Patent Application
20110245849
The inventions described herein relate generally to the treatment of septal defects and more particularly, to the treatment of patent foramen ovales (PFOs) while accommodating anatomical characteristics in the cardiac tissue.
Various defects can occur in the inter-atrial and inter-ventricular septal walls of the heart. For instance, abnormal openings in the inter-atrial septal wall can allow blood to shunt between the left and right atria. Inter-atrial defects can be generally classified as atrial septal defects (ASDs) or patent foramen ovales (PFOs). An ASD is generally defined as a direct opening in the septal wall that can allow blood to flow relatively unobstructed between the left and right atria. A PFO is generally defined as an opening existing between two flaps of septal tissue, referred to as the septum primum and the septum secundum. Between the left and right ventricles, other septal defects known as ventricular septal defects (VSDs) can exist, which are generally defined as direct openings in the ventricular septal wall that can allow blood to flow relatively unobstructed between the left and right ventricles. Another type of cardiac defect, which is generally grouped together with the aforementioned septal defects, is a patent ductus arteriosus (PDA), which is an abnormal shunt between the aorta and pulmonary artery. characteristics of the tissue surrounding the defect, which are generally not apparent to those of skill in the art. For instance, very little in published literature describes variations that can occur in the tissue during the pressure changes that occur within a typical cardiac cycle. Furthermore, devices that seek to treat many of these defects using a transcatheter, or other remote percutaneous procedure, also must take into account the geometry of the access route to the septal defect as well as variations that can occur in that geometry either between patients, or within the cardiac cycle of the patient.
Accordingly, improved systems and methods for treating septal defects, which accommodate anatomical characteristics of the surrounding tissue and vasculature, are needed.
Provided herein are systems and methods configured to treat septal defects and other internal tissue defects. These systems and methods are provided in this section by way of exemplary embodiments that should not be construed as limiting the systems and methods in any way.
In one exemplary embodiment, an implantable closure device having a clip-like configuration is provided. In another exemplary embodiment, a delivery device for delivering the implantable closure device is provided. In other exemplary embodiments, these closure and delivery devices are configured to treat septal defects while accommodating the anatomical nature, dimensions and characteristics of the defect and the surrounding anatomy.
Other systems, methods, features and advantages of the invention will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description, be within the scope of the invention, and be protected by the accompanying claims. It is also intended that the invention is not limited to require the details of the example embodiments.
The details of the invention, both as to its structure and operation, may be gleaned in part by study of the accompanying figures, in which like reference numerals refer to like parts. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. Moreover, all illustrations are intended to convey concepts, where relative sizes, shapes and other detailed attributes may be illustrated schematically rather than literally or precisely.
Provided herein are systems and methods for treating septal defects configured to accommodate anatomical characteristics and dimensions of the defects and the surrounding anatomy. Deformable clip-type devices for treating septal defects are described herein, along with systems for delivery of those devices as well as methods for using the same. For ease of discussion, these devices, systems and methods will be described with reference to treatment of a PFO. However, it should be understood that these devices, systems and methods can be used in treatment of any type of septal defect including ASD's, VSD's and the like, as well as PDA's, pulmonary shunts or other structural cardiac or vascular defects or non-vascular defects, and also any other tissue defect including non-septal tissue defects.
To ease the description of the many alternative embodiments of the systems and methods described herein, the anatomical structure of an example human heart having a PFO will be described in brief.
Many different variations of PFO's can occur. For instance, thickness 220 of septum primum 214, thickness 221 of septum secundum 210, overlap distance 222 and the flexibility and distensibility of both septum primum 214 and septum secundum 210 can all vary. In
In this embodiment, clip 103 has a body 301 and includes a distal portion 303, a proximal portion 304 and a tubular central portion 305, which is preferably a bendable, compressible and/or expandable portion, and is configured as a coil in this embodiment. Clip 103 includes three left atrial (LA) members 306-1, 306-2 and 306-3 and three right atrial (RA) members 307-1, 307-2 and 307-3. Each of anchors 306 and 307 are deflectable (i.e., bendable, shiftable, twistable or turnable) from the housed configuration to the at-rest configuration. In this embodiment, members 306-307 have two primary functions, to act as anchors for clip 103 and to act to compress the septal tissue. For purposes of facilitating the description herein, members 306-307 will be referred to as anchors 306-307.
Here, LA anchors 306 are coupled to distal end 309 of distal end portion 303 of clip 103 and RA anchors 307 are coupled to proximal end 310 of proximal end portion 304. LA anchor 306-3 has a length relatively longer than the other LA anchors 306-1 and 306-2, and will be discussed in more detail below.
LA anchors 306 and RA anchors 307 have end tips 314 and 315, respectively, that are preferably atraumatic. Here, tips 314 and 315 are annular to be atraumatic to tissue, and include inner apertures 348 and 349, respectively. Inner apertures 348 and 349 allow tissue to mechanically anchor to implant 103 in order to reduce chronic abrasion and potential tissue perforation risks. Although not shown, the atraumatic characteristics of end tips 314 and 315 can be improved by deflecting them away from any adjacent tissue surface. Also, radiopaque markers (e.g., tantalum) can be placed within apertures 348 and 349 (or anywhere on clip 103) to increase the visibility of clip 103 in x-ray imaging. Radiopaque markers can be also be placed within the tubular body of clip 103 itself, to increase the visibility of clip 103 and prevent residual shunting through clip 103.
As shown in
Referring now to
As mentioned above, central portion 305 of body 301 is preferably configured to be bendable, expandable and/or compressible to facilitate closure of the PFO tunnel. In this embodiment, central portion 305 is configured to be an elastic, spring-like portion of body 301. Central portion 305 is preferably biased towards a fully compressed state to effectuate the maximum closure force onto septal wall 207 and the PFO tunnel. Central portion 305 can expand to accommodate varying thickness of septal wall 207, i.e., in the event that septal wall 207 is thicker than the length of body 301 between LA anchors 306 and RA anchors 307.
Clip 103 is preferably fabricated from a superelastic material such as NITINOL and the like or an elastic material such as stainless steel and the like, so as to provide the desired biased deflections or shape altering characteristics. Any shape memory characteristics of the material (e.g., NITINOL) can also be incorporated into the functional operation of clip 103. For instance, in one exemplary embodiment, body 301 is composed of NITINOL and heat treated in the deployed configuration so as to instill that shape. A typical heat treatment procedure can occur for 1-20 minutes in a temperature range of 500-550° C. based on factors such as the heating device and the clip material, although clip 103 is not limited to heat treatment in only that range of time and temperature. The process steps and conditions for heat treating NITINOL to instill a desired shape is well known to those of ordinary skill in the art. After heat treatment, members 306 and 307 become biased towards the deployed configuration such that members 306 and 307 will remain deformable yet will resist any deflection or movement away from that configuration. Members 306 and 307 can then be deflected into the undeployed configuration so that clip 103 can be loaded into delivery device 104 (e.g., needle 120, sheath 123, etc.). Therefore, upon exposure of clip 103 from within delivery device 104, members 306 and 307 will begin to return to the heat-treated, deployed configuration.
Clip 103 is preferably configured for use with treatment system 100. Treatment system 100 preferably includes a delivery device 104, which is depicted in
The distal end of OA delivery member 401 is pivotably coupled with upper portion 1033 at a position proximal to the distal end of portion 1033. Portions 1032 and 1033 each include one or more abutments or teeth 1012, which can give portions 1032 and 1033 a forcep (or grasper)-like function. For ease of discussion herein, portions 1032 and 1033 will be referred to as lower jaw 1032 and upper jaw 1033, although they are not limited to such. Distal tip 430 of OA delivery member 401 also includes teeth 1012 at its distal end.
Continued distal advancement of OA delivery member 401 (while body member 101 is held stationary) causes delivery member 401 to deflect upwards and outwards from body member 101 into the deployed, curved stated depicted in the perspective view of
Delivery device 104 is preferably configured such that when placed in the configuration for deployment of clip 103, needle 405 is placed at a desired angle with respect to the septal tissue. In this embodiment, the proper orientation of needle 405 is accomplished by a distal stop 1035 that abuts distal tip 430 of OA delivery member 401. Advancement of delivery member 401 in the distal direction will cause distal tip 430 to abut stop 1035 and cease movement of OA delivery member 401. From this position needle 405 can be advanced into septal tissue at the desired angle, which in this embodiment is approximately 90 degrees from the main axis of body member 101. The desired angle can also be controlled by the distance OA delivery member 401 is advanced with respect to body member 101. The size of the deflected arc of OA delivery member 401 is controlled in part by the location of proximal lumen opening 133, which can be a skive in body member 101, as depicted in this embodiment.
As will be described in more detail below, treatment of a PFO preferably includes inserting treatment system 100 into the vasculature of a patient and advancing body member 101 through the vasculature to the inferior vena cava (e.g., over a guidewire), from which access to the right atrium can be obtained. Once properly positioned within the right atrium, delivery device 104 can be used to deliver one or more clips 103 to the PFO region, preferably by inserting each clip 103 through septum secundum 210 and primum 214 such that it lies transverse to the PFO tunnel and exerts a force that at least partially closes the PFO tunnel. Thus, the use of clip-based devices, systems and methods for treating PFO's allows direct closure of the PFO tunnel, as opposed to occlusive-type devices that merely block the PFO entrance and exit without directly closing the tunnel.
Treatment of a PFO by transeptal placement of an implantable closure device requires the piercing of the septal tissue at an angle generally transverse to the plane of the septal wall (e.g., the plane of the primum, the secundum and the adjacent tissue). Use of a delivery device with the capability to orient the implant to travel along a path transverse to a main longitudinal axis of the device is generally referred to herein as “off-axis delivery.”
When approaching the septal wall from either the right or left atrium, various tissue anatomy can constrain the available workspace in which off-axis delivery can be achieved.
Here, distance 230 is the diameter of the annulus of IVC 202. Distance 231 is the distance between the limbus 211 of septum secundum 210 and the interface between IVC 202 and right atrial chamber 205. Distance 232 is the distance between septum secundum 210 generally adjacent to limbus 211 and the opposite right atrial far wall. Each of these distances 230-232 can constrain an off-axis delivery device. The constraints will depend on the actual configuration of that device, which will vary between designs and between applications. These constraints can cause bending, kinking or other distortion in OA delivery member 401. If the constraints are severe, deployment of delivery device 104 can be prevented altogether.
These distances 231-232 can additionally vary throughout a cardiac cycle. Table 1 quantifies these distances for an exemplary segment of the population.
Table 1 provides the values for these distances at their relative smallest points in a cardiac cycle as compared to their relative largest points in a cardiac cycle. The average values for both the smallest point and largest points are provided for an exemplary segment of the population. Also provided is the degree of variance, shown as one standard deviation, among this segment of the population.
As can be seen, distance 231, between the limbus 211 and tissue junction 233 (located at the interface between the annulus of IVC 202 and right atrial chamber 205) can vary on an average of 5 millimeters (mm) during a cardiac cycle (between 34 and 39 mm for an average member of the population). Likewise, distance 232, between secundum 210 and the opposite right atrial wall 205, can also vary on an average of 5 mm during a cardiac cycle (between 41 and 46 mm for an average member of the population). Distance 230, the diameter of the annulus of IVC 202, remains relatively constant during a cardiac cycle (24 mm). Any device used to achieve off-axis orientation within IVC 202 and/or or right atrium 205 is subject to these anatomical constraints. Similar constraints exist within left atrium 212 that would need to be considered in developing an off-axis device for operation within left atrium 212.
OA delivery member 401 is also constrained by the size of the right atrial chamber 205, which is indicated generally by distance 232. OA delivery member 401 is preferably configured to deploy to a distance less than the minimum length of distance 232 at its smallest point in the cardiac cycle. Contact of delivery member 401 with the right atrial wall can cause bending, kinking or other distortion in, or movement of delivery member 401 that can inhibit the deployment of clip 103. While in this embodiment the effects of distances 231 and 232 result in distortion in OA delivery member 401's preferred deployment profile, the actual effects of the tissue anatomy on a given delivery device will vary based on the configuration of that device. Thus, one of skill in the art will readily recognize that different devices will be affected by the anatomy in different ways.
Preferably, the dimensions of device 104 in its deployed and expanded state are less than the anatomical constraints 230-232. Because the anatomical constraints vary among members of the population, delivery device 104 is preferably configured to accommodate a desired target percentage of the population. Multiple different delivery devices 104 can be provided to a medical professional, each being configured to deploy within anatomies of varying degrees of size. Alternatively, one delivery device 104 can be configured to deploy within a large subset of the population.
For instance, in one exemplary embodiment delivery device 104 is configured to deploy within the anatomy of an average member of the population. In this instance, distance 240, as shown in
However, it should be understood that the device can be configured with any desired dimensions so long as the device is not significantly adversely impacted by the anatomical constraints. Furthermore, anti-kinking catheter designs, such as those described in U.S. patent application Ser. No. 11/744,784, entitled “Systems and Methods for Treating Septal Defects” filed May 4, 2007, can be used to increase the robustness of device 104 and allow the dimensions of device 104 to be further reduced to avoid any of the aforementioned constraints.
In cases where the puncture distance is relatively long, it is possible for the tissue piercing structure to miss primum 214 altogether, or at least not puncture an adequate amount of septal tissue in primum 214 (e.g., creating the risk that the primum tissue will tear loose). For instance, if the puncture distance is greater than PFO tunnel length 1021, then a generally perpendicular trajectory for the tissue piercing structure, such as that indicated by trajectory 501, would miss primum 214 altogether. This is generally undesirable for septal procedures where transeptal puncture of both secundum 210 and primum 214 is desired.
Conversely, even if the puncture distance is kept to a minimum, an excessively short tunnel length 1021 can still result in failure to pierce an adequate amount of primum 214.
As can be seen in
Primum tenting refers to the characteristics of the primum tissue in that it is distensible and stretchable. Contact with the tissue piercing structure does not necessarily result in immediate piercing of primum 214, and can instead force primum 214 to travel away from secundum 210 until the primum is distended to such an extent that further motion of the tissue piercing structure results in the actual piercing.
When implementing device 104 in a configuration suitable for transeptal puncture, a minimum distal translation of needle 405 is desired to ensure repeatable piercing of primum 214 without significant manual intervention. Often in transeptal procedures, visibility to the administering medical professional is limited and it is thus desirable to configure device 104 to achieve primum piercing on a regular and repeatable basis.
Distance 602 in
Distance 603 is defined as the thickness of primum 210 which is approximately a minimum of 1 mm for average members of the population. Distances 604 and 605 relate to the amount of primum excursion and primum tenting that occurs, respectively. Generally the amount of primum excursion 604 for a majority of the population is approximately 5.8 mm. Primum tenting will generally vary based on the size of the tunnel and the individual's tissue characteristics. For instance, a 14 mm wide PFO tunnel having an 5.8 mm excursion when tented is approximately 2.5 mm. Distance 606 reflects the desire for a suitable amount of needle 405 to travel through primum 214 and is preferably half of the length of the opening in the distal end of needle 405 when viewed from the perspective shown here. This distance will vary based on the size and shape of needle 405 as well as the beveled angle (if any) that is present on the distal end of needle 405. Other tissue piercing structures will require different amounts of extra travel 606 based on the actual implementation of the tissue piercing structure. Embodiments that do not have a beveled distal surface, for example, can exclude the extra travel distance 606 altogether. The preferable minimal value of distance 601 is 14.3 mm and delivery device 104 can be configured to achieve a repeatable needle travel of at least 14.3 mm.
Other factors can also be incorporated into a minimal repeatable needle travel 601. Delivery device 104 as described with respect to
Different delivery devices 104 also are subject to different manufacturing tolerances as will be recognized by one of skill in the art. These manufacturing tolerances may also create disparity in the travel of needle 405. Also, tolerances can be introduced as a result of the route taken through the patient's vasculature. Accordingly, an additional tolerance is preferably added to provide adequate translation of needle 405 through septal wall 207. In a preferred embodiment, this tolerance is approximately 2.5 mm. Thus, in certain embodiments it is desirable to achieve a minimal travel 601 greater than 14.3 mm. In one embodiment, the minimum needle travel 601 is 18 mm+/−2 mm. It should be noted any combination of these distances and tolerances can be considered in determining the minimum travel 601. Preferably, the absolute needle travel does not exceed 35-36 mm and more preferably, the absolute needle travel is less than 30 mm.
Needle travel 601 is preferably achieved on a repeatable basis such that the user is not required to manually gauge the amount of travel either by referencing the amount of travel on the proximal end of device 104 or by referencing an image of the heart itself. Any configuration of proximal controller can be used. Some exemplary embodiments of proximal controllers are described in the above-incorporated U.S. patent application Ser. Nos. 11/427,572, and 11/744,784. These applications describe proximal controllers for use in a PFO treatment procedure. Each of these embodiments can be configured to achieve a minimal actual needle travel of the desired amount greater than or equal to distance 601.
To adequately accommodate the cyclic variation in thickness of septal wall 207, the embodiment of clip 103 described with respect to
The PFO tunnel, when viewed from the right atrium, can be converging, diverging or straight and typically bends to the right. Because of this, transeptal punctures can tend to occur on the left side of the tunnel in the absence of techniques or devices that achieve a predetermined puncture position with respect to the left and right walls of the tunnel. The width of the tunnel in about 90 percent of the population having PFOs is approximately 13 mm.
In the embodiments of
If clip 103 is implanted to the left of tunnel 215, LA anchor 306-3 is sufficiently long to maintain adequate coverage. If clip 103 is implanted while a guidewire is disposed within PFO tunnel 215, the guidewire is preferably positioned to the left of clip 103 and forces clip 103 to be implanted just adjacent to the left hand side wall of tunnel 215. This offset (approximately 2 mm) will be enough to provide that LA anchor 306-3 extends the entire way across PFO tunnel 215. Full coverage of primum 214 reduces the likelihood that a residual shunt will remain through PFO tunnel 215 after implantation. It should be noted that LA anchors 306 can be configured with any desired length, although a relatively longer LA anchor 306-3 is preferable.
In the embodiments of
The devices and methods herein may be used in any part of the body, in order to treat a variety of disease states. Of particular interest are applications within hollow organs including but not limited to the heart and blood vessels (arterial and venous), lungs and air passageways, digestive organs (esophagus, stomach, intestines, biliary tree, etc.). The devices and methods will also find use within the genitourinary tract in such areas as the bladder, urethra, ureters, and other areas.
Other locations in which and around which the subject devices and methods find use include the liver, spleen, pancreas and kidney. Any thoracic, abdominal, pelvic, or intravascular location falls within the scope of this description.
The devices and methods may also be used in any region of the body in which it is desirable to appose tissues. This may be useful for causing apposition of the skin or its layers (dermis, epidermis, etc), fascia, muscle, peritoneum, and the like. For example, the subject devices may be used after laparoscopic and/or thoracoscopic procedures to close trocar defects, thus minimizing the likelihood of subsequent hernias. Alternatively, devices that can be used to tighten or lock sutures may find use in various laparoscopic or thoracoscopic procedures where knot tying is required, such as bariatric procedures (gastric bypass and the like) and Nissen fundoplication. The subject devices and methods may also be used to close vascular access sites (either percutaneous, or cut-down). These examples are not meant to be limiting.
The devices and methods can also be used to apply various patch-like or non-patchlike implants (including but not limited to Dacron, Marlex, surgical meshes, and other synthetic and non-synthetic materials) to desired locations. For example, the subject devices may be used to apply mesh to facilitate closure of hernias during open, minimally invasive, laparoscopic, and preperitoneal surgical hernia repairs.
It should be noted that various embodiments are described herein with reference to one or more numerical values. These numerical value(s) are intended as examples only and in no way should be construed as limiting the subject matter recited in any claim, absent express recitation of a numerical value in that claim.
While the embodiments are susceptible to various modifications and alternative forms, specific examples thereof have been shown in the drawings and are herein described in detail. It should be understood, however, that these embodiments are not to be limited to the particular form disclosed, but to the contrary, these embodiments are to cover all modifications, equivalents, and alternatives falling within the spirit of the disclosure.
This application is a continuation of U.S. patent application Ser. No. 12/113,842, filed May 1, 2008, now abandoned, which claims the benefit to U.S. Provisional Application Ser. No. 60/916,264, filed May 4, 2007, each of which is fully incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 60916264 | May 2007 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 12113842 | May 2008 | US |
| Child | 13161287 | US |
