Articulated center post
This invention relates to an occlusion device for the heart, having an articulated center post which prevents rotation of the individual occluder elements around the center post, while allowing the device to better conform to the contours of the heart to increase sealing abilities and reduce breakage resulting from conformation pressure.
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This application is a continuation-in-part of U.S. application Ser. No. 10/348,865, filed Jan. 22, 2003.
BACKGROUND OF THE INVENTIONThis invention relates to an occlusion device for the closure of physical apertures, such as vascular or septal apertures. More specifically, this invention relates to an occlusion device for the heart, having an articulated center post which allows the device to better conform to the contours of the heart.
Normally, permanently repairing certain cardiac defects in adults and children requires open heart surgery, a risky, expensive, and painful procedure. To avoid the risks and discomfort associated with open heart surgery, modern occlusion devices have been developed that are small, implantable devices capable of being delivered to the heart through a catheter. Rather than surgery, a catheter inserted into a major blood vessel allows an occlusion device to be deployed by moving the device through the catheter. This procedure is performed in a cardiac cathlab and avoids the risks and pain associated with open heart surgery. These modern occlusion devices can repair a wide range of cardiac defects, including patent foramen ovale, patent ductus arteriosus, atrial septal defects, ventricular septal defects, and may occlude other cardiac and non-cardiac apertures.
There are currently several types of occlusion devices capable of being inserted via a catheter including button devices, collapsible umbrella-like structures, and plug-like devices. A potential draw back to these devices is the difficulty in ensuring that the occluder conforms to the contours of the defect. Poor conformation to the defect results in poor seating of the device which decreases the ability of the device to occlude the defect. Ensuring the proper seating of an occlusion device once it has been deployed poses a continuing challenge given the uneven topography of the vascular and septal walls of each patient's heart. The challenge in designing an occluder which conforms to the uneven topography is compounded by the fact that the contours of each defect in each individual patient are unique.
Lack of conformation to the walls of the heart can place significant amounts of stress on the occlusion device and decrease fatigue life. Once deployed, different parts of the occluder may experience more or less stress as a result of the uneven topography. At some point, stressed parts of the occluder may break. Broken parts increase the likelihood of damage to the surrounding tissue and lead to patient anxiety.
Another obstacle which maybe encountered is the difficulty in readily distinguishing the individual occluder elements in order to determine their position in relation to each other and allow for repositioning, while still maintaining the flexibility needed for better conformation.
Thus, there is a need in the art for an occlusion device that will occlude cardiac defects and will match the contours of the heart thereby increasing the life of the device and sealing ability while reducing damage to the surrounding tissue. There is also a need for an occlusion device that prevents rotation of the individual occluder elements around the center post, while still maintaining the needed flexibility to properly position the device and successfully match the contours of the heart.
BRIEF SUMMARY OF THE INVENTIONThe present invention allows occlusion devices to more effectively close a physical anomaly. The present invention is an occlusion device having a first occluding body, a second occluding body, and an articulated center section. The articulated center section increases the ability of the occlusion device to more accurately conform to the defect.
The center section includes a ball and socket joint and means for limiting rotation of the first occluding body relative to the second occluding body. The means for limiting rotation of the first occluding body relative to the second occluding body includes interlocking elements. In a first embodiment, the interlocking elements include a peg on a ball of the ball and socket joint and a groove on a socket of the ball and socket joint. In a second embodiment, the interlocking elements include a groove on a ball of the ball and socket joint and a peg on a socket of the ball and socket joint. The occluding bodies are rotationally limited but are still able to articulate, which allows for easier positioning of the occlusion device.
BRIEF DESCRIPTION OF THE DRAWINGS
Once occlusion device 10 is deployed, fixation devices 14, 30 serve to hold proximal and distal sheets 20, 22 in place to seal the defect. To ensure there is sufficient tension to hold sheets 20, 22 in place, fixation devices 14, 30 are made of a suitable material capable of shape memory, such as nickel-titanium alloy, commonly called Nitinol. Nitinol is preferably used because it is commercially available, very elastic, non-corrosive, and has a fatigue life greater than that of stainless steel. To further ensure that fixation devices 14, 30 do not suffer from fatigue failures, one embodiment of the present invention relies on making fixation devices 14, 30 of stranded wire or cables.
Center section 12 shown in occlusion device 10 is articulated. The articulation can be accomplished by a variety of methods. The articulation could comprise one or more joints, or hinges. It could also be a spring or a coil. Additionally, a spot specific reduction in the amount of material used to create center section 12 could render portions of center section 12 sufficiently flexible.
Center section 12 is preferably formed to have a diameter of between about 8 millimeters and about 0.1 millimeters. In addition, the length of center section 12 is preferably less than about 20 millimeters.
Sheets 20, 22 are comprised of a medical grade polymer in the form of film, foam, gel, or a combination thereof. One suitable material is DACRON®. Preferably, a high density polyvinyl alcohol (PVA) foam is used, such as that offered under the trademark IVALON®. To minimize the chance of occlusion device 10 causing a blood clot, foam sheets 20, 22 may be treated with a thrombosis inhibiting material. One such suitable material is heparin.
The size of sheets 20, 22 may vary to accommodate various sizes of defects. When measured diagonally, the size of sheets 20, 22 may range from about 15 millimeters to about 45 millimeters. In some instances, it maybe desirable to form sheets 20, 22 so that they are not both the same size. For instance, one sheet and its associated fixation device can be made smaller (25 millimeters) than the corresponding sheet and its associated fixation device (30 millimeters). This is particularly useful in situations where occlusion device 10 is to be placed at a location in the heart which is close to other nearby cardiac structures. Making sheets 20, 22 different sizes may assist in providing optimal occlusion of a defect, without affecting other structures of the heart which may be nearby.
The placement of catheter 50, or other means that guides occlusion device 10 to septal defect 44, determines the location of and angle at which occlusion device 10 is deployed. Once catheter 50 is properly positioned at septal defect 44, delivery forceps 52 is used to push occlusion device 10 through septal defect 44. Distal side 54 of occlusion device 10 is then allowed to expand against septal wall 40 surrounding septal defect 44.
In
Often, due to limited space, catheter 50 enters the heart at an angle that is not perpendicular to the defective wall. In this situation, occlusion device 10 cannot enter septal defect 44 properly because the line of center section 12 must follow the same line as catheter 50. Occlusion device 10 must be forced into septal defect 44 at an angle, which may cause the tissue surrounding defect 44 to become distorted. If the surrounding cardiac tissue is distorted by catheter 50, it is difficult to determine whether occlusion device 10 will be properly seated once catheter 50 is removed and the tissue returns to its normal state. If occlusion device 10 is not seated properly, blood will continue to flow through septal defect 44 and occlusion device 10 may have to be retrieved and re-deployed. Both doctors and patients prefer to avoid retrieval and re-deployment because it causes additional expense and longer procedure time.
When center section 12 is articulated or flexible, the insertion angle of occlusion device 10 is not restricted to that of catheter 50. Occlusion device 10 can be more easily inserted, because once joint 62 is outside catheter 50, the angle of insertion can be changed by allowing joint 62 to move. This variable insertion angle allows occlusion device 10 to enter defect 44 at an optimum angle, minimizing distortion of surrounding cardiac tissue. If the tissue is not distorted when occlusion device 10 is deployed, the seating of occlusion device 10 should not change drastically once catheter 50 is removed. Because occlusion device 10 can be properly seated at the first insertion, the number of cases that require retrieval and redeployment should decrease.
Another important advantage of the present invention is that articulated center section 12 allows distal and proximal sides 54, 56 to conform more readily to the contours of a heart after it is deployed, providing a custom fit to a variety of defects. Often, when implanted, occlusion device 10 is located in an irregularly shaped defect. Having articulated center section 12 allows occlusion device 10 to conform to a broader spectrum of defects.
For instance, as viewed in
Another feature of occlusion device 10 is that it is fully retrievable. To allow occlusion device 10 to be retrievable, as well as ensure that occlusion device 10 fits into a small diameter catheter, it is important to ensure that arms 16 are not of a length that results in atraumatic tips 18 clustering at the same location. If atraumatic tips 18 all cluster at the same location when occlusion device 10 is inside catheter 50, occlusion device 10 will become too bulky to allow it to be easily moved through catheter 50.
In situations where occlusion device 10 is not properly deployed and must be retrieved into catheter 50, it is possible to withdraw occlusion device 10 back into catheter 50 by grasping either center section 12 or by grasping any arm 16. When occlusion device 10 is retrieved into catheter 50, both upper and lower arms 16 will be folded in the same direction. Once again it is important to vary the length of upper and lower arms 16, so that when occlusion device 10 is retrieved, atraumantic tips 18 on upper arms 16 do not cluster at the same location as atraumatic tips 18 on lower arms 16.
In this example, joint 78 provides the articulation. Though shown with double articulation, articulated center section 70 is not so limited. The number of joints 78 may be varied to accommodate a particular defect or a particular type of defect. For example, one joint may be best for an atrial septal defect while two or three articulations may be best for a larger defect such as patent foramen ovale or a long defect such as patent ductus arteriosus.
First sleeve 112 and second sleeve 114 comprise center connector 76. Second center post 74 connects to center connector 76 by joining second sleeve 114 at joint 116. First center post 72 connects to center connector 76 by joining first sleeve 112 at joint 118. When the occlusion device is fully assembled, occluder elements will be attached to first and second center posts 72, 74, as can be seen in
There are several disadvantages to allowing the occluder elements to rotate around the articulated center post. First, it is possible that the support arms of one support frame will line up with the arms of the other support frame, making it difficult to distinguish one set from the other set when the occlusion device is viewed on a fluoroscope. As a result, it is more of a challenge to determine the exact position of either support frame because when aligned, the two become indistinguishable.
Secondly, preventing rotation of the occluder elements may improve the overall positioning of the device. For example, when inserting a device that allows freedom of rotation, if upon the insertion of the device, the arms of a support frame are laying in an undesirable position, such as resting against the aorta, simply manipulating the device to reposition the arms may not be possible because the center post will rotate consistently relative to the occluder element, leaving the arms in the original position.
Finally, the preliminary loading of the device may be hindered if rotation of the support frames is not prevented. When the individual occluder elements rotate consistently, loading the occlusion device into a delivery device or catheter may be more difficult and time-consuming.
Head 120 located at a first end of second center post 74 is connected to body 124 of second center post 74 at first neck 122. Knob 24 is located on the second end of body 124 and is connected to body 124 by second neck 126. To assist in assembly, which is discussed in more detail below, the body 124 of second center post 74 is preferably smaller in diameter than head 120. Knob 24 has a smaller diameter than both body 124 and head 120. For example, head 120 may have a diameter A of about 1.35 millimeters, body 124 may have a diameter B of about 1.2 millimeters, and knob 24 may have a diameter C of about 1.0 millimeter.
Knob 24 is configured to allow a delivery forceps to attach to occlusion device 10 as it is pushed through a catheter and allows the forceps to manipulate occlusion device 10 as it is delivered. Likewise, a guide forceps can be used to position occlusion device 10 once it reaches the desired location or to retrieve occlusion device 10 should it not be seated properly. Knob 24 may additionally have a cross sectional area which allows the forceps to rotatably move occlusion device 10 while occlusion device 10 is inserted into septal defect 44. Second neck 126 is grasped by a forceps so that there is at least some play between the forceps and second neck 126 when pushing occlusion device 10 through a catheter. For example, the guide forceps may engage second neck 126 by means of a claw-like or hook-like end. In an alternate embodiment, knob 24 is threaded to allow for attachment to a threaded guide forceps.
In this embodiment, head 120 includes pegs 138a-138d positioned around its circumference. Pegs 138a-138d are shown evenly spaced to provide articulation about two orthogonal axes when coupled with a center connector, as described in detail in
First center post 72 is nearly identical to second center post 74 except that it does not include knob 24 or second neck 126. Because occlusion device 10 only needs to be graspable at one end, a second knob is unnecessary. To assist in assembly, body 134 of first center post 72 is preferably smaller in diameter than head 130. For example, head 130 may have a diameter D of about 1.35 millimeters, and body 134 may have a diameter E of about 1.2 millimeters.
Preferably, a hard metal, such as titanium, is used to construct center posts 72, 74 because use of a hard material prevents binding within the joints when the center section if fully assembled. Pegs 138a-138d may be machined directly into the titanium, using a process such as electrical discharge machining.
Although in
The number of channels 139a-139d formed in socket 152 corresponds to the number of pegs 138a-138d formed on head 120. Pegs 138a-138d and channels 139a-139d are identically spaced, which allows for pegs 138a-138d and channels 139a-139d to engage upon assembly, as described in
Although in
Preferably, a hard metal, such as titanium, is used to construct sleeves 112, 114 because use of a hard material prevents binding within the joints when the center section is fully assembled.
Socket 152 of sleeve 114 houses head 120. Pegs 138a-138d located on head 120 engage channels 139a-139d located within socket 152. While shown with respect to head 120 and sleeve 114, as shown in
To assemble the center section, center posts 72, 74 are slipped into corresponding sleeves 112, 114. As described above with respect to
When inserting center posts 72, 74 into sleeves 112, 114, pegs 138a-138d and channels 139a-139d must be correlated to each other. Prior to insertion into sleeve 112, center post 72 should be rotated so that pegs 138a-138d on head 130 are positioned to slide into corresponding channels 139a-139d located within socket 154. Likewise, prior to insertion into sleeve 114, center post 174 should be rotated so that pegs 138a-138d on head 120 are positioned to slide into corresponding channels 139a-139d located within socket 152. Center posts 72, 74 are then inserted into sleeves 112, 114 by sliding pegs 138a-138d into corresponding channels 139a-139d until necks 122, 132 extend out of sockets 152, 154. Finally, sleeve 112 and sleeve 114 are joined by inserting cuff 140 into sleeve 114, which comprises central connector 76. Once assembled, sleeves 112, 114 may be welded together.
The resulting assembly forms two ball and socket joints, which are able to articulate (i.e. pivot) but are rotationally inhibited. As described above, pegs 138a-138d and channels 139a-139d engage. Since pegs 138a-138d of heads 120, 130 are housed within channels 139a-139d of sleeves 112, 114, the rotational movement of center posts 72, 74 with respect to central connector 76 is prevented. In other words, center posts 72, 74 are prevented from turning around an axis extending through sockets 152, 154. As previously described, preventing rotation of center posts 72, 74 in relation to sleeves 112, 114 improves the overall positioning of the device. It also is easier to distinguish individual occluder elements, and the preliminary loading of the occlusion device into a catheter may be simplified.
In order for the occlusion device to adequately conform to the walls of the heart, flexibility of the device is still needed. In this embodiment, the interaction between pegs 138a-138d and channels 139a-139d still permits articulated movement of center posts 72, 74. Center posts 72, 74 are able to pivot with respect to center connector 76, while pegs 138a-138d and channels 139a-139d remain engaged. Because the center section retains the desired flexibility, an occlusion device will have the ability to match the contours of a heart. This results in an increased life for the device, and also improves its sealing ability.
In this embodiment, head 120 includes channels 139a-139b located concentrically around the rounded surface of head 120. Channels 139a-139b may be evenly spaced to provide better articulation when coupled with a center connector, as described in
Although in
Socket 152 of sleeve 114 houses head 120. Pegs 138a-138d located within socket 152 engage channels 139a-139b located on head 120. While shown with respect to head 120 and sleeve 114, as shown in
To assemble the center section, center posts 72, 74 are slipped into corresponding sleeves 112, 114. As described above with respect to
When inserting center posts 72, 74 into sleeves 112, 114, pegs 138a-138d and channels 139a-139b must be correlated to each other. Prior to insertion into sleeve 112, center post 72 should be rotated so that channels 139a-139b on head 130 are positioned to slide onto corresponding pegs 138a-138d located within socket 154. Likewise, prior to insertion into sleeve 114, center post 174 should be rotated so that channels 139a-139b on head 120 are positioned to slide onto corresponding pegs 138a-138d located within socket 152. Center posts 72, 74 are then inserted into sleeves 112, 114 by sliding pegs 138a-138d into corresponding channels 139a-139b until necks 122, 132 extend through sockets 152, 154. Finally, sleeve 112 and sleeve 114 are joined by inserting cuff 140 into sleeve 114, which comprises central connector 76. Once assembled, sleeves 112, 114 may be welded together.
The resulting assembly forms two ball and socket joints, which are able to articulate but are rotationally inhibited. As described above, pegs 138a-138d and channels 139a-139b engage. Since pegs 138a-138d of sleeves 112, 114 are housed within channels 139a-139b of heads 120, 130, the rotational movement of center posts 72, 74 with respect to central connector 76 is prevented. In other words, center posts 72, 74 are prevented from turning around an axis extending through sockets 152, 154. As previously described, preventing rotation of center posts 72, 74 in relation to sleeves 112, 114 improves the overall positioning of the device. It also is easier to distinguish individual occluder elements, and the preliminary loading of the occlusion device into a catheter may be simplified.
In order for the occlusion device to adequately conform to the walls of the heart, flexibility of the device is still needed. In this embodiment, the interaction between pegs 138a-138d and channels 139a-139b still permits articulated movement of center posts 72, 74. Center posts 72, 74 are able to pivot with respect to center connector 76, while pegs 138a-138d and channels 139a-139b remain engaged. Because the center section retains the desired flexibility, an occlusion device will have the ability to match the contours of a heart. This results in an increased life for the device, and also improves its sealing ability.
Though shown in a patent foramen ovale occlusion device, an articulated center post can be adapted for use in any occluding device, including those designed for atrial septal defects, patent ductus arteriosus, and ventricular septal defects. The center section can also be adapted for use in an septal stabilization device.
Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention. In particular, any of the applicable features disclosed in related applications U.S. patent application entitled Septal Stabilization Device, Ser. No. 10/349,744, U.S. patent application entitled Hoop Design for Occlusion Device, Ser. No. 10/349,118, Occlusion Device Having Five or More Arms, Ser. No. 10/348,701, and U.S. patent application entitled Laminated Sheets for Use in a Fully Retrievable Occlusion Device, Ser. No. 10/348,864, filed on even date herewith, may be of use in the present invention. Each of these applications is hereby incorporated by reference.
Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.
Claims
1. An occlusion device comprising:
- a first occluding body;
- a second occluding body; and
- a center section including a ball and socket joint and means for limiting rotation of the first occluding body relative to the second occluding body.
2. The occlusion device of claim 1 wherein the means for limiting rotation of the first occluding body relative to the second occluding body includes interlocking elements.
3. The occlusion device of claim 2 wherein the interlocking elements include a peg on a ball of the ball and socket joint and a groove on a socket of the ball and socket joint.
4. The occlusion device of claim 2 wherein the interlocking elements include a groove on a ball of the ball and socket joint and a peg on a socket of the ball and socket joint.
5. An occlusion device comprising:
- a first collapsible support frame;
- a second collapsible support frame;
- a first center support having a first body, a first neck, and a first head, the first body connected to the first collapsible support frame;
- a second center support having a second body, a second neck, and a second head, the second body connected to the second collapsible support frame;
- a center connector providing an articulated connection between the first center support and the second center support, the center connector including a first socket in which the first head is movable and a second socket in which the second head is movable;
- a first sheet attached to the first collapsible support frame;
- means for preventing rotation of the first head in the first socket; and
- means for preventing rotation of the second head in the second socket.
6. The occlusion device of claim 5 and further comprising:
- a second sheet attached to the second collapsible support frame.
7. The occlusion device of claim 5 wherein each of the first and second collapsible support frames includes a plurality of arms.
8. The occlusion device of claim 7 wherein the first collapsible support frame is oriented relative to the second collapsible support frame to offset the arms of the first collapsible support frame from the arms of the second collapsible support frame.
9. The occlusion device of claim 5 wherein the center connector includes a first sleeve and a second sleeve.
10. The occlusion device of claim 9 wherein the first sleeve contains the first socket.
11. The occlusion device of claim 10 wherein the second sleeve contains the second socket.
12. The occlusion device of claim 11 wherein the first sleeve and second sleeve connect to each other.
13. The occlusion device of claim 5 wherein the means for preventing rotation of the first head in the first socket includes a channel in the first socket.
14. The occlusion device of claim 13 wherein the means for preventing rotation of the first head in the first socket further includes a peg on the first head that is movable in the channel in the first socket.
15. The occlusion device of claim 5 wherein the means for preventing rotation of the second head in the second socket includes a channel in the second socket.
16. The occlusion device of claim 15 wherein the means for preventing rotation of the second head in the second socket further includes a peg on the second head that is movable in the channel in the second socket.
17. The occlusion device of claim 5 wherein the means for preventing rotation of the first head in the first socket includes a peg in the first socket.
18. The occlusion device of claim 17 wherein the means for preventing rotation of the first head in the first socket further includes a channel on the first head for receiving the peg in the first socket.
19. The occlusion device of claim 5 wherein the means for preventing rotation of the second head in the second socket includes a peg in the second socket.
20. The occlusion device of claim 19 wherein the means for preventing rotation of the second head in the second socket further includes a channel on the second head for receiving the peg in the second socket.
21. A center connection for an occlusion device, the center connection comprising:
- a first center post having a first body, a first neck, and a first head;
- a second center post having a second body, a second neck, and a second head; and
- a center connector that engages the first head and the second head to permit articulated movement of the first and second center posts while preventing rotational movement of the first and second center posts with respect to the center connector.
22. The center connection of claim 21 wherein the center connector further comprises a first sleeve and a second sleeve.
23. The center connector of claim 22 wherein the second sleeve has a cuff at a proximal end for attachment to the first sleeve.
24. The center connection of claim 22 wherein the center connector includes a peg.
25. The center connection of claim 22 wherein the first and second heads each comprise a channel which receives a peg on the center connector.
26. The center connection of claim 22 wherein the center connector includes a channel.
27. The center connection of claim 22 wherein the first and second heads each include a peg which engages a channel on the center connector.
Type: Application
Filed: Jan 6, 2006
Publication Date: Jun 1, 2006
Applicant: Cardia, Inc. (Burnsville, MN)
Inventors: Joseph Marino (Apple Valley, MN), Michael Corcoran (Woodbury, MN)
Application Number: 11/328,917
International Classification: A61B 17/08 (20060101);