Patent ID: 12214206

DETAILED DESCRIPTION

The following detailed description is exemplary in nature and is not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the following description provides practical examples, and those skilled in the art will recognize that some of the examples may have suitable alternatives.

Concepts in this application may be related to commonly assigned U.S. patent application Ser. No. 14/039,937, now U.S. Pat. No. 9,526,522, entitled INTERVENTIONAL MEDICAL SYSTEMS, TOOLS, AND ASSEMBLIES, which is incorporated by reference in its entirety.

With reference toFIG.1, such an implantable medical device100is illustrated, wherein an hermetically sealed housing105, preferably formed from a biocompatible and biostable metal such as titanium, contains a pulse generator, or an electronic controller (not shown), to which at least one electrode111is coupled, for example, by a hermetic feedthrough assembly (not shown) like those known to those skilled in the art of implantable medical devices. Housing105may be overlaid with an insulative layer, for example, medical grade polyurethane, silicone, or parylene.

FIG.1further illustrates a distal portion of a standard guiding catheter150having been maneuvered up through the inferior vena cava IVC and into the right ventricle RV from the right atrium RA, according to methods known in the art of interventional cardiology. Although catheter150may be employed to deliver device100to the right ventricle RV, for implant, more sophisticated tools, which are more suitable to facilitate deployment of relatively compact implantable devices, like device100, are desired.

FIG.2Ais a side view of a tool200that may be included in an interventional medical system, according to some embodiments.FIG.2Aillustrates tool200including a handle assembly210, and an outer assembly, which is formed by an elongate deployment tube230and an outer, stabilizing sheath270that surrounds a proximal portion of deployment tube230, in proximity to handle assembly210.FIG.2Afurther illustrates deployment tube230including an enlarged distal-most portion232, which is sized to contain an implantable medical device, for example, the above-described device100; enlarged distal-most portion232also defines a distal opening203of deployment tube230, for example, as seen in the cut-away section view ofFIG.2B.FIG.2Billustrates tool200further including an elongate inner assembly220, around which deployment tube230extends, wherein inner assembly220includes a distal member222, which is configured to engage device, for example, by abutting an end of device100, and a single pull wire224, which is anchored adjacent to member222. Pull wire224preferably extends within a lumen of inner assembly220, for example, as described below, in conjunction withFIG.3B. With reference back toFIG.2A, a first control member211of handle assembly210is coupled to pull wire224, and a second control member212is coupled to deployment tube230.

According to the illustrated embodiment, movement of first control member211, per arrow A, actuates pull wire224to bend inner assembly220and deployment tube230(described in greater detail below), and movement of second control member212, per arrow B, moves deployment tube230, per arrow W, to withdraw, or retract tube230relative to stabilizing sheath270, inner assembly220, and device100, for example, from a first position, in which device100and distal member222of inner assembly220are contained within distal-most portion232of tube230(FIG.2A), to a second position, at which device has passed out through distal opening203(FIG.2B). The end of device100that is engaged by member222may include a tether attachment structure, for example, like a structure122illustrated inFIGS.1and6, according to some embodiments in which the interventional medical system that includes tool200further includes an elongate tether that extends within one or a pair of lumens of inner assembly220and out through a proximal port213(FIG.2A) of handle assembly210. An exemplary tether will be described in further detail below.FIGS.1and2Bfurther illustrate implantable medical device100including a fixation member115, which is mounted to an opposite end of device housing105, in proximity to the aforementioned electrode111, such that upon actuation of pull wire224and subsequent retraction of deployment tube230, fixation member115is directed and exposed to secure device100at a target implant site so that electrode111is held in intimate contact with the tissue at the site.

According to an exemplary embodiment, enlarged distal-most portion232has an inner diameter of approximately 0.275 inch (˜0.7 cm) and an outer diameter of approximately 0.3 inch (˜0.8 cm). AlthoughFIGS.2A-Billustrate the outer diameter of distal-most portion232being enlarged from a remainder of deployment tube230, for example, over a length of approximately 3.5 cm (˜1.4 inch), according to alternate embodiments, an outer diameter along a more significant length, up to an entire length of deployment tube230, may be the same as that of distal-most portion232. A length of deployment tube230, between handle assembly210and distal opening203of deployment tube230, when tube230is in the first position (FIG.2A), may be between approximately 103 cm and approximately 107 cm, for example, to reach the right ventricle RV from a femoral access site, for example, as described below, in conjunction withFIG.4C.

FIG.2Afurther illustrates deployment tube230including an articulating segment234located just proximal to enlarged distal-most portion232. Articulating segment234may extend over a length of up to approximately 10 cm, preferably approximately 5.8 cm, and is defined by a composite sidewall that is constructed to bend in two directions in response to the aforementioned actuation of pull wire224.FIG.3Ais an end view of tool200; andFIG.3Bis a cross-section view through section line B-B ofFIG.3A, according to some embodiments, by which an exemplary construction of the composite sidewall is shown.FIG.3Aillustrates the composite sidewall including a relatively soft section341and a relatively stiff section342, which extend alongside one another and along the length of articulating segment234.FIG.3Billustrates the composite sidewall of articulating segment234including a first, inner portion301, which extends 360 degrees around inner assembly220, and a second, outer portion302, which extends approximately 180 degrees around inner layer301, for example, being bonded thereto, such that inner portion301, itself, forms relatively soft section341, and the combination of inner portion301and outer portion302forms relatively stiff section342. According to some embodiments, first portion301includes an inner layer, which lines an interior of deployment tube230and is surrounded, or reinforced by a metal braid, for example, a polyether block amide, such as PEBAX® 6333, with a stainless steel braid (e.g., 0.0018″×0.008″×45 PPI), and an outer layer, which overlays the inner layer, for example, another grade of polyether block amide, such as PEBAX® 5533, wherein second portion302may be formed by a another grade of polyether block amide, for example PEBAX® 7233. According to the illustrated embodiment, when the single pull wire224is actuated, via control member211, the composite sidewall causes articulating segment234to bend in a first direction, per arrow D1(FIG.2A), and in a second direction, per arrow D2(FIG.3A), toward relatively soft section341, which is more flexible, or provides less resistance to bending than relatively stiff section342.

Enlarged distal-most portion232is preferably formed separately from segment234, for example, from another grade of polyether block amide, such as PEBAX® 7233, and then thermally bonded to segment234. According to some preferred embodiments, distal-most portion232of deployment tube230is fitted with a radiopaque marker30(FIG.3A), for example, a gold foil, with an adhesive backing, which is sandwiched between layers of the polyether block amide, in proximity to distal opening203, and distal member222of inner assembly220is radiopaque, so that the retraction of tube230, relative to member222, can be observed via fluoroscopy. As was mentioned above, the outer diameter of distal-most portion232of deployment tube is shown enlarged from a remainder of deployment tube230, (e.g., over a length of approximately 3.5 cm), which may be preferred, so that a majority of the length of deployment tube230has a smaller outer diameter, which allow for a smaller introducer sheath to provide access for tool200into a patient's venous system. Thus, the aforementioned exemplary construction of marker band30, from a flexible gold foil, allows for some deformation of enlarged distal-most portion232, when passing through the smaller introducer sheath, upon initial insertion of tool200into the patient's venous system.

With further reference toFIG.2A, deployment tube230includes a segment236having a pre-formed curvature, which is located just proximal to articulating segment234, wherein a length of segment236may be up to approximately 20 cm. According to the illustrated embodiment, the pre-formed curvature of segment236orients distal-most portion232of deployment tube230at an angle of approximately 90 degrees with respect to a length of tube230that extends proximally from segment236toward handle assembly210. A radius R about which the pre-formed curvature extends may be between approximately 9 cm and approximately 13 cm. The curvature may be formed in deployment tube230prior to the assembly of inner assembly220therein, for example, by heat setting methods known in the art. With further reference toFIG.3A, in conjunction withFIG.2A, relatively soft section341and relatively stiff section342of the composite wall of articulating segment234meet, or abut one another along a line3(dashed, inFIG.3A) that is tangent to an outside of the pre-formed curvature, and along a similar line on an opposite side of deployment tube230.

Segment236, and the length of deployment tube230that extends proximally therefrom, may be any suitable construction known in the art, to achieve a graduated flexibility and the necessary pushability and torque transfer that facilitates the maneuverability of tool200to a target implant site. For example, the aforementioned construction of inner portion301of articulating segment234may extend proximally along segment236and the proximal length to handle assembly210, wherein varying durometers of polyether block amide are used for the outer layer, to transition the stiffness/flexibility along the length of deployment tube230.

FIG.3Bfurther illustrates inner assembly220including a multi-lumen tube320to which distal member222is coupled (FIG.2B), according to some embodiments. Multi-lumen tube320may be extruded polyether block amide, polyurethane, or silicone rubber, or a composite thereof, and may include an overlay (not shown), for example, formed of braid-reinforced polyether block amide. According to the illustrated embodiment, multi-lumen tube320includes one, relatively large lumen321, and three, relatively small lumens322-324, wherein pull wire224extends within lumen324, and lumens321-323are in fluid communication with distal opening203of deployment tube230, and with proximal port213of handle assembly210(FIGS.2A-B). According to an exemplary embodiment, pull wire224has a diameter of approximately 0.009 inch (˜0.23 mm) and is formed from medical grade 304 stainless steel, which is preferably coated with a fluoropolymer such as polytetrafluoroethylene (PTFE). It should be noted that the orientation, relative to sections341,342of articulating segment234, of pull wire224, within lumen324is not necessarily fixed, so may vary from that illustrated inFIG.3B.

Lumens322,323of multi-lumen tube320are preferably sized to accommodate first and second lengths of an elongate tether36, for example, being looped and secured to tether attachment structure122of device100, when the end of device100abuts distal member222of inner assembly220, as shown inFIG.2B. Elongate tether36may be part of a tether assembly600, according to some embodiments of the interventional medical system, which will be described below, in conjunction withFIGS.6-7B. Although the inclusion of separate lumens322,323, to accommodate the first and second lengths of the looped tether, are useful in preventing a tangling of the first and second lengths, according to some alternate embodiments, multi-lumen tube320need not include lumens322,323, and both lengths of the looped tether36may extend in lumen321. In either case, it should be noted that proximal port213of handle assembly210accommodates passage of tether36therethrough, to provide an operator of tool200access to tether36. Lumen321of multi-lumen tube320is preferably sized to accommodate a snare (not shown), which may be inserted therein, through proximal port213, and used to retrieve device100, if necessary, from an implant site, after tether36is cut and disengaged from tether attachment structure122of device100.

With reference back toFIG.2A, handle assembly210further includes a flushing subassembly215.FIG.2Aillustrates flushing subassembly215including a connector port205, for example, to which a saline-filled syringe may be attached, and a flexible tube25that defines a flush lumen in fluid communication with lumens321-323of multi-lumen tube320. Flushing of tool200, via subassembly215, is useful to purge air therefrom, and is further described below, in conjunction withFIGS.5A-B.

Turning now toFIGS.4A-C, the significance of the response of articulating segment234of deployment tube230, to the actuation of the single pull wire224will be described.FIGS.4A-Bare a side view and a corresponding bottom view of tool200, respectively, upon actuation of pull wire224; andFIG.4Cis a schematic showing tool200within the right ventricle RV of a heart, for example, having been introduced into a patient's venous system through an introducer sheath at a femoral access site.FIGS.4A-Billustrate the aforementioned bending of articulating segment234in the first and second directions D1, D2, respectively, in response to actuation of the single pull wire224via control member211(FIG.2A). It should be noted that that the pre-formed curvature of segment236can facilitate the navigation of tool200within the heart, for example, once distal-most portion232has been passed into the RA of the heart, via the IVC, by orienting distal-most portion232of deployment tube230for passage through the tricuspid valve TV and into the right ventricle RV. Then, with reference toFIG.4C, once distal-most portion232has been passed into the right ventricle RV, actuation of the single pull wire224, for example, via control member211(FIG.2A), results in the simultaneous bending of articulating segment234, in first direction D1(FIG.4A) and second direction D2(FIG.4B), to direct enlarged distal-most portion232of deployment tube230toward a target site that is located along a septal wall SW in an apical region of the right ventricle RV. Then, device100may be deployed through distal opening203of deployment tube230, by the retraction thereof relative to inner assembly220, for example, via control member212(FIG.2A), as was described above. Thus, the composite sidewall construction of articulating segment234allows for a simplified construction of tool200that includes only the single pull wire224and corresponding control member211for articulation; furthermore, such a construction can make tool200easier to use.

FIG.5Ais a plan view of handle assembly210of tool200, according to some embodiments, wherein a first portion of an outer surface, or shell510A of handle assembly210is removed to see an arrangement of components within a second portion of the shell510B.FIG.5Aillustrates first control member211including a base portion511that wraps around a portion of multi-lumen tube320of the above-described inner assembly220, which extends into handle assembly210, so that a first end of the aforementioned pull wire224, for example, that extends out from lumen324(FIG.3B) through an opening (not shown) in the sidewall of tube320, may be coupled to first control member211, for example, by engaging the first end within base portion511. With reference back toFIG.2A, control member211is movable within a slot201, which extends through shell510A,510B, relative to inner assembly220/multi-lumen tube320, which is fixed in handle assembly210by connection to a tether engaging conduit580and the aforementioned flexible tube25of flushing subassembly215, which is shown routed within handle assembly210.FIG.5Afurther illustrates second control member212including a base portion512, which is coupled to a proximal end of deployment tube230within handle assembly210, and, like first control member211, second control member212is moveable in a corresponding slot202, which may be seen inFIG.2A, to move deployment tube230between the above-described first and second positions. According to some embodiments, a seal member (e.g., a silicone O-ring; not shown), which may be lubricated, for example, with silicone oil, forms a dynamic sealing interface between deployment tube230and inner assembly220in proximity to first control member211.

The aforementioned stabilizing sheath270is also shown extending within handle assembly210, for example, being coupled thereto in proximity to a distal end214of handle assembly210. With further reference toFIG.2A, sheath270extends along a limited proximal length of the outer assembly and may be relatively rigid to facilitate the movement of deployment tube230, for example, by preventing an operator who is handling tool200from inadvertently applying a force around tube230in proximity to handle assembly210, which force could impede the movement of tube230relative to handle assembly210and inner assembly220. Sheath270may also provide an enhanced interface between tool200and a valve of an introducer sheath, for example, an interface that provides improved sealing and/or additional radial strength to counteract a compressive force of the valve, which, if the valve is a Tuohy Borst type, can be tightened down around tool200to different degrees depending upon the operator.

With further reference toFIG.5A, handle assembly210includes a receptacle506located in proximity to proximal port213, wherein receptacle506is configured to receive a tether holder660of a tether assembly600, which also includes the aforementioned elongate tether36, and which is illustrated inFIG.6. As was mentioned above, proximal port213allows tether36to pass therethrough, to exit tool200, andFIG.5Afurther illustrates tether engaging conduit580connecting inner assembly220to proximal port213, thereby allowing passage of tether36from inner assembly220(e.g., lumens322,323of multi-lumen tube320) to proximal port213. Conduit580may also allow passage of the aforementioned snare therethrough and into inner assembly220(e.g., lumen321of multi-lumen tube320), for delivery of the snare out through distal opening203(FIGS.2A-B) of tool200. Conduit580is described in greater detail below.

FIG.6is a perspective view of tether assembly600coupled to implantable medical device100, according to some embodiments.FIG.6illustrates a distal end36-dof tether36secured to attachment structure122of device100, a proximal end36-pof tether36attached to tether holder660, and tether36formed in a loop, such that a first length36-1of tether36extends alongside a second length36-2of tether36. With reference back toFIG.3B, first length36-1may extend within lumen322, and second length36-2, within lumen323of multi-lumen tube320, when device100is contained in enlarged distal-most portion232of deployment tube230.FIG.6further illustrates tether holder660including a locking portion663, for securing proximal end36-pof tether36, for example, as seen inFIGS.7A-B, and a pin portion664, for which receptacle506of handle assembly210is configured. Tether36may be formed from a polyester fiber having a fluoropolymer coating, such as PTFE, or any other suitable material, and tether holder660may be formed from a plastic, such as polypropylene, for example, by injection molding.

Locking portion663is shown including a pair of apertures603, each of which extends from a first side660-1to a second side660-2(FIG.7A) of tether holder660, and a corresponding pair of plug members63, wherein each plug member63is configured to fit within the corresponding aperture603, alongside a corresponding length of proximal end36-pof tether36, in order to secure proximal end36-pto tether holder660; and pin portion664is shown including a pair of grooves604, each groove604approximately aligned with a corresponding aperture603and configured to receive a corresponding length36-1,36-2of tether36in proximity to proximal end36-p. According to the illustrated embodiment, plug members63extend from a hinged flap631of locking portion663, wherein flap631may be closed, per arrow S, to force plug members63into apertures603, and then opened, to remove plug members63from apertures603, when the operator desires to release of tether36from holder660.

With reference toFIGS.7A-B, which are perspective views of tether assembly600in relation to handle assembly210, it may be appreciated that grooves604facilitate a folding of lengths36-1,36-2, for example, per arrow F (FIG.7A), in proximity to the secured proximal end36-p, around tether holder660, without tangling, when pin portion664is inserted into receptacle506. It may be seen inFIGS.6and7A, that, according to some preferred embodiments, grooves604extend along first and second sides660-1,660-2of tether holder660. It should be noted that, according to some alternate embodiments, locking portion663of tether holder660may only include one aperture603and corresponding plug member63, and, likewise, pin portion664may include a single groove604approximately aligned with the single aperture603.

FIG.7Aillustrates lengths36-1,36-2of tether36extending out from proximal port213of handle assembly210, and proximal end36-pof tether36being secured to tether holder660prior to folding lengths36-1,36-2around holder660, per arrow F. It should be understood that distal end36-dof tether36is preferably secured to device100(FIG.6), then threaded through inner assembly220(e.g., lumens322,323of multi-lumen tube320) just prior to loading device100into enlarged distal-most portion232of deployment tube230, through distal opening203(FIGS.2A-B), and then proximal end36-p, which extends out from proximal port213, is secured to tether holder660, for example, as was described above.FIG.7Billustrates pin portion664of tether holder660, after tether36has been secured and folded thereabout, being inserted, per arrow u, into receptacle506of handle assembly210, so that, as the operator uses handle assembly210to navigate and articulate of tool200, as described above in conjunction withFIG.4C, and to subsequently deploy device100, tether36is neatly kept out of the way of the operator.FIGS.6and7A-B further illustrate tether holder660including a knob668, which can facilitate the handling of tether holder660, for example, while securing tether36thereto, while folding tether36thereabout, for inserting tether holder660into receptacle506, and for removing tether holder660from receptacle506.

With further reference toFIG.7B, in conjunction withFIG.5A, tether engaging conduit580includes a valve member586integrated therein. According to an exemplary embodiment, valve member586is constructed like a stop-cock valve known to those skilled in the art.FIG.5Ashows first portion of shell510A of handle assembly210including an aperture516, which is formed through a recessed surface518of portion510A, and which provides access to valve member586so that an operator can move valve member586between an open position (FIG.7A) and a closed position (FIG.5A). In the open position, valve member586allows fluid communication between proximal port213of handle assembly210and lumens321-323(FIG.3B) of inner assembly220, and thus, free movement of tether36therethrough. When open, valve member586also allows passage of the aforementioned snare therethrough and into inner assembly220, for example, lumen321of multi-lumen tube320. In the closed position, valve member586clamps tether36, and may provide hemostasis for tool200, that is, prevent a back flow of bodily fluids through tool200during navigation and device deployment. Tether36is preferably clamped while the operator navigates and articulates tool200, and deploys device100, after which, the operator moves valve member586into the open position to release tether36therefrom; then, upon removing tether holder660from receptacle506, the operator may grasp tether holder660and tug on device100, via tether36, to test the fixation thereof at the implant site. If device100is adequately fixed, and the implant site is satisfactory, the operator leaves valve member586in the open position so that, once proximal end36-pis released from tether holder660, one of lengths36-1,36-2may be grasped to release tether36from device100, and withdraw tether36out from inner assembly220, through proximal port213of tool200.

With further reference toFIG.5A, in conjunction withFIG.2A, flexible tube25of flushing subassembly215, which defines the flushing lumen thereof, is routed within handle assembly210and extends out distal end214thereof, alongside sheath270, where an end of tube25is coupled to connector port205(FIG.2A). According to the illustrated embodiment, the location of connector port205at distal end214of handle assembly210, which is generally opposite from proximal port213, by virtue of the routing of tube25out distal end214, can help to facilitate tether management, via tether holder660and receptacle506, and the overall handling of tool200, via handle assembly210. As was mentioned above, the flush lumen defined by tube25is connected to inner assembly220, and the arrow inFIG.5Aindicates the flow of a flushing fluid from the flush lumen to lumens of inner assembly220(e.g., lumens321-323of multi-lumen tube320,FIG.3B).FIG.5Afurther illustrates the flush lumen being connected to tether engaging conduit580, and, when valve member586of conduit580is in the closed position, flow of the flushing fluid, from flush lumen, is blocked from flowing out proximal port213. It should be noted that, according to the illustrated embodiment, the lumens of inner assembly220may also be flushed via proximal port213, when valve member586of conduit580is in the open position to allow the fluid communication between proximal port213and the lumens.

According to some preferred embodiments, the flush lumen of flushing subassembly215is also in fluid communication with the interior of deployment tube230, for example, an annular space formed between deployment tube230and inner assembly220, along a length of inner assembly220, for example, via one or more ports formed through a sidewall of multi-lumen tube320.FIG.5Bis a cut-away section showing a portion of inner assembly220extending within the outer assembly of tool200, just distal to handle assembly210, according to some embodiments.FIG.5Billustrates ports35formed through the sidewall of tube320, for example, at lumen321(FIG.3B), so that lumen321is in fluid communication with the interior of deployment tube230, as indicated by the arrows, to allow flushing between the inner and outer assemblies of tool200. Thus, tool200may be completely purged of air via flushing subassembly215.

In the foregoing detailed description, the invention has been described with reference to specific embodiments. However, it may be appreciated that various modifications and changes can be made without departing from the scope of the invention as set forth in the appended claims.