Cannula ring and related systems and methods

Cannula devices and related methods are provided. In accordance with one embodiment, a cannula ring includes a body portion having a substantially cylindrical member defining an opening therethrough. A plurality of anchor arms coupled with the body portion and configured to be positioned in a first, collapsed state and a second, deployed state, wherein the anchor arms each include a free end that is radially displaced from the body portion while in the second, deployed state relative to their positions while in the first, collapsed state. Suture rings and other associated structures and devices are also described.

TECHNICAL FIELD

Exemplary embodiments relate to a device for coupling a conduit to a vessel of the human body, and, more particularly to a cannula ring that enables attachment of various devices or structure with a chamber of the heart or other vessel.

BACKGROUND

Mechanical circulatory devices (MCDs) such as artificial hearts, ventricular assist devices (VADs) and other blood circulating systems and components have become increasingly recognized as life saving devices for patients whose hearts are diseased or have been injured by trauma, heart attack or other causes. VADs in particular, are recognized as a major life saving modality for assisting patients who suffer from congestive heart failure.

VADs must be physically connected to the natural heart of patients. In order to connect a VAD to the heart of a patient, a conduit assembly is used. The conduit assembly conventionally has a tubular tip body that is inserted into the heart. For proper functioning, the tip body typically penetrates the heart wall to make a fluid connection with the heart (e.g., with a ventricle of the heart) through the heart wall. However, various difficulties may present themselves in connecting a conduit assembly with the heart. For example, it is desirable to ensure that there are no leaks through the heart wall in the opening through which the conduit assembly is placed. On the other hand, it is desirable to enable repositioning, removal and possible replacement using minimally invasive techniques.

For these, and a variety of other reasons, there is a continued desire to provide enhanced methods, systems and devices that will improve the functionality and efficiency of VADs and other similar devices.

BRIEF SUMMARY OF THE INVENTION

In accordance with the present invention, various devices, components and methods associated with the cannulation of a tissue structure are set forth. In accordance with one embodiment, a cannula ring is provided. The cannula ring includes a body portion having a substantially cylindrical member defining an opening therethrough. A plurality of anchor arms are coupled with the body portion and configured to be positioned in a first, collapsed state and a second, deployed state. The anchor arms each include a free end that is radially displaced from the body portion while in the second, deployed state relative to their positions while in the first, collapsed state. In one embodiment, a coupling structure is associated with the body portion and the body portion may include a surface feature configured to engage abutting tissue.

In one embodiment the anchor arms extend substantially axially along the body portion while in the first, collapsed state. In another embodiment the anchor arms extend substantially circumferentially about the body portion while in the first, collapsed state. The anchor arms may be formed of a shape memory material. In one embodiment, each anchor arm includes a wire structure. In one embodiment a portion of each anchor arm is integrally formed with the body portion.

In accordance with another embodiment, a cannula device comprises a first structure having a convex gimbaled surface. The device also includes a suture ring having a body portion and a ring portion. The body portion has a concave gimbaled surface coupled with the convex gimbaled surface of the first structure, wherein the suture ring may pivot in at least two planes relative to the first structure. In various embodiments, the first structure may include a conduit, a blood pump a cannula ring or some other device.

In accordance with another embodiment of the invention, a cannula device is provided that comprises a first structure and a suture ring. The suture ring includes a body portion, a ring portion and a locking mechanism, wherein the suture ring may coupled with the first structure and be selectively locked at a plurality of positions relative to the first structure.

In accordance with another embodiment, a cannula device is provided that comprises a first structure and a suture ring coupled with the first structure. The first structure defines an opening that is eccentrically located relative to a perimeter defined by the suture ring. In one embodiment the perimeter is an outer perimeter of the suture ring. In another embodiment, the perimeter is an inner perimeter of the suture ring.

In accordance with another embodiment of the invention, a suture ring is provided that comprises: a coupling portion having an opening formed therein; a ring portion configured for attachment to a tissue structure; and a valve associated with the coupling portion, the valve being configured to selectively enable or inhibit fluid flow through the opening of the coupling portion.

Other features and advantages may be possible, and it is not necessary to achieve all or any of these features or find any of the stated advantages in any embodiment. Therefore, nothing in the forgoing description can or should be taken as limiting.

DETAILED DESCRIPTION OF THE INVENTION

Referring toFIGS. 1A-1Ba first embodiment of the cannula ring100is shown in a first state (FIG. 1A) and a second state (FIG. 1B). The cannula ring100includes a body portion102which may be formed of a substantially rigid material such as, for example, a metal, metal alloy, or any of a variety of biocompatible plastic materials. The body portion102may be formed generally as a tubular member having a substantially cylindrical wall104defining a lumen106or an opening passing through the body102. The body portion102may include a number of features including a coupling structure108formed at one end of the body portion102that is configured to enable coupling with another device or structure such as, for example, a blood pump or a conduit. The coupling structure108may include, for example, a plurality of threads, a keyed twist-lock structure, a plurality of shoulders used in association with a ratchet structure, or it may be configured for connection with a compression coupling.

The external surface of the body portion102, or at least a portion thereof, may also include one or more surface features110configured to enhance long term placement of the cannula ring100in the body of a patient. For example, a surface feature110may include a textured surface that is formed on the body portion102at a location that is intended to interact with tissue of a patient—e.g., a wall of the patient's heart. The surface feature110may be configured to help maintain the position of the cannula ring100when implanted in a patient. In one embodiment, such a surface feature110may be configured to engage the tissue and provide a desired level of resistance between the cannula ring100and the engaged tissue. In another embodiment, the surface feature may be configured to promote tissue in-growth to the body portion102of the cannula ring100.

The cannula ring100also includes a plurality of anchor arms112positioned about the perimeter of the body portion102in a substantially equally spaced pattern (although other patterns may be used). As shown inFIG. 1A, the anchor arms112may be configured to assume a first position wherein they are positioned adjacent to or even abut the body portion102of the cannula ring100. Such a position may be referred to as a collapsed state or position. The anchor arms112may be placed in a collapsed state when the cannula ring100is being delivered to a site for implantation making the cannula ring100more compact and easier to manipulate when positioning and orienting the cannula ring100at a site for implanting. As seen inFIG. 1B, the anchor arms112may also be configured to assume at least one other position (i.e., other than the collapsed state), which may be referred to as a deployed state or position. While in the deployed state, a portion of the anchor arms112may flare out in a radial direction relative to the body portion102. In the embodiment shown inFIG. 1B, a first end114of each anchor arm112is coupled with the body portion102while a second end116of the anchor arms112is free and displaceable between the collapsed state (FIG. 1A) and the radially flared or displaced position of the deployed state. Stated another way, the first end114and second end116of each anchor arm112may be at a substantially equal radial distance from a longitudinal axis extending through the lumen104while in the collapsed state, while the second end116of each anchor arm112is displaced radially outward of the first end114when in a deployed state.

In one embodiment, the anchor arms112may be formed of a metal material. For example, the anchor arms may be formed of a shape memory alloy such as nitinol. In such a case, the anchor arms112may be configured to be biased toward the deployed state. For example, referring briefly toFIG. 1C, a restraining structure120may be positioned about the anchor arms112, holding them in the collapsed state, while the cannula ring is being delivered and positioned at a desired location. Once the cannula ring has been placed in a desired position (e.g., through an opening formed in a tissue structure such as the wall of a heart), the restraint structure120may be removed from the cannula ring100enabling the anchor arms112to be displaced to the deployed state. With the anchor arms112in the deployed state, the second ends116of the anchor arms may be positioned to abut the tissue structure (e.g., the vessel wall) on the distal side of the tissue structure in order to anchor the cannula ring100within the opening in which it has been placed. As will be described in further detail below, the body portion102may be coupled with another device or component (e.g., a suture ring) to anchor the cannula ring100on the proximal side of the tissue structure, working in concert with the anchor arms112, to fix the cannula ring100in a desired position and orientation relative to the tissue structure.

Referring again toFIG. 1C, the restraint structure120may include a generally circuitous band122that is positioned about the body portion102and the anchor arms112, holding the anchor arms in the collapsed state. A circuitous band122may include a tab portion that may be easily grasped by hand or by an appropriate tool. A series of perforations126may be provided at a circumferential location that corresponds with the tab124, the perforations extend along an axial path through the band122. By applying an appropriate force to the tab124, the band122may be torn through the series of perforations126to remove the band from the cannula ring100and enable the anchor arms112to expand or be displaced to their deployed state (FIG. 1B). In other embodiments, a band or sleeve may be provided about the anchor arms112to maintain them in a collapsed state until slid axially, relative to the body portion, a specified distance in order to enable the anchor arms112to expand radially once free of the band or sleeve.

Referring briefly toFIG. 1D, the body portion102of the cannula ring100is shown. The body portion102is shown without the anchor arms112coupled therewith. Openings130may be formed in the body portion for coupling of the anchor arms112therewith. As previously described, the coupling structure108may include threads, ratchet teeth, or other structures for adjustably coupling another component with the body portion102. Also, as noted above, surface features110may be formed on the body portion102. The surface features110shown inFIG. 1Dinclude a knurled surface, but may include some other texture pattern or may include a tissue growth member formed in or coupled with the body portion102.

It is also noted that the embodiment shown inFIG. 1Dincludes a patterning of openings130for four different anchor arms112while the embodiments shown inFIGS. 1A-1Cinclude eight anchor arms112. The present invention is not limited to any specific number of anchor arms112and different embodiments may have a different number depending on a variety of factors including, for example, the size and geometry of the anchor arms as well as the material from which the anchor arms are formed. Additionally, the openings130formed in the body portion102may be formed as through holes or as blind holes and may include structure configured to help grasp and retain the anchor arms112therein.

When implanted in a tissue opening (such as during a cannulation procedure), the cannula ring creates a predictable opening through a tissue structure, such as the wall of a heart, enabling other devices to pass through and access the area on the opposing side of the tissue structure. The cannula ring100may be placed using known minimally invasive surgical (MIS) techniques such as, for example, a thoracotomy. The cannula ring100may be removed when other components (e.g., blood pumps) are removed, or it may be left in place with a plug or other structure used to prevent any fluid flow through the opening106.

Referring now toFIG. 2A, a cannula ring150is shown in accordance with another embodiment of the invention. The cannula ring includes a body portion152which may be formed generally as a tubular member having a substantially cylindrical wall154defining a lumen156or an opening passing through the body152. The body portion152may include a number of features including, for example, coupling structure158formed at one end of the body portion152that is configured to enable coupling with another device or structure such as, for example, a blood pump or a conduit. The external surface of the body portion152, or at least a portion thereof, may also include one or more surface features160configured to enhance long term placement of the cannula ring150in the body of a patient such as has been described above.

The cannula ring150also includes a plurality of anchor arms162positioned about the outer perimeter or the outer circumference of the body portion152. WhileFIG. 2Ashows the anchor arms162in a deployed position (similar to the deployed position of the anchor arms112shown inFIG. 1B), they may also be placed in a collapsed state or position such as has been described above with respect to the cannula ring100shown inFIGS. 1A and 1C. In the embodiment shown inFIG. 2A, the anchor arms162are formed of the same material and may be integrally formed with the body portion152. For example, the anchor arms162may be formed as flaps extending from the body portion152having a first end154coupled to, or integrally formed with, the body portion152, and a free end156radially displaced from the body portion152(while in the deployed state). One or more surfaces of the anchor arms162may be textured or treated to enhance their interaction with abutting tissue and, in some embodiments, even promote tissue growth.

In one embodiment, the body portion152and the anchor arms162may be formed of a polymer material. In one particular embodiment, the body portion152and the anchor arms may be formed of a shape memory polymer material (sometimes referred to as a smart material). It is noted that with the increased width of the anchor arms162relative to anchor arms112of cannula ring100), a reduced number anchor of arms may be used to secure the cannula ring within an opening of a tissue structure. Of course, the present invention is not limited to a particular number of anchor arms in any of the described embodiments.

Referring now toFIG. 2B, a cannula ring150′ is shown that is similar to the cannula ring150depicted inFIG. 2A. The cannula ring150′ includes a body portion152which may be formed generally as a tubular member having a substantially cylindrical wall154defining a lumen156or an opening passing through the body152. The body portion152may include a number of features including, for example, coupling structure158formed at one end of the body portion152that is configured to enable coupling with another device and one or more surface features160configured to enhance long term placement of the cannula ring150′ in the body of a patient such as has been described above.

The cannula ring150′ also includes a plurality of anchor arms162positioned about the outer perimeter or the outer circumference of the body portion152. The anchor arms162are generally similar to those described with respect toFIG. 2A, but additionally include reinforcing structures168. Thus,FIG. 2Bshows a cannula ring150′ having anchor arms that are the combined structures of those shown inFIGS. 1A-1AandFIG. 2A. In other words, the anchor arms162include the strut-like structures described with respect to cannula ring100(i.e., anchor arms112inFIGS. 1A-1C) embedded within the flap-like structures described with respect to cannula ring150inFIG. 2A. The anchor arms162shown inFIG. 2Bmay provide enhanced support and resistance to the cannula ring becoming dislodged or displaced after it has been implanted and coupled with other devices. Such additional support may be desired in various circumstances depending on a variety of factors including, for example, the size of the opening, the thickness of the tissue structure into which the cannula ring will be implanted, and the overall integrity of the tissue structure.

Referring now toFIG. 3, a cannula ring100is shown with a suture ring180coupled therewith. The suture ring180may include a coupling portion182that engages with the body portion102of the cannula ring100. Such coupling of the two components may be adjustable or it may be non-adjustable. An adjustable connection between the suture ring180and the cannula ring100will accommodate variation in the thickness of a tissue structure (e.g., a vessel wall), with the axial position of the suture ring180being variable with respect to the axial position of the free ends116of the anchor arms112.

The suture ring180includes a ring portion184that may include a cloth or fibrous material configured for stapling, suturing or otherwise fastening the suture ring to adjacent tissue. In addition to fastening mechanisms such as sutures or staples (or as an alternative), adhesive may be used to secure the suture ring to adjacent tissue. As discussed above, when positioned within an opening of a tissue structure, the free ends116of the anchor arms112abut a distal surface of the tissue structure (e.g., the internal surface of a ventricle) while the suture ring180(or some other coupling device) abuts the proximal surface of a tissue structure (e.g., the external surface of a heart) to secure the cannula ring100in a desired position.

Referring now toFIGS. 4A and 4B, a cannula ring200is shown in accordance with another embodiment. The cannula ring200includes a body portion202which may be formed generally as a tubular member having a substantially cylindrical wall204defining a lumen206or an opening passing through the body202. The body portion202may include a number of features including, for example, coupling structure208formed at one end of the body portion202that is configured to enable coupling with another device or structure such as described above. The coupling structure208may include, for example, a plurality of threads, a keyed twist-lock structure, a plurality of shoulder used in association with a ratchet structure, or it may be configured for connection with a compression coupling.

The external surface of the body portion202, or at least a portion thereof, may also include one or more surface features210configured to enhance long term placement of the cannula ring200in the body of a patient such as described above. The cannula ring200also includes a plurality of anchor arms212positioned about the perimeter of the body portion202. As shown inFIG. 4A, the anchor arms212may be configured to assume a first position where they are positioned circumferentially adjacent to, and may abut, the body portion102of the cannula ring100. In one embodiment, as seen inFIG. 4A, the anchor arms212may be disposed within a circumferential groove218formed in an outer surface of the body portion202. Such a position may be referred to as a collapsed state or position. The anchor arms212may be placed in a collapsed state when the cannula ring100is being delivered to a site for implantation making the cannula ring100more compact and easier to manipulate and position at a site for implanting. As seen inFIG. 4B, the anchor arms112may also be configured to assume at least one other position (i.e., other than the collapsed state), which may be referred to as a deployed state or position. While in the deployed state, a portion of the anchor arms212flare out in a radial direction relative to the body portion202. In the embodiment shown inFIG. 4B, a first end214of each anchor arm212is coupled with the body portion202while a second end216of the anchor arms212is free and is displaceable between the collapsed state (FIG. 1A) and the radially flared or displaced position of the deployed state. The anchor arms212extend from the circumference of the body portion202in a spiral-type pattern such that they all lie in a substantially common radial plane.

In one embodiment, the anchor arms212may be formed of a metal material. For example, the anchor arms may be formed of a shape memory alloy such as nitinol. In such a case, the anchor arms212may be configured to be biased toward the deployed state such as has been described with respect to other embodiments. Once the cannula ring200has been placed in a desired position (e.g., through an opening formed in a tissue structure such as the wall of a heart), the anchor arms212may be displaced to the deployed state. In one embodiment, with the anchor arms212in the deployed state, the anchor arms212may be positioned to abut the tissue structure (e.g., the vessel wall) on the distal side of the tissue structure in order to anchor the cannula ring200within the opening in which it has been placed. In such an embodiment, the anchor arms212may be configured so that a substantial portion of the length of each arm (e.g., a majority of the length or more) may be in contact with tissue on the distal side of the tissue structure. In another embodiment, the anchor arms may be displaced from the collapsed state while they are positioned between a distal surface and a proximal surface of the tissue structure so that they engage a perimeter surface of the opening within the tissue structure. If desired, the cannula ring200could then be rotated causing the anchor arms to engage and embed themselves in the tissue structure. As previously described, the body portion202may be coupled with another device or component to anchor the cannula ring200on the proximal side of the tissue structure, working in concert with the anchor arms212, to fix the cannula ring200in a desired position and orientation relative to the tissue structure.

Referring now toFIGS. 5A and 5B, a suture ring250is shown in accordance with another embodiment of the present invention. The suture ring includes a coupling portion252that engages another structure, generically referred to herein as a cannula structure260. The cannula structure260may include, for example, the body portion of a cannula ring, an engagement sleeve (e.g., a compression sleeve or other coupling structure) for engagement with the body portion of the cannula ring, or it may include other structures associated with a cannula device, a blood pump or some other fluid flow device. The suture ring250also includes a ring portion254that may be configured such as described above with respect to other suture rings.

The coupling portion252includes a concave gimbaled surface256that matingly engages a convex gimbaled surface258of the cannula structure260. The gimbaled surfaces256and258may be substantially spherical, meaning that they include a portion of a sphere, such as a sphere that has been truncated on both sides of an equatorial line. The gimbaled coupling of the coupling portion252with the cannula structure260enables the coupling portion252and the ring portion254to pivot in multiple planes relative to cannula structure260. Such a configuration enables the suture ring250to accommodate the variations of anatomy that will be encountered when implanting, for example, a cannula ring in a tissue structure such as the wall of a heart (e.g., to access a ventricle). Additionally, a gimbaled configuration enables the hole or opening that is to be formed in a tissue structure to be located in a greater variety of places while being able to still provide a secure and leak-free connection.

Referring toFIGS. 6A-6D, another suture ring280is shown in accordance with an embodiment of the present invention. The suture ring280includes a coupling portion282configured to couple with a cannula structure (e.g., a cannula ring, an engagement sleeve, or other structures or devices) and a ring portion284configured for attachment with adjacent tissue. The cannula ring280further includes a locking mechanism286. In one embodiment, the locking mechanism286includes a set screw288associated with a split ring290(which may formed in conjunction with the coupling portion282as shown inFIG. 6A). The set screw enables the tightening and loosening of the split ring290so that the suture ring280may be secured in a desired position, loosened and repositioned (if desired), and then secured again. Thus, as shown in FIGS.6B and6C, the suture ring280may be secured at a first position on a cannula structure292(shown as an intraventricular pump—seeFIG. 6B) and then repositioned and secured at its new position (seeFIG. 6C). Such a configuration provides securement of the suture ring280, regardless of its position relative to the associate cannula structure292, and accommodates variation in tissue thickness as well as the ability to adjust depending, for example, the position and orientation of related components coupled to the cannula structure292. The use of an adjustable, locking mechanism286also enables the removal and insertion of various components through the ring portion282of the suture ring280. For example, referring briefly toFIG. 6D, while implanting or explanting a cannula structure292, it may be desirable to place a plug294within the ring portion and lock it into place, thereby preventing fluid flow while the cannula structure292or other components are absent (e.g., are being prepared for implant or have been explanted).

It is noted that the locking mechanism of suture ring280and the gimbaled configuration of suture ring250(FIGS. 5A and 5B) may be combined in a single suture ring to provide further adjustability.

Referring now toFIGS. 7A and 7B, another suture ring300is shown in accordance with an embodiment of the present invention. The suture ring300includes a coupling portion302and a ring portion304such as has been described above in various embodiments. An opening306in the coupling portion302is positioned eccentrically relative to either, or both, of an inner perimeter308of the ring portion304and an outer perimeter310of the ring portion304. In the embodiment shown inFIGS. 7A and 7B, the opening306is eccentrically located relative to both of the circular perimeters of the ring portion304. The eccentricity of the opening306enables the suture ring300to be rotated, relative to an opening in a tissue structure, and relative to a cannula structure or other device that may be positioned through an opening in a tissue structure, to accommodate variations in the specific anatomy encountered by a practitioner during implant of a device. Thus, depending on the conditions encountered, the suture ring300may be oriented with the opening306offset to the right, as shown inFIG. 7A, with the opening306offset to the left, as shown inFIG. 7B, or in some different orientation as may be required.

As with other embodiments, the eccentricity of the opening is not limited to the embodiments shown inFIGS. 7A and 7B, but may be combined with other features, other components and other embodiments described herein.

Referring now toFIGS. 8A and 8B, another suture ring320is shown in accordance with an embodiment of the present invention. The suture ring320includes a coupling portion322and a ring portion324such as described above with respect to other embodiments. Additionally, the suture ring320includes a valve326associated with the coupling portion302to enable selective fluid flow through the ring portion322. For example, with the suture ring coupled to an implanted cannula ring (e.g., cannula ring100), it may be desirable to prevent fluid flow through the cannula ring prior to coupling the cannula ring with another device (e.g., a blood pump). Thus, the valve326may be placed in a closed position (seeFIG. 8A) until the various components are connected, at which time, the valve326may be opened (seeFIG. 8B) to enable fluid flow. As shown inFIGS. 8A and 8B, the valve326may be configured as a simple gate valve with a gate or partition328that slides in a substantially linear direction through a slot330formed in the coupling portion322. While not specifically shown, a locking mechanism may also be incorporated to maintain the gate328in one or more desired positions relative to the coupling portion322(e.g., closed, open, partially opened). Additionally, the valve may include seals, or be so constructed, to maintain a fluid tight barrier when in the closed position.

Referring toFIGS. 9A and 9Banother suture ring350is shown in accordance with an embodiment of the present invention. The suture ring350includes a coupling portion352and a ring portion354such as described above with respect to other embodiments. Additionally, the suture ring350includes a valve356associated with the coupling portion302to enable selective fluid flow through the ring portion352. As shown, the valve356may be configured as a leaflet valve having a plurality of leaflets358that slides in a substantially linear direction through slots360formed in the coupling portion352. Again, while not specifically shown, a locking mechanism may also be incorporated to maintain the leaflets358in one or more desired positions relative to the coupling portion352(e.g., closed, open, partially opened).

Referring now toFIGS. 10A-10C, another suture ring380is shown in accordance with an embodiment of the present invention. The suture ring380includes a coupling portion382and a ring portion384such as described above with respect to other embodiments. Additionally, the suture ring380includes a valve386associated with the coupling portion382to enable selective fluid flow through the ring portion382. As shown, the valve386may be configured as a tricuspid valve with cusps or flaps388that are normally in a closed position. Upon application of pressure of a specified magnitude and direction, the flaps will open to enable fluid flow in a single direction. In one embodiment, the flaps may be configured to resist opening based on any negative pressure applied from a distal side of the valve386, but will open upon application of a stated amount of pressure applied from the proximal side of the valve386. Again, such a configuration provides substantial flexibility to a practitioner during cannulation procedures and while implanting or adjusting, for example, blood pumps and other associated components.

The various embodiments described herein may be practiced in combination with a variety of know cannulation techniques and components, as well as with various blood pumps and other assist devices. For example, they may be combined with various components, features and techniques as described in U.S. patent application Ser. No. 13/197,605 entitled CONFORMAL CANNULA DEVICE AND RELATED METHODS, filed on Aug. 3, 2011, the disclosure of which is incorporated by reference herein in its entirety.

While the invention may be susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and have been described in detail herein. However, it should be understood that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the following appended claims. Aspects of one described embodiment may be combined with aspects of other embodiments without limitation.