HK1021125A - Ultrasound transmission apparatus and method of using same - Google Patents

Description

Ultrasound transmission device and method of use thereof

Background

The present invention relates generally to medical devices and, more particularly, to an improved ultrasound probe and method of using the same for treating diseases such as vascular stenosis or vessel occlusion.

Currently, treatment of arterial stenosis or blockage is commonly performed using one or more of balloon angioplasty, laser angioplasty, atherectomy (atherectomy), or bypass surgery. Although these methods have met with some success, they all have some less than satisfactory side effects. For example, following treatment with balloon angioplasty, the occlusion often rebounds and reoccludes the vessel; laser angioplasty and atherectomy are at risk of damaging the arterial vessel structure; bypass surgery can cause trauma and requires a long recovery period.

In recent years, a number of U.S. patents have described the use of ultrasonic energy to ablate obstructions in blood vessels, such as U.S. Pat. Nos.4,870,953 (DonMohal), 4,920,954(A1liger et al) and 5,269,287(Weng et al), the contents of which are incorporated herein by reference. It is generally believed that the use of ultrasound transmission devices to remove obstructions from peripheral vessels, such as the femoral artery, has been quite successful. However, conventional ultrasound devices are not entirely satisfactory. For example, in some applications in small vessels, such as the distal portion of a coronary artery, it is more difficult to achieve satisfactory results, in part because of the more tortuous paths and the smaller diameter of the vessel to be treated.

Although there have been many devices in recent years that describe the use of ultrasound energy to ablate obstructions in blood vessels, there is little text describing methods of using these devices. U.S. patent No.4,773,413(hussei et al), the contents of which are incorporated herein by reference, describes a method of ablating an object from a blood vessel using heat. Another U.S. patent No.5,324,255(Passafaro et al), the contents of which are also incorporated herein by reference, describes a method of treating vasospasm using ultrasound. However, methods of using ultrasound devices have been described only rarely, apparently because of the general inability to successfully provide a safe, effective ultrasound device capable of ablating coagulated tissue.

It would be highly desirable, therefore, to provide an improved device and method for treating diseases such as arterial stenosis and arterial occlusion that overcomes the deficiencies of the prior art.

Brief description of the invention

Broadly, in accordance with the present invention, there is provided an ultrasound treatment apparatus and method for treating a stenosis or occlusion in a general blood vessel or in a graft or bypass artificial blood vessel used in dialysis patients using ultrasound. An ultrasound treatment system includes an ultrasound probe having a proximal end and a distal end and an ultrasound energy source. When ultrasonic energy is applied to the proximal end, the tip vibrates at an ultrasonic frequency in the treatment area. The vibration amplitude is here expressed as a displacement. The system provides a guide tube in which the probe can be slidably disposed. A guide wire is also provided, over which the probe can be slidably disposed. The probe includes a horn section at its proximal end, a transmission member having a proximal end and a distal end connected to the horn section at its proximal end, and a tip at the distal end of the transmission member. The transmission member comprises one or more coaxial transmission lines in series having a proximal end and a distal end.

A part of the transmission member may be composed of a plurality of transmission lines connected in parallel. Moving toward the distal end of the probe, whether in series or in parallel, the proximal diameter or cross-sectional area of each successive transmission line is smaller than that of the previous transmission line.

The proximal end of the initial transmission line has a smaller diameter or cross-sectional area than the diameter or cross-sectional area of the distal end of the horn section. For some of the reasons previously described, the cross-sectional area suddenly diminishes at the trapezoidal connections between the horn segments and the first transmission line and between each successive transmission line and the rest of the probe. Some or all of these trapezoidal shaped connections should be at or near the displacement node (minimum) in order to maximize displacement amplification and maximize the transmission of ultrasonic energy to the working end of the device tip. All trapezoidal connections at or near the displacement node are at or near the maximum stress. The present invention therefore benefits from high displacement amplification at trapezoidal connections located at or near displacement nodes, as the design of these connections can be subject to high stresses.

It will be appreciated by those skilled in the art that the resonant (or anti-resonant) frequency and wavelength of the probe, and the associated standing wave formed along the probe, may shift with the curvature of the treated vessel. Thus the position of the individual nodes or anti-nodes of the standing wave will shift as the probe is extended, retracted or manipulated within the vessel. Therefore, the probe is designed based on the average frequency and the average standing wave. More specifically, the positions of the nodes and anti-nodes of the standing wave relative to the structural elements of the probe are referred to herein in terms of geometry or bending during therapeutic use.

It is a feature of the present invention to locate one or more trapezoidal shaped joints at or near the displacement node to reduce the sensitivity of the probe to bending, particularly when the trapezoidal shaped joints are located close to the most curved. Thus, according to another aspect of the invention, trapezoidal shaped junctions at or near the displacement nodes can be used to effectively reduce the bending sensitivity of the probe.

Of course, the assembly techniques of the various parts of the present invention are equally applicable to devices that promote drug absorption by enhancing or focusing ultrasonic energy, introduce apoptosis into cells, and/or treat tissues, tumors, obstructions, etc. in or out of the body, or for tissue heating such as in laparoscopic surgery, ultrasonic scalpels, and in the radiation treatment of cancer.

Furthermore, although several examples of intravascular applications of the present invention using guide tubes, introducer sheaths, guide wires, etc. are given herein, the present invention is equally applicable to topical or surface treatments, intraluminal treatments, intramuscular or intraluminal treatments, which include ultrasound-assisted ablation of accumulated fat, use of ultrasound to promote healing, and to stimulate or inhibit the function of body organs.

According to another aspect of the invention, some or all of the trapezoidal shaped joints are formed as knuckles, where the same or different materials are selected based on the characteristics of the materials and then joined to form the trapezoidal shaped joint. For example, a large diameter aluminum wire may be joined to a smaller diameter titanium wire having a higher strength.

According to another aspect of the invention, all the articulately shaped trapezoidal connections are designed for high strength coupling. For example, a reinforced necking joint may be used by grinding the surface of one or all of the connecting members.

In accordance with another aspect of the present invention, an improved tool tip (tip) design for an ultrasound probe is provided that includes a radiopaque marker in the tip to facilitate tracking of the position of the tool tip relative to a stenosis or obstruction during positioning of the tool tip during and prior to occlusion sonication.

In accordance with another aspect of the present invention, an improved ultrasonic transmission member having a moisture-proof covering is provided. The cover of the transmission member is used to reduce or minimize stress corrosion and may be comprised of a variety of thin film cover materials, including hydrocarbon materials such as parylene. Vacuum deposition of parylene can be used to provide a compositionally pure micro-scale coating or even a thin film.

According to another embodiment of the invention, a low friction sheath material for a delivery member is provided which improves the delivery quality of the delivery member. The low friction sheath material is selected to minimize friction of the transmission member and is made of a flexible polymeric material such as polyimide. Polyimide is a low friction, high temperature polymer that can be formed into very thin walled tubing.

According to another embodiment of the invention, the end working head or tool head may have the form of an axial through hole. A tubular assembly may be mounted in the hollow. The tubular member may be configured to be movably disposed within a second tubular member located proximate thereto to form a tubular cylindrical piston structure. Such a tubular cylindrical piston structure can be used as a guide path having excellent wear resistance.

It is therefore an object of the present invention to provide an improved device for treating conditions such as thrombosis and vascular stenosis.

It is another object of the present invention to provide an improved ultrasound probe.

It is a further object of the present invention to provide an ultrasound probe with improved bendability and guidance and a reduced diameter.

It is a further object of the present invention to provide an apparatus designed to locate the nodal and anti-nodal points of the standing wave to maximize the transmission of ultrasonic energy in a given application.

It is a further object of the present invention to provide an ultrasonic tool head that prevents wear caused by a guide wire fed through its cavity.

Other objects and features of the present invention will be apparent from or are obvious from the specification and drawings.

Accordingly, the present invention includes ladder connections and the relationship of one or more of the ladder connections to other ladder connections, and the apparatus including features, component connections, and component arrangements for making the ladder connections, all as exemplified in the detailed description that follows. The scope of the invention is described in the specification.

Brief Description of Drawings

For a further understanding of the invention, reference may be made to the following description, taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a side view of an ultrasonic transmission device made in accordance with an embodiment of the present invention;

FIG. 2 is a side view of an ultrasonic transmission device made in accordance with another embodiment of the present invention;

FIG. 3 is a side view of an ultrasonic transmission device having a flat transmission member and a horn section integral therewith made in accordance with an embodiment of the present invention;

FIG. 4A is a side view of a horn section of an ultrasonic transmission device having a straight transmission member integral with the horn section and constructed in accordance with an embodiment of the present invention, FIG. 4A also showing the method of attaching another transmission member at the distal end of the horn section, showing the method of attaching the outer sheath through a keyed "o" -shaped annular notch portion and the method of attaching the transducer at the proximal end of the horn section;

FIG. 4B is an enlarged view of the tip of the transfer member of FIG. 4A;

FIG. 4C is an end view of the transfer member tip of FIG. 4B;

FIG. 5 is a cross-sectional view taken along line 5-5 of FIG. 4A;

FIGS. 6A and 6B are side and end views, respectively, of a keyed "o" -shaped annular groove portion on the horn segment of FIG. 4A;

FIG. 7A is a side view of an additional embodiment of an ultrasonic transmission member according to one embodiment of the invention;

FIG. 7B is an enlarged view of the tip of the transfer member of FIG. 7A;

FIG. 7C is an end view of the tip of FIG. 7B;

FIG. 7D is a cross-sectional view taken along line 7D-7D of FIG. 7A;

FIGS. 7E and 7F are side and end views, respectively, of the keyed "o" -shaped annular groove portion on the horn of FIG. 7A;

FIGS. 8-13 and 13A are side views of an ultrasound transmission device made in accordance with an embodiment of the present invention;

FIG. 14 is an enlarged side view of a portion of an ultrasonic transmission device having a multiline configuration made in accordance with one embodiment of the present invention;

FIGS. 15-27 and 29 are side views of various modifications of the distal tip portion of an ultrasonic transmission device made in accordance with an embodiment of the present invention, wherein the energy transmission line is not shown;

FIGS. 28 and 30 are side views of various variations of the distal head portion of an ultrasonic transmission device made in accordance with an embodiment of the present invention;

FIG. 31 is a cross-sectional view taken along line 31-31 of FIG. 30;

FIGS. 32-39 are side views of additional examples of various end head portions of ultrasound transmission devices made in accordance with embodiments of the present invention;

FIGS. 40A and 40B are side schematic views showing the relationship between the length and wavelength of the first transmission member; and

fig. 41A and 41B are also side schematic views showing the relationship between the length and the wavelength of the first transmission member.

Description of The Preferred Embodiment

The use of a transmission probe to transmit ultrasound energy to a selected region in a patient's blood vessel has proven to be an effective method of ablating thrombi, vessel occlusions, and the like. However, in order to reach areas of the blood vessel that are relatively inaccessible, it is necessary to provide a device that is extremely flexible, has sufficient length and sufficient guidance. In order to transmit sufficient energy, a probe having a larger diameter proximal end is used to receive ultrasound energy from the transmission source. However, the large diameter leads to negative strength and insertion difficulties. Accordingly, to achieve the foregoing objects, an ultrasound probe is provided which quickly transitions from a large diameter horn section receiving energy from an ultrasound source to a relatively thin pliable transmission body while minimizing energy transmission, strength and conductivity losses.

An improved ultrasound probe is generally described for the foregoing purposes, in accordance with one embodiment of the present invention, as shown by probe 100 in fig. 1. The probe 100 is formed with a conical member horn 125 and a proximal end 129 of diameter Ai for coupling with an ultrasonic energy source. When the proximal end 129 is coupled to a source of ultrasonic energy, it is preferably placed at the maximum displacement of the ultrasonic standing wave carried by the entire device. The proximal end 129 is coupled directly to the transducer, other energy source, or an intermediate member between it and the energy source. The tapered member 125 tapers from a proximal end 129 over portion A to a reduced diameter distal end 130 having a diameter Af at the connection region B. The proximal end 129 must be sufficiently large to receive sufficient energy to treat a thrombus, vascular occlusion, or the like. However, in order to provide optimal bending performance, it is desirable to minimize the diameter of the distal portion of the probe 100 while minimizing the loss of energy, strength, and steerability. In addition, the reduction in diameter must be done in a manner that amplifies, i.e., increases, the ultrasonic amplitude.

At the end with a diameter of A_fIs followed by a conical portion A of constant diameter C_iComponent C of (1), wherein C_i＜A_f. If a further reduction in diameter is desired, a second connection zone D may be provided for coupling C to one or more transmission members, which have a diameter E_iIn which E_i＜C_i。

Component C may be composed of a different material than component a. For example, part A is composed of aluminum, which has excellent ultrasonic transmission characteristics and is easy and inexpensive to machine, while part C may be composed of titanium, titanium alloys, or other materials (including other metallic materials, glass, ceramics, cermets, polymeric materials, or composites) which have good ultrasonic transmission characteristics and greater tensile strength on the smaller diameter members required.

Fig. 41A and 41B provide a simplified partial schematic of a component having a longitudinal standing wave that can be introduced into portion a of fig. 1. The displacement of the longitudinal displacement is indicated by the ordinate in the figure, and the longitudinal position on the portion a is indicated by the abscissa. Fig. 41A shows part a of fig. 1, which consists of first a straight part, followed by a second tapered part extending to 351 and finally a straight part extending to 355. This structure is also shown in fig. 3. Similarly, if section a in fig. 1 has a constant diameter, fig. 40A and 40B also provide a partially simplified view of the compressive standing wave that can be excited thereon. Such a configuration is shown in fig. 8 and 9.

In order to maximize the displacement amplification, it is advantageous to place the sudden drop in cross-sectional diameter where the displacement is minimal. Thus, referring to fig. 40A and 40B, assuming that the proximal end 340 of the first large diameter transport 341 is at the maximum displacement 342, the discontinuity in transport diameter, such as discontinuity 343, should be placed at the minimum displacement 444, which is at an odd multiple of λ/4. For convenience of illustration, the abrupt drop point shown in FIG. 40B is placed at 9. lamda./4. Also, as shown in FIGS. 41A and 41B, assuming that the proximal end 353 of the first large diameter transmission body 350 is at the maximum displacement 417, the abrupt drop-off point 355 is at the minimum displacement or at an odd multiple of λ/4. For convenience of illustration, the abrupt drop point 355 shown in FIG. 41B is located at 11 λ/4.

Of course, fig. 40B and 41B are simplified representations of partial standing wave patterns. In practice, the ultrasonic length is related to the shape, size and material of the horn section and probe. Thus, the wavelength does not have to be constant as shown in FIGS. 40B and 41B, but varies depending on the shape of the device and the geometry of the blood vessel during use. In addition, the ultrasonic wave length is also a function of the transmission line diameter, so that even for a constant diameter section, the wavelength of the standing wave changes if the cross-sectional shape of one section differs from that of another section.

With further reference to figures 40B and 41B, the method of coupling the proximal end of the horn section to the ultrasound energy source, the mode of operation (i.e., resonance or anti-resonance), and the transmission characteristics of the ultrasound source itself (i.e., the structure in which the transducer is assembled) will determine the precise location of the displacement maximum 342 produced. It must be noted that the fabrication of the present invention should not be limited to the maximum displacement being exactly coincident with the location in fig. 40B and 41B. That is, the displacement maximum 342 shown in fig. 40B and 41B is for convenience of illustration only. The precise location of the displacement maxima 342 is independent of the location of the displacement nodes and anti-nodes of the standing wave patterns associated with the trapezoidal junctions or other structures described in this disclosure.

In addition, the standing wave pattern excited in the probe, which is partially depicted in FIGS. 40B and 41B, is a function of the bending of the probe in use. That is, the geometry of the vessel into which the probe is inserted will determine to a greater or lesser extent the exact operating frequency and the precise location of the nodal and anti-nodal points of the standing wave at any given time as the probe is extended or retracted into the vessel. In practice, by selecting the dimensions of the probe and the frequency of operation, suitable standing wave node locations as described herein can be obtained within a selected range of geometries. Using this method, the probe node position can be located at a specific place in the vessel with little deviation at other locations. Thus, the positions of the displacement nodes and anti-nodes of the standing wave patterns described herein, which are associated with the trapezoidal junctions and other structures represented herein, are preferred, ideal or average node positions that naturally deviate when the probe is manipulated in a curved vessel. It is for this reason that the standing wave positions referred to herein are all labeled "approximate" or "averaged".

If the transmission member is tapered, as in the transmission body 350 in the member in fig. 41A, the tip 351 of the tapered portion is located at the maximum displacement 352. This cone portion functions as a half-wavelength horn, the amplification characteristics of which are well understood. Thus, if the proximal end 353 is located at the maximum displacement 417, the tip of the taper 351 should be located at a distance that is an integer multiple of λ/2. For convenience of illustration, the end 351 is shown at 3 λ/2 in FIG. 41B. The tapered section is followed by a constant diameter section having a terminal abrupt descent point 355 that should be located at the displacement minimum 356.

Referring again to fig. 1, in accordance with a preferred embodiment of the present invention, section a, if it includes a tapered section, is preferably a tapered section having a length equal to an integer multiple of a half-wavelength of the set operating frequency. At the end of portion A there is a transition zone B, which is an abrupt junction zone connected to portion C, wherein the diameter C of portion C_i＜A_f. To maximize displacement amplification, the abrupt connecting region B is preferably located at or near the displacement node (i.e., where displacement is minimal). Thus, if section a comprises a tapered section having a length that is an integer multiple of a half wavelength, the length of the subsequent flat section should be an odd multiple of a quarter wavelength (e.g., 1,3,5 …). In this way, portion A begins at a proximal end 129 at the maximum displacement and ends at a distal end 130 at the minimum displacement (at the displacement node). If section A is straight (i.e., has a constant diameter as shown in FIG. 40A), it should begin where the displacement is greatest and end at the displacement node.

The probe 100 also includes a mass 150 at the distal end that is designed and constructed to scatter ultrasonic energy and/or to operate in accordance with the application of interest.

The ultrasound probe 100 (as with the other probes discussed herein) generally operates in a resonant (or anti-resonant) mode; i.e., ultrasonic energy is excited at the proximal end 129, it carries a standing wave, preferably a longitudinal wave. Therefore, the mass 150 is preferably located at the maximum displacement (anti-node). The connecting region D may be placed at the displacement node or the anti-node. For example, the joint region D is a joint which has several parallel joints of diameter E_iIs coupled to the section C. At this time, the mechanical strength of the connecting region D must be insufficient to resist the maximum stress. For this case, the connection region D may be located at or near the maximum displacement, since the displacement maximum corresponds to the stress minimum (stress node).

Of course, the assembly techniques of the various parts of the present invention are equally applicable to other devices that promote drug absorption by enhancing or focusing ultrasonic energy in vivo or in vitro, or to introduce apoptosis into cells, and/or to treat tissues, tumors, obstructions, etc., or for tissue heating such as in laparoscopic surgery, ultrasonic scalpels, and in the radiation treatment of cancer.

In addition, although several examples of the intravascular use of the present invention using guide tubes, introducer sheaths, guide wires, etc. are given herein, the present invention is equally applicable to topical or surface treatments, intraluminal treatments, intramuscular or intraluminal treatments, which include ultrasound-assisted ablation of accumulated fat, use of ultrasound to promote healing, and to stimulate or inhibit the function of body organs.

An ultrasound probe made in accordance with another embodiment of the present invention is an ultrasound probe 200 substantially as shown in figure 2. Probe 200 is similar in construction to probe 100, except that probe 200 is subdivided into sections B, C and D to provide more abrupt drop points in cross-sectional area. Thus, the length of the tapered portion a, which is preferably made of a metal such as aluminum, can be reduced. This can significantly reduce the cost of the probe 200 relative to the probe 100. The formation of the tapered portion A of the probe 100 or 200 may be any connection of a constant diameter portion and a tapered portion of decreasing diameter, or with a diameter A_iAny connection of the single portions of (a).

The probe 200 comprises n constant diameter sections (C)₁To C_n) They consist of n connecting zones B₁To B_nDivided, wherein the diameter C is preferred₁＜C_fAnd C is_i+l＜C_iWhere i =1 to n. B and B₁To B_nIs either mutated or tapered, while the moieties A and C, or C, respectively₁To C_nMay be made of one or more materials such as aluminum or titanium. Thus, the constant diameter portion C₁Or C_iCan be made separately (e.g. as drawn wires) and then in the connection areas B or B_iTo portions A, D, E and F. Alternatively, the constant diameter portion C or C_iCan be made as one piece from one single wire, in order to comply with the rules described above. Thus, portions A, B and C or A, B, C and D can be made of a unitary body, such as a single post, that is made to comply with the rules set forth above. If the probe 100 or 200 is composed of a plurality of connections B (or B)_iThe subparts of (D) and (F) should be void free to provide a tight connection of the connecting elements. The material of each sub-portion should be carefully selected so as to optimise the performance of the device by meeting the specific requirements of the device along its length. In particular, some devices require varying material along their length, such as some portions requiring greater bending properties, others requiring greater strength, and others requiring greater wear resistance, among others.

When the probe 100 or 200 is in the joint area B (or B)_i) D, E and F connections can be made using several methods including, but not limited to, welding, gluing, molding, necking, clamping, bolting, or bolting. In addition, one or more of these connections should be made detachable, thus allowing some parts to be exchanged during the manufacturing process. For example, part A of probe 100 or 200 may be formed by exchanging or adding additional components C (or C)_i) Can be recycled and reused, and can be sterilized or modified again. Likewise, the portion 25 of FIG. 3 may also be recycled, re-sterilized or modified by exchanging or adding additional transfer members 40 and tool heads 50.

It should also be noted that all surfaces may be covered with a wetting barrier or sealing layer to extend the life of the material by reducing stress corrosion.

The mass 150 may be spherical, cylindrical, or grooved cylindrical. It may be flat or may be textured with other patterns, voids or grooves, etc. to enhance or focus the ultrasonic emission, enhance surface cavitation effects or enhance selected energy flow patterns. These shapes are described in U.S. patent No.5,269,297, the contents of which are incorporated by reference as appropriate.

The mass 150 may be fabricated directly as an integral part of the section E or separately and then added to the section E. For example, the mass 150 may be fabricated as a general welded or brazed part at the end of the portion E, followed by machining to impart additional texture or structure to the surface of the mass 150, if desired. Alternatively, the mass 150 may be separately fabricated or machined and then attached to the section E using methods including, but not limited to, welding, adhesive bonding, molding, necking, clamping, bolting, or bolting.

The mass 150 may be selected from a wide variety of materials depending on the particular application. For example, the mass 150 may be made of one or more metals, ceramics, cermets, glasses, or polymeric materials. The mass 150 may be cast or otherwise formed directly on the portion E of fig. 1 or 2.

A probe according to the invention may be cooled by flushing with a coolant, taking into account energy consuming heating and/or damping of unwanted vibration modes. For example, coolant may be applied directly to or around the probe by coating the probe with a sheath over a portion or all of the probe. The sheath may be affixed to the probe at one or more displacement nodes of the standing wave, but is preferably affixed at the displacement node of portion a closest to the connection region B. The additional sheath may provide a channel for a guide wire or other auxiliary tool to move or position the device to a predetermined position.

The coolant channel may additionally or alternatively be used as a conduit for the delivery or withdrawal of another liquid, or body tissue, gel, suspension, or the like. For example, the sheath channel may be used as a channel for delivery of therapeutic agents or for withdrawal of ablates. In addition, drugs such as streptococcal activating enzymes, urinary hormones, platelet inhibitors, liners and other liquids which enhance their function or effect by ultrasound, or which enhance the effect of the ultrasound application at the treatment site, may be injected into the cooling fluid which cools the ultrasound probe, or may be injected into the treatment site through separate channels internal or external to the ultrasound probe.

Referring to FIG. 3, a probe having a section of constant diameter section at the horn section is shown generally as probe 20. The horn section 25, having a tapered portion T and a first constant diameter portion S, is formed as a member to be coupled to an ultrasonic energy source. The probe 20 further includes a transmission member 40 coupled to the horn section 25 at a connection region B' and a tool head 50 coupled to an end of the transmission member 40. The source of ultrasonic energy is described in U.S. patent No.5,269,297, the contents of which are incorporated herein by reference.

The flared section 25 includes a proximal end 29, a distal end 30, a tapered portion 26 of decreasing diameter from the proximal end 29 to the junction 28, and a straight portion 27 of constant diameter from the junction 28 to the distal end 30. The horn section 25 is preferably machined or cut from a piece of metal, preferably aluminum 7075. The horn section 25 transitions from the tapered portion 26 to the straight portion 27 at a connection point 28, the connection point 28 being located approximately at the displacement antinode. The length of the portion 26 is approximately an integer multiple of lambda/2, where lambda/2 is a half wavelength of the standing wave, and is obtained by measuring the distance between anti-nodes. The frequency of the ultrasonic energy generated by the ultrasonic energy source to excite the device into resonance is denoted as f. In a preferred embodiment according to the invention, f ranges from 10 to 100KHz, better than 42 KHz. Of course, the operating frequency of the device may be chosen to be an overtone, i.e., the frequency of the device may not necessarily be the fundamental resonance (or anti-resonance) frequency. The horn section 25 is preferably 7075 aluminium and the length of the tapered portion T is 144 mm. In the preferred embodiment described, the proximal end of the horn section 25 is 12.7mm in diameter, reducing to 1.0mm in diameter at the connection point 28 of the horn. The flared section 25 is preferably tapered, while in other embodiments it may have a constant diameter.

In a preferred embodiment of the invention the diameter of the straight portion 27 is kept at 1.0mm from the connection point 28 to the end 30 of the horn section. The end 30 is connected at a connection region B' to a transmission member 40 comprising at least one transmission line 45 having a line proximal end 46 and a line distal end 47. The horn's distal end 30 may be attached to the transmission line's proximal end 46 by a number of coupling means and techniques well known in the art or other methods such as welding, including laser, diffusion and fusion welding, adhesive, molding, necking, clamping, bolting, bayonet fitting or mechanical attachment. The joint should be free of voids to provide a tight connection of the connecting members.

The transmission member 40 further includes a highly bendable portion E 'composed of three thin diameter wires 60, as shown in fig. 3, coupled to the wires 45 at the 1-to-3 coupling joints of the connection region D'. In this embodiment the portion E' is preferably made up of three wires, but it is advantageous that at least two wires form a pair to provide the device with redundant bending properties and high power transfer. Junction 55 includes an opening at its proximal end for insertion of the distal end of wire 45 and three openings at its distal end for insertion of the proximal ends of three filaments 60. The connection region D 'may be designed as a single-step trapezoidal amplification structure, wherein the portion E' consists of one single wire having a diameter smaller than the wire 45. In one embodiment of the invention, wires 45 and 60 are comprised of high strength titanium wire.

Bullet-shaped tool head 50 is coupled to three filaments 60 through three openings at its proximal end. In a preferred embodiment, the junction 55 and the three openings in the tool head 50 are arranged in an equilateral triangle concentric with the longitudinal central axis of the junction 55 and the tool head 50, as shown in FIG. 31.

The tool head 50 has a recess 51 to enhance cavitation, as shown in fig. 14. Of course, for a particular type of liquid, displacement amplitudes exceeding a threshold can be used to excite cavitation therein. Cavitation bubbles in the acoustic field can be conveniently used to concentrate energy, promote ablation, or other desired effects. The tool head 50 may also have a proximal bevel 52, as shown in FIG. 14, to assist in retracting the probe after the procedure is completed. A radiopaque marker is affixed to the tool head 50. The radio-opaque tape may be affixed to the proximal or distal end of the tool head 50 and contained within the recess or affixed to the exterior of the tool head. In addition, the tool head 50 may be made of a radiation opaque material or covered with a radiation opaque film. In a preferred embodiment, the distal end of the tool head 50 is formed with a pocket or recess 53, as shown in FIG. 14, in which the radiopaque tape is affixed with adhesive.

The tool head 50 also has an opening for a guide wire, the sheath of which is mounted within the opening and extends a little bit from the distal end. In a preferred embodiment, the guide wire opening is located in the center of the tool head 50 along its longitudinal axis. The filament 60 is individually wrapped with an outer sheath that extends between the tool head 50 and the junction 55. The wire 45 also covers an outer sheath that is attached to a separate outer sheath of the wire 60 and extends proximally of the coolant port so that coolant can be injected into all or part of the irrigation portions 26, 27 and 40.

Referring to fig. 4A, 4B, 4C and 5, another embodiment of the invention is illustrated by a horn section 525, which therefore includes a straight portion 527 of constant diameter and a connecting portion in the form of a knuckle 535 at its distal end. The joint 535 is perforated to receive a transmission line. This embodiment includes an increased diameter region 529 located before knuckle 535 so that knuckle 535 has a diameter slightly larger than the diameter of straight portion 527 to provide a stronger knuckle 535 between horn tip 530 and the transmission line (not labeled). In one specific example of this embodiment, the flared section 525 has a straight portion 527 of 1mm diameter, increasing to 1.09mm in diameter at the end of the region of increased diameter 529.

In a preferred embodiment, knuckle 535 has a hole with a diameter of about 0.63mm and a depth of about 5mm and is mechanically crimped (crimp) onto a transmission line, preferably made of titanium and having a diameter of about 0.62 mm. To further increase the strength of the compression connection, according to a preferred embodiment of the invention, the surface of the transmission line, which is about 4mm long, is roughened before compression.

In another embodiment, joint 535 is replaced with joint 735 of FIG. 7B, which does not include an area of increased diameter.

Notably, the location of the abrupt decrease in diameter from the segment of horn 525 to the transmission line is at or near the displacement node, which maximizes displacement amplification. However, the prior art generally does not advocate the use of a trapezoidal dip in this manner because of the high strength of the stresses present at such a connection. However, this disadvantage of the prior art can be overcome by introducing a joint of high strength material and having the ability to attach various suitable materials to the joint. In addition, energy transfer may be made more efficient by placing the joint near the displacement node.

Other embodiments have different lengths and diameters than the preferred embodiment because the ultrasound transmission means must be sized to fit different treatment locations, with different distances between the probe's entry into the patient's body and the treatment site in the body. These changes in length are depicted by the diagrams in figures 1, 2 and 3.

Referring to fig. 8 through 13, a number of probe designs are described that satisfy the fabrication principles described herein. These various designs use trapezoidal joints having joints that are made in accordance with the features described herein, although the details of these joints are not shown in connection with fig. 4B and connection member 55 of fig. 3. Of course, the diameters and lengths of the subcomponents in these figures, or in other figures herein, are not drawn to scale, nor are the proportions between the components in the figures to be considered standard or limiting. FIG. 8 shows that there are three consecutive trapezoidal connections (801,802, and 803) that are all located at the displacement node. The first trapezoidal connection is shown as a rounded transition, which is equally applicable to all trapezoidal connections described herein to effectively reduce strain.

Fig. 9 is similar to fig. 8 except that all connections (901, 902 and 903) therein are shown as sharp trapezoidal connections. Fig. 10 uses a proximal conical horn section 1001. Figure 11 uses an elongated flat 1101 attached to a proximal flared portion 1102. Fig. 12 shows the use of two parallel wires 1201a and 1201b in the extreme transmission line section, which section has better bending performance. The use of two or more wires in the end portion enables passage of the guide wire along the central longitudinal axis of the end tip. Fig. 13 is similar to fig. 12 except that the two wire parts at the ends are partially replaced by three wires (1301a,1301b and 1301 c). In fig. 13A, the proximal portion is shown as being comprised of two consecutive half-wavelength horn sections followed by an integral flat portion that terminates at a displacement node at connection point B.

Referring again to FIG. 3, in a preferred embodiment of the invention designed for coronary vessels, the ultrasonic horn 26 includes a proximal tapered portion T formed to a length of 144mm and starting diameter of 12.7mm and then tapering to 1mm at the junction 28. The horn then extends distally, terminating at the distal end 30 through a constant diameter section S of 567mm in length. The horn is connected to a transmission line 45 of length 544mm by a joint 735 in fig. 7B. In another preferred modification of the coronary embodiment, the portion S extends for a total length of 847mm and the length of the transmission line 45 is 264 mm. In a further modification of the modified embodiment of the coronary artery, the total length of the portion T is 233 mm.

Referring again to fig. 3, in a preferred embodiment designed for use in a bypass vessel such as an AV bypass vessel, the ultrasonic horn 525 comprises a tapered portion T of length 144mm and initial diameter 12.7mm, which decreases to 1mm at the point of connection 28. The horn then extends distally through a constant diameter section S of length 17mm, terminating at a distal end 30. The horn is connected to a transmission line 45 having a length of 30mm by a joint 735 in fig. 7B, and the end of the transmission line 45 is connected to the end single line portion E' by a connection 55. Portion E' has a wire of 227mm length and is attached to the tool head 50. In another modification of the preferred bypass line embodiment described above, joint 735 is replaced by joint 535 in fig. 4B. In yet another modification of the preferred bypass line embodiment described above, the transmission line 45 has a length of 89mm and the portion E' is formed as a two-or three-wire structure having a length of 160 mm. In yet another modification of the preferred bypass vessel embodiment described above, the transmission line 45 has a length of 544mm and the portion E' is formed as a two-wire or three-wire structure having a length of 160 mm.

As mentioned above, the transmission line 40 in fig. 3 may include one or more transmission lines of constant diameter, with the subsequent transmission lines being of smaller diameter. The latter transmission line may be manufactured as a single piece of reduced diameter section from a single post material, or the sections may be manufactured separately and then connected.

Referring again to fig. 3, in a preferred embodiment of the invention, the end 47 of the transmission line 45 is connected to a multi-wire section 60, which in a preferred embodiment comprises three titanium wires. The diameter of the transmission line 45 ranges between 1.0mm and 2.0mm and the length of the thin wire 60 ranges between 0.5mm and 0.01 mm. The diameter of the transmission line 45 ranges between 0mm and 1000mm and the length of the thin wire 60 ranges between 0mm and 300 mm. In a preferred embodiment, the transmission line 45 is about 0.62mm in diameter and about 544mm in length, and the respective line diameters of the multi-line section 60 are constant at about 0.29mm and about 160mm in length. The junction 55 of the transmission line 45 and the thin line 60 can be placed anywhere along the standing wave, in this case near where the displacement is greatest.

In a preferred embodiment, the connection 55 is made of high strength aluminum (preferably aluminum 6061), including high strength clamped connections with the transmission line 45 and aerospace epoxy connections with the thin wire 60. In this example, the diameter of the clamping connection hole is about 0.63mm and the depth is 3mm, and the diameter of the thin wire bonding connection hole is about 0.31mm and the depth is about 1.5 mm.

In another preferred embodiment of the invention, the proximal end of the horn section 29 of FIG. 3 and the proximal end 29' of FIG. 4A may contain a threaded bore having a diameter of 0.25 inches and 12mm depth to receive the distal end of the ultrasound source. In other embodiments, the connection between the ultrasound source and the horn section may be a bayonet type twist connection, a snap connection with a spring, and various other quick connections. Referring to fig. 6A and 6B, the keyed "o" -shaped annular groove 600 serves both to create a fluid seal between the proximal end of the outer sheath 155 and the horn section 525 of fig. 14, and to prevent relative twisting therebetween. The "o" -shaped annular groove 600 is preferably located at the displacement node (i.e., where the displacement is minimal) to avoid attenuation of the transmitted energy by the "o" -shaped annular groove 600. In one embodiment, the "o" -shaped annular groove 600 is located 83mm from the proximal end of the first transmission member, and the annular ring 601 preferably extends 0.25mm high and 0.5mm wide from the horn section surface. The hexagonal ring 602 extends 0.5mm high and 0.8mm wide from the horn section surface with a diameter of 3.7mm between the flat surfaces and a diameter of 4.2mm between the opposing vertices. It will be clear to one of ordinary skill in the art that ultrasound transmission devices made in accordance with the present invention, including the foregoing examples, can be easily placed into and extended through a 7 french catheter to the thrombus of the coronary artery.

Referring again to fig. 3, the tool head 50 is connected to the end of at least one transmission line 60. The tool head 50 is preferably shaped to receive the multi-wire portion three wires and is positioned at the maximum displacement so that it has the greatest amplitude of vibration along its length. In a preferred embodiment, the tool head 50 is made of aluminum, preferably 6061 aluminum and 1.65mm in diameter.

The device should be flushed with coolant in view of the energy consumption of heating or in order to damp unwanted vibration modes. The coolant may be applied directly or through a thin flexible sheath, preferably made of polyimide or other high strength, thin wall, low friction material, around part or all of the device. The sheath is preferably bonded to the device at one or more displacement nodes. The other sheath is used to provide a channel for the device to guide wires or other auxiliary tools, which carry the ultrasound probe to a desired location.

In another preferred embodiment, part or all of the surfaces of the horn section and/or transmission line are covered with a moisture barrier or sealant such as parylene to reduce stress abrasion and increase the life of these parts.

Referring to fig. 6A and 14, the outer sheath 155 on one or more portions is placed around the horn section 525 and extends distally just above the attachment member 1455. The diameter of the outer sheath may decrease as the diameter of the transmission body decreases. Polyimide is an excellent sheath material because it can be made very fine in diameter and has high strength and low friction.

Referring to fig. 14, which shows how a relatively large diameter transmission line 1445 is connected to three smaller diameter lines 1403, 1403 including 1401 and 1402 shown in the figure, and a third line, not shown, is located behind 1401 and 1402. The wire connection 55 is made in the form of a single hole at the proximal end of the mounting wire 1455 and three holes at the distal end of the mounting wire 1403. In a preferred embodiment, the three lines 1403 and their mounting holes on the connection 55 are arranged equidistantly on a circle, forming an equilateral triangle concentric with the central longitudinal axis of the connection 55.

In a preferred embodiment, the connection 55 is mechanically clamped to the single wire transmission line 1445, and to further increase the strength of the clamped connection, the end surface of the transmission line 1445 is roughened prior to clamping, in accordance with a preferred embodiment of the present invention. In a preferred embodiment, the connections 55 are bonded to the filaments 1403 using a high strength aerospace grade epoxy. Other methods of adhesively bonding 55 as previously described herein may also be used.

The outer sheath 155 is disposed around the horn section 525, the single wire transmission line 1445, the wire connection 55, and extends proximally over the proximal end of the connecting member 1455. Sheaths 1481 and 1482 are disposed about wires 1401 and 1402, respectively, with the third wire also having a similar sheath. The distal end 155a of the outer sheath 155 is folded over a portion of the attachment 1455 and secured to the attachment 1455 using adhesive. The connection 1455 with the sheath is made in the form of three deep holes positioned and sized to fit the sheath disposed around the wire 1403. The sheath around the wire 1403 is secured to the attachment 1455 by adhesion. The outer sheath around the coupling 1455 and wire 1403 may be several single members coupled together as described above. Or a single member forming a multi-lumen overhanging tube. Of course, other embodiments of wire and sheath arrangements are also encompassed within the invention, including designs using more or less than three wires 1403 and sheaths associated therewith. In one embodiment, a fluid, such as saline solution, flows through the outer sheath 155, through the coupling 1455, and out the end of the outer sheath around the wire 1403.

If the design of the ultrasound probe includes a multi-wire end portion, as in the example of FIG. 14, it is important to prevent rotation of the outer sheath 155 relative to the central ultrasound transmission member 1445 and the connection 55. In this case, if relative rotation is allowed, transmission line 1403 may become the wound proximal end of connection 1455 and one or more of the transmission lines may fail. To prevent this, an "o" ring groove 600 (see fig. 6A) at the displacement node may be formed or keyed. The sheath body is then formed with a similarly shaped mounting cavity such that the sheath cannot rotate relative to the horn section so long as the horn section is of such a configuration. Of course, for embodiments in which the transmission member is always located on the central axis of the probe as in fig. 14, or a single wire instead of wire 1403 as in fig. 8-11, keying is not necessary. However, whether keyed or not, the location of the "o" ring or similar sealing means for establishing a fluid passage between the outer sheath and the horn section (transmission member) should be at the displacement node.

In another preferred embodiment, as shown in fig. 14, the end of the outer sheath of wire 1403 terminates in a tool tip 1450 to create an expansion gap between the tool tip 1450 and the outer sheath. The expansion gap 1480 is typically several millimeters in length so that there is sufficient space for the sheath and the sheath 155 disposed about the wire 1403 to extend or retract during use without interference from the tool tip 1450. When the probe is energized or manipulated during operation, the sheath stretches or retracts as a result of normal elongation or compression of the polymeric sheath material.

Fig. 14 also shows a guide wire 1430 which assists in positioning the tool head 1450 of the probe in a desired position. In the configuration shown in fig. 14, the guide tube 1430 has a similar diameter to the outer sheath of wire 1403 and extends into the tool head 1450 from a distance of 10 to 15 cm from the proximal end of the tool head 1450. The tube 1430 may include a flared tip to provide a secure connection when the tool head 1450 is broken by the application of energy, such as at groove 1451. Tube 1430 has a tape wrapped around the outer sheath of the wire 1430 secured in place. Cross-sectional views of the strip 1490 are shown as 3190 in fig. 31 and 3190 in fig. 30.

In another embodiment of the present invention, tool head 1550 is secured by safety plug 1501,1601,1701,1801 or 1901 of FIGS. 15-19, respectively. The guide tube 1430 of fig. 14 is shown in fig. 15-19 as 1510,1610,1710,1810 and 1910, respectively. Safety plugs 1501,1601,1701,1801 and 1901 are used to secure various portions of tool tip 1550, such as a radiopaque marker or a broken front end of tool tip 1550, against breakage during use. It also serves to separate the tool bit 1550 from the guide wire inserted in the safety plug. The safety plug is preferably tightly attached or locked to the tool bit 1550 in a manner that reduces or minimizes the differential between it and the tool bit 1550.

The various methods of attaching the safety plug to the tool head 1550 depend on the materials of construction selected for the particular application. The joining methods include, but are not limited to, adhesive bonding, clamping, casting, fusion bonding, molding, expansion bonding, bolting, bayonet bonding, or cladding bonding. In addition, the safety plug and tool head are formed as a single piece from a material that has multiple functions of applying ultrasound to the treatment site, resisting guide wire wear, and safely securing the crushing member.

It is advantageous to separate the safety plug from the probe sheath, which is extended or retracted during operation to energize or manipulate the probe, as described above. This separation prevents rubbing or abrasion of the tool head against the sheath. A preferred embodiment of such a separating mechanism is shown in fig. 15-35. The attachment flare is shown in fig. 15-19 as a means of attaching the safety plug to the tool head, but there are other attachment structures including adhesive and fusion bonding as shown in fig. 20-28.

Fig. 15 shows the guide tube 1510 terminating in a proximal tool head 1550. The safety plug is located within tube 1510 and fits snugly within the tube in the form of a slidable cylindrical piston. The plug 1501 preferably conforms to the interior of the tube 1510, and vice versa to prevent the tube interior from creating a point where a guide wire can snag the plug 1501 as it passes through the end 1501a of the plug to the proximal end of the probe.

Fig. 16-28 illustrate additional embodiments of the present invention, including different safety plugs. The safety plug is preferably made of a wear-resistant material. The plug is preferably contained within the cavitation head. While in other embodiments there may be a gap at the proximal end of the safety plug, in other embodiments the guide wire tube may terminate at the proximal end of the cavitation head, the guide wire passing through the tool head without the use of a guide wire tube or safety plug therebetween.

Referring to fig. 16, safety plug 1601 is shown slidably disposed outside the distal end of the guide tube. However, the proximal diameter of guide tube 1610 or male 1601 is preferably sized so that guide tube 1610 can fit over the exterior of male 1601, as shown in fig. 15.

Referring to fig. 17, plug 1701 is shown slidably disposed outside of guide tube 1710 similar to the configuration of fig. 16. However, a butt 1711 is formed at the end of the tube 1710 and a constriction 1702 is formed at the proximal end of the plug 1701. In this manner, tube 1701 and tube 1710 are tightened against each other.

Referring to fig. 18, the plug 1801 is shown slidably disposed outside the distal end of the guide tube 1810 similar to that of fig. 15. However, a constriction 1811 is formed at the end of the tube 1810 and a butt 1802 is formed at the proximal end of the plug 1801. Thus, tube 1801 and tube 1810 are nested one within the other.

Referring to fig. 19, plug 1901 is shown slidably disposed outside of the end portion of guide conduit 1910. Guide conduit 1910 passes through plug 1901. A tube 1910 may extend distally through 1901 and be attached to a safety butt (expanded port) 1911. Safety butt 1911 grasps tube 1901 or tool head 1550 when released.

Referring to fig. 20, plug 2001 is shown slidably disposed within guide tube 2010. The plug 2001 is made of two parts, tube 2002 and tube 2003, which are joined together and then attached to the tool head 1550. Tube 2002 is mounted on the outside of tube 2003.

Referring to fig. 21, plug 2101 is shown slidably disposed within guide tube 2110. The plug 2101 is comprised of two parts, tube 2103 and tube 2102 attached to the outside of it, which are connected together and then attached to tool head 1550.

Referring to fig. 22, the plug 2201 is shown slidably disposed within a guide tube 2210. Plug 2201 is comprised of two parts, tube 2203 and tube 2202 mounted on its exterior, which are connected together and then attached to tool head 1550.

Referring to fig. 23, plug 2301 is shown slidably disposed within guide conduit 2310. The plug 2301 is comprised of two parts, a tube 2303 and a tube 2302 that fits over the outside of the plug, which are joined together and then attached to the tool head 1550.

Referring to fig. 24, plug 2401 is slidably disposed outside guide tube 2410. Plug 2401 is made up of two parts, tube 2403 and tube 2402 mounted on its exterior, which are connected together and then attached to tool head 1550.

Referring to fig. 25, plug 2501 is shown slidably disposed within guide tube 2510. Plug 2501 is comprised of three parts, tube 2503 and tube 2502 which fits over its exterior and over proximal safety barrier tube 2504, all three parts being joined together and then attached to tool head 1550.

Referring to fig. 26, guide tube 2610 is shown with plug 2601 in a piston configuration with plug 2601 passing through tool head 1550. Plug 2601 is made up of three parts: the proximal safety barrier tube 2604, tube 2603 and tube 2602 mounted on its exterior, all of which are connected together inside the proximal safety barrier tube 2604 and then attached to the tool head 1550.

Referring to fig. 27, plug 2701 is shown slidably disposed within guide tube 2710. Plug 2701 is comprised of two parts, tube 2703 and tube 2702 fitted to the outside thereof. Tube 2703 is shown enlarged to serve as a proximal safety barrier. Tube 2702 and tube 2703 are connected together and then to tool head 1550.

Referring to fig. 28, a plug 2801 similar to the structure of fig. 25 is shown housed in a multi-wire end structure comprising three titanium wires 2880 (two shown) and their respective sheaths 2881. The plug 2801 is slidably disposed within the guide tube 2810. It is made up of three parts, a tube 2803, a proximal safety barrier tube 2804 and a tube 2802 that fits over them, all three parts being joined together and then attached to a tool head 1550. The plug 2801 is shown with a terminal safety butt (flared end) 2805. Of course, the terminal safety butt may be incorporated into any of the plug designs disclosed herein.

Figure 29 is a partial view of a plug similar to that of figure 28. Plug 2901 is comprised of three parts, tube 2903, proximal safety catch 2904, and tube 2902 attached thereto. All three parts are joined together and then attached to the tool head 1550. Plug 2901 is shown having terminal safety butt 2905. Fig. 29 also shows a tool head 1550 in which a radiopaque marker 2906 is secured.

Referring to FIG. 31, a partial view of the outer sheath construction is shown. Tube 3110 corresponds to tube 2810 in fig. 28. The plurality of outer sheaths 3181 correspond to 2881 in fig. 28 and the band 3190 corresponds to 1490 in fig. 14. Corresponding straps may also be used with the structure of fig. 28. Tubes 3110 and 3181 and 3190 are tied to each other. The outer sheath 3181 is shown loosely fitted around the thread 3103. The distal end portion of the guide conduit 3110 is located between an outer sheath 3181 coaxial with the central axis of the device and a band 3190 wrapped around the outer sheath 3181 of the thread 3103. Thus, the end portion of the tube 3110 is placed where a slidably arranged safety plug, such as plug 2801, can be mounted.

Referring to fig. 30, the guide tube 3010 is shown extending through the outer sheath 3081. This arrangement may be used to mount a slidably arranged safety plug of the type shown in figures 16,19 and 24.

Referring to fig. 32, an end head configuration is shown wherein plug 3201 is shown separated from the end of conduit 3210. In fig. 33, plug 3201 is replaced with a polymer cladding 3301. In yet other embodiments, both the polymer cladding and plug 3201 may be omitted.

Referring to fig. 34, a structure similar to that of fig. 19 is shown, except that the end of the guide conduit 3410 slidably disposed with respect to the plug 3401 terminates inside the plug 3401. In fig. 35, a pair of plug retention ferrules are shown attached to tube 3502. In fig. 36, sleeve 3511 is replaced by plug retention bulb 3611.

Referring to fig. 37, guide conduit 3710 is slidably disposed through tool head 1550. To enhance the abrasion resistance, tube 3710 may be made of an abrasion resistant polymer, such as polyethylene, nylon, polyester, polyurethane, and polypropylene.

Referring to fig. 38, the structure is similar to that of fig. 37, except that guide tube 3710 is replaced by tube 3810. Tube 3810 has a safety butt or safety bulb 3811 to prevent the breaking of the distal portion of tool head 1550 in the event of failure of tool head 1550.

FIG. 39 shows a tool tip 1550 in which the radiopaque marker or tool tip itself is flared to reduce the wear surface contact between the tool tip 1550 and the guide wire or safety plug structure shown therein.

An ultrasonic treatment method for ablating an occluded thrombus in a coronary vessel of a human body is set forth below to illustrate features or aspects of the present invention but is not intended to be so described in a limiting sense.

Prior to the ablation procedure, the patient was administered coronary intravascular glycerol (200mg), aspirin (250-325mg oral or intravenous) and intravenous heparin (15,000 units) to achieve an ACT (active clotting time) of over 300 throughout the procedure. First, the introducer sheath is used to define the point of introduction into the body. A relatively stiff wire is introduced through the introducer sheath, over which the guide lumen has previously reached the vicinity of the failure zone. In one embodiment of the invention, the guide lumen is advanced to the introduction port of the coronary artery. The guide wire is then advanced through the guide lumen and the introduction port. The ultrasound transmission device according to the present invention is then loaded onto a guide wire (not shown) and advanced through the guide lumen until its tool tip is placed in the blood vessel proximal to the occlusion. Alternatively, the ultrasound probe may be loaded onto a guide wire, the two projecting together through the guide lumen. The tool head preferably includes radiopaque markers to enable the physician to accurately determine the position of the tool head using fluoroscopy.

The tool head is then positioned immediately adjacent the obstruction, preferably about 1-2mm before the proximal end of the obstruction. Sonication of the obstruction is then performed by transmitting ultrasonic energy from the ultrasonic source through the ultrasonic transmission means to the tool head for a period of several about 60 seconds. In acoustic treatment, the ultrasound transmission device is preferably kept stationary during the first approximately 30-60 seconds and then moved slowly back and forth over a distance of 3 mm. The obstruction is thus ablated by cavitation.

In another method, after placing the ultrasound delivery device next to the obstruction and sonicating the thrombus for about 30-36 seconds, the operator can weaken the plug by changing the operation of the probe. One method of attenuating the thrombus plug is to move the probe progressively through the thrombus as the probe is vibrated longitudinally. In doing so, the obstruction is effectively torn or mechanically disrupted by the vortex created when the tool head is retracted drawing the obstruction toward the tool head. Moreover, moving the tool head toward or away from the obstruction accelerates ablation of the obstruction.

Of course, the ultrasound delivery device and the illustrated and described method of using the device are readily adapted for introduction into a body vessel to remove additional unwanted material. The ultrasound transmission device may be used in other fields and is therefore not limited to coronary angioplasty procedures, even medical applications.

It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained and, since certain changes may be made in the above construction without departing from the spirit and scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Rather, the following claims are intended to cover all generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

Claims (87)

1. An ultrasound transmission device coupled to an ultrasound energy source that emits ultrasound waves at one or more frequencies f, comprising: the device is sized and configured for insertion into a blood vessel for applying ultrasonic energy in the blood vessel or lumen, and for generating a standing wave having a maximum displacement and a minimum displacement along each location of the ultrasonic transmission device, comprising:

a first transmission member connectable to a source of ultrasound energy and formed of a first material as a unitary body having a proximal end and a distal end, the first transmission member being configured such that the proximal end thereof is connected to the source of ultrasound energy and when energized by the source of ultrasound, a standing wave is simultaneously generated on the first transmission member and other transmission members connected thereto, the distal end of the first transmission member terminating adjacent to the point of minimum displacement;

the second transmission member is formed of a second material, which may be the same as the first material, having a proximal end and a distal end, the proximal end of the second transmission member being connected to the distal end of the first transmission member where the cross-sectional area of the distal end of the first transmission member is greater than the cross-sectional area of the proximal end of the second transmission member, the distal end of the second transmission member terminating adjacent the point of maximum displacement; and

a tool tip coupled to the distal end of the second transmission member and configured and dimensioned to apply ultrasonic energy to the first transmission member when the device is energized by the ultrasonic source and to transmit energy to said tool tip through the first and second transmission members.

2. The ultrasound transmission device of claim 1, wherein the first and second transmission members are both made of only a single continuous material.

3. The ultrasound transmission device of claim 1 wherein the tool tip is configured and dimensioned for cavitation to ablate, dissolve or otherwise remove or loosen obstructive material in the blood vessel.

4. The ultrasonic transmission device of claim 1, wherein the tool tip and the second transmission member are formed from only a single continuous material.

5. The ultrasonic transmission device of claim 1, wherein the tool tip is machined by welding or brazing the portion at the end of the second transmission member.

6. The ultrasound transmission device of claim 1, wherein the second transmission member is connected to the first transmission member by a detachable connector.

7. The ultrasound transmission device of claim 1, wherein the first transmission member is made of aluminum and the second transmission member is made of titanium.

8. The ultrasound transmission device of claim 1, wherein the first transmission member is made of aluminum 7075.

9. The ultrasonic transmission device of claim 1, wherein the second transmission device is made of Ti/4 Al/6V.

10. The ultrasound transmission device of claim 1, wherein the second transmission member is mechanically coupled to the first transmission member.

11. The ultrasound transmission device of claim 1, wherein the second transmission member is attached to the first transmission member by at least one of welding, molding, crimping, clamping, latching, and adhesive attachment.

12. The ultrasound transmission device of claim 1, wherein the first transmission member has first and second portions, each of the first and second portions having a proximal end and a distal end; the first portion having a tapered portion with a decreasing cross-sectional area from its proximal end to its distal end; the cross-sectional area of the second portion is constant; the end of the second part terminates during operation in the vicinity of the displacement minimum.

13. The ultrasound transmission device of claim 1, wherein the second transmission member comprises at least two portions, a proximal end of at least two successive portions having a larger cross-sectional area than a distal end of at least two portions.

14. The ultrasound transmission device of claim 13, wherein at least one of the connections between portions of the at least two portions of the second transmission member is at a minimum of displacement.

15. The ultrasound transmission device of claim 12, wherein the length of the first portion of the first transmission member is substantially equal to an integer multiple of λ/2, where λ is the wavelength of the standing wave over the portion.

16. The ultrasound transmission device of claim 12, wherein the first portion and the second portion of the first transmission member have lengths substantially equal to an odd multiple of λ/4, where λ is the wavelength of the standing wave over the portion.

17. The ultrasound transmission device of claim 1, wherein the second transmission member has a substantially constant diameter.

18. The ultrasound transmission device of claim 13, wherein the extreme ends of the at least two portions of the second transmission member comprise at least two parallel transmission lines.

19. The ultrasound transmission device of claim 1, wherein the first transmission member and the second transmission member are at least partially covered with a moisture barrier.

20. The ultrasound transmission device of claim 19, wherein the moisture barrier is parylene.

21. The ultrasound transmission device of claim 1, comprising an outer sheath, the first transmission section and the second transmission section being at least partially covered by the outer sheath.

22. The ultrasound transmission device of claim 21, wherein the outer sheath comprises a polyimide tube.

23. The ultrasound transmission device of claim 18, comprising an outer sheath, wherein the outer sheath comprises a single lumen to multiple lumen articulation to increase fluid passage around the first and second portions of the second transmission articulation.

24. The ultrasound transmission device of claim 18, comprising an outer sheath, wherein the outer sheath is attached to the first transmission member at the displacement minima.

25. The ultrasound transmission device of claim 24, wherein the outer sheath is attached to the first transmission device using an "o" ring seal.

26. The ultrasound transmission device of claim 25, wherein the "o" ring seal comprises a keyed or angled element to prevent independent rotation of the outer sheath relative to the first and second transmission members.

27. The ultrasound transmission device of claim 1 wherein the distal end of the first transmission member includes a region of slightly larger cross-sectional area than the proximal end of the region of increased cross-sectional area, the region of increased cross-sectional area being perforated to receive the proximal end of the second transmission member.

28. The ultrasound transmission device of claim 1, wherein the first transmission member and the second transmission member are at least partially covered with parylene and at least partially contained within the outer sheath.

29. The ultrasound transmission device of claim 1, wherein said device is sized and configured for attachment to a 7 french guide tube.

30. The ultrasound transmission device of claim 1, wherein each of the at least two transmission lines is equally spaced along a circle in a cross-sectional view thereof, the circle being concentric with the longitudinal axis of the ultrasound transmission device.

31. The ultrasound transmission device of claim 1, wherein the tool tip includes a through-hole for passage of a guide wire.

32. The ultrasound transmission device according to claim 18, wherein the tool head includes a through-hole for passage of a guide wire, said through-hole being disposed coaxially with the longitudinal axis of the tool head.

33. The ultrasound transmission device of claim 23, comprising a first guide wire tube for tracking the guide wire, running substantially parallel to and having substantially the same length as said at least two transmission lines.

34. The ultrasound transmission device of claim 33, wherein the first guide wire tube is attached to the outer sheaths of the at least two transmission lines.

35. The ultrasound transmission device of claim 33, wherein the first guide wire terminates at the proximal end of the tool tip.

36. The ultrasound transmission device according to claim 35, wherein the tool head includes a through-hole through which the second guide wire means passes, the second guide wire means being slidably disposed relative to the first guide wire means.

37. An ultrasonic transmission device connectable to an ultrasonic generating source which generates a standing wave on a transmission device having a maximum displacement and a minimum displacement along a length direction thereof to transmit ultrasonic waves to a position in a human body, the ultrasonic transmission device comprising:

a first member extending from a proximal end to a distal end of the ultrasound generating source, the first member having a cross-sectional dimension selected from a group of substantially exponential, catenary, straight, quadratic or hyperbolic tapers or having a uniform cross-sectional dimension or a combination thereof, the distal end of the first member being located at about the minimum displacement;

a second member extending distally from the distal end of the first member and formed of a second material, which may be the same material as the first member, the second member being attached to the distal end of the first member, the second member having a substantially uniform cross-sectional dimension that is slightly smaller than the cross-sectional dimension of the distal portion of the first member; and

a third member extending distally from the distal end of the second member and formed of a third material, which may be the same as the second material, the third member being connected to the distal end of the second member and comprising one or more parallel transmission lines, all of which have a substantially uniform cross-sectional dimension slightly less than the cross-sectional dimension of the second member, the distal end of the third member terminating adjacent the point of maximum displacement.

38. The ultrasonic transmission device of claim 1, comprising a tool tip attached to the distal end of the third member, the tool tip being configured and dimensioned to apply ultrasonic energy generated by the attached source of ultrasonic energy when driving the device to the proximal end of the first member and to transmit ultrasonic energy to the tool tip through the first, second and third members.

39. The ultrasound transmission device of claim 38 wherein the tool tip is configured and dimensioned for cavitation ablation, dissolution or other removal or loosening of obstructive material in the blood vessel or lumen upon activation.

40. The ultrasonic transmission device of claim 38, wherein the tool head and the second member are made from a single continuous material.

41. The ultrasonic transmission device of claim 38, wherein the tool tip is formed by welding or brazing the portion of the end of the third member.

42. The ultrasound transmission device of claim 38, wherein the first member is made of aluminum.

43. The ultrasound transmission device of claim 38, wherein the length of the first member is equal to an odd multiple of λ/4 of the standing wave on the device.

44. The ultrasound transmission device of claim 38, wherein the first member includes a portion having a substantially exponentially tapered cross-sectional shape.

45. The ultrasound transmission device of claim 38, wherein the first member includes a portion having a substantially catenary, tapered cross-sectional shape.

46. The ultrasound transmission device of claim 38, wherein the first member includes a portion having a substantially hyperbolic tapered cross-sectional shape.

47. The ultrasound transmission device of claim 38, wherein the first member includes a portion having a substantially constant first cross-sectional shape.

48. The ultrasound transmission device of claim 38, wherein the second member includes at least two portions interconnected along a longitudinal axis of the device, the substantially constant cross-sectional dimension of the more distal portion being smaller than the cross-sectional dimension of the proximal portion.

49. The ultrasound transmission device of claim 48, wherein at least one of the at least two portions of the second member is sized to have its proximal end positioned at the location of minimal displacement.

50. The ultrasound transmission device of claim 38, wherein the third member comprises at least two substantially parallel transmission lines.

51. The ultrasound transmission device of claim 38, comprising a first guide wire tube for tracking the guide wire, the first guide wire tube having a length substantially equal to and extending parallel to said at least two transmission lines.

52. The ultrasound transmission device of claim 40 comprising a first guide wire tube for tracking the guide wire, the first guide wire tube having a length substantially equal to and extending parallel to said at least two transmission lines.

53. The ultrasound transmission device of claim 51, wherein the first guide wire tube extends through an aperture in the tool head.

54. The ultrasound transmission device of claim 51, wherein the third member comprises three transmission lines.

55. The ultrasound transmission device of claim 52, wherein the third member comprises three transmission lines.

56. The ultrasound transmission device of claim 38, wherein the first member includes a proximal portion and a distal portion, the distal portion having a substantially constant cross-sectional dimension that is smaller than a proximal cross-section of the proximal portion.

57. The ultrasound transmission device of claim 56, wherein the length of the proximal portion is approximately equal to an integer multiple of λ/2, where λ is a wavelength of a standing wave on the proximal portion.

58. The ultrasound transmission device of claim 51, wherein said at least two transmission line portions are contained within a sheath, and the first guide tube is attached to the sheath of the at least two transmission lines.

59. The ultrasound transmission device of claim 38, wherein the first, second, and third members are at least partially contained within the outer sheath.

60. The ultrasound transmission device of claim 59, wherein the outer sheath is formed at least in part of polyimide.

61. The ultrasound transmission device of claim 38, wherein the device is sized for attachment to a 7 french guide tube.

62. The ultrasound transmission device of claim 1, wherein the first and second transmission members have a length substantially equal to an odd multiple of λ/4, where λ is the wavelength of the standing wave of the portion in use.

63. The ultrasound transmission device of claim 37, wherein the first member has a length between 50mm and 1000 mm.

64. The ultrasound transmission device of claim 37, wherein the first member has a length of about 317 mm.

65. The ultrasound transmission device of claim 37, wherein the first member has a length of about 711 mm.

66. The ultrasound transmission device of claim 37, wherein the diameter of the first member decreases from the proximal end to the distal end between 15mm and 0.5 mm.

67. The ultrasound transmission device of claim 37, wherein the first member has a distal end diameter of about 1.0 mm.

68. The ultrasound transmission device of claim 37, wherein the second member has a length of less than 1000 mm.

69. The ultrasound transmission device of claim 37, wherein the second member has a diameter of between 1.0mm and 0.2 mm.

70. The ultrasound transmission device of claim 50, wherein said at least two transmission lines each have a diameter between 0.5mm and 0.01 mm.

71. The ultrasound transmission device of claim 50, wherein said at least two transmission lines each have a length of less than about 300 mm.

72. The ultrasound transmission device of claim 37, wherein the first member has a length of about 567mm and the second member has a length of about 156 mm.

73. The ultrasound transmission device of claim 12, wherein the first portion has a length of about 144 mm.

74. The ultrasound transmission device of claim 1, wherein the distal end of the first transmission member has a diameter of about 1 mm.

75. The ultrasound transmission device of claim 1, wherein the first transmission member is approximately 711mm in length.

76. The ultrasound transmission device of claim 18, wherein the diameter of the first portion of the second transmission member is about 0.62 mm.

77. The ultrasound transmission device of claim 18, wherein said at least two transmission lines have a diameter of about 0.29 mm.

78. The ultrasound transmission device of claim 18, wherein said at least two transmission lines have a length of about 160 mm.

79. The ultrasound transmission device of claim 1, wherein the device is sized and configured to extend from an opening into the body through a portion having a proximal portion and a more curved distal portion to an internal location in the body, the first transmission member being sized to terminate at its distal end near the proximal end where the vessel portion curves.

80. The ultrasound transmission device of claim 79 wherein the proximal portion of the blood vessel is a portion of the vicinity of the femoral artery, the iliac artery, and the descending aorta, and the curved portion of the blood vessel is the aortic arch, the ascending aorta, and the coronary artery.

81. The ultrasound transmission device of claim 37, wherein the device is sized and configured to extend from an opening into the body, through a pathway comprising a portion of a blood vessel having a proximal portion and a more curved distal portion, to an internal location in the body, the first member being sized to terminate the distal end of the first member in a first portion of the pathway.

82. The ultrasound transmission device of claim 81 wherein the proximal portion of the pathway includes a guide lumen or introducer sheath and the curved portion of the blood vessel is located within the blood vessel.

83. The ultrasound transmission device of claim 1, wherein the tool tip comprises a radiopaque material.

84. The ultrasound transmission device of claim 38, wherein the tool tip comprises a radiopaque material.

85. The ultrasound transmission device of claim 21, wherein the outer sheath of the second transmission member terminates before the tool tip.

86. The ultrasound transmission device of claim 38, wherein the first, second and third members are at least partially covered with a moisture barrier.

87. The ultrasound transmission device of claim 1 wherein the probe is excited by the transducer and carries a standing wave.