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Retrievable septal defect closure device

Retrievable septal defect closure device description/claims

This application is a continuation of U.S. application Ser. No. 10/930,321, filed Aug. 31, 2004, which is a continuation of U.S. application Ser. No. 10/093,091, filed Mar. 6, 2002 and issued as U.S. Pat. No. 6,911,037 on Jun. 28, 2005, which is a continuation of International Application Number PCT/US99/20430 filed Sep. 7, 1999, which was published in English under PCT Article 21(2), the teachings of which are incorporated herein by reference.

The present invention generally relates to minimally invasive devices for occluding a defect and has particular utility in connection with occluding defects in septa, such as atrial septal defects.

Considerable efforts have been made to develop remotely deployable occluding devices which can be used to occlude body passageways without requiring significant surgical intervention. A number of researchers have attempted to develop a safe, reliable device which can be deployed through a catheter to occlude a septal defect, such as atrial and ventricular septal defects in the heart. Many of the same devices are used in connection with occluding patent ductus arteriosis (PDA) defects.

One of the first practical systems for reliably occluding septal defects using a transcatheter approach was developed by Dr. Gladwin S. Das and is described in U.S. Pat. Nos. 5,334,217 and 5,578,045 (the teachings of both of which are incorporated herein by reference). All of the devices designed for minimally invasive septal defect occlusion prior to Das' development were cumbersome and relatively difficult to deploy. Most of them were also mechanically complex, greatly increasing the chance of mechanical failure. The simplicity of the Das design greatly facilitated delivery and reduced the likelihood of any mechanical failure of the device.

Briefly, the Das occluder includes a pair of occluding disks attached to one another. In one embodiment illustrated in that patent, each of the disks comprises a membrane with an elastically deformable frame carried about its periphery. The frame is capable of being collapsed so the device may be delivered through a catheter, but is said to be flexible enough to elastically deploy the membrane upon exiting the catheter. The central portions of the two membranes may be attached to one another to define a central “conjoint disk.”

In deploying the Das device, the frames of the two disks are collapsed and the device is inserted into the distal end of a delivery catheter. The catheter is passed through the septal defect to be occluded and the first of the two disks is urged out of the catheter for elastic deployment. The second disk is then urged out of the distal end of the catheter on the other side of the defect to position the central conjoint disk within the defect to be occluded.

While the Das device has proven to be a remarkable advance over the state of the art, it has become clear that some further refinements may be advantageous. In particular, the Das device can be a little difficult to retract once deployed. The Das patents discuss a system for holding the occluder on the distal end of the delivery device using a tether. This permits an operator to retain hold of the device in the event of an improper deployment so the device does not float free within the patient's heart or vascular system. Unfortunately, though, it has proven relatively difficult to reliably and safely retract an inappropriately deployed device back into the lumen of the delivery catheter. While it may be possible to retract the right occluding disk (the second disk to exit the catheter) by retaining a grip on the frame of that disk, it can be much more difficult to retract the left disk (the first occluding disk to be deployed) back into the catheter.

A number of other researchers have attempted to provide improved occlusion devices which can be delivered through a transcatheter approach. For example, in U.S. Pat. No. 5,741,297, Simon discloses a device which has a series of arms used to stretch two separate pieces of fabric. In addition to the single wire joining both of the membranes, the membranes are bonded directly to one another, with the bond being spaced well inwardly of the frame. (This relationship is perhaps best seen in FIGS. 2 and 3.) Simon does not discuss in any detail how this device would be retracted if improperly deployed.

Shaw et al. propose a system for manufacturing occlusion devices which are based on some of the same concepts underlying the Das occluder. In particular, in U.S. Pat. No. 5,879,366, Shaw et al. utilize a pair of membranes which are deployed utilizing a wire frame (38 and 54). These two membranes are joined together at an “attachment point 70” which is formed by sintering a relatively small disk 48 of a bonding polymer. As best seen in FIG. 6B, this attachment point is spaced well inwardly of the two frames and represents a relatively small portion of the overall surface area of the occlusion device. This can make it more difficult to center the device within the defect. This also appears to make it more difficult to retract the device back into a catheter once the second disk has been deployed.

The present invention provides a septal defect closure device which can be used to occlude abnormal body openings, such as septal defects, patent ductus arteriosis or perforations through the wall of a body organ. This device represents an improvement over the Das device in that it can be more readily retracted into a catheter after it has been deployed.

In one particular embodiment, the present invention provides a septal defect closure device which includes a first occluding disk having a first flexible membrane attached to a first frame and a second occluding disk having a second flexible membrane attached to a separate second frame. The first frame has at least two outwardly extending loops joined to one another by flexible joints, with the loops being attached to the first membrane to define taut fabric petals when the first disk is in a deployed configuration. A central portion of the first membrane is attached to a central portion of the second membrane to define a joining segment, which is preferably a conjoint disk. The flexible joints of the first frame are received within the conjoint disk, which greatly simplifies the process of withdrawing the first frame into a catheter for retrieval.

The frame of the second disk may be shaped similarly to the frame of the first disk and have two or more joints received within the conjoint disk. Alternatively, the second frame can be attached to the second membrane entirely outside the conjoint disk.

In a somewhat different embodiment, the invention provides a septal defect closure device having first and second occluding disks, with each disk comprising a flexible, biologically compatible membrane and a frame for elastically deploying the membrane. A central portion of the membrane of the first disk is joined to a central portion of the membrane of the second disk to define a flexible joining segment having a collapsible periphery. Preferably, the frame of the first disk and the frame of the second disk are formed from separate lengths of resilient wire. The frame of the first disk in a deployed configuration defines at least two petals joined to one another via at least two flexible joints, with the petals of the deployed first disk extending outwardly from the joining segment to elastically deploy the first membrane. The flexible joints of the first frame are positioned within the periphery of the joining segment.

In a related embodiment, a septal defect closure device includes a first occluding disk having a first flexible membrane attached to a first frame and a second occluding disk having a second flexible membrane attached to a separate second frame. A central portion of the first membrane is joined to the central portion of the second membrane to define a flexible joining segment having a collapsible periphery. The first frame is attached to the first membrane such that in its deployed configuration it will define at least two petals of taut fabric joined to each other by at least two flexible joints. Again, the flexible joints of the first frame are positioned within the periphery of the joining segment.

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• Utility Patent

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