Patent Application
20210128331
Some applications of the present invention generally relate to medical apparatus.
Specifically, some applications of the present invention relate to stent-based electrodes for placement in a blood vessel.
Heart failure is a condition in which a problem with the structure or function of the heart impairs its ability to supply sufficient blood flow to meet the body's needs. The condition impairs quality of life and is a leading cause of hospitalizations and mortality in the Western world. Treatment of heart failure is typically aimed at removal of precipitating causes, prevention of deterioration in cardiac function, and control of congestive state.
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, including lifestyle changes and medication.
For some applications of the present invention a stent is inserted into a subject's aorta. Typically, the stent has one or more electrodes and a first antenna coupled thereto. A second antenna is placed on the subject, such that the second antenna extends at least from above a left clavicle of the subject to below a jugular notch of the subject and from below the subject's jugular notch to above a right clavicle of the subject. The second antenna transmits an electrical signal to the first antenna via inductive coupling.
For some applications, the stent is placed within a lumen e.g., a lumen of a blood vessel of a subject, such as the subject's aorta. Typically, the stent defines a stent body, a plurality of antenna posts that protrude from a distal end of the stent body, a plurality of electrode posts that protrude from the distal end of the stent body, and one or more coupling elements for coupling a control capsule to the inner surface of the stent body. Further typically, the first antenna is coupled to the stent by being sutured to the antenna posts that protrude from the stent body, a plurality of coiled electrodes are coupled to the stent by being placed upon respective electrode posts, and a control capsule is coupled to stent via the coupling elements. For some applications, a control unit and the second antenna (i.e., the transmitter) are disposed outside the subject's body. The control unit transmits a signal and/or power toward the stent, via the transmitter. The antenna on the stent receives the transmitted signal and/or power, and the control capsule drives the electrodes to drive a current into the blood vessel, in response to the antenna receiving the signal and/or power.
Typically the stent is placed inside the subject's aorta such that the distal end of the stent is in the vicinity of the subject's aortic arch. For some applications, the stent is placed such that the electrodes are disposed between the bifurcation of the aorta with the left subclavian artery and the bifurcation of the aorta with the fifth intercostal artery. For some applications, the control capsule drives the electrodes to drive a current into the subject's aorta, e.g., in order to treat the subject for a condition such as congestive heart failure, diastolic heart failure, and/or hypertension, e.g., as described in U.S. Ser. No. 13/210,778 to Dagan (published as US 2012/0035679), U.S. Ser. No. 12/957,799 to Gross (published as US 2011/0137370), and/or U.S. Ser. No. 12/792,227 to Gross (published as US 2010/0305392), all of which applications are incorporated herein by reference.
It is noted that in the context of the present application, 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. For applications in which the stent is placed inside the subject's aorta, the term “distal” typically means the portion of the stent or the aorta that is closer to the subject's left ventricle, and the term “proximal” means the portion of the stent or the aorta that is further from the subject's left ventricle.
There is therefore provided, in accordance with some applications of the present invention, apparatus including:
a stent configured to be placed inside an aorta of a subject, the stent including one or more electrodes, control circuitry, and a first antenna coupled thereto; and
a second antenna configured to be placed on the subject, such that the second antenna extends at least from above a left clavicle of the subject to below a jugular notch of the subject and from below the subject's jugular notch to above a right clavicle of the subject, the second antenna being configured to transmit an electrical signal to the first antenna via inductive coupling.
In some applications, the second antenna is configured to transmit power to the first antenna, and the control circuitry is configured to drive a current into the subject's aorta, via the electrodes, using the received power.
In some applications, at least a portion of the stent is configured to be placed in a descending aorta of the subject.
In some applications, at least a portion of the stent is configured to be placed in an aortic arch of the subject.
In some applications, the stent is configured to be placed in the aorta such that the electrodes are placed in contact with a site disposed between a bifurcation of the aorta with a left subclavian artery and a bifurcation of the aorta with a fifth intercostal artery.
In some applications, the stent and the second antenna are configured such that when the stent is placed in the aorta, and the second antenna is placed on the subject such that the second antenna extends at least from above the subject's left clavicle to below the subject's jugular notch and from below the subject's jugular notch to above the subject's right clavicle, a coupling coefficient between the first and second antennas is greater than 0.004, the coupling coefficient being defined as:
coupling coefficient=(V1/V2)*√(L2/L1)
where V1 and V2 are voltage gains of the first and second antennas, respectively, and L1 and L2 are inductances of the first and second antennas, respectively.
In some applications, the second antenna is configured to be implanted subcutaneously.
In some applications, the apparatus further includes a support selected from the group consisting of: an undershirt, a bra-like housing, silicone configured to stick to skin of the subject, and string, and the second antenna is configured to be supported on the subject, such that the second antenna extends at least from above the subject's left clavicle to below the subject's jugular notch and from below the subject's jugular notch to above the subject's right clavicle, using the selected support.
In some applications, the second antenna is configured not to circumscribe a neck of the subject.
In some applications, the second antenna is configured to circumscribe a neck of the subject.
In some applications, the second antenna includes at least one turn of wire configured to form a complete loop that extends from below the subject's jugular notch to behind a vertebra of the subject that is between C1 and T3 vertebrae.
In some applications, the stent and the second antenna are configured such that when the stent is placed in the aorta, and the second antenna is placed on the subject such that the second antenna extends at least from above the subject's left clavicle to below the subject's jugular notch and from below the subject's jugular notch to above the subject's right clavicle, an effective sagittal angle between the first and second antennas is between 20 and 70 degrees.
In some applications, the stent and the second antenna are configured such that when the stent is placed in the aorta, and the second antenna is placed on the subject such that the second antenna extends at least from above the subject's left clavicle to below the subject's jugular notch and from below the subject's jugular notch to above the subject's right clavicle, the effective sagittal angle between the first and second antennas is between 30 and 60 degrees.
In some applications, the second antenna includes a plurality of turns of wire, and a plurality of capacitors, and each of the turns of wire is coupled to a respective one of the capacitors.
In some applications, the capacitors are configured to prevent the second antenna from becoming detuned as a result of becoming misshapen.
There is further provided, in accordance with some applications of the present invention, a method including:
inserting into an aorta of a subject a stent having one or more electrodes, and a first antenna coupled thereto; and
placing a second antenna on the subject, such that the second antenna extends at least from above a left clavicle of the subject to below a jugular notch of the subject and from below the subject's jugular notch to above a right clavicle of the subject,
the second antenna being configured to transmit an electrical signal to the first antenna via inductive coupling.
In some applications, the method further includes operating the second antenna to transmit power to the first antenna, such that a current is driven a current into the subject's aorta via the electrodes, using the received power.
In some applications, inserting the stent into the subject's aorta includes inserting at least a portion of the stent into a descending aorta of the subject.
In some applications, inserting the stent into the subject's aorta includes inserting at least a portion of the stent into an aortic arch of the subject.
In some applications, inserting the stent into the subject's aorta includes inserting the stent such that the electrodes are placed in contact with a site disposed between a bifurcation of the aorta with a left subclavian artery and a bifurcation of the aorta with a fifth intercostal artery.
In some applications, placing the second antenna on the subject such that the second antenna extends at least from above the subject's left clavicle to below the subject's jugular notch and from below the subject's jugular notch to above the subject's right clavicle includes placing the second antenna such that a coupling coefficient between the first and second antennas is greater than 0.004, the coupling coefficient being defined as:
coupling coefficient=(V1/V2)*√(L2/L1),
where V1 and V2 are voltage gains of the first and second antennas, respectively, and L1 and L2 are inductances of the first and second antennas, respectively.
In some applications, placing the second antenna on the subject includes subcutaneously implanting the second antenna.
In some applications, placing the second antenna on the subject includes supporting the second antenna on the subject such that the second antenna extends at least from above the subject's left clavicle to below the subject's jugular notch and from below the subject's jugular notch to above the subject's right clavicle using a support selected from the group consisting of: an undershirt, a bra-like housing, silicone configured to stick to skin of the subject, and string.
In some applications, placing the second antenna on the subject includes placing the second antenna on the subject such that the second antenna does not circumscribe a neck of the subject.
In some applications, placing the second antenna on the subject includes placing the second antenna on the subject such that the second antenna circumscribes a neck of the subject.
In some applications, placing the second antenna on the subject includes placing the second antenna on the subject such that at least one turn of wire of the second antenna forms a complete loop that extends from below the subject's jugular notch to behind a vertebra of the subject that is between C1 and T3 vertebrae.
In some applications, placing the second antenna on the subject such that the second antenna extends at least from above the subject's left clavicle to below the subject's jugular notch and from below the subject's jugular notch to above the subject's right clavicle includes placing the second antenna such that when the stent is inside the aorta an effective sagittal angle between the first and second antennas is between 20 and 70 degrees.
In some applications, placing the second antenna on the subject such that the second antenna extends at least from above the subject's left clavicle to below the subject's jugular notch and from below the subject's jugular notch to above the subject's right clavicle includes placing the second antenna such that when the stent is inside the aorta the effective sagittal angle between the first and second antennas is between 30 and 60 degrees.
In some applications, placing the second antenna on the subject includes placing on the subject a second antenna that includes a plurality of turns of wire, and a plurality of capacitors, each of the turns of wire being coupled to a respective one of the capacitors.
In some applications, placing on the subject a second antenna that includes a plurality of turns of wire, and a plurality of capacitors, each of the turns of wire being coupled to a respective one of the capacitors includes preventing the second antenna from becoming detuned as a result of becoming misshapen.
There is further provided, in accordance with some applications of the present invention, a method for use with a subject in whose aorta a stent has been placed, the stent having a first antenna coupled thereto, the method including:
placing a second antenna on the subject, such that the second antenna extends at least from above a left clavicle of the subject to below a jugular notch of the subject and from below the subject's jugular notch to above a right clavicle of the subject; and
driving the second antenna to transmit an electrical signal to the first antenna via inductive coupling.
There is further provided, in accordance with some applications of the present invention, apparatus including:
an antenna including:
There is further provided, in accordance with some applications of the present invention, apparatus including:
an antenna including:
There is further provided, in accordance with some applications of the present invention, apparatus including:
a stent including:
an antenna disposed annularly on the antenna posts; and
one or more fastening elements that couple the antenna to the antenna posts by fastening the antenna against the one or more flat portions.
There is further provided, in accordance with some applications of the present invention, apparatus including:
a stent including a generally cylindrical stent body that includes a plurality of struts,
a first one of the struts including a first widened portion that defines a flat surface having a first width,
a second one of the struts including a second widened flat portion that defines a flat surface having a second width that is different from the first width;
at least one antenna coupled to the stent;
at least one electrode coupled to the stent;
control circuitry coupled to the stent;
an antenna wire configured to transmit electrical energy between the antenna and the control circuitry, the antenna wire being coupled to the stent by being fastened against the first widened flat portion; and
an electrode wire configured to transmit electrical energy between the electrode and the control circuitry, the electrode wire being coupled to the stent by being fastened against the second widened flat portion.
There is further provided, in accordance with some applications of the present invention, apparatus including:
a stent including a generally cylindrical stent body that includes a plurality of struts,
a first one of the struts including a first widened flat portion that defines a flat surface having a first width,
a second one of the struts including a second widened flat portion that defines a flat surface having a second width that is greater than the first width;
at least first and second electrodes coupled to the stent;
control circuitry coupled to the stent;
a first electrode wire configured to transmit electrical energy between the first electrode and the control circuitry, a first portion of the first electrode wire being coupled to the stent by being fastened against the first widened flat portion; and
a second electrode wire configured to transmit electrical energy between the electrode and the control circuitry, a second portion of the first electrode wire and a first portion of the second electrode wire being coupled to the stent by being fastened against the second widened flat portion.
There is further provided, in accordance with some applications of the present invention, a method for operating one or more electrodes, a capacitor and a first antenna that are electrically coupled to each other, and that are disposed inside a subject's body, the method including:
during a first type of time period, driving current into the subject's body via the electrodes by discharging the capacitor, and, simultaneously, transmitting power to the antenna from outside the subject's body;
during a second type of time period, charging the capacitor using the power received by the antenna during the first type of time period; and
alternating between the first and second types of time periods.
The present invention will be more fully understood from the following detailed description of embodiments thereof, taken together with the drawings, in which:
Reference is now made to
Typically, a control unit 24 and a transmitting antenna (i.e., a transmitter) 26 are disposed outside the subject's body, as shown in
Typically, electrodes 22 are placed in contact with an aortic site, which is as described in U.S. Ser. No. 13/210,778 to Dagan (issued as U.S. Pat. No. 8,626,290), U.S. Ser. No. 12/957,799 to Gross (issued as U.S. Pat. No. 8,626,299), and/or U.S. Ser. No. 12/792,227 to Gross (published as US 2010/0305392), all of which applications are incorporated herein by reference. The aortic site is typically between the bifurcation of the aorta with the left subclavian artery and the bifurcation of the aorta with the fifth intercostal artery. Further typically, the aortic site is between the bifurcation of the aorta with the left subclavian artery and the bifurcation of the aorta with the fourth intercostal artery, e.g., between the bifurcation of the aorta with the left sub clavian artery and the bifurcation of the aorta with the first intercostal artery. For some applications, the aortic site is between the bifurcations of the aorta with the first and fifth intercostal arteries. For some applications, at least a portion of the stent is placed inside the descending aorta, and/or at least a portion of the stent is placed in the aortic arch.
Typically, a current is driven into the subject's aorta, e.g., in order to treat the subject for a condition such as congestive heart failure, diastolic heart failure, and/or hypertension, e.g., as described in U.S. Ser. No. 13/210,778 to Dagan (issued as U.S. Pat. No. 8,626,290), U.S. Ser. No. 12/957,799 to Gross (issued as U.S. Pat. No. 8,626,299), and/or U.S. Ser. No. 12/792,227 to Gross (published as US 2010/0305392), all of which applications are incorporated herein by reference. For some applications, stent 20 is cut from a nitinol tube (or a tube made from a different material, such as stainless steel) having a wall thickness of more than 0.2 mm (e.g., more than 0.4 mm), and/or less than 0.7 mm (e.g., less than 0.6 mm). For some applications, the length of the stent is more than 25 mm (e.g., more than 30 mm), and/or less than 100 mm (e.g., less than 40 mm). The stent is shape set to a desired expanded configuration of the stent, using techniques that are known in the art. For some applications, the stent is shape set such that in its expanded configuration (i.e., in the absence of any forces acting on the stent), the stent has a maximum outer diameter of more than 10 mm (e.g., more than 15 mm), and/or less than 60 mm (e.g., less than 50 mm). The stent is typically configured such that, upon being deployed in its expanded configuration inside the subject's aorta, the stent anchors itself within the aorta by at least the ends of the stent body (and, typically, the entire stent body) expanding such as to contact the inner wall of the aorta. Furthermore, the stent is typically configured such that, upon being deployed in its expanded configuration inside the subject's aorta, the stent maintains electrodes 22 in contact with the aortic site, and the stent maintains antenna 28 in an open configuration, as described in further detail hereinbelow.
Stent 20 is typically configured to be placed inside the blood vessel (e.g., the aorta) percutaneously (e.g., transfemorally) using a delivery system, e.g., using a 12 Fr-20 Fr catheter (e.g., a 16 Fr catheter). In order to facilitate the percutaneous placement of the stent into the blood vessel (e.g., the aorta), using the catheter, the stent is crimped. Typically, the stent has a crimped profile of less than 20 Fr (e.g., 18 Fr or less), and/or more than 8 Fr (e.g., 10 Fr or more). Typically, stent 20 defines coupling elements 31 at a proximal end of the stent. For some applications, the coupling elements are disposed at a location along the length of the stent other than the proximal end of the stent. During insertion of the stent via the catheter, the delivery system holds the stent in place with respect to the catheter using the coupling elements. In order to place the stent inside the blood vessel at a deployment location, the catheter is retracted at the deployment location, such that the stent is released from the catheter. The stent becomes anchored to the blood vessel via radial expansion of the stent against the inner wall of the blood vessel. Subsequently, the coupling elements are decoupled from the delivery system, and the catheter is withdrawn from the blood vessel.
For some applications, upon being placed inside the blood vessel, the stent is partially deployed by retracting the catheter with respect to the stent, such that (a) electrodes 22 contact the wall of the blood vessel at a given location within the blood vessel, and (b) a proximal portion of the stent is disposed inside the catheter, such that the stent may be retrieved into the catheter. For some applications, the response of the subject to electrical stimulation of the blood vessel at the current location of the electrodes within the blood vessel is determined. In response thereto, the stent is (a) fully deployed at the current location of the stent, (b) retrieved into the catheter and redeployed at a different location within the blood vessel, or (c) retrieved into the catheter and removed from the subject's body (e.g., if the subject does not respond in a suitable manner to electrical stimulation of the blood vessel at any location at which the stent is deployed). Alternatively or additionally, prior to stent 20 being placed inside the blood vessel (e.g., inside the aorta), a mapping device is placed inside the blood vessel, the mapping device including stimulation electrodes. The subject's blood vessel is electrically stimulated at a plurality of stimulation sites using the stimulation electrodes of the mapping device, and the subject's response to electrical simulation at respective sites within the blood vessel is monitored. Subsequently, the mapping device is retrieved from the blood vessel, and stent 20 is placed inside the blood vessel. The location at which to deploy stent 20 within the blood vessel is determined, in response to the monitoring of the subject's responses to the stimulation at the respective sites using the mapping device.
Typically, the compliance of stent 20 is such that pulsation of the blood vessel is substantially maintained upon the stent being deployed inside the blood vessel. Further typically, the stent and components coupled thereto (such as control capsule 30) are shaped such as to substantially maintain blood flow through the blood vessel upon deployment of the stent inside the blood vessel.
As shown in
Typically, at least one electrode 22 is configured to be coupled to stent 20. For some applications, electrode 22 is coiled and is coupled to stent 20 by being placed upon an electrode post 42 that protrudes from the body of stent 20. The electrode is typically disposed on an electrode construction that is configured such that, when the electrode construction is placed on the electrode post, electrode 22 is electrically isolated from the antenna and from the stent body, for example as described with reference to FIGS. 8A-B of US 2014/0180391 to Dagan, which is incorporated herein by reference. For some applications, electrode post 42 is shaped to define protrusions 44, such as to prevent the electrode construction from sliding toward the stent body, when the electrode construction is coupled to the electrode post. Typically, at least 2 electrodes (e.g., at least 3 electrodes), and/or less than 12 electrodes (e.g., less than 6 electrodes) are coupled to stent 20, respective electrodes being placed upon respective electrode posts that protrude from the stent body. For example, 3-5 electrodes (e.g., 4 electrodes) may be coupled to stent 20, respective electrodes being placed upon respective electrode posts that protrude from the stent body.
Typically, antenna 28 is made of a metal wire, e.g., a gold wire. In order for transmitter 26 to communicate with antenna 28 via inductive coupling, it is typically desirable that the antenna become fully expanded inside the blood vessel, such that the antenna is in contact with the inner wall of the blood vessel. For some applications, in order to facilitate expansion of the antenna inside the subject's blood vessel, nitinol wire 29 is coupled to the gold wire, and the nitinol wire is shape set in a desired expanded configuration of the antenna. The distal end of the delivery catheter that is used to deliver stent 20 is retracted at the deployment location of the stent, as described hereinabove. The retraction of the delivery catheter causes the nitinol wire to self-expand inside the subject's blood vessel, and due to the coupling of the nitinol wire to the gold wire, the nitinol wire causes the antenna to expand into the desired expanded configuration (e.g., such that the antenna is in contact with the inner wall of the blood vessel). Typically, the antenna includes a plurality of turns of the gold wire. For example, the antenna may include more than 2 turns, and/or less than 12 turns, e.g. 2-12 turns or 2-6 turns. For some applications, the antenna includes 6 turns of the gold wire, the six turns of wire being separated into 3 levels that are separated from another, as shown. For some applications, the antenna wires are shaped in a waved configuration, as shown.
Antenna 28 and nitinol wire 29 are typically coupled to stent 20 by being sutured to antenna posts 46, which protrude from the stent body of stent 20 separately from electrode posts 42. As described hereinabove, for some applications, antenna 28 is used to receive electrical power for powering the control circuitry 32 of control capsule 30 to drive a current via electrodes 22. Typically, the antenna receives power via inductive coupling, e.g., by transmitter 26 (shown in
As described hereinabove, stent 20 defines electrode posts 42, which are separate from antenna posts 46. The electrode posts and the antenna posts are configured such as to provide a longitudinal separation between the electrodes and the antenna. In this manner, electrical interference between the antenna and the electrodes is reduced relative to if, for example, the electrodes were to be placed upon the antenna posts.
Typically, antenna 28 is wiredly coupled to control circuitry 32 of control capsule 30 (wires shown in
Reference is now made to
As shown in the enlarged portion on the top right of
For some applications, at least one of struts of ring 67 of struts (which is the ring of struts that is closest to antenna posts 46) includes a widened flat surface that is wider than most of struts of strut ring 67. For example, as shown in
Reference is now made to
Reference is now made to
As described hereinabove, and as shown in
Typically, the width of most of the struts belonging to strut ring 66 is more than 150 micrometers, and/or less than 300 micrometers, e.g., 150-300 micrometers. Typically, the width of flat surface 132 is at least 300 micrometers (e.g. greater than 350 micrometers), and the diameter of each of electrode wires 150 and 152 is less than 150 micrometers. Thus, flat surface 132 is typically able to accommodate both wire 150 and wire 152 being fastened, alongside one another, directly against surface 132. By fastening the wires to the inner surface of the stent alongside one another, the radial diameter to which the stent may be constrained during insertion may be reduced relative to if, for example, wire 150 were to be fastened directly against the inner surface of the stent, and wire 152 were to be placed over wire 150 and fastened to wire 150, such that wire 150 separates between wire 152 and the inner surface of the stent. Furthermore, by accommodating wires 150 and 152 being fastened, alongside one another, directly against surface 132, surface 132 is configured to reduce the likelihood of either of the wires being squeezed between a gap between two of the stent struts, when the stent is radially constrained during insertion of the stent, relative to if surface 132 were unable to accommodate the two wires in the aforementioned manner.
For some applications, a third electrode wire 158 couples a third electrode to the control circuitry of the control capsule. As described hereinabove, struts 160 and 162 are wider than most of the struts belonging to strut ring 66, and define flat surfaces 134, that each have a width that is greater than the width of each of flat surfaces 132. Typically, the width of flat surface 134 is at least 400 micrometers (e.g., greater than 450 micrometers), and the diameter of each of electrode wires 150, 152 and 158 is less than 150 micrometers. (It is noted that the wires are not drawn to scale in
For some applications, antenna 28 is coupled to control circuitry of the control capsule via an antenna wire 166. As described hereinabove, and as shown in
As described with reference to
As described hereinabove, typically first, second, and third electrodes are coupled to control circuitry of the control capsule via electrode wires 150, 152 and 158, respectively. For some applications, a fourth electrode is coupled to the control circuitry via a fourth electrode wire 172, the fourth electrode wire typically having the same diameter as wire 150, 152, and 158. Typically, widened flat surface 140 accommodates antenna wire in addition to at least one of (e.g., between one and four of) electrode wires 150, 152, 158 and 172 being fastened, alongside one another, directly against surface 140. Typically, the width of widened flat surface 140 is at least 500 micrometers (e.g., more than 550 micrometers). Further typically, the diameter of each of electrode wires 150, 152, 158, and 172 is less than 150 micrometers mm, and the diameter of antenna wire is less than 400 micrometers.
Referring again to
Reference is now made to
Antenna 26 is typically placed with respect to the subject (e.g., subcutaneously implanted within the subject, or placed outside the subject's skin) such that the antenna extends at least from above a left clavicle 182 of the subject to below a jugular notch 184 of the subject and from below the subject's jugular notch to above a right clavicle 186 of the subject. For some applications, antenna 26 circumscribes the subject's neck, as shown in
A computer simulation was conducted by the inventors of the present application. Data were collected from CT images of 30 heart failure patients, of whom 28 patients had a CT resolution sufficient for data analysis. The heights and body-mass indices of each of the patients were recorded. CT measurements from the 28 heart failure patients were analyzed to determine, for each of the patients, if a first antenna were to be placed in the patient's aorta in the manner described herein with respect to antenna 28, and a second antenna were to be placed on the subject's upper body, in the manner described herein with reference to antenna 26, what would be (a) the height offset between the wire coils of the two antennas, (b) what would be the effective sagittal angle between the wire coils of the two antennas, and (c) what would be the effective transverse angle between the wire coils of the two antennas. In addition, for each of the patients, a coupling coefficient between the two antennas was measured using a geometrical phantom and using a Virtual Network Analyzer (VNA, Omicron BODE 100).
Typically, a wire coil through which an electrical current is driven generates magnetic flux lines that extend axially through the center of the coil perpendicularly to a plane defined by a 2D projection of the coil. As used herein, the effective sagittal angle is the angle, in the sagittal plane, between the planes defined by the effective 2D projections of antennas, perpendicular to which the magnetic flux lines generated by the respective antennas extend axially through the antennas. The plane defined by the effective 2D projection of antenna 26, perpendicular to which the magnetic flux lines generated by antenna 26 is indicated by dashed line 192, in
As stated hereinabove, for each of the patients, a coupling coefficient between the two antennas was measured. The coupling coefficient was determined using antennas having the following characteristics:
Aortic antenna (corresponding to antenna 28): A gold coil having 6 turns, the coil defining a diameter of 26 mm, and having an inductance of 1.75 micro-henries, and being disposed at an offset of 40 degrees from the horizontal in the sagittal plane.
Upper body antenna (corresponding to antenna 26): A wire coil made of 3 turns of 26 AWG copper wire, the coil having an inductance of 6.85 micro-henries, and defining a major axis of 22 cm, and a minor axis of 19 cm (the major and minor axes being as defined hereinbelow with reference to
The coupling coefficient was defined as:
coupling coefficient=(V28/V26)*√(L26/L28)
where V28 and V26 are the voltage gains of antenna 28 and 26, respectively, and L28 and L26 are the inductances of antenna 28 and 26, respectively.
In general, the inventors have found that it is typically the case that, in order for antennas 28 and 26 to communicate effectively through tissue of the subject's upper body, a coupling coefficient of greater than 0.004 is desirable. In the above described experiment, it was found that for the 28 patients, the mean coupling coefficient was 0.0109, with a standard deviation of 0.00136. The maximum coupling coefficient was 0.01515, and the minimum was 0.00857.
In addition to determining the coupling coefficients of the antennas for each of the patients, the correlation between the coupling coefficient and a number of parameters was determined. There was a negative correlation between the effective sagittal angular offset between the two antennas, and the coupling coefficient (i.e., as the angle alpha increased, the coupling coefficient decreased). Similarly, there was a negative correlation between the height offset between the two antennas, and the coupling coefficient (i.e., as the angle alpha increased, the coupling coefficient decreased). There was determined to be substantially no correlation between the coupling coefficients of the antennas and any of the following factors: (a) the patients' heights, (b) the patients' body-mass indices, and (c) the effective transverse angle between the coils of the two antennas.
As described hereinabove, typically antenna 28 and antenna 26 are configured to transmit electrical energy between one another via inductive coupling. In general, when a first and a second coil communicate via induction, other factors being equal, the coupling coefficient between first and second coils is maximized when the magnetic flux lines that are generated by the first coil are aligned with the magnetic flux lines defined by the second coil. Typically, this is the case when the effective angle between the two coils is zero. The coupling coefficient between first and second coils is zero when the magnetic flux lines that are generated by the first coil are at 90 degrees with respect to with the magnetic flux lines defined by the second coil. By placing antenna 26 upon the subject in the above-described manner, the effective sagittal angle alpha between antenna 26 and antenna 28 is typically between 20 and 70 degrees, e.g., between 30 and 60 degrees. Based upon the above described computer simulation that was conducted by the inventors of the present application, when antenna 28 and antenna 26 are disposed with respect to one another in this configuration, the coupling coefficient between the two antennas is typically at least greater than 0.004, and is typically greater than 0.008. Therefore, the antennas are able to transfer electrical energy via inductive coupling, when the antennas are disposed with respect to one another in the configurations described herein.
Reference is now made to
Typically, the length of each of elongate portions 204 (i.e., the length measured along coil 200 from dashed line 207 to bifurcation 206) is greater than 15 cm (e.g., greater than 20 cm), and/or less than 40 cm (e.g., less than 30 cm), e.g., 15-40 cm, or 20-30 cm. Further typically, the length of curved portion 208 (i.e., the length measured along the along the wire from the first of dashed lines 207 to the second of dashed lines 207) is greater than 15 cm (e.g., greater than 20 cm), and/or less than 40 cm (e.g., less than 30 cm), e.g., 15-40 cm, or 20-30 cm.
With reference to
Although
Reference is now made to
Typically, a length L3 of each of elongate portions 214 (i.e., the length measured along coil 210 from where the coil loops until bifurcation 216) is greater than 15 cm (e.g., greater than 20 cm), and/or less than 40 cm (e.g., less than 30 cm), e.g., 15-40 cm, or 20-30 cm.
As described hereinabove, with reference to
Reference is now made to
For some applications, each of the turns of coil 200 of antenna 26 is electrically coupled to a respective capacitor 222. For example, as shown in
Reference is now made to
As shown schematically in
During a subsequent time period, the capacitor of the control circuitry charges, using the power that was transmitted to antenna 28 during the previous time period. During this time period, there is no transmission of power from transmitter 26 to antenna 28. This type of period, during which the capacitor charges, and power is not transmitted from the transmitter to the antenna, is denoted period type 2, as indicated by the box with the “2” inside at the top of the graph.
For some applications, for the duration of the stimulation of the blood vessel by control circuitry 32, the charge-discharge cycle of the capacitor, and the cycle of transmission of power from transmitter 26 to antenna 28 alternates between period types 1 and 2, as illustrated in
For some applications, the techniques described with reference to
It is noted that in the context of the present application, the term coil is used to denote a conductive wire that defines one or more turns that form one or more complete closed loops. The term coil should not be interpreted to be limited to any particular shape.
It is noted that, although some applications of the present invention have been described as being used in conjunction with a stent, the scope of the present invention includes applying the apparatus and methods described herein to a stent graft, mutatis mutandis. For example, an antenna may be coupled to the body of a stent graft via posts that longitudinally separate the antenna from a distal end of the body of the stent graft, in accordance with the techniques described hereinabove. It is further noted that the term “stent” as used in the present application should not be interpreted as being limited to a device that is configured to hold open a bodily lumen. Rather the term “stent” as used herein should be interpreted as being interchangeable with the term “scaffold,” the term denoting a device that is configured to support elements inside a bodily lumen, e.g., a blood vessel, such as the aorta.
It is noted that although some applications of the present invention have been described as being used in conjunction with a stent that is placed inside a subject's aorta, the scope of the present invention includes applying the apparatus and methods described herein to a stent that is placed inside a different blood vessel, mutatis mutandis. For example, a stent as described herein may be placed in the abdominal aorta, the vena cava, veins of the leg, the pulmonary artery, the pulmonary vein, the jugular vein, a carotid artery, the subclavian artery, a hepatic vein, a hepatic artery, a renal vein, a renal artery, a femoral vein, a femoral artery, and/or a different blood vessel of a subject, and techniques as described herein may be practiced using such a stent. Similarly, although the stent is shown at least partially disposed in the descending aorta, the scope of the present invention includes placing the stent at any location within the aorta, such as in the ascending aorta, the descending aorta, the aortic arch, or a combination thereof.
For example, the stent may be used to stimulate a neural pathway by driving a current into the wall of the blood vessel in which the stent is implanted, in accordance with the techniques described herein. Alternatively or additionally, the stent may be placed in the renal artery, in order to treat renal dysfunction, and/or in the pulmonary artery, in order to treat pulmonary hypertension. Further alternatively or additionally, the stent may be placed in the pulmonary artery and/or the carotid artery in order to be used for vagal stimulation (e.g., vasovagal stimulation), for example, in order to treat gastroesophageal reflux disease (GERD).
For some applications, the subject's cardiac cycle is determined by detecting an electrical signal from the subject's aorta, via electrodes 22, and deriving the subject's ECG and/or blood pressure from the electrical signal detected at the aorta, e.g., in accordance with techniques described in U.S. Ser. No. 12/792,227 to Gross (published as US 2010/0305392). For some applications, physiological parameters of the subject (such as the subject's cardiac cycle) are detecting using antenna 28, for example using techniques as described in US 2014/0180391 to Dagan, which is incorporated herein by reference. For some applications, electrical stimulation is applied to the aorta in coordination with the subject's cardiac cycle, based upon the signal detected at the aorta.
For some applications, in response to detecting that a subject is undergoing an epileptic seizure, the subject's vagus nerve is stimulated by driving a current into the subject's aorta. For some applications, a current is driven into the subject's aorta in order to treat the subject for sleep apnea.
For some applications, the techniques described herein are practiced in combination with techniques described in any one of the following applications:
International Application PCT/IL2014/050972 to Dagan (published as WO 15/068167), filed Nov. 6, 2014, entitled “Wireless endovascular stent-based electrodes,” which claims priority from U.S. Provisional Patent Application 61/900,461 to Dagan, entitled “Wireless endovascular stent-based electrodes,” filed Nov. 6, 2013;
International Application PCT/IL2013/050375 (published as WO 13/164829), filed May 2, 2013, entitled “Wireless endovascular stent-based electrodes,” which claims priority from the following US provisional patent applications:
U.S. Ser. No. 13/741,154 to Dagan (published as 2014/0180391), which is the US national phase of International Application PCT/IL2012/000336 (published as WO 13/035092), filed Sep. 9, 2012, entitled “Wireless endovascular stent-based electrodes,” which claims priority from U.S. Provisional Patent Application 61/532,660 to Dagan, filed Sep. 9, 2011, entitled, “Wireless endovascular stent-based electrodes;”
U.S. Ser. No. 13/210,778 to Dagan (issued as U.S. Pat. No. 8,626,290), filed Aug. 16, 2011, which is a continuation-in-part of U.S. Ser. No. 12/957,799 to Gross (issued as U.S. Pat. No. 8,626,299), filed Dec. 1, 2010, entitled “Thoracic aorta and vagus nerve stimulation,” which is a continuation-in-part of U.S. Ser. No. 12/792,227 to Gross (published as US 2010/0305392), filed Jun. 2, 2010, entitled “Thoracic aorta and vagus nerve stimulation,” which claims the benefit of (a) U.S. Provisional Patent Application 61/183,319 to Reisner, filed Jun. 2, 2009, entitled “Thoracic aorta and vagus nerve stimulation,” and (b) U.S. Provisional Patent Application 61/331,453 to Dagan, filed May 5, 2010, entitled “Thoracic aorta and vagus nerve stimulation;”
U.S. Ser. No. 12/023,896 to Gross (issued as U.S. Pat. No. 9,005,106), filed Jan. 31, 2008, entitled “Intra-aortic electrical counterpulsation;” and
U.S. Ser. No. 11/995,904 to Gross (issued as U.S. Pat. No. 8,862,243), which is the US national phase of International Application PCT/IL2006/000856 to Gross (published as WO 07/013065), filed Jul. 25, 2006, entitled “Electrical stimulation of blood vessels,” which claims priority from: (a) U.S. Provisional Application 60/702,491, filed Jul. 25, 2005, entitled, “Electrical stimulation of blood vessels,” and (b) U.S. Provisional Application 60/721,728, filed Sep. 28, 2005, entitled, “Electrical stimulation of blood vessels.”
All of the above-referenced applications are incorporated herein by reference.
It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described hereinabove. Rather, the scope of the present invention includes both combinations and subcombinations of the various features described hereinabove, as well as variations and modifications thereof that are not in the prior art, which would occur to persons skilled in the art upon reading the foregoing description.
The present application claims priority from U.S. Provisional Patent Application 62/140,141 to Dagan, filed Mar. 30, 2015, entitled “Antenna for use with an intravascular device.” The above-referenced application is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 62140141 | Mar 2015 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 15562467 | Sep 2017 | US |
| Child | 17149904 | US |
