An embodiment of the present disclosure a bioabsorbable occlusion system for occluding defects or openings in a heart.

TECHNICAL FIELD

The present disclosure relates to a bioabsorbable occlusion system for openings or defects in a heart.

BACKGROUND

Openings and defects in a heart are often treated by placing an occlusion device at the site of the opening. Conventional occlusion devices, e.g., a Amplatzer Septal Occluders, for heart defects are metallic braided structures. These devices have a pre-defined shape and are collapsed inside a delivery tube for insertion into the heart and expand upon exit of the delivery tube to occlude the opening. Such conventional occlusion devices are designed to be permanently implanted in place in the heart and do not absorb or biodegrade into the surrounding tissue. Long term implantation may lead to cardiac erosion in some cases. In addition, septal closure with permanent implant can preclude septal crossing for future interventions

SUMMARY

An embodiment of the present disclosure is a bioabsorbable occlusion system for an opening or defect in a wall of a heart. The bioabsorbable occlusion system includes an occlusion implant having a first anchor, a second anchor, and a connector element coupled to the first anchor and the second anchor and configured to draw the first and second anchors toward each other. In such a system, an entirety of the occlusion implant is bioabsorbable. In addition, the occlusion implant has an insertion configuration, where the first anchor and the second anchor are collapsed and have an initial cross-sectional dimension, and an expanded configuration, where the first anchor and the second anchor are expanded outwardly and have expanded cross-sectional dimension that is substantially greater than the initial cross-sectional dimension.

Another embodiment of the present disclosure is a method for occluding an opening or a defect in a heart. The method includes inserting a guide catheter over a guidewire so that its distal end is located proximate the opening or defect in the tissue of the heart. The method includes advancing a delivery device in a distal direction through a channel of the guide catheter so that a first anchor and a connector element of an occlusion implant is positioned adjacent to a first side of the tissue of the heart and the opening or defect. In such a method, an entirety of the occlusion implant is bioabsorbable. The method includes further advancing the delivery device in the distal direction through the channel of the guide catheter so that a second anchor of the occlusion implant is positioned adjacent to a second side of the tissue of the heart and overlies the opening or defect. Next, the method includes retracting the connector element to draw the first anchor toward the second anchor to secure the occlusion implant in place. Then, the occlusion implant will be bioabsorb. The method may be used for a number of different openings or defects, which include, but are not limited to patent foramen ovale, ductus arteriosis, an iatrogenic transcaval defect, a ventricular septal defect, or an arterio-venous fistulae.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

As shown inFIG.1, embodiments of the present disclosure include a bioabsorbable occlusion system10for an opening or defect in a tissue, e.g., a wall, of a heart H. More specifically, the bioabsorbable occlusion system10includes an occlusion implant20that is configured to occlude defects/openings in the heart H and a delivery assembly60(FIG.11). The occlusion implant20is configured to entirely absorb into the patient over a defined time period. For example, the occlusion implant may fully resorb between 6 months and 18 months after implantation. In another example, the occlusion implant may fully absorb between 9 months and 18 months from implantation. In another example, the occlusion implant may fully absorb between 12 months and 18 months from implantation. As used herein, the term “bioabsorbable” means that the material will degrade over time by enzymatic action, by hydrolytic action and/or by other similar mechanisms in the human body, such that the products of biodegradation will either be absorbed by tissue within the body or excreted or through endothelialization, where implant is replaced by human tissue.

Continuing toFIG.1, an atrial septal defect (ASD) is shown in a schematic of a heart H. The bioabsorbable occlusion implant20is implanted in the ASD to occlude flow between the left atrium LA and right atrium RA. While an atrial septal defect ASD is shown in the figures, other indications are suitable for the bioabsorbable occlusion implant20. For example, the bioabsorbable occlusion implant20may be used for several types of openings or defects in the heart, which also include, but are not limited to, patent foramen ovale, ductus arteriosis, an iatrogenic transcaval defect, a ventricular septal defect, and/or an arterio-venous fistulae. Accordingly, the bioabsorbable occlusion implant20is not limited for use solely for occluding atrial septal defects.

Referring toFIGS.2A,2B, and11, the bioabsorbable occlusion system10includes an occlusion implant20having a first anchor24, a second anchor28, and a connector element32coupled to the first anchor24and the second anchor28and configured to draw the first anchor24and the second anchor28toward each other. In such a bioabsorable occlusion system10, an entirety of the occlusion implant20is bioabsorbable into the patient.

The occlusion implant20has an insertion configuration, as shown inFIGS.2A and11, where the first anchor24and the second anchor28are collapsed and have an initial cross-sectional dimension while being carried by the delivery assembly60(FIG.11).

The occlusion implant20also has an expanded configuration, as shown inFIG.2Bwhere the first anchor24and the second anchor28are ejected from the delivery assembly60and expanded outwardly.FIG.11illustrates components of the delivery assembly60and is described in more detail further below. In the expanded configuration, the occlusion implant20has an expanded cross-sectional dimension that is substantially greater than the initial cross-sectional dimension. Furthermore, the first anchor and the second anchor each have a cross-sectional dimension that is substantially greater than a cross-sectional dimension of the connector element32. Accordingly, when the occlusion implant20is in the expanded configuration, the first anchor expands outwardly to overlies an entirety of a first side of the tissue of the heart around the edge of the opening or defect. Likewise, a second anchor in the expanded configuration overlies an entirety of a second side of the tissue of the heart around the edge of the opening or defect.

Referring toFIGS.2-6, an embodiment of the first anchor24and second anchor28is shown. The first anchor24and the second anchor28are substantially the same. However, as illustrated in the figures, the first anchor24may be considered a distal anchor and define a distal end36of the occlusion implant20. The second anchor28may be considered a proximal anchor and define a proximal end38of the occlusion implant20. In the insertion configuration as show inFIG.2A, the occlusion implant20may be elongated along an axis A. Furthermore, a distal direction D refers to the direction from proximal end38toward the distal end36and a proximal direction P refer to the direction from the distal end36toward the proximal end38. In this disclosure, the terms distal anchor and first anchor may be used interchangeably, and the terms proximal anchor and second anchor may be used interchangeably.

Turning toFIGS.3and4, the first anchor24has a size and shape (when in the expanded configuration) that is sufficient cover and overlie a defect. As shown, the first anchor24has a central portion44and a plurality of lobes48that extend radially outwardly from the central portion44. In the example shown, the first anchor has three lobes. The three lobes48may extend outwardly along axes that define an angle α1 between about 110 and about 130 degrees with respect to each other. For example, angle α1 may be about 120 degrees.

Continuing withFIGS.3and4, the first anchor24includes a wall facing surface30and an opposing surface34spaced apart from the wall-facing surface40. The wall facing surface30is configured to face the tissue of the heart H when expanded and implanted to overly the defect2(FIG.2B). The first anchor24is configured to be coupled to the connector element32.

As shown inFIGS.2B-3, the first anchor24includes a coupler26disposed along the wall facing surface30. The coupler26connects the connector element32to the first anchor24. The coupler26may be any mechanical connector that can be secured to the connector element32. For instance, the coupler26may be two through-bores29that extend through the anchor through which a connector element32can be looped and knotted, for instance, when the connector element32is a suture. In another example, the coupler26can be a threaded bore or shaft for threadably coupling to the connector element32. The coupler26may be absorbable. However, in alternative embodiments, the coupler may not be absorbable.

Continuing withFIGS.5and6, the second anchor28also has a size and shape (when in the expanded configuration) that is sufficient to cover and overlie a defect2. As shown, the second anchor28has a central portion52and a plurality of lobes56that extend radially outwardly from the central portion52. As shown, the second anchor52has three lobes56that complement and correspond to the lobes48of the first anchor24(seeFIG.3). Furthermore, the three lobes56may extend outwardly along axes that define an angle α2 between about 110 and about 130 degrees with respect to each other. For example, angle α2 may be about 120 degrees.

Continuing withFIGS.5-6, a central bore58extends through the second anchor28and sized so that the connector element32extends through the bore58. The second anchor28also includes a wall facing surface40and an opposing surface42spaced apart from the wall-facing surface40. The wall facing surface40is configured to face the tissue of the heart H when expanded and implanted to overlie the defect2.

FIGS.7-10illustrate an alternative embodiment of the first anchor124and the second anchor128. Features common to anchors24,28and anchors124,128will use like reference numbers. As shown, each of the first anchor124and the second anchor128have four separate lobes48,56that extend outwardly from their respective central portions. Furthermore, the four lobes may extend outwardly along axes that define an angle β1, β2 between about 80 and about 100 degrees with respect to each other. For example, angle β1, β2 may be about 90 degrees. The first anchor124also includes a coupler26for connection to the connector element32(not shown inFIGS.7-10) and the second anchor128includes a bore58through which the connector element32may extend.

In yet another embodiment (not shown), each of the first anchor and the second anchor have two outwardly extending lobes and an enlarged central portion. The anchor body itself has a coverage area sufficient to overlie and occlude the target defect.

In yet another embodiment (not shown), each of the first anchor and the second anchor may be a substantially disc shaped body having a coverage area sufficient to overlie and occlude the target defect. In such an embodiment, the first and second anchors may have a generally circular perimeter, an ovular perimeter, or a rectilinear perimeter.

In yet another embodiment (not shown), each of the the first anchor and the second anchor are formed from a frame of separate anchor members that are entirely absorbable. In such an embodiment, the frame of anchor members may be braided materials or other frame like structures with shape memory such that, when the anchors are ejected from the delivery assembly60, the anchors expanded outwardly. The anchor member may be made from bioabsorable polymers as described herein.

FIGS.11A-11Dillustrate yet another embodiment of the present disclosure. In the embodiment shown, each anchor224may have an inflatable edge portion226that extends around the anchor outer perimeter. The inflatable edge portion226may be defined by an internal channel or bladder like member that extends around the outer perimeter. An injection solution, such as saline, contrast, and the like, may be injected into the internal channel to cause edge expansion as described. In this manner, the outer edge of the first anchor is at least partially inflatable to define its expanded shape. Likewise, the outer edge of the second anchor is at least partially inflatable to define its expanded shape. In such an embodiment, the first and second anchor may include an injection element coupled to first and second anchors and controllable via an actuator at the proximal end of the delivery assembly. The embodiment shown inFIGS.11A-11Dmay be similar structure and features to the embodiment shown inFIGS.1-10.

The first anchor and the second anchor may be arranged on the connector element such that their shapes complement each other to maximize the surface contact with the tissue of the heart H. For example, in embodiments where each anchor has a plurality of lobes, the first anchor is offset with the respect to second anchor so that their respective lobes do not overly along a common axis.

Referring toFIGS.2and12, the connector element32may be any absorbable device or element that can be used to couple the first and second anchor together. In the example shown, the connector element32may be an absorbable suture that is coupled to and knotted to the first anchor at the coupler26. Such a suture can extend proximally from the coupler26and through the bore58of the second anchor28. In one example, a slip knot or other knot configuration can be used to secure the first and second anchors relative to each other. That is, once the first anchor is implanted and in place, and the second anchor is implanted and in place, tension applied to the suture (or connector element) can draw the two anchors together, at which point a knot or the like can be used to secure the positions of the anchors along the suture, thereby keeping the occlusion implant20in place. In an alternative embodiment, the occlusion implant20may include an optional lock, in the form of slidable and crimped element can be sliding secured in place along the connector element.

In another embodiment (not illustrated), the connector element32may include surface with a plurality of teeth while a lock element can include a plurality of teeth, that when engaged, allow move of the lock distally but inhibit movement of the lock proximally. In addition, the lock element in such an example may be formed directly in the bore58of the second anchor and the connector element may be integrally formed with first anchor24. Thus, in one example, the connector element includes a plurality of teeth that are configured to engage a plurality of teeth located in a bore of the first anchor and the second anchor.

In yet another embodiment (not illustrated), the connector element32may be an elongated shaft that is integrally coupled to the first anchor24. The elongated shaft may include any number projections (or recesses) that are configured to couple to a lock element that includes corresponding recesses (or projections) that when engaged with the elongated shaft serve to fix the position of the first and second anchor relative to each other. In addition, the lock element in such an example may also be formed directly in the bore58of the second anchor28. In such an example, the elongate shaft of the connector element has a plurality of engagement members that are configured to engage to a plurality of corresponding engagement members in the bore of the first anchor or the second anchor.

The first anchor, second anchor, and connector element may be formed from biocompatible and bioabsorbable, polymers, copolymers, or polymer mixtures. Exemplary bioabsorbable materials include polymers and co-polymers of glycolide, lactide, caprolactone, trimethylene carbonate, dioxanone, and physical and chemical combinations thereof. Other examples include polylactic acid (PLA), polyglocolic acid (PGA), poly lactide-co-glycolide (PLGA), among others. In addition, metal alloys that are bioabsorbable may be used if sufficient degradation is possible for a given time.

In certain examples, the first and second anchors may be made of braided and/or woven textile structures that can 1) retain an expanded shape once ejected from the delivery assembly, and 2) bioabsorb over time. For example, the anchors may be braided constructs formed from heat set-able and bioabsorable polymer yarns and/or filaments that are formed into the expanded shape. Such materials can be collapsed for insertion into the delivery assembly for use.

In an example, each component of the occlusion implant20is formed from similar polymeric materials so that each component has a somewhat similar degradation profile. However, in certain cases, the material make-up of each component, such as between the anchors24,28and the connector element32, may differ such that an entirety of the implant can bioabsorb at substantially the same rate. For example, the first anchor and the second anchor may be formed from a first polymeric material and the connector element may be formed from a second polymeric material that is different from the first polymeric material. In another example, the first anchor may be formed from a first polymeric material, the connector element may be formed from a second polymer material, and the second anchor may be formed from a third polymeric material where the first, second, and third polymeric materials are different.

In addition, as further described below, the occlusion implant may be formed from an inflatable polymeric membrane (FIGS.15-19) that has a pre-defined shape and is subject to degradation in accordance with the teaching as disclosed in the present application.

Referring toFIGS.12-14, bioabsorbable occlusion system10includes a delivery assembly60for inserting and implanting the occlusion implant20. The delivery assembly60includes a guide catheter64, a delivery device74, and an optional access sheath (not shown or numbered).

As shown inFIG.12, the guide catheter64includes a proximal end (not shown or numbered), a distal end66opposite the proximal end), and a channel68that extends therethrough. The guide catheter64carries occlusion implant20in the insertion configuration.

The delivery device74is movable within and relative to the guide catheter. As shown, the delivery device74is configured to advance the occlusion implant20from inside the channel68to a location outside the channel68(or distal to the distal end66). The delivery device74includes an elongated shaft78with a proximal end (not shown or numbered) and a distal end76opposite the proximal end. In one example, the delivery device74is an elongated push rod. In another example, the delivery device74is an elongated tube having a channel for receiving a portion of the connector element therein. Furthermore, the delivery device may be configured to be releasably coupled to the occlusion implant20.

Continuing withFIG.12, the occlusion implant20may be carried by the delivery assembly60for insertion into the defect2. More specifically, the second anchor28, which is referred to sometimes as the proximal anchor, is in the guide catheter64at the distal end76of the delivery device74. In one example, the proximal anchor or second anchor is in contact with but necessarily coupled to the delivery device74. In another example, the distal end of the delivery device74is coupled to the second anchor28. The connector element32may extend through (or along-side) the second anchor28and further into the channel of the guide catheter. The first anchor24, sometimes referred to as the distal anchor is positioned in the guide catheter adjacent to the second anchor24. In this manner, the occlusion implant20is disposed in the insertion configuration in a generally elongated state. Furthermore, the first anchor24and second anchor28are formed in a pre-defined shape and are carried by the guide catheter so that upon ejection from the guide catheter, the first and second anchors can be expanded into the expanded configuration.

In typical procedure for occluding defects, the bioabsorable occlusion system10may include an access sheath (not shown). The access sheath can have a proximal end, a distal end, and an access sheath channel that extends from the proximal end to the distal end. The delivery assembly60, e.g., the guide catheter, is insertable into the access sheath channel.

As shown in the sequence ofFIGS.13A-14, advancement of the delivery device74in a distal direction ejects the first anchor24from the guide catheter64, thereby causing the first anchor24to expand into the expanded configuration. Further advancement of the delivery device74in the distal direction ejects the second anchor28from the guide catheter, thereby causing the second anchor28to expand into the expanded configuration. While advancement of the delivery device74is described as causing ejection of the anchors24,28, retraction of the guide catheter relative to the delivery device74could also cause ejection of the anchors,24,28in the sequence shown.

An alternative embodiment of a bioabsorable occlusion system210is shown inFIGS.15-19. The bioabsorbable occlusion system210is similar to the bioabsorable occlusion system10described above and shown inFIGS.2A-14and common reference numbers are used to identify features common to both systems.

Continuing withFIGS.15-19, the bioabsorable occlusion system210includes an occlusion implant220having a first anchor224, a second anchor228, and a connector element232coupled to the first anchor224and the second anchor228that couples and second anchors224,228together. In the bioabsorable occlusion system210, an entirety of the occlusion implant220is bioabsorbable into the patient. However, occlusion implant220generally includes an expandable body formed from a flexible membrane230that defines an inner volume (not shown) configured to receive therein a fluid that causes expansion of the membrane230and thus the implant. The flexible membrane230may be a woven structure with an impermeable coating, a braided structure with an impermeable coating, or any polymeric material or composite, with can mono-layered or multi-layered, which can contain a fluid to but is flexible enough to permit expansion.

Like occlusion implant20, the occlusion implant220has an insertion configuration, as shown inFIG.15, where the first anchor24and the second anchor28are collapsed and have an initial cross-sectional dimension while be carried by the delivery assembly60(FIG.16). The occlusion implant220also has an expanded configuration, as shown inFIG.16, where the first anchor24and the second anchor28are ejected from the delivery assembly60(FIGS.16and19) and expand outwardly. In the expanded configuration, the first anchor224and second anchor228have an expanded cross-sectional dimension that is substantially greater than the initial cross-sectional dimension. In addition, the cross-sectional dimension of the connector member232is substantially less the respective cross-sectional dimensions of the first anchor224and the second anchor228.

The occlusion implant220also includes an injection member236that is used to inject a fluid into to inner volume of the occlusion implant220. A fluid may be saline, a contrast, or methyl-acrylate. Other injectable materials that are biocompatible may be used to cause expansion of the implant. In addition, the entirety of the occlusion implant220is bioabsorable.

As shown in the sequence ofFIGS.16-19, advancement of the delivery device74in a distal direction ejects the first anchor224from the guide catheter64. Further advancement of the delivery device74in the distal direction ejects the second anchor228from the guide catheter. While advancement of the delivery device74is described as causing ejection of the anchors24,28, retraction of the guide catheter relative to the delivery device74could also cause ejection of the anchors,24,28in the sequence shown. Next, an injection fluid is inserted into the inner volume of the occlusion implant220via the injection member236until the implant attains it fully expanded state, as shown inFIGS.16and19.

While the disclosure is described herein, using a limited number of embodiments, these specific embodiments are not intended to limit the scope of the disclosure as otherwise described and claimed herein. The precise arrangement of various elements and order of the steps of articles and methods described herein are not to be considered limiting. For instance, although the steps of the methods are described with reference to sequential series of reference signs and progression of the blocks in the figures, the method can be implemented in an order as desired.