Flexible Electronic Circuit for an Ultrasonic Catheter

Abstract

A flexible electronic circuit that may be used in an intravascular catheter includes a flexible substrate having opposing first and second surfaces, one or more recesses in the first surface, one or more localization elements disposed within the recesses, and conductive connector pads on the substrate. Additional components, such as a thermistor or ultrasound transducer, may also be attached to the substrate.

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims the benefit of U.S. Provisional Application No. 63 / 157,232, filed Mar. 5, 2021, which is hereby incorporated herein by reference in its entirety as if fully set forth herein.

[0002] The present disclosure generally relates to catheters for use in the human body. In particular, the present disclosure relates to intravascular catheters and, for example, small form factor flexible electronic circuits suitable for incorporation within the tip of such catheters.

Background Art

[0003] Catheters are being used in an increasing number of procedures. For example, catheters are used in procedures such as, to name a few, diagnosis, treatment, ablation, etc. Typically, a catheter is maneuvered through a patient's vasculature to a site of interest, such as a site within the patient's heart.

Summary of the Invention

Problems to be Solved by the Invention

[0004] It is known to incorporate various electronic components within the tip of an intravascular catheter. For example, as disclosed in U.S. Patent Application Publication No. 2018 / 0289356 and U.S. Provisional Application No. 62 / 987,574, which are hereby incorporated herein by reference in their entirety as if fully set forth herein, piezoelectric ultrasonic transducers and support electronic circuit packages (e.g., implemented as application - specific integrated circuits (ASICs) or field - programmable gate arrays (FPGAs)) may be mounted within the tip of an intracardiac echocardiogram (ICE) catheter. However, since the size of such components is relatively small, the complexity of manufacturing and thus the cost increase.

Means for Solving the Problems

[0005] Disclosed herein is a flexible substrate having a first surface and a second surface facing the first surface, the flexible substrate having a recess in the first surface, a positioning element disposed within the recess, and a conductive connector pad disposed on the flexible substrate, which constitutes a flexible electronic circuit.

[0006] The flexible substrate may comprise a first portion having a first thickness and a second portion having a second thickness thinner than the first thickness. The recess may be located within the first portion of the flexible substrate, and the conductive connector pad may be disposed on the second portion of the flexible substrate.

[0007] The positioning element may comprise a magnetic positioning element and / or an impedance-based positioning element.

[0008] In an embodiment of the present disclosure, there are a plurality of recesses and a corresponding plurality of positioning elements respectively disposed within the plurality of recesses.

[0009] An aspect of the present disclosure also includes a thermistor attached to the substrate, for example, attached within the recess.

[0010] A further aspect of the present disclosure includes an ultrasonic transducer assembly attached to the substrate, for example, attached to the second surface of the substrate.

[0011] A further aspect of the present disclosure includes an adhesive covering at least a portion of the substrate.

[0012] This specification also discloses a tip assembly for an intravascular catheter. The tip assembly includes a shell and a flexible electronic circuit disposed within the shell. The flexible electronic circuit comprises a flexible substrate having a first surface and a second surface facing the first surface, the first surface having a recess, a positioning element disposed within the recess, and a conductive connector pad disposed on the flexible substrate.

[0013] In an embodiment of the distal assembly, the flexible electronic circuit comprises a plurality of recesses and a corresponding plurality of positioning elements respectively disposed within the plurality of recesses. The flexible electronic circuit may also comprise a thermistor and / or an ultrasonic transducer assembly attached to the flexible substrate. The thermistor may be attached within the recess.

[0014] The present disclosure also relates to an intravascular catheter comprising an elongate catheter body terminating at a distal end, a distal assembly fixed to the distal end of the elongate catheter body, and a flexible electronic circuit disposed within the distal assembly. The flexible electronic circuit is a flexible substrate having a first surface and a second surface facing the first surface, the first surface comprising a recess, a positioning element disposed within the recess, and a conductive connector pad disposed on the flexible substrate.

[0015] In an embodiment of the intravascular catheter, the flexible electronic circuit comprises a plurality of recesses and a corresponding plurality of positioning elements respectively disposed within the plurality of recesses. The flexible electronic circuit may also comprise a thermistor and / or an ultrasonic transducer assembly attached to the flexible substrate. The thermistor may be attached within the recess.

[0016] The foregoing and other aspects, features, details, utilities and advantages of the present invention will become apparent by reading the following description and claims and by viewing the accompanying drawings.

Brief Description of the Drawings

[0017]

Figure 1

[0018]

Figure 2

[0019]

Figure 3A

[0020]

Figure 3B

[0021]

Figure 4

[0022] Although multiple embodiments are disclosed, additional embodiments of the present disclosure will become apparent to those skilled in the art from the following detailed description which illustrates and describes exemplary embodiments. Accordingly, the drawings and detailed description are to be regarded as illustrative and not restrictive.

[0023] Aspects of the present disclosure relate to flexible electronic circuits suitable for use in connecting an electronic circuit package incorporated at a distal end of an intravascular catheter (e.g., disposed within a distal tip assembly of such a catheter). Those skilled in the art will understand that the teachings herein are advantageously applicable in connection with various types of catheters including, but not limited to, intracardiac echocardiogram (ICE) catheters.

[0024] For illustrative purposes, FIG. 1 shows a perspective view of a representative catheter 100 comprising a shaft 105 having a proximal portion 110 and a distal portion 190 terminating at a tip portion 195. To the extent that the basic structure of catheter 100 is well known to those skilled in the art, its details are omitted herein except as relevant to understanding the present disclosure.

[0025] FIG. 2 is a schematic view of the interior of the distal portion 190 of catheter 100 including the tip portion 195. The tip portion 195 may comprise a shell 198 and a flexible electronic circuit 200 disposed within the shell 198.

[0026] The flexible electronic circuit 200 includes a flexible substrate 202 and transducer packages (e.g., electronic circuit package 204 and ultrasonic transducer assembly 206) attached to the substrate 202. A wire harness 208 including a plurality of wires interconnects the flexible electronic circuit 200 and an external device such as an electroanatomical mapping system (e.g., the EnSite Precision® Cardiac Mapping System from Abbott Laboratories) or a catheter interface module. Although only three wires are shown in the wire harness 208, this is merely exemplary, and it should be understood that more or fewer wires may be used in the device according to the present teachings.

[0027] Various details of the flexible electronic circuit 200 are shown in FIGS. 3A and 3B. Generally, the substrate 202 includes a first surface (visible in the plane of FIG. 3A) and a second surface opposite the first surface. The thickness of the substrate 202 at any given point is defined between the first surface and the second surface at that point.

[0028] More specifically, as best shown in FIG. 3B, the thickness of the substrate 202 can vary along its length. For example, in an embodiment of the present disclosure, the substrate 202 includes a thicker first portion 304 (e.g., for supporting a positioning element) and a thinner second portion 306 (e.g., for increasing flexibility at the connection point with the wire harness 208). The first and second surfaces 301, 302 respectively define the thickness of the thicker first portion 304 of the substrate 202, and the first and second surfaces 300, 302 respectively define the thickness of the thinner second portion 306 of the substrate 202. It is contemplated that the thicker first portion 304 of the substrate 202 may be formed by bonding one or more additional flexible circuit layers to the first surface 300 to increase the thickness.

[0029] The first surface 301 of the substrate 202 also includes recesses 308 (e.g., trenches or grooves) into the thickness of the substrate 202. Typically, but not necessarily, the recesses 308 are located in the thicker first portion 304 of the substrate 202.

[0030] The recesses 308 facilitate the reliable and accurate positioning of components on the substrate 202. In embodiments of the present disclosure, a pair of positioning elements 310 (e.g., magnetic or impedance-based positioning elements) are mounted to the substrate 202 within a corresponding pair of recesses 308 as part of the electronic circuit package 204. For example, as shown in FIG. 3A, a pair of five-degree-of-freedom (5DOF) magnetic positioning elements 310 mounted at a slight angle to each other within corresponding recesses 308 create a six-degree-of-freedom (6DOF) positioning sensor, as described in U.S. Patent Application Publication No. 2018 / 0289356. Solder pads 312 provide electrical connection to the positioning elements 310.

[0031] One or more conductive connector pads 314 are disposed on the substrate 202. In FIG. 3A, the conductive connector pads 314 are shown only on the first surface 300 of the substrate 202, which is merely illustrative, and those of ordinary skill in the art will understand that the conductive connector pads 314 may be disposed at other locations on the substrate 202 without departing from the scope of the present disclosure.

[0032] The conductive connector pads 314 provide an interconnection point with the wire harness 208. The conductive connector pads 314 are also conductively connected to the positioning elements 310 (e.g., solder pads 312) to exchange signals such as power signals and communication signals, and are further conductively connected to temperature sensing elements, as will be described in more detail below. Since the conductive connection between the attachment point of the wire harness 208 and the flexible circuit component is well known to those of ordinary skill in the art, it need not be further described herein.

[0033] In embodiments of the present disclosure, the flexible electronic circuit 200 may include additional components. For example, FIGS. 3A and 3B illustrate a thermistor 316 attached to a substrate 202. According to aspects of the present disclosure, the thermistor 316 may be attached within an additional recess similar to recess 308. By doing so, not only is it easy to securely and accurately position the thermistor 316, but also, by reducing the thickness of the substrate 202 accordingly and bringing it closer to the ultrasonic transducer assembly 206, a faster thermal response becomes possible. Other components such as a power supply, a preamplifier, a multiplexer, an imaging element driver, additional positioning elements, etc. may also be attached to the substrate 202.

[0034] According to aspects of the present disclosure, an adhesive may be applied to cover at least a portion of the first and / or second surfaces 300, 302 of the substrate 202.

[0035] FIG. 4 shows the flexible electronic circuit 200 with the positioning element 310 and the ultrasonic transducer assembly 206 attached for assembly to the tip portion 195.

[0036] Although some embodiments have been described in some detail above, those skilled in the art will be able to make many changes to the disclosed embodiments without departing from the spirit or scope of the invention.

[0037] For example, instead of using individual wires, the wire harness 208 may utilize one or more long flexible circuits and / or printed circuits.

[0038] All references to directions (e.g., upper, lower, above, below, left, right, leftward, rightward, top, bottom, up, down, vertical, horizontal, clockwise, and counterclockwise) are used for identification purposes only to assist the reader's understanding of the present invention and do not particularly impose limitations on the position, orientation, or use of the present invention. References to connections (e.g., attached, coupled, connected, etc.) should be construed broadly and may include intermediate members between the connections of elements and relative movement between the elements. Therefore, references to connections do not necessarily mean that two elements are directly connected and in a fixed relationship with each other.

[0039] All matters included in the above description or shown in the accompanying drawings are intended to be construed as illustrative only and not limiting. Changes in details or structure may be made without departing from the spirit of the present invention as defined in the appended claims. The following items are elements described in the claims at the time of international filing. (Item 1) A flexible electronic circuit comprising: A flexible substrate having a first surface and a second surface opposite the first surface, the first surface having a recess; A positioning element disposed within the recess; A conductive connector pad disposed on the flexible substrate. (Item 2) The flexible electronic circuit according to Item 1, wherein the flexible substrate comprises a first portion having a first thickness and a second portion having a second thickness thinner than the first thickness. (Item 3) The flexible electronic circuit according to Item 2, wherein the recess is located in the first portion of the flexible substrate. (Item 4) The flexible electronic circuit according to Item 2, wherein the conductive connector pad is disposed on the second portion of the flexible substrate. (Item 5) The flexible electronic circuit according to Item 1, wherein the positioning element comprises a magnetic positioning element. (Item 6) The flexible electronic circuit according to Item 1, wherein the positioning element comprises an impedance-based positioning element. (Item 7) The recess comprises a plurality of recesses, The flexible electronic circuit according to Item 1, wherein the positioning element disposed within the recess comprises a plurality of positioning elements respectively disposed within the plurality of recesses. (Item 8) The flexible electronic circuit according to Item 1, further comprising a thermistor attached to the substrate. (Item 9) The flexible electronic circuit according to Item 8, wherein the thermistor is attached to the flexible substrate within the recess. (Item 10) The flexible electronic circuit according to Item 1, further comprising an ultrasonic transducer assembly attached to the substrate. (Item 11) The flexible electronic circuit according to Item 10, wherein the transducer assembly is attached to the second surface of the substrate. (Item 12) The flexible electronic circuit according to Item 1, further comprising an adhesive covering at least a portion of the substrate. (Item 13) A tip assembly for an intravascular catheter, comprising: A shell; A flexible electronic circuit disposed within the shell, wherein the flexible electronic circuit is A flexible substrate having a first surface and a second surface opposite the first surface, wherein the first surface comprises a recess, and the flexible substrate; A position - specifying element disposed within the recess; A conductive connector pad disposed on the flexible substrate, and a tip assembly comprising the same. (Item 14) The recess comprises a plurality of recesses; The tip assembly according to item 13, wherein the position - specifying element disposed within the recess comprises a plurality of position - specifying elements respectively disposed within the plurality of recesses. (Item 15) The tip assembly according to item 13, further comprising a thermistor attached to the flexible substrate within the recess. (Item 16) The tip assembly according to item 13, further comprising an ultrasonic transducer assembly attached to the second surface of the flexible substrate. (Item 17) An intravascular catheter comprising: An elongated catheter body terminating at a distal end; A tip assembly fixed to the distal end of the elongated catheter body; A flexible electronic circuit disposed within the tip assembly, and the flexible electronic circuit comprises: A flexible substrate having a first surface and a second surface opposite the first surface, wherein the first surface comprises a recess; A position - specifying element disposed within the recess; A conductive connector pad disposed on the flexible substrate, and an intravascular catheter comprising the same. (Item 18) The recess comprises a plurality of recesses; The intravascular catheter according to item 17, wherein the position - specifying element disposed within the recess comprises a plurality of position - specifying elements respectively disposed within the plurality of recesses. (Item 19) The intravascular catheter according to item 17, further comprising a thermistor attached to the flexible substrate within the recess. (Item 20) The intravascular catheter according to item 17, further comprising an ultrasonic transducer assembly attached to the second surface of the flexible substrate. ​

Claims

**Claim 1**: A flexible electronic circuit incorporated into an intravascular catheter, comprising: A flexible substrate having a first surface and a second surface opposite the first surface, wherein the first surface has a recess; and A position-determining element disposed within the recess; and A conductive connector pad disposed on the flexible substrate, The flexible substrate includes a first portion having a first thickness and a second portion having a second thickness thinner than the first thickness, The recess is located in the first portion of the flexible substrate, The conductive connector pad is disposed on the second portion of the flexible substrate. A flexible electronic circuit. **Claim 2**: The flexible electronic circuit according to claim 1, wherein the position-determining element comprises a magnetic position-determining element. **Claim 3**: The flexible electronic circuit according to claim 1, wherein the position-determining element comprises an impedance-based position-determining element. **Claim 4**: The recess includes a plurality of recesses, The flexible electronic circuit according to claim 1, wherein the position-determining element disposed within the recess comprises a plurality of position-determining elements respectively disposed within the plurality of recesses. **Claim 5**: The flexible electronic circuit according to claim 1, further comprising a thermistor attached to the flexible substrate. **Claim 6**: The flexible electronic circuit according to claim 5, wherein the thermistor is attached to the flexible substrate within the recess. **Claim 7**: The flexible electronic circuit according to claim 1, further comprising an ultrasonic transducer assembly attached to the flexible substrate. **Claim 8**: The flexible electronic circuit according to claim 7, wherein the ultrasonic transducer assembly is attached to the second surface of the flexible substrate. **Claim 9**: The flexible electronic circuit according to claim 1, further comprising an adhesive covering at least a portion of the flexible substrate. **Claim 10**: A tip assembly for an intravascular catheter, comprising: A shell; and A flexible electronic circuit disposed within the shell, The flexible electronic circuit is: A flexible substrate having a first surface and a second surface opposite the first surface, wherein the first surface has a recess; and A position-determining element disposed within the recess; a conductive connector pad disposed on the flexible substrate the flexible substrate includes a first portion having a first thickness and a second portion having a second thickness thinner than the first thickness the recess is located in the first portion of the flexible substrate the conductive connector pad is disposed on the second portion of the flexible substrate, the tip assembly

11. the recess includes a plurality of recesses the position specifying element disposed in the recess includes a plurality of position specifying elements respectively disposed in the plurality of recesses, the tip assembly according to claim 10

12. the tip assembly according to claim 10 further includes a thermistor attached to the flexible substrate within the recess

13. the tip assembly according to claim 10 further includes an ultrasonic transducer assembly attached to the second surface of the flexible substrate

14. an intravascular catheter, comprising an elongated catheter body terminating at a distal end a tip assembly fixed to the distal end of the elongated catheter body a flexible electronic circuit disposed within the tip assembly, comprising the flexible electronic circuit a flexible substrate having a first surface and a second surface facing the first surface, the first surface having a recess, the flexible substrate a position specifying element disposed within the recess a conductive connector pad disposed on the flexible substrate, comprising the flexible substrate includes a first portion having a first thickness and a second portion having a second thickness thinner than the first thickness the recess is located in the first portion of the flexible substrate the conductive connector pad is disposed on the second portion of the flexible substrate, the intravascular catheter

15. the recess includes a plurality of recesses the position specifying element disposed in the recess includes a plurality of position specifying elements respectively disposed in the plurality of recesses, the intravascular catheter according to claim 14

16. the intravascular catheter according to claim 14 further includes a thermistor attached to the flexible substrate within the recess

17. The intravascular catheter according to claim 14, further comprising an ultrasonic transducer assembly attached to the second surface of the flexible substrate.

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