US20140180391.pdf

US 20140180391A1

(19) United States (12) Patent Application Publication (10) Pub. No.: US 2014/0180391 A1

Dagan et al. (43) Pub. Date: Jun. 26, 2014

(54) WIRELESS ENDOVASCULAR STENT-BASED Publication Classi?cation ELECTRODES

(51) Int. Cl. (75) Inventors: Amir Dagan, KibbutZ Megiddo (IL); A61F 2/82 (200601)

Moshe Elazar, Azor (IL); Nitai Hanani, A613 5/04 (200601) Haifa (IL); Gal Ariav, Givaat Ada (IL); A61N 1/05 (2006.01) Oded Meiri, Rarn-On (IL); Igor Gindin, (52) us CL Nesher (IL); Vaqllm Bernshtelfl, cpc A61F 2/82 (2013.01); A61N1/05 (2013.01); Netanya (I_L); Nlr Armory, Ra anana A6IB 5/04 (2013.01) (1L); YOSSI Gross, Moshav MaZOr (1L); USPC ....................................................... .. 623/115 Offer Glasberg, Zichron Yaakov (IL)

(73) Assignee: Enopace Biomedical Ltd., Caesarea (57) ABSTRACT (1L)

_ Apparatus and methods are provided for use With a blood (21) Appl' NO" 13/741154 vessel of a subject, including a stent (20) con?gured to be 22 PCT 13-1 (12 s _ 9 2012 placed inthe bloodvessel. The stent includes atleast ?rst (32),

( ) 1 e ep second (34), and third (36) strut portions disposed along the (86) PCT NO; PCT/IL12/00336 stent. The ?rst and second strut portions are coupled to one

another at a ?rst junction (3 7A) that facilitates bending of the 371 (6X1), ?rst and second strut portions With respect to one another. The (2), (4) Date? Jun- 28: 2013 second and third strut portions are coupled to one another at a

. . second junction (37B) that facilitates bending of the second Related U's' Apphcatlon Data and third strut portions With respect to one another. At least

(60) Provisional application No. 61/532,660, ?led on Sep. one electrode (22) is disposed on at least an outer surface of 9,2011. the stent. Other applications are also described.

Patent Application Publication Jun. 26, 2014 Sheet 1 0f 16 US 2014/0180391 A1


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Patent Application Publication Jun. 26, 2014 Sheet 13 0f 16 US 2014/0180391 Al

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US 2014/0180391 A1 Jun. 26, 2014 Sheet 14 0f 16 Patent Application Publication

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FIG. 1 1

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170 -

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US 2014/0180391A1

WIRELESS ENDOVASCULAR STENT-BASED ELECTRODES

CROSS-REFERENCES TO RELATED APPLICATIONS

[0001] The present application claims priority from US. Provisional Patent Application 61/ 532,660 to Dagan, ?led Sep. 9, 2011, entitled, Wireless endovascular stent-based electrodes. [0002] The present application is related to US. Ser. No. 13/210,778 to Dagan (published as US 2012/0035679), ?led Aug. 16, 2011, which is a continuation-in-part of US. Ser. No. 12/957,799 to Gross (published as US 2011/0137370), ?led Dec. 1, 2010, entitled Thoracic aorta and vagus nerve stimulation, which is a continuation-in-part of US. Ser. No. 12/792,227 to Gross (published as US 2010/0305392), ?led Jun. 2, 2010, entitled Thoracic aorta and vagus nerve stimu lation, which claims the bene?t of (a) US. Provisional Patent Application 61/183,3 1 9 to Reisner, ?led Jun. 2, 2009, entitled Thoracic aorta and vagus nerve stimulation, and (b) US. Provisional Patent Application 61/331,453 to Dagan, ?led May 5, 2010, entitled Thoracic aorta and vagus nerve stimu lation. [0003] All of the above-referenced applications are incor porated herein by reference.

FIELD OF EMBODIMENTS OF THE INVENTION

[0004] Some applications of the present invention gener ally relate to medical apparatus. Speci?cally, some applica tions of the present invention relate to stent-based electrodes for placement in a blood vessel.

BACKGROUND

[0005] Heart failure is a condition in which a problem with the structure or function of the heart impairs its ability to supply su?icient blood ?ow to meet the bodys needs. The condition impairs quality of life and is a leading cause of hospitalizations and mortality in the western world. Treat ment of heart failure is typically aimed at removal of precipi tating causes, prevention of deterioration in cardiac function, and control of congestive state. [0006] Hypertension, or chronic high blood pressure, is an extremely prevalent medical condition, which can lead to strokes, heart attacks, and heart failure. There are a variety of treatments that are available for treating hypertension, includ ing lifestyle changes, and medication.

SUMMARY OF EMBODIMENTS

[0007] For some applications of the present invention, a stent is placed in a blood vessel. The stent de?nes at least ?rst, second, and third strut portions disposed along the stent. The ?rst and second strut portions are coupled to one another at a ?rst junction that facilitates bending of the ?rst and second strut portions with respect to one another, and the second and third strut portions are coupled to one another at a second junction that facilitates bending of the second and third strut portions with respect to one another. At least one electrode (typically, at least one pair of electrodes) is disposed on at least an outer surface of the stent. Typically, a current is driven into the blood vessel wall via the electrode. [0008] Typically, the stent is inserted into the blood vessel via a delivery system, such as a catheter. For some applica

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tions, the junctions of the stent are con?gured to cause at least a portion of the outer surface of the stent to assume a convex pro?le upon protruding from catheter. For some applications, causing the outer surface of the stent to assume the convex pro?le reduces damage to the vessel wall that could be caused by the distal end of the stent contacting the vessel wall, relative to if the stent were to assume a straight pro?le upon protruding from the catheter. For some applications, the assumption of the convex pro?le by the outer surface of the stent brings the electrodes into contact with the vessel wall. For some applications, the junctions of the stent are con?g ured to facilitate retrieval of the stent into the catheter. [0009] It is noted that in the context of the present applica tion, the terms proximal and distal are to be understood to be with respect to an access point of the stent into the subject s body. Thus, the distal end of the stent is the end of the stent that is further from the access point, and the proximal end of the stent is the end of the stent that is closest to the access point. [0010] For some applications, the stent de?nes a stent body, and a plurality of posts that protrude longitudinally from a distal end of the stent body. An antenna is disposed annularly on distal portions of the posts, such that the posts separate the stent from the antenna. Typically, the stent electrode is pow ered via an inductive current that is generated in the antenna. Further typically, the posts, by separating the antenna from the stent body, facilitate an ef?cient transfer of electrical power to the antenna by reducing an inductive current that may be generated through the stent body and that may inter fere with the inductive current in the antenna. [0011] For some applications of the present invention, a stent is con?gured to be placed inside a subjects blood vessel (e.g., the subjects aorta, pulmonary artery, carotid artery, and/or renal artery), the stent being shaped to de?ne at least one post. At least one coiled electrode is con?gured to be coupled to the stent by being placed on the post. An electrode ?xation member (e.g., a cap) is con?gured to ?xedly couple the electrode to the post by being placed on the post. [0012] There is therefore provided, in accordance with some applications of the present invention, apparatus for use with a blood vessel of a subject, including: [0013] a stent con?gured to be placed in the blood vessel, the stent including:

[0014] at least ?rst, second, and third strut portions dis posed along the stent,

[0015] the ?rst and second strut portions being coupled to one another at a ?rst junction that facilitates bending of the ?rst and second strut portions with respect to one another, and

[0016] the second and third strut portions being coupled to one another at a second junction that facilitates bend ing of the second and third strut portions with respect to one another; and

[0017] at least one electrode disposed on at least an outer surface of the stent. [0018] For some applications, the strut portions include portions of the stent that provide resistance against longitu dinal compression of the stent, that permit radial compression of the stent, and that are less compliant than the junctions of the stent. [0019] For some applications, the junctions include springs. [0020] For some applications, the strut portions include struts that are made from a material selected from the group

US 2014/0180391A1

consisting of: a metal and an alloy, and the junctions include longitudinal locations along the stent body at which the struts of the stent are shaped such as to facilitate bending of the stent at those locations. [0021] For some applications, the junctions are con?gured to act as joints around which the strut portions ?ex. [0022] For some applications, the stent includes a fourth strut portion, the fourth strut portion being coupled to the third strut portion at a third junction that facilitates bending of the third and fourth strut portions with respect to one another. [0023] For some applications, the blood vessel includes a curved blood vessel, and the junctions of the stent are con?g ured to facilitate placing of the stent in the curved blood vessel, by facilitating bending of the strut portions of the stent with respect to one another. [0024] For some applications, the stent is for use with a catheter, the stent is con?gured to be placed inside the blood vessel by being advanced out of a distal end of the catheter, and the junctions of the stent are con?gured to cause at least a portion of an outer surface of the stent to assume a convex pro?le upon protruding from catheter. [0025] For some applications, the electrode is disposed on an outer surface of the stent, and, by causing at least the portion of the outer surface of the stent to assume the convex pro?le upon protruding from catheter, the junctions of the stent are con?gured to bring the electrode into contact with a wall of the blood vessel. [0026] For some applications, by causing at least the por tion of the outer surface of the stent to assume the convex pro?le upon protruding from catheter, the junctions of the stent are con?gured to cause an angle that the outer surface of the stent makes with a wall of the blood vessel, as the stent protrudes from the catheter, to be less than if the stent were to assume a straight pro?le upon protruding from the catheter. [0027] For some applications, by causing the angle that the outer surface of the stent makes with a wall of the blood vessel as the stent protrudes from the catheter, to be less than if the stent were to assume a straight pro?le upon protruding from the catheter, the junctions are con?gured to reduce damage to the blood vessel wall. [0028] For some applications, the stent is for use with a catheter, the stent is con?gured to be partially deployed inside the blood vessel by a distal portion of the stent being advanced out of a distal end of the catheter, and the junctions of the stent are con?gured, subsequent to the partial deployment of the stent, to facilitate retrieval of the stent into the catheter. [0029] For some applications, the ?rst junction of the stent is con?gured to facilitate retrieval of the stent into the catheter by allowing the ?rst strut portion of the stent to radially expand, while the second strut portion remains substantially compressed inside the catheter. [0030] For some applications, the second junction of the stent is con?gured to facilitate retrieval of the stent into the catheter by allowing the second strut portion of the stent to radially expand, while the third strut portion remains sub stan tially compressed inside the catheter. [0031] For some applications, the strut portions include struts that are made from a material selected from the group consisting of: a metal and an alloy, and the junctions include waved strips of the selected material. [0032] For some applications, at least the ?rst junction includes a waved strip of the selected material, the strip hav ing a width ofmore than 0.1 mm.

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[0033] For some applications, the strip has a width of less than 1 mm. [0034] There is further provided, in accordance with some applications of the present invention, apparatus for use with a blood vessel of a subject, including: [0035] a stent con?gured to be placed in the blood vessel, the stent including:

[0036] a generally cylindrical stent body; [0037] a plurality of posts protruding longitudinally from an end of the stent body;

[0038] an antenna disposed annularly on the posts, such that the posts separate the antenna from the end of the stent body.

[0039] For some applications, the apparatus further includes at least one coiled electrode, the coiled electrode being con?gured to be coupled to the stent by being placed on one of the posts. [0040] For some applications, a length of each of the posts is greater than 1 mm. [0041] For some applications, the length of each of the posts is greater than 5 mm. [0042] For some applications, a length of each of the posts is less than 20 mm. [0043] For some applications, the length of each of the posts is less than 15 mm. [0044] For some applications, the antenna is con?gured to receive power by RF energy being transmitted toward the antenna, such as to generate an inductive current through the antenna. [0045] For some applications, the posts are con?gured, by separating the antenna from the end of the stent body, to reduce a strength of the inductive current that is generated in the stent body, due to a magnetic ?eld that is generated by the inductive current of the antenna. [0046] For some applications, the posts are con?gured to provide electrical resistance, such that a current from the antenna to the stent body is negligible. [0047] For some applications, the apparatus further includes a control capsule coupled to the stent, the control capsule being con?gured to be powered using the inductive current of the antenna. [0048] For some applications, the apparatus further includes an electrode coupled to the stent, the control capsule being con?gured to drive a current into the blood vessel, via the electrode. [0049] For some applications, the apparatus further includes an electrode coupled to the stent, the control capsule being con?gured to receive an electrical parameter of the blood vessel, via the electrode. [0050] There is additionally provided, in accordance with some applications of the present invention, apparatus for use with a blood vessel of a subject, including: [0051] an annular antenna con?gured to be placed inside the blood vessel such that radial expansion of the antenna is limited by a circumference of the blood vessel; [0052] a transmitter con?gured to generate an inductive current in the antenna, by transmitting RF energy toward the antenna; and [0053] a control unit con?gured to measure the inductive current in the antenna and, in response thereto, to determine a physiological parameter of the subject. [0054] For some applications, the annular antenna includes at least a portion of a stent.

US 2014/0180391A1

[0055] For some applications, the apparatus further includes a stent, the antenna being coupled to the stent. [0056] For some applications, the control unit is con?gured to determine the physiological parameter of the subject by determining a parameter of the subject selected from the group consisting of: cardiac rate, respiratory rate, blood pres sure, and blood vessel pulsation. [0057] For some applications, the control unit is con?gured to determine the physiological parameter of the subject by interpreting variations in the inductive current that are mea sured at the antenna as being caused by variations in geometry of the antenna over the course of the subjects cardiac cycle. [0058] For some applications, the control unit is con?gured to determine the physiological parameter of the subject by determining a respiratory cycle of the subject by analyZing an envelope of a variation of the inductive current with time. [0059] For some applications, the transmitter is con?gured to transmit the RF energy at a frequency of more than 50 kHZ. [0060] For some applications, the transmitter is con?gured to transmit the RF energy at a frequency of more than 90 kHZ. [0061] For some applications, the transmitter is con?gured to transmit the RF energy at a frequency of less than 100 MHZ. [0062] For some applications, the transmitter is con?gured to transmit the RF energy at a frequency of more than 60 MHZ. [0063] There is further provided, in accordance with some applications of the present invention, a method for use with a blood vessel of a subject, including: [0064] providing:

[0065] a stent that includes: [0066] at least ?rst, second, and third strut portions

disposed along the stent, [0067] the ?rst and second strut portions being

coupled to one another at a ?rst junction that facili tates bending of the ?rst and second strut portions with respect to one another, and

[0068] the second and third strut portions being coupled to one another at a second junction that facili tates bending of the second and third strut portions with respect to one another; and

[0069] at least one electrode disposed on at least an outer surface of the stent; and

[0070] placing the stent and the electrode inside the blood vessel.

[0071] There is further provided, in accordance with some applications of the present invention, a method for use with a blood vessel of a subj ect, including: [0072] providing a stent that includes:

[0073] a generally cylindrical stent body; [0074] a plurality of posts longitudinally protruding from an end of the stent body;

[0075] an antenna disposed annularly on the posts, such that the posts separate the antenna from the end of the stent body; and

[0076] placing the stent inside the blood vessel. [0077] There is additionally provided, in accordance with some applications of the present invention, a method for use with a blood vessel of a subject, comprising: [0078] placing into the blood vessel:

[0079] a stent having a generally cylindrical stent body; [0080] at least one electrode that is coupled to the stent body; and

[0081] an antenna that is coupled to the stent body,

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[0082] the placing being performed such that the antenna is separated from the stent body; and

[0083] operating a transmitter: [0084] to generate an inductive current through the

antenna by transmitting RF energy toward the antenna; and

[0085] using the inductive current, to drive a current into the blood vessel via the electrode.

[0086] For some applications, placing the stent and the antenna into the blood vessel includes reducing a strength of the inductive current that is generated in the stent body, due to a magnetic ?eld that is generated by the antenna, by placing the stent and the antenna such that the antenna is separated from the stent body. [0087] For some applications, placing the stent and the antenna into the blood vessel includes placing the stent and the antenna into the blood vessel such that the stent body is separated from the antenna by a distance that is greater than 1 mm.

[0088] For some applications, placing the stent and the antenna into the blood vessel includes placing the stent and the antenna into the blood vessel such that the stent body is separated from the antenna by a distance that is greater than 5 mm.

[0089] For some applications, placing the stent and the antenna into the blood vessel includes placing the stent and the antenna into the blood vessel such that the stent body is separated from the antenna by a distance that is less than 20 mm.

[0090] For some applications, placing the stent and the antenna into the blood vessel includes placing the stent and the antenna into the blood vessel such that the stent body is separated from the antenna by a distance that is less than 15 mm.

[0091] There is further provided, in accordance with some applications of the present invention, a method for use with an annular antenna that has been placed in a blood vessel and allowed to expand radially, such that radial expansion of the antenna is limited by a circumference of the blood vessel, the method comprising: [0092] generating an inductive current in the antenna, by transmitting RF energy toward the antenna; [0093] measuring the inductive current in the antenna; and [0094] in response thereto, determining a physiological parameter of the subject. [0095] There is further provided, in accordance with some applications of the present invention, apparatus, including: [0096] a stent shaped to de?ne struts and at least one post; [0097] a coiled electrode con?gured to be coupled to the stent by being placed on the post; and [0098] an electrode-?xation member con?gured to ?xedly couple the coiled electrode to the post by being placed on the post. [0099] The present invention will be more fully understood from the following detailed description of embodiments thereof, taken together with the drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

[0100] FIG. 1 is schematic illustrations of a stent placed inside a subjects aorta, electrodes being disposed on the stent, in accordance with some applications of the present invention;

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