 166 can cooperate to rotate the distal part 160 relative to the proximal part 162 to the extent required to release the wire 14.

[0254] The collets shown in these embodiments may include an internal reverse taper to optimize the platform length that grips the wire 14. This advantageously limits point loading on the wire 14 and possible ensuing microstructural damage that may otherwise promote the formation of microstructural defects.

[0255] Fig.33 An internal expansion collet 168 is shown housed in the head of a transducer 170. In this embodiment, the collet 168 is integrated into the transducer 170 and is thus integral with the device itself. The wire 14 extends through the full length of the collet 168 and protrudes distally and proximally from the transducer 170.

[0256] Fig.33 The transducer 170 shown in FIG. 1 has a tubular body 172 surrounding a collet 168. The collet 168 has an enlarged distal head 174 that protrudes from the distal end of the body 172 and has a diameter greater than the inner diameter of the body 172. An inclined ramp surface 176 on the proximal side of the head 174 abuts against the distal end of the body 172.

[0257] A torque screw 178 is disposed at the proximal end of the body 172. An annular backing nut 180 and a piezoelectric stack 182 are sandwiched between the torque screw 178 and the body 172.

[0258] Collet 168 has a threaded proximal portion that is threadedly engaged with torque screw 178. Thus, torque screw 178 couples collet 168, and therefore wire 14, to transducer 170 to transmit ultrasonic energy from transducer 170 into wire 14. Additionally, turning torque screw 178 draws collet 168 proximally into the body of transducer 170. As collet 168 moves proximally relative to body 172, angled ramp surface 176 of enlarged distal head 174 abuts against the distal end of body 172 and radially clamps collet 168 onto wire 14.

[0259] Fig.34a and Fig.34b Wire 14 is shown having a substantially straight proximal segment 184, a distally tapered intermediate segment 186, and a substantially straight distal excavation segment 188 for passing through a lesion. Due to the taper of the intermediate segment 186 between them, the distal segment 188 has a smaller diameter than the proximal segment 184. For example, the proximal segment 184 may have a diameter of 0.43 mm and the distal segment 188 may have a diameter of 0.25 mm. Since the length of the intermediate segment 186 may extend over a length of one meter, the taper between the proximal segment 184 and the distal segment 188 is very small and is therefore greatly exaggerated in these figures.

[0260] The overall geometry of the wire, including its nominal diameter and length, is determined by the characteristic velocity of sound in the wire material. This characteristic is dependent on the materials chosen for the transducer and the wire. The straight and tapered sections of the wire are sized at functional intervals of the wavelength.

[0261] Where Nitinol material is selected, λ, λ / 2 and λ / 4 are determined to be 168 mm, 84 mm and 42 mm in this example. The selected frequencies will produce harmonics along the length of the wire and the loading at the tip of the wire will help to establish a standing wave for the non-characteristic lesion.

[0262] The distal section 188 may be tapered or may be uniform in diameter along its length and the harmonics may be λ or at least λ / 4. The system may generate harmonics over a range.

[0263] Since the goal of activating the wire 14 is to excavate the lesion, the size is optimized to excavate as large a volume as possible for a given waveform. Fig.34b The distal segment 188 of the wire 14 is shown to move in a primary longitudinal mode once activated, moving in and out, and also in a radial direction, which maps out and taps a larger volume at the distal end through the longitudinal movement of the wire 14. The distal segment 188 of the wire 14 is also seen to move in other modes through lateral and wave movement at differential harmonics of the resonant wave and secondary modes, depending on the activation frequency and the length of the distal segment 188.

[0264] Fig.35 184 is a schematic diagram illustrating how the wire 14 can be manufactured from segments welded together end to end. In this embodiment, the proximal segment 184 is machined to a standard diameter to provide for enlargement and to provide a standard connection for a proximal loaded activation device. The proximal segment 184 serves as an axis that can be Fig.35 The welded joint 190 of the wire 14 is welded to one of a selection of different diameter wires that may have custom distal ends and tips. This advantageously reduces the requirement to maintain stock with a variety of wire diameters, since several segments of different wire diameters can be assembled to produce wires with many desired configurations. Since the welded joint 190 of the wire 14 is in a low stress location, the load applied to the joint 190 during activation will not result in catastrophic fatigue failure.

[0265] Move to Fig.36 and Fig.37 , these figures show a wire 14 formed or shaped with an angled offset distal excavation segment for passing through a lesion. In this embodiment, the distal segment is not straight but is tilted due to a heat-set formed tip 192. The size of the tip 192 is optimized to provide improved performance in manipulating to the lesion and excavating the lesion. In particular, the angle of the tip 192 relative to the longitudinal axis of the distal segment and the length of the tip 192 determine the ability of the wire 14 to be converted into a specific side branch artery. The angle and length of the tip 192 also affect the way that the wire 14 will excavate a section of stenotic material once activated.

[0266] If the tip 192 is of a harmonic nature, such as a length of λ / 8 or about 22 mm, the wire 14 will open a significantly larger tunnel in the lesion than, for example, a 25 mm tip segment. The amplitude of the waveform and the number of times the distal segment of the wire 14 passes through the calcified segment will determine the diameter of the tunnel excavated.

[0267] If the angle of the tip 192 is too large, a larger lever arm will be generated, thereby causing excessive fatigue to the wire 14; conversely, if the angle of the tip 192 is too small, the wire 14 may not be effectively manipulated. In this regard, Fig.37 The tip 192 is shown to be offset from the longitudinal axis of the wire 14 by about 15° to 45°, thereby allowing the tip 192 to disrupt and excavate a larger volume of lesions. The tip 192 is suitably heat treated, for example, at over 500° C. for less than 10 minutes, to produce a microstructure that reliably resists crack propagation and thus fatigue.

[0268] Fig.38a and Figure 38bHow to enhance the visibility of the position of the wire 14 in the patient's body by using a marker band 194, such as gold, is shown. For example, such a marker band 194 can be fixed near the distal tip 196 of the wire 14 (e.g., about 3 mm away from it) and also at a position away from the distal end of the proximal segment 184, just before the beginning of the tapered intermediate segment 186. The marker band 194 is placed at the position of the minimum load when the wire 14 is used. This minimizes the possibility that the marker band 194 can be removed or that the wire 14 may fail at these locations. The marker band 194 is easily flush-fitted into the circumferential groove ground around the wire 14.

[0269] Fig.39 A variation is shown in which the distal tip 196 of the wire 14 is rounded without a sharp transition. As an example, in this case, the proximal segment 184 may be 1800 mm long, the tapered intermediate segment 186 may be 84 mm long, and the distal segment 188 may be 10 mm long. Again, the marker band 194 surrounds the wire 14 near the distal tip 196 of the wire 14 and the distal end of the proximal segment 184.

[0270] Fig.40 and Fig.41 Other variations of wire 14 are shown, each having a bulbous distal tip 198 that is rounded to avoid a sharp transition. The bulbous tip 198 may be, for example, 3 to 4 mm in length and may have a diameter of just over 0.4 mm.

[0271] In addition to its bulbous tip 198, Fig.40 The wire shown in is otherwise similar to Fig.39 The wire 14 shown in FIG.

[0272] same, Fig.40 and Fig.41 The wire 14 shown in FIG. 1 has a circumferential marker band 194 that can fit flush into a circumferential groove milled around the wire 14. Conveniently, the bulbous tip 198 can be surrounded by one of the marker bands 194 as shown.

[0273] exist Fig.41 In the example shown, the wire has a proximal portion that includes a straight segment 200 and a distally tapered segment 202. The straight segment 200 may have a textured surface as shown to improve engagement with the activation device. The proximal portion is welded to the middle portion that constitutes most of the length of the wire 14. The middle portion also includes a straight segment 204 and a short distally tapered segment 206. The marker band 194 is shown as surrounding the straight segment 204 with the distally tapered segment 206 near the middle portion 194. Finally, a short, narrow distal segment 208 extends distally from the middle portion 186 to a bulbous tip 198.

[0274] Finally go to Figures 42a to 42c , these schematic diagrams illustrate how the wire 14 may initially be used as an active wire to pass through a lesion 210 and then used as a guidewire to deliver a subsequent diagnostic or therapeutic device 214 to the lesion 210 .

[0275] exist Fig.42a , the wire 14 is shown extending distally through the introducer sheath 135 and into the patient's body 137. The distal tip of the wire 14 has been navigated through the patient's vasculature 212 to reach the lesion 210. The wire 14 shown here is activated by the activation unit 2 and thus digs and passes through the lesion 210 by vibration of the distal tip.

[0276] In this example, the activation unit 2 is shown at the proximal end of the wire 14. However, the activation unit 2 may alternatively be positioned at any of a plurality of intermediate locations along the proximal portion of the wire 14 protruding from the patient's body 137.

[0277] Once Figure 42b After successfully crossing the lesion 210, the wire 14 is deactivated and remains in place within the patient's vasculature 212. The activation unit 2 is then removed from the wire 14, thereby exposing the proximal end of the wire 14.

[0278] The deactivated wire 14 can now be used as a guidewire to deliver a subsequent diagnostic or therapeutic device 214 to the lesion 210, such as Fig.42c The device 214 may most conveniently be screwed onto the proximal end of the wire 14. However, in principle, the device 214 may alternatively be attached to the wire 14 at any location along the proximal portion of the wire 14 that remains outside the patient's body 137.

Claims

1. An activation unit for transmitting ultrasound energy into an elongated intravascular wire, the unit comprising: a source of said ultrasonic energy, said source comprising an ultrasonic transducer; as well as a coupling arranged to couple the source to the wire at any one of a plurality of discrete operating positions along the length of the wire, the coupling arranged to clamp the wire when in any of the operating positions; and The unit is arranged such that the wire extends through the coupling and the source and such that portions of the wire extend proximally and distally from a housing of the unit, respectively, wherein excitation of the portion of the elongated intravascular wire extending proximally from the housing is damped.

2. A unit according to claim 1, wherein the coupling is arranged to effect relative longitudinal movement between the source and the wire when moving between the operating positions.

3. A unit according to claim 2, wherein the coupling is arranged to enable the relative longitudinal movement while remaining attached to the wire.

4. A unit according to claim 2, wherein the link is arranged to achieve the relative longitudinal movement by removal from and reattachment to the wire.

5. A unit according to any preceding claim, wherein the ultrasonic transducer is configured to vibrate at a frequency between 20 kHz and 60 kHz, or at a frequency between 35 kHz and 45 kHz, or at a frequency between 37 kHz and 43 kHz, or at a frequency substantially equal to 40 kHz.

6. The unit according to any of the preceding claims 1-4, further comprising a visual, tactile and / or audio user interface.

7. An intravascular device for passing an obstruction in a blood vessel, the device comprising: An activation unit according to any preceding claim; as well as an elongated intravascular wire extending through the coupling and source of the unit and having portions extending proximally and distally from the coupling and source, respectively; Wherein the coupling is used to transmit ultrasonic energy from the source along the wire to the active tip at the distal end of the wire in use.

8. Apparatus according to claim 7, wherein the coupling is arranged to effect relative longitudinal movement between the source and the wire by removal from and reattachment to the wire when moving between operating positions, and the coupling and / or the source comprises distal and proximal or lateral openings for longitudinal insertion and withdrawal of the wire.

9. An apparatus according to claim 7, wherein the connector is arranged to enable relative longitudinal movement between the source and the wire by removing from and reattaching to the wire when moving between operating positions, and the connector and / or the source includes at least one longitudinal slot for the wire to enter or leave in a lateral direction transverse to the longitudinal axis of the wire.

10. The apparatus of claim 9, further comprising a locking mechanism arranged to capture the wire after the wire has entered laterally through the slot and to release the wire to allow the wire to exit laterally through the slot.

11. The apparatus of claim 10, wherein the locking mechanism comprises at least one locking member rotatable about the wire to capture and release the wire.

12. Apparatus according to any one of the preceding claims 7 to 11, wherein the coupling comprises a collet which is radially compressible onto the wire in response to longitudinal movement or longitudinal compression of the collet.

13. The apparatus of claim 12, wherein the collet includes at least one mating surface for engagement with the source, the surface being inclined relative to a longitudinal axis of the collet.

14. The apparatus of claim 13, wherein the mating surface is defined by a tapered end portion of the collet.

15. Apparatus according to claim 13 or claim 14, wherein the cartridge is movable longitudinally within or relative to the ultrasonic transducer.

16. The apparatus of claim 15, comprising threads between the collet and the ultrasonic transducer, the threads being arranged to longitudinally move the collet and couple the collet to the ultrasonic transducer.

17. The apparatus of any preceding claim 7-11, wherein the proximally extending portion of the wire exits a proximal end of the source.

18. The apparatus of any one of claims 7-11, wherein the proximally extending portion of the wire exits the source on an axis transverse to a longitudinal axis of the distally extending portion of the wire.

19. Apparatus according to any of the preceding claims 7-11, wherein the operating position is marked on the wire.

20. Apparatus according to any one of the preceding claims 7 to 11, wherein the operating position is characteristic of a harmonic of the wire at an activation frequency of the source.

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