INTERVENTIONAL MEDICAL SYSTEMS, CATHETERS, AND METHODS

• US 20170095662A1
• Filed: 10/01/2015
• Published: 04/06/2017
• Est. Priority Date: 10/01/2015
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Geraghty, Brendan P., Francis, Gwenda, McDonnell, Paula, Wood, Rnn, Ward, Sean, McHugh, Pat, Kelly, Tomas K.
• Granted Patent: US 10,758,729 B2
• Time in Patent Office: Days
• CPC Class Codes: A61N 1/057 Anchoring means; Means for fixing the head inside the heart
• CPC Class Codes: A61N 1/0573 chacterised by means penetrating the heart tissue, e.g. helix needle or hook
• CPC Class Codes: A61N 1/362 Heart stimulators heart defibrillators A61N1/39
• CPC Class Codes: A61N 1/37205 Microstimulators, e.g. implantable through a cannula
• CPC Class Codes: A61N 1/3756 Casings with electrodes thereon, e.g. leadless stimulators
• CPC Class Codes: A61N 2001/0578 having means for removal or extraction
• CPC Class Codes: A61N 2001/058 Fixing tools

Abstract

In a system for retrieving an implanted device, a flared inner surface of a catheter tubular sidewall may define a distal-most opening of a device receptacle; the opening has a first diameter equal to that of the receptacle, and a second diameter, coincident with a distal-most edge of the tubular sidewall, and at least 5% greater than the receptacle diameter. Alternately, a retrieval tool in sliding engagement within a lumen of a catheter includes a shaft assembly, through which a snare member passes, and which includes a collapsible spring-biased perimeter sidewall; the sidewall defines a capture member passageway approximately coaxial, and in fluid communication with a lumen of the shaft assembly. A distal-most opening of the passageway has a spring-biased diameter that is greater than that of a distal-most opening of a device receptacle of the catheter, and a collapsed diameter that is less than the receptacle distal-most opening diameter.

Claims

1. An interventional medical system comprising an implantable medical device, a catheter, and a retrieval tool;

the medical device comprising an electronic controller, a hermetically sealed housing containing the controller, an electrode electrically coupled to the controller and mounted in proximity to a distal end of the housing, an attachment feature joined to a proximal end of the housing, and a fixation member mounted to the distal end of the housing;

the catheter comprising an elongate shaft and a device receptacle joined to a distal end of the shaft, the shaft including a longitudinally extending lumen, and the device receptacle being sized to contain the medical device therein and having a distal-most opening that allows passage of the medical device therethrough, and the device receptacle being in fluid communication with the shaft lumen; and

the retrieval tool comprising an elongate snare member and a shaft assembly, the shaft assembly comprising an elongate tubular sidewall that defines a lumen configured to receive passage of the snare member therethrough, the elongate tubular sidewall configured for sliding engagement within the lumen of the catheter shaft; and

wherein the shaft assembly of the retrieval tool further comprises;

a capture member comprising a collapsible spring-biased perimeter sidewall, the perimeter sidewall defining a passageway that is approximately coaxial, and in fluid communication with the lumen of the tubular sidewall of the retrieval tool shaft assembly, the perimeter sidewall extending from a proximal end thereof to a distal end thereof, the proximal end being coupled to the tubular sidewall of the shaft assembly, and the distal end defining a distal-most opening of the passageway; and

wherein the distal-most opening of the capture member passageway has a spring-biased diameter that is greater than a diameter of the distal-most opening of the device receptacle of the catheter;

the distal-most opening of the capture member passageway has a collapsed diameter that is less than the diameter of the device receptacle distal-most opening, when the capture member is received within the device receptacle; and

the capture member passageway is sized to contain the attachment member of the medical device and the proximal end of the medical device housing.

2. The system of claim 1, wherein:

the collapsible spring-biased perimeter sidewall of the capture member of the retrieval tool shaft assembly defines a flared outer surface of the capture member, when the distal-most opening of the passageway defined thereby is at the spring-biased diameter; and

a length of the capture member passageway is approximately equal to an overall length of the medical device.

3. The system of claim 2, wherein the collapsible spring-biased perimeter sidewall comprises a flexible polymer mesh supported by a plurality of spring-biased ribs, a proximal end of each rib defining the proximal end of the perimeter sidewall, and the rib proximal ends being spaced apart from one another around a circumference of the tubular sidewall of the retrieval tool shaft assembly.

4. The system of claim 1, wherein:

the spring-biased diameter of the distal-most opening of the capture member passageway of the retrieval tool shaft assembly is 2 to 5 times greater than the diameter of the distal-most opening of the device receptacle of the catheter; and

the collapsible spring-biased perimeter sidewall of the capture member comprises a flexible polymer mesh supported by a plurality of spring-biased ribs, a proximal end of each rib defining the proximal end of the perimeter sidewall, and the rib proximal ends being spaced apart from one another around a circumference of the tubular sidewall of the retrieval tool shaft assembly.

5. The system of claim 4, further comprising:

a vacuum source adapted for coupling to the retrieval tool shaft assembly, so that suction can be applied through the lumen defined by the tubular sidewall and through the capture member passageway of the retrieval tool shaft assembly; and

wherein a length of the capture member passageway is approximately equal to an overall length of the medical device.

6. The system of claim 1, wherein:

the tubular sidewall of the retrieval tool shaft assembly includes a flared distal end; and

the collapsible spring-biased perimeter sidewall of the capture member comprises a ‘

serpentined’

wire loop mounted to the flared distal end of the shaft assembly tubular sidewall.

7. The system of claim 6, wherein:

the retrieval tool shaft assembly further comprises a pair of elongate tethers extending along a length of the tubular sidewall thereof and on opposite sides of the lumen defined by the sidewall; and

the proximal end of the collapsible spring-biased perimeter sidewall is coupled to the shaft assembly tubular sidewall by the pair of elongate tethers.

8. The system of claim 1, wherein the retrieval tool shaft assembly further comprises a steering subassembly;

and wherein the steering subassembly comprises an elongate pull wire, a pull band, and an actuator, the pull wire extending along a length of the tubular sidewall of the shaft assembly from a proximal end of the wire to a distal end of the wire, the pull band being mounted to a distal end of the tubular sidewall of the shaft assembly, in proximity to the capture member, and being coupled to the distal end of the pull wire, and the actuator being mounted to a handle of the retrieval tool and being coupled to the proximal end of the pull wire.

9. An assembly comprising a snare member and a shaft subassembly, the shaft subassembly comprising a tubular sidewall that defines a lumen configured to receive passage of the snare member therethrough, the tubular sidewall having a flared distal end defining a distal-most opening of the lumen, and the tubular sidewall being configured for sliding engagement within a catheter of an interventional medical system, the catheter including an elongate shaft and a device receptacle coupled to a distal end of the shaft, the device receptacle being in fluid communication with a lumen of the catheter shaft, and being sized to contain an implantable medical device therein, the device receptacle having a distal-most opening that allows passage of the medical device therethrough;

and wherein the shaft subassembly of the assembly further comprises;

a capture member comprising a collapsible spring-biased perimeter sidewall formed by a ‘

serpentined’

wire loop mounted to the flared distal end of the tubular sidewall, the perimeter sidewall defining a passageway, the passageway being approximately coaxial, and in fluid communication with the lumen of the tubular sidewall; and

wherein the passageway has a spring-biased diameter that is greater than a diameter of the device receptacle of the catheter, and has a collapsed diameter that is less than the diameter of the device receptacle, when the capture member is received within the device receptacle; and

the capture member passageway is sized to contain a proximal end of a housing of the medical device and an attachment member of the medical device that is coupled to the proximal end of the housing.

10. The assembly of claim 9, wherein:

the shaft subassembly further comprises a pair of elongate tethers extending along a length of the tubular sidewall thereof and on opposite sides of the lumen defined by the sidewall; and

the collapsible spring-biased perimeter sidewall of the capture member is coupled to the tubular sidewall by the pair of elongate tethers.

11. The assembly of claim 10, wherein the shaft subassembly further comprises a handle coupled to the proximal end of the tubular sidewall, the handle including a clamping member through which the pair of elongate tethers extend, the clamping member configured to alternately secure and release the tethers.

12. A method for converting a catheter from a first configuration to a second configuration, the first configuration suitable for deploying an implantable medical device to an implant site, and the second configuration suitable for retrieving an implantable medical device from an implant site;

and the method comprising;

removing a device tether from first and second lumens of an inner assembly of the catheter, the first and second lumens being defined by a tubular sidewall of the inner assembly;

mounting a capture member to a flared distal end of a tubular sidewall of the inner assembly by inserting a pair of capture member tethers into the first and second lumens, after removing the device tether therefrom, the flared distal end defining a distal-most opening for the first and second lumens and for a snare lumen defined by the tubular sidewall;

collapsing a spring-biased sidewall of the mounted capture member within a device receptacle of the catheter, the device receptacle being coupled to a distal end of a shaft of an outer assembly of the catheter, the device receptacle being in fluid communication with a lumen of the shaft and having a distal-most opening that allows passage of a medical device therethrough, and the inner assembly being slideably engaged within the lumen of the outer assembly shaft; and

inserting a snare member through the snare lumen of the inner assembly.

13. The method of claim 12, further comprising securing a proximal end of each of the capture member tethers within a clamping member of a handle of the catheter, after mounting the capture member to the inner assembly, the handle being coupled to a proximal end of the inner assembly tubular sidewall and to the outer assembly shaft.

14. A method for retrieving an implantable medical device from an implant site, the medical device comprising a hermetically sealed housing, an electrode mounted in proximity to a distal end of the housing, an attachment feature joined to a proximal end of the housing, and a fixation member mounted to the distal end of the housing, the fixation member comprising a plurality of fingers spaced apart from one another around a perimeter of the distal end of the housing, each finger being elastically deformable between a relaxed condition and an extended condition, a free end of each finger extending distally away from the distal end of the device housing, when the finger is in the extended condition, and the method comprising:

advancing a device receptacle of a catheter of an interventional medical system to the implant site so that a distal-most opening of the device receptacle is located in proximity to the medical device, the device receptacle being coupled to a distal end of a shaft of the catheter, the device receptacle being in fluid communication with a lumen of the shaft and having a distal-most opening that allows passage of the medical device therethrough;

snaring the attachment feature of the medical device with a snare member of a retrieval tool, the retrieval tool being in sliding engagement within the lumen of the catheter shaft, and the snare member being in sliding engagement within a lumen of a shaft assembly of the tool;

causing a spring-biased sidewall of a capture member of the retrieval tool shaft assembly to open to a spring-biased diameter, the spring-biased sidewall defining a passageway in fluid communication and approximately coaxial with the lumen of the shaft assembly of the tool;

advancing the capture member of the retrieval tool shaft assembly, with the spring-biased sidewall opened to the spring-biased diameter, over the snared device attachment feature and the proximal end of the device housing;

applying a pull force, after advancing the capture member over the snared device attachment feature and the proximal end of the device housing, to disengage the device fixation member from the implant site; and

advancing the device receptacle over the advanced capture member and the disengaged device to contain the capture member and the device in the receptacle so that the fingers of the device fixation member are held in the extended condition by the receptacle.

15. The method of claim 14, further comprising advancing the device receptacle of the catheter over the snared device with the capture member advanced thereover, prior to applying the pull force.

16. The method of claim 15, wherein the device receptacle of the catheter is advanced over the snared device until the distal-most opening thereof abuts the implant site.

17. The method of claim 14, further comprising deflecting the shaft assembly of the retrieval tool after snaring the device attachment feature and prior to advancing the device receptacle of the catheter over the snared device.

18. The method of claim 14, wherein the capture member of the retrieval tool is advanced over the snared device until a distal end of the spring-biased sidewall thereof abuts the implant site;

and further comprising applying a suction force through the lumen of the retrieval tool shaft assembly while applying the pull force.

19. An interventional medical system comprising an implantable medical device, a device retrieval tool, and a catheter;

the medical device comprising a hermetically sealed housing, an electrode mounted in proximity to a distal end of the housing, an attachment feature joined to a proximal end of the housing, and a fixation member mounted to the distal end of the housing, the fixation member comprising a plurality of fingers spaced apart from one another around a perimeter of the distal end of the housing, each finger being elastically deformable between a relaxed condition and an extended condition, a free end of each finger extending distally away from the distal end of the device housing, when the finger is in the extended condition;

the device retrieval tool configured to snare the attachment feature of the medical device; and

the catheter comprising an elongate shaft and tubular sidewall that defines a device receptacle, the tubular sidewall being joined to a distal end of the shaft, the shaft including a longitudinally extending lumen configured to receive passage of the device retrieval tool therethrough, the device receptacle being in fluid communication with the shaft lumen, the receptacle having a length and a diameter uniform along the length, to hold the fingers of the device fixation member in the extended condition when the medical device is contained therein; and

wherein an improvement to the tubular sidewall of the catheter comprises;

a flared inner surface defining a distal-most opening into the receptacle, the opening having a first diameter and a second diameter, the first diameter being equal to the diameter of the receptacle and the second diameter being at least 5% greater than the diameter of the receptacle, the second diameter being coincident with a distal-most edge of the tubular sidewall; and

wherein a length of the flared inner surface is between 0.003 inch and 0.005 inch.

20. The system of claim 19, wherein the improvement further comprises a radiopaque filler blended into the tubular sidewall along the length of the flared inner surface.