The present invention relates generally to less invasive surgical equipment and surgical procedures. More particularly, the present invention relates to devices and methods for crossing from the right atrium to the left atrium by perforating the intra-atrial septum of the heart for the treatment of intracardiac arrhythmias and defects such as, for example, atrial fibrillation and valve defects related to cardiac disease as well as for pacing, ablating, and correction of other structural defects.
Since the 1950's, transseptal procedures of the heart have been traditionally performed using Brockenbrough needles in which a puncture is made through an intact atrial septum from the right atrium to the left atrium. Several risks, however, have been associated with the use of Brockenbrough needles. One risk is the perforation of the lateral atrial wall after crossing the atrial septum. Another risk is the potential perforation of the aortic root.
Attempts have been made to reduce these and other risks. For example, U.S. Pat. No. 5,312,341 relates to the problem of inadvertent withdrawal of a catheter tip from the left atrium, through the atrial septum, and back into the right atrium. A retaining means for retaining the distal tip of a sheath which has been placed through a septum, such as the interatrial septum, across the septum, in the left atrium during left heart procedures was therefore proposed.
U.S. Pat. No. 6,650,923 relates to a method for accessing the left atrium by locating the fossa ovalis of the intra-atrial septum. An access catheter with a detector for identifying and providing access through the fossa ovalis was proposed.
U.S. Patent Publication No. 2006/0064062 relates to transseptal puncture needles and transseptal puncture needle assemblies. More specifically, it relates to curved transseptal puncture needles and needle assemblies that facilitate insertion through curved transseptal introducers. Each curved transseptal puncture needle includes a needle tip with a tangential back bevel configuration, a reverse tangential back bevel configuration, or a conical reverse bevel configuration.
U.S. Patent Publication No. 2005/0101984 relates to septal puncture in patients in which a communication is present between the two atria of the heart, for example, a patient with a patent foramen ovale (PFO). A device and method are proposed to safely puncture both an intact atrial septum and an atrial septum having a PFO. The proposed device includes a blunt outer needle, and a second inner needle disposed longitudinally through the lumen of the outer needle, wherein the inner needle is flexible, e.g., has a flexible portion and/or a bend or other non-traumatic conformation at its tip.
U.S. Patent Publication Nos. 2005/0159738 and 2005/0065507 relate to devices for septal perforation utilizing radio frequency energy. Each device includes a functional tip with at least one active electrode capable of creating a controlled perforation in body tissue. The device is introduced into the right atrium and the functional tip is positioned against the atrial septum. Energy is applied to the tip to create the perforation.
U.S. Pat. No. 6,890,353 relates to a method and apparatus for reducing mitral regurgitation by applying a force to the wall of the coronary sinus so as to force the posterior leaflet anteriorly and thereby reduce mitral regurgitation. A guidewire uses a sharp tip for allowing the distal end of a guidewire to penetrate tissue.
U.S. Patent Publication No. 2006/0241648 relates to methods and apparatus for modifying tissue. The proposed method includes advancing a beveled distal tip of a guide member to facilitate advancement of the guide member through tissue. A modification device is advanced along the guide member.
Nevertheless, there remains a need for improved devices and methods for perforating the intra-atrial septum of the heart with devices that improve the safety of the procedure.
In one aspect, the invention provides a transseptal guidewire configured to perforate the intra-atrial septum. The transseptal guidewire has an elongated body with an end section and a tapered distal section. At least a portion of the end section has a first dimension in a first direction transverse to a longitudinal axis of the elongated body. The first dimension is larger than a second dimension of the portion of the end section in a second direction transverse to the longitudinal axis.
In another aspect, the invention provides a transseptal guidewire having an elongated body with an end section biased to a curved configuration and a tapered distal section. The elongate body has an imagable section proximal of the end section, and the imagable section includes at least one radiopaque marker. At least a portion of the end section has a first dimension in a first direction transverse to a longitudinal axis of the elongated body that is larger than a second dimension in a second direction transverse to the longitudinal axis.
In yet another aspect, a method of fabricating a transseptal guidewire is provided. The method includes coupling at least one radiopaque marker to an elongate body to form an imagable section of the elongate body, ovalizing at least a portion of an end section of the elongate body distal of the imagable section, and heat curving at least a portion of the end section to a provide a curved configuration.
In still yet another aspect, a method of confirming traversal of an intra-atrial septum is provided. The method includes perforating the intra-atrial septum from a right atrium of a heart to a left atrium of the heart using a transseptal guidewire, extending at least a portion of an end section of the transseptal guidewire into the left atrium, and imaging an imagable section of the transseptal guidewire proximal of the end section in the left atrium by means of at least one radiopaque marker coupled to the transseptal guidewire at the imagable section.
In another aspect, a method of providing vascular access to the left atrium is provided. The method includes perforating the intra-atrial septum from a right atrium of a heart to a left atrium of the heart using a transseptal guidewire, extending at least a portion of an end section of the transseptal guidewire into the left atrium, and imaging an imagable section of the transseptal guidewire proximal of the end section in the left atrium by means of at least one radiopaque marker coupled to the transseptal guidewire at the imagable section. The method further includes advancing the transseptal guidewire into one of the pulmonary veins to confirm location and advancing a transseptal introducer over the transseptal guidewire into the left atrium.
The invention is best understood from the following detailed description when read in connection with the accompanying drawings, with like elements having the same reference numerals. This emphasizes that according to common practice, the various features of the drawings are not drawn to scale. On the contrary, the dimensions of the various features are arbitrarily expanded or reduced for clarity. Included in the drawings are the following figures:
Aspects of the invention will now be described with reference to the figures. Such figures are intended to be illustrative rather than limiting and are included herewith to facilitate the explanation of the present invention.
Referring generally to the figures (
Referring now to the individual figures in detail,
By a method described in greater detail below, the transseptal trocar device 50, which includes a transseptal sheath 10, dilator 12, outer needle 14, and transseptal guidewire 20, is placed against a septum, such as the intra-atrial septum 104. In an exemplary embodiment, when the distal tip of outer needle 14 is properly positioned in contact with the thin walled fossa ovalis 103 of the intra-atrial septum 104, transseptal guidewire 20 is abruptly extended from the lumen of outer needle 14 to perforate the fossa ovalis 103. Following penetration of the intra-atrial septum 104, and without changing the position of outer needle 14, the distal tip of dilator 12, along with the distal tip of transseptal sheath 10 is passed through the septum and into the left atrium 105.
At times, dilator 12 and sheath 10 do not have sufficient stiffness to pass through the perforation hole (not shown) made in the fossa ovalis 103. In such instances, outer needle 14 may be passed over the guidewire 20 to dilate the septum prior to inserting dilator 12 and sheath 10 through the perforation. The outer needle 14 can also provide support while dilator 12 and sheath 10 are advanced beyond outer needle 14 and through the perforation hole into the left atrium 105. In another embodiment, dilator 12 is optionally made from material that provides sufficient support during the transseptal perforation procedure and the outer needle 14 may not be needed and can be eliminated from device 50.
Referring now to
According to an exemplary embodiment, sheath 10 is made from soft polymer materials such that sheath 10 is pliable and atraumatic when advanced through vasculature. For example, polymers such as polyimide, polyamide, polyetherblockamide, polyethylene, polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), and polyurethane may be used. Other biocompatible polymer materials that minimize damage to tissue during the delivery of device 50 to the right atrium 102 may also be used. Transseptal trocar device 50 also includes a dilator 12 slidingly positioned within a sheath lumen 11 of sheath 10 axially disposed along longitudinal axis 1. Dilator 12 is configured to dilate a perforation hole (not shown) made in the intra-atrial septum 104 to provide improved access for the sheath 10 into the left atrium 105. In an exemplary embodiment, the distal end of dilator 12 may be blunted or tapered (not shown) toward outer needle 14 to provide gradual dilation of the perforation hole as dilator 12 is slidingly advanced into the left atrium 105.
As shown in
According to an exemplary embodiment, dilator 12 and outer needle 14 may be made of a polymer material, as described above. Other materials that provide sufficient support during the transseptal procedure are contemplated. For example, various metals, such as nitinol, steel, or titanium, or alloys thereof may be used.
Referring now to
Now referring to
In an exemplary embodiment, transseptal guidewire 20 may be coated with a material to ease insertion through the lumen 15 of commercially available transseptal outer needles 14 and/or to prevent clots from forming on the guidewire 20. For example, the entire length of transseptal guidewire 20 or a portion of its length may be coated with a material that has antithrombogenic properties to prevent clots from forming on the wire. Exemplary coatings may be hydrophobic or hydrophilic. Typical coatings may be formed from Teflon, a silicone fluid, or urethane based polymers. Other biocompatible coatings that provide the above mentioned properties may also be used.
As will be described in further detail below, a portion of end section 26 is ovalized such that end section 26 has a substantially non-circular cross section. Ovalizing a portion of end section 26 partly assists with biasing end section 26 in a curved configuration such as that shown in
As also illustrated in
In an exemplary embodiment, when a portion of imagable section 24 extends into the left atrium 105 from the perforation hole (not shown), x-ray imaging of radiopaque markers 25a-e may confirm successful perforation of the intra-atrial septum 104. Radiopacity of markers 25a-e is generally equal to, or greater than, transseptal needle 20, thus eliminating the need for radiopaque contrast solution.
Radiopaque markers 25a-e are retained on imagable section 24 since end section 26 is ovalized and has a dimension (such as a width) greater than the diameter of imagable section 24. Additionally, a portion 21 of elongated body 22 proximal to imagable section 24 has a tapered transition to imagable section 24 with a diameter also greater than the diameter of imagable section 24. Thus, radiopaque markers 25a-e are retained to imagable section 24 between adjacent portion 21 and end section 26.
Referring now to
In one embodiment, superelastic nitinol wire having a substantially circular cross-section is formed into elongate body 22a by a centerless grinding process. The superelastic nitinol wire, for example, may have a substantially uniform diameter and is threaded into a grinding machine to gradually decrease the diameter of the wire. Elongate body 22a may have a maximum diameter of about 0.015 inches at a proximal portion 21a which is tapered by centerless grinding to portion 24a. Portion 24a is sharpened to tapered distal section 28 terminating at pointed tip 29. Pointed tip 29 has a substantially circular cross-section and is positioned at the distal end of tapered distal section 28.
In another embodiment, elongate body 22a may have a maximum diameter of about 0.050 inches at a proximal portion 21a when used without an outer needle such as a Brockenbrough needle. In such an embodiment, portion 24a can be up to about 0.032 inches in diameter.
In an exemplary embodiment, after elongate body 22a is formed, radiopaque markers (25,
One or more radiopaque markers (25,
Referring now to
The first dimension, for example, may have a width between about 0.008 and about 0.014 inches and greater than the inner and outer diameters of radiopaque marker bands (25,
Due to ovalization or pressing or other forming, the second dimension of end section 26 is smaller than the diameter of imagable section 24 and may have a thickness, for example, less than about 0.008 inches such as about 0.005 inches. Accordingly, end section 26 of the transseptal guidewire 20 is thinner and therefore more flexible than proximal portion 21a, imagable section 24, and tapered distal section 28 in a direction of curvature about an axis parallel to the first dimension. In other words, the end section 26, like an “I-beam,” is more flexible in one direction (about an axis parallel to the first dimension) as compared to another direction (about an axis parallel to the second dimension).
Referring now to
For example, the radius “B” of the loop that forms the curved configuration can be about 0.125 inches or the diameter may be about 5-8 mm, though other dimensions are optionally selected. When the tapered distal section 28 is enclosed within the lumen (13,
As shown in
Referring now to
The exemplary embodiments of end section 26 are illustrated schematically as having a portion with a cross-sectional shape that is like an oval. This oval shape may be formed by pressing or other techniques. It is contemplated that this shape may be something other than an oval as well, while still maintaining first and second respective dimensions. For example, the shape may be flattened or somewhat rectangular. It may also take any other geometric shape. In any shape selected, however, the subject portion of end section 26 preferably serves at least one of the functions of retaining radiopaque bands, promoting increased flexibility in at least one direction, and providing an outer perimeter close to the outer perimeter of the radiopaque bands.
Referring now to
Referring to
Once outer needle 14 is positioned, transseptal guidewire 20 is advanced relative to the outer needle 14 through the septum 104. The perforation force of transseptal guidewire 20 is less than or equal to the perforation force of currently available transseptal needles such as a Brockenbrough needle. According to one embodiment, at its most distal position, about 10 mm of the transseptal guidewire 20 should extend from the distal end of outer needle 14. Alternatively, the most distal position could be extended about 30 mm to 50 mm, e.g., 3-5 cm, if end section 26 of transseptal guidewire 20 has a hook shape, as is shown in
In an embodiment of this procedure, as elongate body 22 is advanced through outer needle 14, the straight configuration of transseptal guidewire 20 shown in
In an embodiment of this procedure, outer needle 14 follows the path of transseptal guidewire 20 through the septum 104. Alternatively, because of the added stiffness provided by outer needle 14, transseptal guidewire 20, dilator 12, and sheath 10 can be advanced through septum 104. The motion of the transseptal guidewire 20 may be forward, vibrating, reciprocating, linear, or rotational, for example. In one embodiment, movement of the transseptal guidewire 20 is accomplished manually, thus providing easier manipulation for the surgeon.
As shown in
The method for transseptal perforation using the transseptal device described herein offers several significant advantages. For example, when using the devices and methods according to exemplary embodiments of the invention, inadvertent contact of the transseptal guidewire 20 with the left atrial free wall immediately after the septum 104 is perforated does not result in damage to or perforation of the left atrial free wall because the end section 26 of the transseptal guidewire 20 is flexible and/or biased to a curved configuration when fully extended from the distal end of outer needle 14. In other words, the flexibility and/or curvature of the end section renders it atraumatic.
When the end section 26 of the transseptal guidewire 20 contacts the left atrial free wall or pulmonary vein, for example, end section 26 of transseptal guidewire 20 harmlessly bends rather than perforates the left atrial free wall. In one embodiment, the end section 26 of the transseptal guidewire 20 bends because of the enhanced flexibility of the ovalized end section 26, as described above. In an embodiment, perforation of the left atrial wall is avoided by modifying the shape of the end section 26 of transseptal guidewire 20 to form, for example, a hook or a bend. In yet another embodiment, end section 26 of transseptal guidewire 20 may be advanced into one of the pulmonary veins in the left atrium 105 and straightened by advancing a transseptal introducer, such as dilator 12 or sheath 10, over end section 26.
Another advantage of the transseptal trocar device embodiments described herein is the ability of the device to perforate through thick septum such as septum secundum. The transseptal trocar devices according to the invention can also be used for remote suturing of a patent foramen ovale or other defects that may be accessed vascularly. This is possible, for example, because the fit between the outer needle 14 and the guidewire 20, especially when provided with an ovalized end section, promotes the column strength of the guidewire and reduces the bending or buckling tendency of the guidewire. This fit, promoted by the ovalized end section, improves the ability of the guidewire to perforate tougher tissue yet, when extended from the end of the needle 14, becomes relatively atraumatic.
In an exemplary embodiment, the pointed tip of the guidewire 20 is significantly sharper and/or smaller than the tip of the transseptal outer needle 14. Thus, the guidewire 20 is able to perforate through the fossa ovalis 103 with less force. When needle 14 punctures the fossa ovalis 103, the needle 14 continues on a path towards the lateral wall of the left atrium. According to exemplary embodiments described herein, however, when the guidewire 20 is extended from the tip of the transseptal outer needle 14, guidewire 20 prevents the needle 14 from puncturing the lateral wall of the left atrium.
By way of example, the flexible members are manufactured using nickel-titanium material, such as superelastic nitional, or other shape memory alloy materials. The nickel-titanium wire, when properly manufactured, exhibits elastic properties for the wire to be manipulated (e.g., bent) by an operator and then returned to substantially the same shape the wire possessed prior to it being manipulated. Thus, transseptal guidewire 20 does not kink or buckle during use with transseptal trocar device 50.
In an exemplary embodiment, components of transseptal trocar device 50 are passed through a straightener and optional hemostatic Y adapter (not shown) without resistance. The hemostatic Y adapter may be used to supply contrast imaging fluid through the sheath 10, dilator, and/or needle 14. Alternatively, the Y adapter may be coupled to a pressure monitor to measure atrial pressure change when the intra-atrial septum 104 is perforated.
In yet another embodiment, transseptal trocar device 50 may be provided in a sterilized kit which includes intravascular sheath 10, dilator 12, outer needle 14, transseptal guidewire 20, and the hemostatic Y valve. The components of the kit may be packaged in a tyvek/polymylar pouch for one time use such that the transseptal trocar device 50 may be disposable after a surgical procedure. Additional aspects of the Y adapter and transseptal catheterization methods are described in U.S. Pat. No. 5,312,341, U.S. Patent Publication 2006/0064062, and U.S. Patent Publication 2005/0101984, which are incorporated herein fully by reference.
Accordingly, a surgical device is provided, according to exemplary embodiments of the invention, that reduces the risk of inadvertent perforation or trauma in transseptal procedures with the added benefit of confirming the puncture location prior to dilation. In particular, such embodiments provide accurate placement and safe access to the left atrium through the atrial septum. The device, according to exemplary embodiments, preferably performs with commercially available transseptal needle systems and allows for safer and easier penetration of a transseptal needle through the atrial septum.
Although the invention is illustrated and described herein with reference to specific embodiments, the invention is not intended to be limited to the details shown. Rather, various modifications may be made in the details within the scope and range of equivalents of the claims and without departing from the invention.