Patent foramen ovale closure device

Abstract

The present invention is a method and device for closing a passageway in a body, for example a patent foramen ovale (PFO) in a heart, and related methods of using such closure devices for closing the passageway. The closure device includes a closure line having a first and a second end. A first expandable device is connected to the first end of the closure line. A second expandable device is located along the second end of the closure line, and is capable of sliding along the closure line in one direction while preventing sliding movement in the opposite direction. Alternatively the second closure line is fixed along the second end of the closure line.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Applications, Ser. No. 60/686,863, filed Jun. 2, 2005, and Ser. No. 60/713,388, filed Sep. 1, 2005, both of which are incorporated by reference herein.

FIELD OF THE INVENTION

This invention relates to devices for closing a passageway in a body, for example a patent foramen ovale (PFO) in a heart, and related methods of using such closure devices for closing the passageway.

BACKGROUND OF THE INVENTION

Patent foramen ovale (PFO) is an anatomical interatrial communication with potential for right-to-left shunting of blood. Foramen ovale has been known since the time of Galen. In 1564, Leonardi Botali, an Italian surgeon, was the first to describe the presence of foramen ovale at birth. However, the function of foramen ovale in utero was not known at that time. In 1877, Cohnheim described paradoxical embolism in relation to patent foramen ovale.

Patent foramen ovale is a flap-like opening between the atrial septa primum and secundum at the location of the fossa ovalis that persists after age one year. In utero, the foramen ovale serves as a physiologic conduit for right-to-left shunting of blood in the fetal heart. After birth, with the establishment of pulmonary circulation, the increased left atrial blood flow and pressure presses the septum primum (SP) against the walls of the septum secundum. (SS), covering the foramen ovale and resulting in functional closure of the foramen ovale. This closure is usually followed by anatomical closure of the foramen ovale due to fusion of the septum primum (SP) to the septum secundum (SS).

Where anatomical closure of the foramen ovale does not occur, a patent foramen ovale (PFO) is created. A patent foramen ovale is a persistent, usually flap-like opening between the atrial septum primum (SP) and septum secundum (SS) of a heart. A patent foramen ovale results when either partial or no fusion of the septum primum (SP) to the septum secundum (SS) occurs. In the case of partial fusion or no fusion, a persistent passageway (PFO track) exists between the septum primum (SP) and septum secundum (SS). This opening or passageway is typically parallel to the plane of the septum primum, and has a mouth that is generally oval in shape. Normally the opening is relatively long, but quite narrow. The opening may be held closed due to the mean pressure in the left atrium (LA) being typically higher than in the right atrium (RA). In this manner, the septum primum acts like a one-way valve, preventing fluid communication between the right and left atria through the PFO track. However, at times, the pressure may temporarily be higher in the right atrium, causing the PFO track to open up and allow some fluid to pass from the right atrium to the left atrium. Although the PFO track is often held closed, the endothelialized surfaces of the tissues forming the PFO track prevent the tissues from healing together and permanently closing the PFO track.

Studies have shown that a relatively large percentage of adults have a patent foramen ovale (PFO) . It is believed that embolism via a PFO may be a cause of a significant number of ischemic strokes, particularly in relatively young patients. It has been estimated that in 50% of cryptogenic strokes, a PFO is present. Blood clots that form in the venous circulation (e.g., the legs) can embolize, and may enter the arterial circulation via the PFO, subsequently entering the cerebral circulation, resulting in an embolic stroke. Blood clots may also form in the vicinity of the PFO, and embolize into the arterial circulation and into the cerebral circulation. Patients suffering a cryptogenic stroke or a transient ischemic attack (TIA) in the presence of a PFO often are considered for medical therapy to reduce the risk of a recurrent embolic event.

Pharmacological therapy often includes oral anticoagulants or antiplatelet agents. These therapies may lead to certain side effects, including hemorrhage. if pharmacologic therapy is unsuitable, open heart surgery may be employed to close a PFO with stitches, for example. Like other open surgical treatments, this surgery is highly invasive, risky, requires general anesthesia, and may result in lengthy recuperation.

Nonsurgical closure of a PFO is possible with umbrella-like devices developed for percutaneous closure of atrial septal defects (ASD) (a condition where there is not a well-developed septum primum (SP)). Many of these conventional devices used for ASD, however, are technically complex, bulky, and difficult to deploy in a precise location. In addition, such devices may be difficult or impossible to retrieve and/or reposition should initial positioning not be satisfactory. Moreover, these devices are specially designed for ASD and therefore may not be suitable to close and seal a PFO, particularly because the septum primum (SP) overlaps the septum secundum (SS).

SUMMARY OF THE INVENTION

The present invention relates to devices for closing a passageway in a body, for example a patent foramen ovale (PFO) in a heart, and related methods of using such. closure devices for closing the passageway. The closure device includes a closure line having a first and a second end. A first expandable device is connected to the first end of the closure line. A second expandable device is located along the second end of the closure line, and is capable of sliding along the closure line in one direction while preventing sliding movement in the opposite direction. Alternatively the second closure line is fixed along the second end of the closure line.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a short axis view of the heart at the level of the right atrium (RA) and the left atrium (LA), in a plane generally parallel to the atrio-ventricular groove, and at the level of the aortic valve, showing a PFO track.

FIG. 2 is a cross-sectional view of the PFO track of FIG. 1 in a closed configuration.

FIG. 3 is a close-up section view illustrating the PFO track held in the closed position by left atrial pressure.

FIG. 4A is a cross-sectional view of the PFO track of FIG. 2 in an open configuration.

FIG. 4B is a close-up section view illustrating the PFO track in an open configuration.

FIG. 5A is a cross-sectional view illustrating the PFO tract of FIG. 1.

FIG. 5B is a section view taken along line A-A in FIG. 4B.

FIG. 5C is a section view taken along line A-A in FIG. 3.

FIG. 5D is a close-up section view of the PFO track, showing the tunnel formed by the tissue extension.

FIG. 6A is a perspective view illustrating the relationship between the components comprising the closure device and deployment device according to one aspect of the present invention.

FIG. 6B illustrates the closure device deployed through the septum secundum and septum primum along the PFO track to close the PFO according to one embodiment of the present invention.

FIG. 7A is a perspective view of the anchor structure in the cut pre-expanded form according to one embodiment of the present invention.

FIG. 7B is a perspective view of the expanded anchor according to one embodiment of the present invention.

FIG. 7C is a perspective view of the anchor under tensioning of the closure line according to one embodiment of the present invention.

FIG. 8A illustrates substantial closure of the PFO track with the closure device deployed through the septum secundum and septum primum along the PFO track to close the PFO according to one embodiment of the present invention.

FIG. 8B illustrates substantial closure of the PFO track with the closure device deployed through the septum secundum and septum primum according to one embodiment of the present invention.

FIG. 8C illustrates substantial closure of the PFO track with the closure device deployed through the septum secundum and septum primum according to one embodiment of the present invention.

FIG. 8D illustrates substantial closure of the PFO track with one leg of the closure device penetrating only through the septum secundum, while the second leg of the closure device penetrates only through the septum primum according to one embodiment of the present invention.

FIG. 8E illustrates substantial closure of the PFO track with each leg of the closure device penetrating through the septum primum, but not the septum secundum according to one embodiment of the present invention.

FIG. 8F illustrates substantial closure of the PFO tract with a single penetration through both the septum primum and septum secundum according to one embodiment of the present invention.

FIG. 8G illustrates substantial closure of the PFO track with a single penetration through the septum primum according to one embodiment of the present invention.

FIG. 8H illustrates substantial closure of the PFO, where an ASA is present, with a single penetration only through the septum primum according to one embodiment of the present invention.

FIG. 8I illustrates substantial closure of the PFO with a single penetration through the septum primum according to one embodiment of the present invention.

FIG. 8J illustrates the deployment of the closure device through a single penetration in the septum secundum according to one embodiment of the present invention.

FIG. 9A is a section view of the heart illustrating a deployment device having backup support in the form of an axially asymmetric spline according to one embodiment of the present invention.

FIG. 9B is a section view of the heart illustrating a deployment device with a shape along the distal end to provide backup support, according to one embodiment of the present invention.

FIG. 10 is a perspective view illustrating exemplary sensors, such as a hydraulic pressure port sensor and electrical pressure transducer.

FIG. 11 is a perspective view showing the relationship between components comprising the deployment device and closure device after the outer needle punctures through the septum secundum and septum primum into the left atrium, according to one embodiment of the present invention.

FIG. 12 is a perspective view showing the relationship between components comprising the deployment device and closure device after the inner needle is advanced from the distal end of the outer needle into the left atrium, according to one embodiment of the present invention.

FIG. 13 is a perspective view showing the relationship between components comprising the deployment device and closure device after the inner needle penetrates back into the right atrium, according to one embodiment of the present invention.

FIG. 14 is a perspective view showing the relationship between components comprising the deployment device and closure device after a anchor is deployed from the inner needle by the plunger, according to one embodiment of the present invention.

FIG. 15 is a perspective view showing the relationship between components comprising the deployment device and closure device after the inner needle is retracted back through the outer needle, according to one embodiment of the present invention.

FIG. 16 is a perspective view showing the relationship between components comprising the deployment device and closure device after the plunger device is retracted back through both the outer needle and inner needle, according to one embodiment of the present invention.

FIG. 17 is a perspective view showing the relationship between components comprising the deployment device and closure device after outer needle is withdrawn from the septum primum and septum secundum, releasing the anchor, according to one embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The various figures show embodiments of the patent foramen ovale (PFO) closure device and methods of using the device to close a PFO. The device and related methods are described herein in connection with mechanically closing a PFO. These devices, however, also are suitable for closing other openings or passageways, including other such openings in the heart, for example atrial septal defects, ventricular septal defects, and patent ducts arterioses, as well as openings or passageways in other portions of a body such as an arteriovenous fistula. The invention therefore is not limited to use of the inventive closure devices to close PFO's.

A human heart has four chambers. The upper chambers are called the left and right atria, and the lower chambers are called the left and right ventricles. A wall of muscle called the septum separates the left and right atria and the left and right ventricles. That portion of the septum that separates the two upper chambers (the right and left atria) of the heart is termed the atrial (or interatrial) septum while the portion of the septum that lies between the two lower chambers (the right and left ventricles) of the heart is called the ventricular (or interventricular) septum.

FIG. 1 illustrates a short-axis view of the heart 100 at the level of the right atrium (RA) and left atrium (LA), in a plane generally parallel to the atrio-ventricular groove, and at the level of the aortic valve. This view is looking from caudal to cranial. FIG. 1 also shows the septum primum (SP) 105, a flap-like structure, which normally covers the foramen ovale 115, an opening in the septum secundum (SS) 110 of the heart 100. In utero, the foramen ovale 115 serves as a physiologic conduit for right-to-left shunting of blood in the fetal heart. After birth, with the establishment of pulmonary circulation, the increased left atrial blood flow and pressure presses the septum primum (SP) 105 against the walls of the septum secundum (SS) 110, covering the foramen ovale 115 and resulting in functional closure of the foramen ovale 115. This closure is usually followed by anatomical closure of the foramen ovale 115 due to fusion of the septum primum (SP) 105 to the septum secundum (SS) 110.

The PFO results when either partial or no fusion of the septum primum 105 to the septum secundum 110 occurs. When this condition exists, a passageway (PFO track) 120 between the septum primum 105 and septum secundum 110 may allow communication of blood between the atria. This PFO track 120 is typically parallel to the plane of the. septum primum 105, and has an opening that is generally oval in shape. FIG. 2 illustrates the opening of the PFO track 120 as viewed from an end of the track. Normally the opening is relatively tall, but quite narrow. The opening may be held closed by the mean pressure in the left atrium, which is typically higher than the right atrium. FIG. 3 is a close-up section view of the PFO track 120 held in the closed position by left atrial pressure. In this position, the septum primum 105 acts like a one-way valve, preventing fluid communication between the right and left atria through the PFO track 120. Occasionally, the pressure in the right atrium may temporarily be higher than the left atrium. When this condition occurs, the PFO track 120 opens and allow some fluid to pass from the right atrium to the left atrium, as indicated in FIGS. 4A and 4B. In particular, FIG. 4A is a cross-sectional view showing the PFO track of FIG. 2 in an open configuration. Similarly, FIG. 4B is a close-up section view illustrating the PFO track in an open configuration.

Although the PFO track 120 is often held closed, the endothelialized surfaces of the tissues forming the PFO track 120 prevent the tissue from healing together and permanently closing the PFO track 120. As can be seen in FIGS. 5A-5C, (a view from line “C-C” of FIG. 1), the septum primum 105 is firmly attached to the septum secundum 110 around most of the perimeter of the Fossa Ovalis 115, but has an opening along one side. The septum primum 105 is often connected, as shown, by two or more extensions of tissue along the sides of the PFO track 120 forming a tunnel. FIG. 5D is a magnified section view of the PFO track 120, showing the tunnel formed by the tissue extensions. Typically, the tunnel length in an adult human can range between 2 and 13 mm.

The present invention relates to a system and method for closing a passageway in a body. In a particular embodiment, the device is used to close the Patent Foramen Ovale in a human heart. One of ordinary skill in the art would understand that similar embodiments could be used to close other passageways and openings in the body without departing from the general intent or teachings of the present invention.

FIGS. 6A and 6B illustrate a device used to close the PFO according to one embodiment of the present invention. The device 600 comprises a flexible closure line 625 coupled to two expandable anchors 620, 621. Anchor 620 is coupled to distal end of the closure line 625, while anchor 621 is coupled to the proximal end of the flexible closure line 625. Anchor 621 is capable of sliding along closure line 625 and locking in desired location to cinch or take-up slack in closure line 625 length, bringing the proximal and distal anchors 621, 620 respectively, closer together and effectively bringing the septum secundum 110 and the septum primum 105 in close proximation.

It should be noted that the septum secundum 110 and the septum primum 105 do not have to be tightly touching to effect proper closure of the PFO. Instead, the septum secundum 110 and the septum primum 105 must just be brought close enough to minimize flow from atria to atria (typically flow from left atria to right atria).

The locking mechanism incorporated into anchor 621 may be a device capable of allowing the closure line 625 to slide through anchor 621 in one direction, and prevent sliding movement in the opposite direction. Examples of functionally similar commercial locking mechanisms include the DePuy Mitek RAPIDLOC™ device; zip ties; and similar linear locking devices known in the art.

Alternatively, the anchor 621 may be fixed to the closure line 625 at a predetermined distance from anchor 620. This may particularly be the case when the closure line 625 has an elastic or recoil ability and is capable of exerting tension when deployed, pulling the anchors 620, 621 together and effectively compressing the septum primum 105 to the septum secundum 110. In still a further embodiment of the invention, a closure device 600 may include an elastic closure line 625 and a slideable anchor 621. In this embodiment, the anchor 621 is capable of allowing the flexible closure line 625 to slide through the anchor 621 in one direction, and prevent sliding movement in the opposite direction, while the closure line 625 exerts tension between the two anchors 620, 621. These configurations should not necessarily be considered limiting, and other combinations of components are contemplated, such as, for example, both anchors 620 and 621 being slideable along a substantially elastic or inelastic closure line 625.

The closure line 625 may be any biocompatible filament known in the art that is capable of securing the septum primum 105 to the septum secundum 110. In a preferred embodiment the closure line 625 is a surgical suture, such as a multifilament non-biodegradable suture, or a forced entangled fiber filament. Alternatively, the closure line 625 may be made from an elastic material capable of exerting tension when stretched. In yet another alternative embodiment, the closure line 625 may be geometrically configured to exhibit structurally elastic behavior. In another alternative embodiment, the closure line 625 may be made from an anelastic material such as elastomeric polymers that are capable of exerting tension when stretched. In yet another alternative embodiment, the closure line 625 may be made from a super elastic material such as a nickel titanium alloy.

The anchors 620, 621 are expandable from a first, predeployed unexpanded configuration to a second expanded configuration. The anchors 620, 621 are preferably constructed from a structurally deformable material.

Structurally deformable materials are materials that can elastically or plastically deform without compromising their integrity. Geometric structures, such as anchors 620, 621, made from a deformable material are capable of changing shape when acted upon by an external force, or removal or an external force.

Geometric structures made from structurally deformable materials are typically self expanding or mechanically expandable. In a preferred embodiment, the anchors 620, 621 are made from a self-expanding material, such as Nitinol or a resilient polymer. However, the self-expanding anchors 620, 621 may also be made from an elastically compressed spring temper biocompatible metals. These self-expanding structures are held in a constrained configuration by an external force, typically a capture sheath, and elastically deform when the constraining force is released.

Some structurally deformable materials may also be mechanically expandable. Geometric structures can be mechanically expanded by introduction of an external force, through, for example, a mechanical expansion means. Mechanical expansion means are well known in the art and include balloon or cage expansion devices.

Once an external mechanical force is introduced to the geometric structure, the structure plastically deforms to its desired final configuration.

The anchors 620, 621 in their constrained state are capable of being held in a restrained low profile geometry for delivery, and assume an expanded shape capable of preventing the anchor 620, 621 from retracting through the septum primum 105 or septum secundum 110, as the case may be, once deployed.

In a preferred embodiment, the anchors 620, 621 are cut from a Nitinol hypotube 700 by methods known in the art. FIG. 7A is a perspective view of the anchor 620 in the cut pre-expanded form.

The anchor 620 is then formed into a desired expanded configuration and annealed to assume a stress-free (relaxed) state. In one embodiment of the invention, the anchor 620, 621 is formed into a basket shaped configuration, having a plurality of legs 710. A perspective view of the expanded basket anchor 620 according to one embodiment of the present invention is illustrated in FIG. 7B.

Once the closure device 600 is deployed, the basket shaped anchors 620, 621 collapse under tensioning of the closure line 625, into a flattened “flower petal” shape as illustrated in FIG. 7C. In this state, the anchors 620, 621 are under strain. The super elastic properties of the anchors 620, 621 under strain exert an axially outward force against the adjacent tissue, putting the closure line 625 in tension.

FIG. 8A illustrates the closure device 600 having flower petal shaped anchors 620, 621 deployed through the septum secundum and septum primum along the PFO tract to close the PFO according to one embodiment of the present invention. The proximal anchor 621 in FIG. 8A also includes a locking mechanism 622 integrated therein.

This anchor design should not be considered a limiting feature of the invention, as other shapes and configurations of anchors 620, 621 are also contemplated by the present design. This may include, for example, expandable disc design, star design, j-hook design, or any expandable geometric shape. In addition other materials exhibiting similar characteristics, such as non-biodegradable swellable polymers, are similarly contemplated by the present invention. Still, other designs for anchors 620, 621 may include long-aspect dimensioned objects axially aligned in needles 605, 610 in the constrained state. Once deployed, the long axis of the anchor 620, 621 rotates substantially perpendicular to the needle 605, 610 longitudinal axis, effectively anchoring the closure line 625 in place.

Although FIG. 8A illustrates the closure device 600 deployed through the septum secundum 110 and septum primum 105 along the PFO track 120, it should be understood that the closure device 600 may be deployed through other locations to achieve the same results, as illustrated in FIGS. 8B through 8J. For example, FIG. 8B illustrates one leg of the closure device 600 deployed through both the septum secundum 110 and septum primum 105, while the second leg of the closure device 600 penetrates only through the septum secundum 110.

Similarly, FIG. 8C illustrates one leg of the closure device 600 deployed through both the septum secundum 110 and septum primum 105, while the second leg of the closure device 600 penetrates only through the septum primum 105.

FIG. 8D illustrates one leg of the closure device 600 penetrating only through the septum secundum 110, while the second leg of the closure device 600 penetrates only through the septum primum 105.

FIG. 8E illustrates each leg of the closure device 600 penetrating through the septum primum 105, but not the septum secundum 110. However, the distal anchor 620 is located to exert pressure against the septum secundum 110 and septum primum 105 when the closure device 600 is tensioned. This pressure forces the septum secundum 110 and septum primum 105 into close proximity and facilitates the PFO closure.

Each of the above FIGS. 8A through 8E illustrate the anchors 620, 621 and closure line 625 in a particular orientation. It should be understood that position of the anchor structures 620, 621 may be reversed.

FIGS. 8A through 8E illustrate the final position of each anchor device 620, 621 in the right atrial chamber, with the closure line 625 looping from the right atrial chamber through the left atrial chamber and back into the right atrial chamber. However, it should be understood that the closure device 600 may be deployed such that the distal anchor 620 is located in the left atrial chamber, while the proximal anchor 621 is located in the right atrial chamber.

FIGS. 8F through 8J illustrate the closure device 600 deployed at various locations across the septum primum 105 and/or septum secundum 110. Although the penetration through the septum primum 105 and/or septum secundum 110 are shown at different locations, common to each of the illustrated deployments is the location of the distal anchor 620 and the proximal anchor 621 in the left and right atrial chambers respectively.

FIG. 8F illustrates substantial closure of the PFO tract 120 with a single penetration through both the septum primum 105 and septum secundum 110.

It should be noted that both the septum primum 105 and septum secundum 110 do not have to be penetrated to maintain close enough proximity between the septal tissues to achieve proper closure of the PFO. FIG. 8G illustrates substantial closure of the PFO with a single penetration only through the septum primum 105. In the illustrated embodiment, there is significant overlap between the septum primum 105 and septum secundum 110 creating a fairly long track 120. The distal and proximal anchors 620, 621 respectively are sized to exert enough force on the septum primum 105 and septum secundum 110 to facilitate closing of the PFO track 120 when the closure line 625 is tensioned.

The PFO closure device 600 can be used to facilitate closing the PFO track 120 when other defects in the septal wall are present. For example, the PFO closure device 600 may be used when an atrial septal aneurysm (ASA) 805 is present. An ASA is characterized as a saccular deformity, generally at the level of the fossa ovale, which protrudes to the right or left atrium, or both. FIG. 8H illustrates substantial closure of the PFO, where an ASA is present, with a single penetration only through the septum primum 105. However, the distal and proximal anchors, 620 and 621 respectively, are sized to contact both the septum primum 105 and septum secundum 110 to facilitate closing of the PFO track 120.

The single penetration method may also be employed where there is minimal overlap between the septum primum 105 and septum secundum 110. This so called “short tunnel” PFO may not be readily closed with prior art “intra-tunnel methods. FIG. 8I illustrates substantial closure of the PFO with a single penetration through the septum primum 105.

Similar to the single penetration method illustrated in FIGS. 8F through 8I, the closure device 600 may be deployed using a single penetration through the septum secundum 110 as illustrated in FIG. 8J.

The present invention utilizes a removable deployment device to introduce the mechanical closure device 600 into the atrium of the heart, preferably through a minimally invasive, transluminal procedure. One such deployment device 630 is shown in FIG. 6B.

Minimally invasive heart surgery refers to several approaches for performing heart operations that are less difficult and risky than conventional open-heart surgery. These approaches restore healthy blood flow to the heart without having to stop the heart and put the patient on a heart-lung machine during surgery. Minimally invasive procedures are carried out by entering the body through the skin, a body cavity or anatomical opening, but with the smallest damage possible to these structures. This results in less operative trauma for the patient. It also less expensive, reduces hospitalization time, causes less pain and scarring, and reduces the incidence of complications related to the surgical trauma, speeding the recovery.

One example of a minimally invasive procedure for performing heart surgery is a trans-thoracic laparoscopic (endoscopic) procedure. The part of the mammalian body that is situated between the neck and the abdomen and supported by the ribs, costal cartilages, and sternum is known as the thorax. This division of the body cavity lies above the diaphragm, is bounded peripherally by the wall of the chest, and contains the heart and lungs. Once into the thorax, the surgeon can gain access to the atrium of the heart through an atriotomy, a surgical incision of an atrium of the heart. For example, if the surgeon wishes to gain access to the right atrium they will perform an atriotomy in the right atrial appendage.

The primary advantage of a trans-thoracic laparosopic procedure is that there is no need to make a large incision. Instead, the surgeon operates through 3 or 4 tiny openings about the size of buttonholes, while viewing the patient's internal organs on a monitor. There is no large incision to heal, so patients have less pain and recover sooner. Rather than a 6- to 9- inch incision, the laparoscopic technique utilized only 4 tiny openings—all less than ½ inch in diameter.

Another minimally invasive technique for gaining access to the heart and deploying the closure device is a percutaneous transluminal procedure. Percutaneous surgical techniques pertain to any medical procedure where access to inner organs or other tissue is done via needle-puncture of the skin, rather than by using an “open” approach where inner organs or tissue are exposed (typically with the use of scalpel). The percutaneous approach is commonly used in vascular procedures, where access to heart is gained through the venous or arterial systems. This involves a needle catheter getting access to a blood vessel, followed by the introduction of a wire through the lumen of the needle. It is over this wire that other catheters can be placed into the blood vessel. This technique is known as the modified Seldinger technique. The PFO closure device 600 may also be deployed via percutaneous methods by steerable catheters or guidewires.

In the Seldinger technique a peripheral vein (such as a femoral vein) is punctured with a needle, the puncture wound is dilated with a dilator to a size sufficient to accommodate an introducer sheath, and an introducer sheath with at least one hemostatic valve is seated within the dilated puncture wound while maintaining relative hemostasis.

Penetration of the interatrial septum requires piecing the septal wall. In a preferred embodiment this penetration is accomplished by using a needle, trocar or similar device to accomplish non-core cutting of the interatrial septum. In one embodiment of the invention, the non-core cutting device is a tubular needle-like structure, however other configurations and shaped structures may be used as would be understood by one skilled in the art. The needle tube is a substantially rigid structure capable of penetrating the septum secundum 110 and septum primum 105 along the PFO track 120. The needle is preferably sized to be 13 French or smaller, most preferably 10 French or smaller, and made from a biocompatible material, such as, for example surgical stainless steel, Nitinol, or Cobalt-Chromium alloys. It should be understood that these materials are not meant to limit the scope of the invention. Any biocompatible material capable of being sharpened and holding a sharp edge, and having sufficient strength to facilitate penetration through the septum secundum 110 and/or septum primum 105, may be suitable. The needle is constructed with a tapered distal end, as is known in the art. In a preferred embodiment, the geometric configuration of the tapered distal end is optimized to minimize induced tissue trauma at the site of penetration. In addition, the needle is of sufficient body length to penetrate both the septum secundum 110 and septum primum 105, while still maintaining the needed size and axial flexibility to navigate the tortuous vessel anatomy when being delivered to the heart percutaneously.

In another embodiment of the invention, penetrating the interatrial septum may be accomplished by drilling through the septum.

With the introducer sheath in place, the guiding catheter or delivery member 630 of the closure device is introduced through the hemostatic valve of the introducer sheath and is advanced along the peripheral vein, into the region of the vena cavae, and into the right atrium.

In one embodiment of the invention, the distal tip of the delivery device 630 is positioned against the interatrial septal wall. In the case of a septum having a PFO, the interatrial septal wall may be the septum primum 105 and/or septum secundum 110, as the case may be. A needle or trocar associated with the delivery device 630 is then advanced distally until it punctures the septum primum 105 and or septum secundum 110. A separate dilator may also be advanced with the needle through the septum primum 105 and/or septum secundum 110 to prepare an access port through the septum primum 105 and/or septum secundum 110 for seating the delivery device 630. The delivery device 630 traverses across the septum and is seated in the left atrium, thereby providing access for closure devices 600 through its own inner lumen and into the left atrium.

It is however further contemplated that other left atrial access methods- may be suitable substitutes for using the delivery device 630 and closure device 600 of the present invention. In one alternative variation not shown, a “retrograde” approach may be used, wherein the delivery device 630 is advanced into the left atrium from the arterial system. In this variation, the Seldinger technique is employed to gain vascular access into the arterial system, rather than the venous, for example, at a femoral artery. The delivery device 630 is advanced retrogradedly through the aorta, around the aortic arch, into the ventricle, and then into the left atrium through the mitral valve.

Once in the desired atrium of the heart the closure device 600 is deployed transeptally from one atria to the other. For the purpose of this invention, transeptally is defined as deployment from one atria to the other through the septum (septum primum 105 and/or septum secundum 110), as apposed to intra-atrial access through the PFO tract 120 (tunnel). In the case of a heart having a patent foramen ovale, transeptal penetration may be through the septum primum (SP) 105 and/or septum secundum (SS) 110, or visa versa, whichever the case may be. Preferably, the angle of transeptal penetration is between 45 and 135 degrees to the surface of the septum, but is most preferably orthogonal to the surface of the septum.

By way of example, in one embodiment of the present invention using right atrial access, the right atrium is first accessed by the delivery device 630 (and closure device 600). The closure device 600 may then be deployed by penetrating the interatrial septum (septum primum 105 and/or septum secundum 110) from the right atrial chamber to the left atrial chamber in the heart, and deploying the distal anchor 620 associated with the closure device 600 into the left atrial chamber. After successful deployment of the distal anchor 620, the delivery device 630 may be partially withdrawn from the left atrial chamber to the right atrial chamber, leaving the distal anchor 620 in place. The proximal anchor 621 associated with the closure device 600 can then be deployed into the right atrial chamber. This substantially linear atrial deployment method is shown in FIGS. 8F through 8J.

In another embodiment of the invention, the right atrium is first accessed by the delivery device 630 (and closure device 600). The closure device 600 may then be deployed by penetrating the interatrial septum (septum primum 105 and/or septum secundum 110) from the right atrial chamber to the left atrial chamber in the heart. Once in the left atrial chamber, the delivery device 630 (and closure device 600) are turned and re-penetrate the interatrial septum (septum primum 105 and/or septum secundum 110) from the left atrial chamber to the right atrial chamber in the heart though a different access point. The various preferred access points are shown in FIGS. 8A through 8E. Once back in the right atrial chamber of the heart, the distal anchor 620 may be deployed. After successful deployment of the distal anchor 620, the delivery device 630 may be partially withdrawn from the right atrial chamber to the left atrial chamber, leaving the distal anchor 620 in place in the right atrium. The delivery device 630 may then be withdrawn back through the interatrial septum (septum primum 105 and/or septum secundum 110) from the left atrium to the right atrium. The proximal anchor 621 associated with the closure device 600 can then be deployed into the right atrial chamber.

Similar procedures are employed when left an atrial access technique is used. For example, in one embodiment of the present invention using left atrial access, the left atrium is first accessed by the delivery device 630 (and closure device 600). The closure device 600 may then be deployed by penetrating the interatrial septum (septum primum 105 and/or septum secundum 110) from the left atrial chamber to the right atrial chamber in the heart, and deploying the distal anchor 620 associated with the closure device into the first atrium. After successful deployment of the distal anchor 620, the delivery device 630 may be partially withdrawn from the right atrial chamber to the left atrial chamber, leaving the distal anchor 620 in place. The proximal anchor 621 associated with the closure device can then be deployed into the left atrial chamber.

Once the proximal anchor is deployed, the closure device may be cinched to bring the proximal and distal anchors closer together. This results in the septum secundum 110 and the septum primum 105 being brought in close proximation to facilitate closure of the Patent Foramen Ovale. It should be noted that the septum secundum 110 and the septum primum 105 do not have to be tightly touching to effect proper closure of the PFO. Instead, the septum secundum 110 and the septum primum 105 must just be brought close enough to minimize flow from atria to atria (typically flow from right atria to left atria).

To achieve and maintain the proximity between the septum secundum 110 and the septum primum 105, it may be necessary to adjust the proximal anchor by uni-axially cinching or sliding the proximal anchor 620 along closure line 625. In one embodiment of the invention, cinching comprises uni-axially adjusting the proximal anchor relative to a closure line associated with the closure device. In another embodiment of the invention, cinching comprises incrementally adjusting the proximal anchor relative to a closure line associated with the closure device.

Once the closure device is cinched in place the method may further comprise assessing the degree of proximation between the septum secundum 110 and the septum primum 105.

In one embodiment of the. invention, the clinician may visually assess the proximation though an endoscopic or. fluoroscopic procedure. In addition, other methods may be used to measure the proximation between the septum secundum 110 and the septum primum 105, such as through pressure observation or infrared imaging.

After proper cinching, any unwanted length of closure line 625 that remains unconstrained within the right atrium may be mechanically removed. Devices known in the art capable of removing the excess closure line 625 include catheter-based snare and cut devices. In addition to independent devices, a mechanical cut and removal mechanism may be integrated into the deployment device.

The closure device will then be in position, with the anchors 620, 621 opened against the septum secundum 110, and the closure line 625 connecting the anchors 620, 621 through the septum primum 105 and septum secundum 110, thus holding the septum primum 105 in place.

In one embodiment of the invention, the removable deployment device 630 comprises three tube-like structures that are coaxially aligned. However, other configurations and shaped structures may be used as would be understood by one skilled in the art. The first outer tube 605 is a substantially rigid needle like structure capable of penetrating the septum secundum 110 and/or septum primum 105 along the PFO track 120. The outer needle 605 is preferably sized to be 10 French or smaller and made from a biocompatible material, such as, for example surgical stainless steel, Nitinol, or Cobalt-Chromium alloys. It should be understood that these materials are not meant to limit the scope of the invention. Any biocompatible material capable of being sharpened and holding a sharp edge, and having sufficient strength to facilitate penetration through the septum secundum 110 and/or septum primum, may be suitable. The outer. needle 605 is constructed with a tapered distal end, as is known in the art. In a preferred embodiment, the geometric configuration of the tapered distal end is optimized to minimize induced tissue trauma at the site of penetration. In addition, the outer needle 605 is of sufficient body length to penetrate both the septum secundum 110 and septum primum 105, while still maintaining the needed size and axial flexibility to navigate the tortuous vessel anatomy when being delivered to the heart 100.

The second or inner tube-like structure is inner needle 610. The inner needle 610 is substantially coaxial with outer needle 605 and diametrically sized such that the inner needle 610 is slideably engaged within outer needle 605. That is to say, the outside diameter of inner needle 610 is smaller than the inner bore diameter of outer needle 605, allowing the inner needle 610 to telescope from outer needle 605.

The inner needle 610 is substantially straight when constrained inside outer needle 605, but is capable of assuming a curved shape after being telescopically released from the distal end of outer needle 605. This curved shape may be assumed by mechanical manipulation, such as through manipulation of a pullwire, or preferably by some inherent characteristic or property of the inner tube 610. These inherent characteristics and properties. may include fabricating the inner tube 610 with features, such as circumferential kerf cuts and/or axially spiraling strain relief cuts that allow the inner tube 610 to naturally curve in the desired direction, or preferably, by fabricating the inner tube 610 from a material having shape memory characteristics. In addition, kerf cuts and axially spiraling strain relief cuts may be used on materials having shape memory characteristics.

In a preferred embodiment, the inner needle 610 is fabricated to resume a pre-determined configuration when telescoped from outer needle 605. As can be seen in the embodiment illustrated in FIG. 6, the inner needle 610 resumes a “U-Shape” configuration. One material exhibiting shape memory or super-elastic characteristics is Nitinol.

Nitinol is utilized in a wide variety of applications, including medical device applications as described above. Nitinol or NiTi alloys are widely utilized in the fabrication or construction of medical devices for a number of reasons, including its biomechanical compatibility, its biocompatibility, its fatigue resistance, its kink resistance, its uniform plastic deformation, its magnetic resonance imaging compatibility, its ability to exert constant and gentle outward pressure, its dynamic interference, its thermal deployment capability, its elastic deployment capability, its hysteresis characteristics, and is moderately radiopaque.

Nitinol, as described above, exhibits shape memory and/or super-elastic characteristics. Shape memory characteristics may be simplistically described as follows. A metallic structure, for example, a Nitinol tube that is in an Austenitic phase may be cooled to a temperature such that it is in the Martensitic phase. Once in the Martensitic phase, the Nitinol tube may be deformed into a particular configuration or shape by the application of stress. As long as the Nitinol tube is maintained in the Martensitic phase, the Nitinol tube will remain in its deformed shape. If the Nitinol tube is heated to a temperature sufficient to cause the Nitinol tube to reach the Austenitic phase, the Nitinol tube will return to its original or programmed shape. The original shape is programmed to be a particular shape by well-known techniques.

Super-elastic characteristics may be simplistically described as follows. A metallic structure for example, a Nitinol tube that is in an Austenitic phase may be deformed to a particular shape or configuration by the application of mechanical energy. The application of mechanical energy causes a stress induced Martensitic phase transformation. In other words, the mechanical energy causes the Nitinol tube to transform from the Austenitic phase to the Martensitic phase. By utilizing the appropriate measuring instruments, one can determined that the stress from the mechanical energy causes a temperature drop in the Nitinol tube. Once the mechanical energy or stress is released, the Nitinol tube undergoes another mechanical phase transformation back to the Austenitic phase and thus its original or programmed shape. As described above, the original shape is programmed by well know techniques. The Martensitic and Austenitic phases are common phases in many metals. Medical devices constructed from Nitinol are typically utilized in both the Martensitic phase and/or the Austenitic phase. The Martensitic phase is the low temperature phase. A material is in the Martensitic phase is typically very soft and malleable. These properties make it easier to shape or configure the Nitinol into complicated or complex structures. The Austenitic phase is the high temperature phase. A material in the Austenitic phase is generally much stronger than the material in the Martensitic phase. Typically, many medical devices are cooled to the Martensitic phase for manipulation and loading into delivery systems. When the device is deployed at body temperature, they return to the Austenitic phase.

Other materials that have shape memory characteristics may also be used, for example, some polymers and metallic composition materials. It should be understood that these materials are not meant to limit the scope of the invention. Any biocompatible material capable of being sharpened and holding a sharp edge, and having sufficient strength to facilitate penetration through the septum secundum 110 and/or septum primum, may be suitable. The inner needle 610 is constructed with a tapered distal end, as is known in the art. In a preferred embodiment, the geometric configuration of the tapered distal end is optimized to minimize induced tissue trauma at the site of penetration.

Regardless of the material used, the inner needle 610 must be flexible enough to remain substantially straight when constrained inside outer needle 605, but rigid enough to puncture through the septum secundum 110 and septum primum 105 once deployed from the distal end of outer needle 605.

The third concentric tube-like structure is plunger 615. Similar to the relationship between the outer needle 605 and inner needle 610, the plunger 615 is substantially coaxial with inner needle 610 and diametrically sized such that the plunger 615 is slideably engaged with inner needle 610. That is to say, the outer diameter of plunger 615 is smaller than the inner bore diameter of inner needle 610, allowing the plunger 615 to be pushed through and telescope from inner needle 610. In the illustrated embodiment, plunger 615 is also appropriately sized to push anchor 620 from the distal end of the inner needle 610.

During deployment, plunger 615 pushes against anchor 620 until anchor 620 is deployed from the distal end of inner needle 610. The movement of anchor 620 necessarily translates, through closure line 625, to movement of anchor 621. Accordingly, the inside diameter of plunger 615 is smaller than the outside diameter of anchor 620. Conversely, the outside diameter of anchor 620 must be smaller than the inside diameter of inner needle 610. Anchor 621 slides through plunger 615 when pulled by anchor 620 via closure line 625. Accordingly, the outside diameter of anchor 621 must be smaller than the inside diameter of plunger 615.

In one embodiment of the invention, the plunger 615 is made from a flexible material such that it can be deformed by inner needle 610 upon inner needle 610's release from the distal end of outer member 605. Flexibility may also be imparted to the plunger 615 by geometry, such as fabricating the plunger 615 from spring steel into a tightly wound coil. However, the plunger 615 must also have the necessary longitudinal stiffness or “pushability” to be able to deploy the closure device 600 from the distal end of inner needle 610. In a preferred embodiment, the plunger 615 is made from stainless steel, Nitinol, or Cobalt-Chromium alloy, but any material exhibiting the desired characteristics of flexibility and push-ability may be used.

Another embodiment of the invention may include a location monitoring system to facilitate placement of the deployment device 630. In particular, the location monitoring device will assist in determining whether the clinician is in the correct chamber of the heart.

In a preferred embodiment, the location monitoring system includes the ability to measure localized pressure relative to the distal end of the deployment device 630. The pressure measurement read by the location monitoring system may be achieved by electronic, mechanical and/or physical means, such as a solid-state pressure transducer, spring loaded diaphragm, hydraulic pressure port, and/or communicating manometer. These and other pressure measurement techniques would be known by one of skill in the art. FIG. 10 is a perspective view illustrating exemplary sensors, such as a hydraulic pressure port 655 or electrical pressure transducer 660.

By way of example it is well known that pressures vary in different locations within the cardiovascular system. Specifically, gage pressure in the right and left atrium are know to range from approximately 1-6 mmHg to 10 mmHg respectfully. Similarly, gage pressure within the ascending aorta ranges from approximately 120 to 160 mmHg during systole.

Before deployment, the clinician will first monitor pressure within the right atrium. This reading should indicate a pressure of 1-6 mmHg. The distal end of the outer needle 605 will be inserted through the septal wall (septum primum 105 and/or septum secundum 110) and into the left atrium. The monitored pressure should change to approximately 10 mmHg. A much higher reading, such as in the range of approximately 120 to 160 mmHg, indicates puncture of the aorta. The clinician will then have to retract the outer needle 605 and reposition the delivery device 630 for re-entry. Similarly, once in the left atrium the inner needle 610 is advanced back into the right atrium. The clinician should observe a pressure change from 10 mmHg to 1-6 mmHg.

For delivery to the heart, the deployment device 630 (and thus the closure device 600) is used in conjunction with an accessory device (not shown) known in the art. In a preferred embodiment, the accessory device may be a guiding catheter that tracks over a guidewire, and is steered through the vasculature into the right atrium.

In another embodiment, the accessory device and deployment device 630 may be formed as an integrated component, capable of being steered through the vasculature.

To facilitate deployment of the closure device 600, the deployment device 630 may include features that provide backup support. This backup support may include, for example: an axially asymmetric expansion member attached along an outer shaft 635, such as a balloon or self expanding cage 640; a spline 645; or imparting a shape 650 along the body of the deployment device 630. Examples of these backup support features are illustrated in Figures FIGS. 9A through 9C, respectively. It should be understood that the outer shaft 635 may be part of the guiding catheter, or integrated into the deployment device 630. These and other such backup support devices would be understood by one of skill in the art. These backup support features can also be incorporated onto accessory devices, such as the guide catheter.

Still other embodiments utilizing known methods and apparatus to deliver the deployment device 630 and closure device 600 into the atrium of heart 100 would be obvious to one of skill in the art.

In one embodiment of the invention, the deployment device 630 is part of a guiding catheter assembly. The distal tip of a guiding catheter comprising the deployment device 630 is first positioned within the left atrium according to a transeptal access method, which is further described in more detail as follows. The right venous system is first accessed using the “Seldinger” technique, wherein a peripheral vein (such as a femoral vein) is punctured with a needle, the puncture wound is dilated with a dilator to a size sufficient to accommodate an introducer sheath, and an introducer sheath with at least one hemostatic valve is seated within the dilated puncture wound while maintaining relative hemostasis. With the introducer sheath in place, the guiding catheter or sheath is introduced through the hemostatic valve of the introducer sheath and is advanced along the peripheral vein, into the region of the vena cavae, and into the right atrium.

Once in the right atrium, the distal tip of the guiding catheter is positioned against the septum secundum 110 in the intra-atrial septal wall. The deployment device 630 is then advanced distally until the outer needle 605 punctures through both the septum secundum 110 and septum primum 105 into the left atrium. The configuration of the deployment device 630, including closure device 600 puncturing through the septum secundum 110 and septum primum 105 is shown in FIG. 11.

Once the deployment device 630 penetrates through both the septum secundum 110 and septum primum 105, the inner needle 610 is advanced from the distal end of the outer needle 605 into the left atrium. As earlier described the inner needle 610 is constructed from a shape memory material and designed to assume a curved shape when telescopically released from the outer needle 605. FIG. 12 illustrates the configuration of the deployment device 630 and closure device 600 after the inner needle 610 is advanced from the distal end of the outer needle 605 into the left atrium.

After the inner needle 610 is deployed from the distal end of the outer needle 605, the deployment device 630 is pulled back until the inner needle 610 penetrates through the septum primum 105 and septum secundum 110, respectively, into the right atrium. In one embodiment of the invention, this is accomplished by ensuring that the inner needle 610 remains fixed relative to outer needle 605, and then withdrawing the outer needle from the left atrium until the inner needle 610 makes the necessary penetration into the right atrium. FIG. 13 illustrates the final position of the deployment device 630 and closure device 600 after the inner needle 610 penetrates into the right atrium.

After the inner needle 610 has penetrated the septum primum 105 and septum secundum 110 into the right atrium, the distal anchor 620 can be deployed. As earlier described, the anchor 620 is deployed into the right atrium by holding the inner needle 610 steady, and advancing the plunger 615 through the inner needle 610. During deployment, plunger 615 pushes against the back portion of anchor 620 until anchor 620 is advanced from the distal end of inner needle 610. The movement of anchor 620 necessarily translates, through closure line 625, to movement of anchor 621. As anchor 620 enters the right atrium the shape memory material properties allow the anchor 620 to assume it unconstrained shape. FIG. 14 illustrates the anchor 620 deployed from the inner needle 610 by the plunger 615. according to one embodiment of the present invention.

To deploy proximal anchor 621, the inner needle 610 is retracted back through outer needle 610 to a position indicated in FIG. 15. This will leave the plunger 615 and the closure assembly in place penetrating the septum primum 105 and septum secundum 110 in two places. The anchor 621 will remain in the constrained position inside plunger 615. The plunger 615 is then retracted back through both outer needle 605 and inner needle 610 as shown in FIG. 16. This will leave the closure device 600 in place, with anchor 620 fully deployed against the septum secundum 110, and anchor 621 constrained inside outer needle 605. The outer needle 605 can then be withdrawn from the septum primum 105 and septum secundum 110 respectively, releasing the anchor 621 to the fully unrestrained shape. If necessary, anchor 621 may be slid toward anchor 620 along closure line 625 until sufficient compression is achieved between septum primum 105 and septum secundum 110. Any unwanted length of closure line 625 that remains unconstrained within the right atrium may be mechanically removed. Devices known in the art capable of removing the excess closure line 625 include catheter-based snare and cut devices. In addition to independent devices, a mechanical cut and removal mechanism may be integrated into the deployment device 630.

The closure device will then be in position, with the anchors 620, 621 opened against the septum secundum 110, and the closure line 625 connecting the anchors 620, 621 through the septum primum 105 and septum secundum 110, thus holding the septum primum 105 in place.

FIG. 17 illustrates the closure device 600 in the fully deployed position.

These and other objects and advantages of this invention will become obvious to a person of ordinary skill in this art upon reading of the detailed description of this invention including the associated drawings.

Various other modifications, adaptations, and alternative designs are of course possible in light of the above teachings. Therefore, it should be understood at this time that within the scope of the appended claims the invention might be practiced otherwise than as specifically described herein.

Claims

1. A medical device for closing a passageway in a body comprising:

a closure line having a first and a second end;

a first expandable anchor connected to the first end of the closure line; and

a second expandable anchor located along the second end of the closure line, the second expandable anchor having a locking mechanism integrated therein, the locking mechanism allowing the closure line to uni-axially slide through the second expandable anchor in one direction, and preventing sliding movement in the opposite direction.

2. The medical device of claim 1 wherein the closure line is elastic.

3. The medical device of claim 2 wherein the closure line is comprised of a linear-elastic material.

4. The medical device of claim 2 wherein the closure line is geometrically configured to exhibit elastic behavior.

5. The medical device of claim 4 wherein the closure line is comprised of a coil.

6. The medical device of claim 5 wherein the coil comprises a linear spring.

7. The medical device of claim 5 wherein the coil comprises a non-linear spring.

8. The medical device of claim 1 wherein the closure line is comprised of an anelastic material.

9. The medical device of claim 3 wherein the anelastic material is comprised of a family of elastomeric polymers.

10. The medical device of claim 1 wherein the closure line is comprised on a super elastic material.

11. The medical device of claim 4 wherein the super elastic material comprises a nickel titanium alloy.

12. The medical device of claim 1 wherein the closure line is a biocompatible filament.

13. The medical device of claim 12 wherein the biocompatible filament is a surgical suture.

14. The medical device of claim 13 wherein the surgical suture is a multifilament non-biodegradable suture.

15. The medical device of claim 12 wherein the surgical suture is a forced entangled fiber filament.

16. The medical device of claim 1 wherein the first and second expandable anchors are made from a structurally deformable material.

17. The medical device of claim 1 wherein the first and second expandable anchors are self-expanding.

18. The medical device of claim 17 wherein the first and second self-expanding anchors are made from a super elastic material.

19. The medical device of claim 18 wherein the super elastic material is a nickel titanium alloy.

20. The medical device of claim 18 wherein the super elastic material is a resilient polymer.

21. The medical device of claim 18 wherein the super elastic material is an elastically compressed spring temper biocompatible metal.

22. The medical device of claim 1 wherein the first and second expandable anchors are mechanically expandable.

23. The medical device of claim 22 wherein the first and second mechanically expandable anchors are made from a plastically deformable material.

24. The medical device of claim 23 wherein the plastically deformable material is spirally wound stainless steel.