Catheter for treating calcified plaque

Abstract

A medical treatment system is used to treat calcified plaque at a treatment site within a body lumen of a subject. Magnetic particles include magnetic material and calcium-binding material at an exterior of the magnetic material. The magnetic particles bind to the calcified plaque at the treatment site. An electromagnetic field (EMF) applicator generates an alternating electromagnetic field at the treatment site to induce oscillation of the magnetic particles after the magnetic particles bind to the calcified plaque. The EMF applicator includes an EMF emitter that generates an electromagnetic field to isolate the magnetic particles in a plane that is generally tangential to the body lumen.

Description

CATHETER FOR TREATING CALCIFIED PLAQUE

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 661,436, filed June 18, 2024, the entire content of which is incorporated herein by reference.FIELD

[0002] The present technology is generally related to a catheter and method for treating calcified plaque within a body of a subject.BACKGROUND

[0003] A variety of techniques and instruments have been developed to percutaneously treat calcified plaque within a body of a subject. As an example, calcified plaque may build up within the circulatory system of the subject. A common example is the buildup of fatty deposits (atheromas) in the intimal layer (under the endothelium of a patient's blood vessels). Over time, what is initially deposited as relatively soft, cholesterol-rich atheromatous material often hardens into a calcified atherosclerotic plaque. The atheromas may be referred to as stenotic lesions or stenoses while the blocking material may be referred to as stenotic material. If left untreated, such stenoses can so sufficiently reduce perfusion that angina, hypertension, myocardial infarction, strokes and the like may result. Angioplasty or atherectomy may be performed to improve blood flow. However, the presence of calcified plaque typically leads to difficulty in adequately treating the blood vessel.SUMMARY

[0004] The techniques of this disclosure generally relate to modifying and / or disrupting calcified plaque within a subject.

[0005] In one aspect, the present disclosure provides a medical treatment system for treating calcified plaque at a treatment site within a body lumen of a subject. The system comprises magnetic particles each including magnetic material and calcium-binding material at an exterior of the magnetic material. The magnetic particles are configured to bind to the calcified plaque at the treatment site. An electromagnetic field (EMF)applicator configured to generate an alternating electromagnetic field at the treatment site to induce oscillation of the magnetic particles after the magnetic particles bind to the calcified plaque.

[0006] In another aspect, the disclosure provides a medical treatment system for treating calcified plaque at a treatment site within a body lumen of a subject. The system comprises magnetic particles deliverable to the treatment site. An electromagnetic field (EMF) applicator is configured to generate an alternating electromagnetic field at the treatment site to induce oscillation of the magnetic particles after the magnetic particles bind to the calcified plaque. The EMF applicator includes at least one EMF emitter configured to generate an electromagnetic field to isolate the magnetic particles in a plane that is generally tangential to the body lumen.

[0007] The details of one or more aspects of the disclosure are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the techniques described in this disclosure will be apparent from the description and drawings, and from the claims.BRIEF DESCRIPTION OF DRAWINGS

[0008] FIG. l is a conceptual drawing depicting a medical treatment system for treating calcified lesion within a body of a subject.

[0009] FIG. 2 is a conceptual drawing of the medical treatment system treating calcified lesion.

[0010] FIG. 3 is a conceptual cross-sectional drawing of a magnetic particle for use with medical treatment system.

[0011] FIG. 4 is a conceptual drawing of an electromagnetic field applicator of the medical treatment system.

[0012] FIG. 5 is a conceptual drawing another embodiment of an electromagnetic field applicator of the medical treatment system.

[0013] FIG. 6 is a conceptual drawing depicting oscillation direction of magnetic particles on calcified lesion.

[0014] FIG. 7 is a conceptual drawing depicting removal of magnetic particles from calcified lesion.

[0015] FIG. 8 diagram depicting a suitable method of modifying or disrupting a calcified lesion in a body lumen of a subject.DETAILED DESCRIPTION

[0016] The following description is generally related to embodiments and examples of a system for treating calcified plaque within a body of a subject. The illustrated examples are suitable for treating calcified plaque within a circulatory system of the subject, such as blood vessels and / or the heart of the subject. The illustrated examples may also be suitable for treating other body lumens outside the circulatory system.

[0017] Referring to FIG. 1, one embodiment of a system for treating calcified plaque within a body of a subject is generally indicated at reference numeral 10. In general, the system 10 is configured to create oscillations of magnetic particles in the calcified plaque to modify or disrupt the calcified plaque. For example, the oscillations may fracture the calcified plaque and / or heat the plaque, thereby facilitating treatment. In one example, the calcified plaque may be treated further, such as through angioplasty or atherectomy or other treatments, or the treatment using oscillating magnetic particles may be the primary or only treatment of the calcified plaque.

[0018] Referring still to FIG. 1, the system 10 generally includes a source of magnetic particles 12 configured to be delivered into the body, a delivery device, generally indicated at 14, configured to deliver the magnetic particles from the source into a treatment site (e.g., calcified plaque in a blood vessel BV or heart), and an electromagnetic field applicator, generally indicated at 16, configured to generate an electromagnetic field (i.e., alternating electromagnetic field) at the treatment site to induce oscillation of the magnetic particles.

[0019] Referring to FIG. 2, the illustrated magnetic particles 12 each include magnetic material 20 (e.g., magnetic core) and calcium-binding material 22 (e.g., calcium-binding protein) on an exterior of the magnetic material to enable the magnetic particles to bind to calcified plaque at the treatment site. The calcium-binding material 22 may be coated, or chemically bonded to, or otherwise applied on the exterior of the magnetic material 20, and the calcium-binding material may be directly coupled to the magnetic material or there may be one or more intermediate layers or materials between the magnetic material and the calcium-binding material as binding agent. In one example, the magnetic material 20includes superparamagnetic iron oxide nanoparticles (SPIONs). SPIONs are small synthetic y-Fe2O3 (maghemite), Fe3O4 (magnetite) or a-Fe2O3 (hermatite) particles. In addition, mixed oxides of iron with transition metal ions such as copper, cobalt, nickel, and manganese, are known to exhibit superparamagnetic properties and also fall into the category of SPIONs. Other examples include ferromagnetic cobalt nanoparticles (CoNPs) or cobalt alloys, such as Co80Fe20. The magnetic particles 20 may have diameters from about 10 nm to about 3 mm, and in one embodiment, from 10 nm to about 500 pm, or from about 10 nm to about 100 nm. The calcium-binding material 22 on the magnetic material 20 (e.g., SPION) may include a calcium-binding protein, such as but not limited to calmodulin, calretinin, parvalvumin, SI 00 protein, or calcineurin. The magnetic particles 12 may be configured to bind to plaque in other ways, including other types of coatings or other binding structures attached to the magnetic material. The magnetic particles 12 may be suspended in a fluid (e.g., saline) to enable delivery to the treatment site using the delivery device.

[0020] Referring to FIGS. 1 and 3, the illustrated delivery device 12 includes a catheter 30 configured to be inserted into lumen of the body (e.g., vasculature) so that a distal end margin of the catheter is trackable to be adjacent the treatment site (e.g., calcified lesion CL). The catheter 30 defines a fluid lumen 32 extending along a length of the catheter and configured to be in fluid communication with the source of magnetic particles 12 (e.g., the magnetic particles suspended in saline). The distal end margin of the catheter 30 may define one or more openings for delivering the magnetic particles 12 to the treatment site. In one or more examples, the delivery device 14 includes a pump 36 (e.g., positive displacement pump, peristaltic pump, etc.), gravity feed system, or other type of device or system for moving fluid. In the illustrated embodiment, the delivery device the pump 36 is a syringe, which may also function to hold or contain the source of magnetic particles 12 when filled with the nanoparticle suspension.

[0021] The delivery device may be of other types or configurations. In another example, the delivery device may include a balloon catheter. The balloon catheter includes a catheter body and a balloon at a distal end of the catheter body. The balloon is coated with magnetic particles (such as magnetic particles described above), which are configured to release from the balloon during expansion. In one example, the magnetic particles are combined with a chemical excipient, such as Urea, that is applied to anoutside of the balloon. In use, the balloon is delivered to the treatment site and expanded, whereupon the magnetic particles are released from the balloon and delivered to the calcified lesion.

[0022] In another example the delivery device may include a catheter body (e.g., guidewire). A distal end of the catheter body is coated with the magnetic particles (such as the magnetic particles described above). The magnetic particles are dispersed in a polymer matrix layer (e.g., PLLA). In use, the distal end of the catheter body is delivered to the treatment site, and the polymer matrix layer degrades to release the magnetic particles.

[0023] Referring to FIGS. 1 and 4, the electromagnetic field applicator (EMF applicator) 16 includes an electromagnetic field generator (EMF generator), generally indicated at reference numeral 40. The EMF generator 40 generally includes one or more alternating electric current sources (AC source) 42 electrically connected to one or more EMF emitters 44, such as by electrical conductors 46. The AC source 42 may be an alternating voltage source for generating the AC current. The AC current at the EMF emitter(s) 44 generates an alternating magnetic field at the treatment site. The EMF applicator 16 may include a control unit (e.g., processor and memory including processor- readable instructions) configured to operate the AC source 42 to generate the electromagnetic field. In one example, the EMF applicator 16 may be configured to generate an electromagnetic field at the treatment site having a frequency from about 1Hz to about 1000Hz. The EMF emitter(s) 44 may comprise an electrical conductor (e.g., electrically conductive wire) extending generally along (i.e., parallel to) the body lumen and the treatment site, either outside or inside the lumen. In use, as shown in FIG. 6, the EMF applicator 16 induces the magnetic particles 12 to oscillate in a plane that is generally tangential to the wall of the lumen at the treatment site, as shown by dash arrows in the figure.

[0024] In the embodiment shown in FIG. 4, the EMF emitter(s) 44 is configured to be disposed outside the body, generally adjacent the treatment site. In this illustrated embodiment, the EMF emitter(s) 44 is coupled to (e.g., mounted on or secured to) includes a wearable article 50 that is securable to a body part of the subject. For example, the wearable article 50 may be a cuff or sleeve that is worn on leg of the subject so that the EMF emitter(s) 44 are disposed over or around a calcified lesion in an artery in a leg. In this example, a plurality of the EMF emitters 44 are spaced apart from one anothercircumferentially around the wearable article 50. Each of the EMF emitters 44 extend along a length of the wearable article 50. In one example, each of the EMF emitters 44 may be configured to generate individual, alternating electromagnetic fields. For example, each of the EMF emitters 44 may have a dedicated source of alternating current 42 electrically coupled thereto. The sources of alternating current 42 may be controllable by a control unit to individually control operation of the sources.

[0025] Referring to FIG. 5, in another embodiment the EMF emitter(s) 44' is configured to be disposed inside the body, and in particular, inside the body lumen that includes the treatment site. In this illustrated embodiment, the EMF emitter(s) 44' includes one or more electrical conductors (e.g., electrically conductive wire(s)) that are deliverable via the body lumen (e.g., artery) to the treatment site (e.g., calcified lesion). In one example, the EMF emitter(s) 44' may be incorporated into or deliverable via the delivery catheter. As with the first embodiment, the EMF emitter(s) 44' extends axially along the treatment site such that the magnetic particles isolate in a plane that is generally tangential to the wall of the lumen at the treatment site.

[0026] Referring to FIG. 7, in one or more embodiments, the system 10 may further include a retrieval device 58 configured to remove modified calcified lesion fragments from the body lumen after treatment. In the illustrated embodiment, the removal device 58 includes a magnet 60 at a distal end of a catheter configured to magnetically attract the magnetic particles 12. In this way, fragments of the modified calcified lesion including the magnetic particles 12 bonded thereto are drawn to the retrieval device 58, thereby removing the calcified fragments from the lesion and enabling the calcified fragments to be withdrawn with the removal device.

[0027] Referring to FIG. 8, a suitable method of modifying or disrupting a calcified lesion in a body lumen of a subject is disclosed. In this embodiment, the any of the disclosed embodiments of the system may be utilized to perform the method.

[0028] At step 100, the magnetic particles 12 are delivered to the treatment site (e.g., calcified lesion) of the body lumen (e.g., artery, such as a peripheral artery). For example, the catheter 30 may be introduced into the lumen and the magnetic particles 12 delivered from the source (e.g., syringe 36) through the distal end of the catheter. In one example, the magnetic particles 12 include the calcium -binding coating 22 and bind to the calcified plaque CL. In other examples, the magnetic particles 12 may be delivered to the treatmentsite in other ways, such as by using a magnet outside the body and adjacent the treatment site to magnetically attract the magnetic particles to the calcified lesion.

[0029] At step 102, the EMF applicator 16 is operated to produce an alternating electromagnetic field at the treatment site, whereby the delivered magnetic particles 12 oscillate in a plane that is generally tangential to the wall of the body lumen (e.g., arterial wall) to modify and / or disrupt the calcified plaque. In one example, the wearable article 50 with the EMF emitter(s) 44 is wearable on the subject over the treatment site (e.g., leg). In another example, the EMF emitter 44' is delivered to the treatment site inside the lumen.

[0030] At step 104, the magnetic particles 12 bonded to the calcified plaque are retrieved and withdrawn from the lumen. For example, the retrieval device 58 is introduced into the lumen and the magnetic particles 12 are attracted to the magnet 60 at the distal end of the retrieval device. As shown in FIG. 7, the attracted force may fragment the calcified plaque CL so that fragmented portions of the calcified plaque couple to the distal end of the retrieval device 58. The retrieval device 58 is then withdrawn along with the fragmented portions of the calcified plaque. In other examples, the magnetic particles 12 may be removed in other ways.

[0031] The invention may be further described by reference to the following numbered paragraphs:1. A medical treatment system for treating calcified plaque at a treatment site within a body lumen of a subject comprising: magnetic particles each including magnetic material and calcium-binding material at an exterior of the magnetic material, wherein the magnetic particles are configured to bind to the calcified plaque at the treatment site; and an electromagnetic field (EMF) applicator configured to generate an alternating electromagnetic field at the treatment site to induce oscillation of the magnetic particles after the magnetic particles bind to the calcified plaque.2. The medical treatment system set forth in paragraph 1, wherein the magnetic material includes superparamagnetic iron oxide nanoparticles.3. The medical treatment system set forth in paragraph 2, wherein the superparamagnetic iron oxide nanoparticles include at least one of y-Fe2O3 (maghemite), Fe3O4 (magnetite) or a-Fe2O3 (hermatite) particles with a core ranging from 10 nm to 100 nm in diameter.4. The medical treatment system set forth in any one of paragraphs 1 to 3, wherein the calcium-binding material includes a calcium-binding protein.5. The medical treatment system set forth in paragraph 4, wherein the calcium -binding protein includes at least one of calmodulin, calretinin, parvalvumin, SI 00 protein, or calcineurin.6. The medical treatment system set forth in any one of paragraphs 1 to 5, wherein the magnetic particles are suspended in a fluid.7. The medical treatment system set forth in any one of paragraphs 1 to 6, further comprising a delivery device configured to deliver the magnetic particles to the treatment site.8. The medical treatment system set forth in paragraph 7, wherein the delivery device includes a catheter configured to be inserted into the lumen so that a distal end margin is trackable to be adjacent the treatment site.9. The medical treatment device set forth in paragraph 8, wherein the distal end margin of the catheter defines at least one opening configured to direct the magnetic particles to the treatment site.10. The medical treatment device set forth in any one of paragraphs 1 to 9, wherein the EMF applicator includes at least one EMF emitter configured to generate an electromagnetic field to isolate the magnetic particles in a plane that is generally tangential to the body lumen.11. The medical treatment device set forth in paragraph 10, wherein the at least one EMF emitter comprises at least one electrical conductor extending along the body lumen, wherein the EMF applicator includes at least one source of electrical current electrically coupled to the at least one electrical conductor.12. The medical treatment device set forth in paragraph 11, wherein EMF applicator includes a wearable article configured to be worn by the user and surround the body lumen, wherein the at least one electrical conductor is coupled to the wearable article.13. The medical treatment device set forth in paragraph 12, wherein the at least one electrical conductor includes a plurality of electrical conductors spaced apart from one another around the wearable article.14. The medical treatment device set forth in paragraph 11, wherein the at least one electrical conductor is configured to be delivered to the treatment site within the body lumen.15. The medical treatment device set forth in paragraph 11, wherein the at least one electrical conductor includes a plurality of electrical conductors, wherein the at least one source of electrical current includes a plurality of sources of electrical current each electrically connected to a dedicated one of the plurality of electrical conductors.16. The medical treatment device set forth in any one of paragraphs 1 to 15, further comprising a retrieval device configured to remove modified calcified lesion fragments from the body lumen after treatment, wherein the retrieval device includes a magnet configured to magnetically attract the magnetic particles at the treatment site.17. The medical treatment device set forth in paragraph 16, wherein the retrieval device includes a catheter configured to be delivered to the treatment site in the lumen, wherein a distal end margin of the catheter has the magnet coupled thereto.18. A medical treatment system for treating calcified plaque at a treatment site within a body lumen of a subject comprising: magnetic particles deliverable to the treatment site; and an electromagnetic field (EMF) applicator configured to generate an alternating electromagnetic field at the treatment site to induce oscillation of the magnetic particles after the magnetic particles bind to the calcified plaque, wherein the EMF applicator includes at least one EMF emitter configured to generate an electromagnetic field to isolate the magnetic particles in a plane that is generally tangential to the body lumen.19. The medical treatment device set forth in paragraph 18, wherein the at least one EMF emitter comprises at least one electrical conductor extending along the body lumen, wherein the EMF applicator includes at least one source of electrical current electrically coupled to the at least one electrical conductor.20. The medical treatment device set forth in paragraph 19, wherein EMF applicator includes a wearable article configured to be worn by the user and surround the body lumen, wherein the at least one electrical conductor is coupled to the wearable article

[0032] It should be understood that various aspects disclosed herein may be combined in different combinations than the combinations specifically presented in the description and accompanying drawings. It should also be understood that, depending on theexample, certain acts or events of any of the processes or methods described herein may be performed in a different sequence, may be added, merged, or left out altogether (e.g., all described acts or events may not be necessary to carry out the techniques). In addition, while certain aspects of this disclosure are described as being performed by a single module or unit for purposes of clarity, it should be understood that the techniques of this disclosure may be performed by a combination of units or modules associated with, for example, a medical device.

[0033] In one or more examples, the described techniques may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored as one or more instructions or code on a computer-readable medium and executed by a hardware-based processing unit. Computer-readable media may include non-transitory computer-readable media, which corresponds to a tangible medium such as data storage media (e.g., RAM, ROM, EEPROM, flash memory, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer).

[0034] Instructions may be executed by one or more processors, such as one or more digital signal processors (DSPs), general purpose microprocessors, application specific integrated circuits (ASICs), field programmable logic arrays (FPGAs), or other equivalent integrated or discrete logic circuitry. Accordingly, the term “processor” as used herein may refer to any of the foregoing structure or any other physical structure suitable for implementation of the described techniques. Also, the techniques could be fully implemented in one or more circuits or logic elements.

Claims

WHAT IS CLAIMED IS:

1. A medical treatment system (10) for treating calcified plaque at a treatment site within a body lumen of a subject comprising: magnetic particles (12) each including magnetic material (20) and calcium- binding material (22) at an exterior of the magnetic material, wherein the magnetic particles are configured to bind to the calcified plaque (CL) at the treatment site; and an electromagnetic field (EMF) applicator (16) configured to generate an alternating electromagnetic field at the treatment site to induce oscillation of the magnetic particles after the magnetic particles bind to the calcified plaque.

2. The medical treatment system set forth in claim 1, wherein the magnetic material (20) includes superparamagnetic iron oxide nanoparticles (SPIONs).

3. The medical treatment system set forth in claim 2, wherein the superparamagnetic iron oxide nanoparticles (SPIONs) include at least one of y-Fe2O3 (maghemite), Fe3O4 (magnetite) or a-Fe2O3 (hermatite) particles with a core ranging from 10 nm to 100 nm in diameter.

4. The medical treatment system set forth in any one of claims 1 to 3, wherein the calcium-binding material (22) includes a calcium-binding protein.

5. The medical treatment system set forth in claim 4, wherein the calcium -binding protein includes at least one of calmodulin, calretinin, parvalvumin, SI 00 protein, or calcineurin.

6. The medical treatment device set forth in any one of claims 1 to 5, wherein the EMF applicator (16) includes at least one EMF emitter (44) configured to generate an electromagnetic field to isolate the magnetic particles (12) in a plane that is generally tangential to the body lumen.

7. The medical treatment device set forth in claim 6, wherein the at least one EMF emitter (44) comprises at least one electrical conductor (46) extending along the body lumen, wherein the EMF applicator (16) includes at least one source (42) of electrical current electrically coupled to the at least one electrical conductor.

8. The medical treatment device set forth in claim 7, wherein EMF applicator (16) includes a wearable article (50) configured to be worn by the user and surround the body lumen, wherein the at least one electrical conductor (46) is coupled to the wearable article.

9. The medical treatment device set forth in claim 8, wherein the at least one electrical conductor (46) includes a plurality of electrical conductors spaced apart from one another around the wearable article.

10. The medical treatment device set forth in claim 7, wherein the at least one electrical conductor (46) includes a plurality of electrical conductors, wherein the at least one source (42) of electrical current includes a plurality of sources of electrical current each electrically connected to a dedicated one of the plurality of electrical conductors.

11. The medical treatment device set forth in any one of claims 1 to 10, further comprising a retrieval device (58) configured to remove modified calcified lesion fragments from the body lumen after treatment, wherein the retrieval device includes a magnet (60) configured to magnetically attract the magnetic particles (12) at the treatment site.

12. The medical treatment device set forth in claim 11, wherein the retrieval device (58) includes a catheter (30) configured to be delivered to the treatment site in the lumen, wherein a distal end margin of the catheter has the magnet coupled thereto.

13. A medical treatment system for treating calcified plaque (CL) at a treatment site within a body lumen of a subject comprising: magnetic particles (12) deliverable to the treatment site; andan electromagnetic field (EMF) applicator (16) configured to generate an alternating electromagnetic field at the treatment site to induce oscillation of the magnetic particles after the magnetic particles bind to the calcified plaque, wherein the EMF applicator includes at least one EMF emitter (44) configured to generate an electromagnetic field to isolate the magnetic particles in a plane that is generally tangential to the body lumen.

14. The medical treatment device set forth in claim 13, wherein the at least one EMF emitter (44) comprises at least one electrical conductor (46) extending along the body lumen, wherein the EMF applicator includes at least one source (42) of electrical current electrically coupled to the at least one electrical conductor.

15. The medical treatment device set forth in claim 4, wherein EMF applicator (16) includes a wearable article (50) configured to be worn by the user and surround the body lumen, wherein the at least one electrical conductor (46) is coupled to the wearable article.

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