Patent Description:
In medical practice, there is often a need to connect conduits to one another or to a replacement conduit to treat disease or dysfunction of the existing conduits. The connection created between conduits is called an anastomosis.

In blood vessels, anastomoses are made between veins and arteries, arteries and arteries, or veins and veins. The purpose of these connections is to create either a high flow connection, or fistula, between an artery and a vein, or to carry blood around an obstruction in a replacement conduit, or bypass. The conduit for a bypass is a vein, artery, or prosthetic graft.

An anastomosis is created during surgery by bringing two vessels or a conduit into direct contact, and to create a leak-free blood flow path between them. The vessels are joined together with suture or clips, in an open surgical procedure. The anastomosis can be end-to-end, end-to-side, or side-to-side. In blood vessels, the anastomosis is elliptical in shape and is most commonly sewn by hand with a continuous suture. Other methods for anastomosis creation have been used including carbon dioxide laser, and a number of methods using various connecting prosthesis, clips, and stents. Such procedures are time consuming, clinician dependent (open to surgical error), and often result in strictures, or clotting of the vein or artery.

An arterio-venous fistula (AVF) is created by connecting an artery to a vein. This type of connection is used for hemodialysis, to increase exercise tolerance, to keep an artery or vein open, or to provide reliable access for chemotherapy.

An alternative is to connect a prosthetic graft from an artery to a vein for the same purpose of creating a high flow connection between artery and vein. This is called an arterio-venous graft, and requires two anastomoses. One is between artery and graft, and the second is between graft and vein.

A bypass is similar to an arteriovenous graft. To bypass an obstruction, two anastomoses and a conduit are required. A proximal anastomosis is created from a blood vessel to a conduit. The conduit extends around the obstruction, and a second distal anastomosis is created between the conduit and vessel beyond the obstruction.

As noted above, in current medical practice, it is desirable to connect arteries to veins to create a fistula for the purpose of hemodialysis. The process of hemodialysis requires the removal of blood from the body at a rapid rate, passing the blood through a dialysis machine, and returning the blood to the body. The access to the blood circulation is achieved with catheters placed in large veins, prosthetic grafts attached to an artery and a vein, or a fistula where an artery is attached directly to the vein.

Fistulas for hemodialysis are required by patients with kidney failure. The fistula provides a high flow of blood that can be withdrawn from the body into a dialysis machine to remove waste products and then returned to the body. The blood is withdrawn through a large access needle near the artery and returned to the fistula through a second large return needle. These fistulas are typically created in the forearm, upper arm, less frequently in the thigh, and in rare cases, elsewhere in the body. It is important that the fistula be able to achieve a flow rate of <NUM> per minute or greater. Dialysis fistulas have to be close to the skin (< <NUM>), and large enough (> <NUM>) to access with a large needle. The fistula needs to be long enough (> <NUM>) to allow adequate separation of the access and return needle to prevent recirculation of dialysed and non-dialysed blood between the needles inserted in the fistula.

Fistulas are created in anesthetized patients by carefully dissecting an artery and vein from their surrounding tissue, and sewing the vessels together with fine suture or clips. The connection thus created is an anastomosis. It is highly desirable to be able to make the anastomosis quickly, reliably, with less dissection, and with less pain. It is important that the anastomosis is the correct size, is smooth, and that the artery and vein are not twisted. <CIT>, <CIT> & <CIT> all disclose devices for carrying out intraluminal surgical procedures comprising a control handle, an elongate body portion and instrumentation located at the end of the body portion for carrying out the procedure. <CIT> discloses an electromechanical device for carrying out surgical procedures comprising an elongate drive shaft, a motor located within a handle actuated by a trigger and instrumentation located at one end of the drive shaft. <CIT> describes a surgical instrument having a locking handle. <CIT> describes a high-frequency treatment tool for an endoscope. <CIT> describes forceps with a guide wire.

The present invention comprises a device to allow extension, elongation or repair of a previously created arteriovenous fistula between a first blood vessel and an adjacent second blood vessel which comprises a main body having a primary lumen and an articulating jaw member disposed at the distal end of the main body and configured with two elements to allow rotation of one element about a pivot point to grasp tissue while being rotated. The jaw member is also configured to allow thermal energy delivery to one or both elements of the jaw member that allow tissue welding and cutting with DC, RF, Laser or Ultrasonic energy. A second lumen located within one element of the jaw member is configured to allow advancement over a guidewire into the second vessel while the other element of the jaw member remains within the first blood vessel at the position where the arteriovenous fistula, or aperture, exists between the first and second blood vessel.

In one embodiment, the articulating jaw member is configured to allow rotation of both elements about a pivot point to grasp tissue and apply thermal energy.

In an example, a method (not claimed) of elongation of the passage between adjacent first and second blood vessels comprises a step of positioning a main body of the device within the first vessel and advancing one element of the jaw member through the aperture between the vessels, and into the second vessel, so that the jaw element is disposed within the second vessel. The articulating element is actuated to rotate about the pivot point of the jaw member for grasping and compressing tissue adjacent to the aperture between the first blood vessel and the adjacent second blood vessel.

The method further comprises the step of applying thermal energy to one or both elements of the jaw member to cut an extension to the aperture and weld the adjacent first and second blood vessel using DC, RF, Laser or ultrasonic energy.

More particularly, there is provided in one aspect of the invention a device for elongating, extending, or repairing a tissue aperture, which comprises a handle, a body connected to and extending distally from the handle, comprised of a flexible material and having a primary lumen, a rigid jaw member connected to and extending distally from the flexible body, and a tissue cutting element disposed on the jaw member. Preferably, the flexible material comprising the body is a polymer having a Shore A hardness of <NUM>-<NUM>. The rigid jaw member is preferably fabricated of a rigid material comprising either a metal or a rigid polymer having a Shore A hardness greater than <NUM>, though, of course, other equivalent materials may be utilized alternatively, in both instances.

The jaw member comprises two elements, each having distal ends, wherein one of the elements is pivotable relative to the other element to create a spacing of varying sizes between the two elements at their respective distal ends. In one of the disclosed embodiments, one of the elements is a stationary element and the other element is an articulating element, the articulating element being pivotable about a pivot point disposed on a proximal end thereof. In another disclosed alternative embodiment, both of the elements are articulating elements.

In the disclosed embodiments, the tissue cutting element comprises an electrode for energizing the tissue to be cut. Two electrodes are illustrated in the drawings. A power supply and an activation switch are disposed on the handle for activating the electrode(s). The supplied energy may be thermal energy, RF energy, laser energy, ultrasonic energy, or the like.

A lever is provided on the handle for moving at least one of the jaw member elements relative to the other one to increase or decrease the spacing between the distal ends of the elements, thereby opening or closing the jaws of the jaw member. As disclosed, a wire connects the lever to the jaw member for opening or closing the jaw member. A ratcheting mechanism is provided on the lever for applying variable incremental pressure to the jaw member.

A conductor connects the power supply and activation switch to the electrode. The electrode may be comprised of aluminum or other suitable conductive material. A secondary lumen is disposed in one of the jaw elements.

The jaw member has a closed orientation wherein both jaw elements are substantially aligned with a longitudinal axis of the primary lumen, and open orientations wherein at least one of the jaw elements is disposed at a substantial angle of varying sizes from the longitudinal axis of the primary lumen.

In an example, there is disclosed a method (not claimed) of extending, elongating, or repairing a fistula between adjacent first and second vessels. The method comprises a step of inserting a main body of a device into the first vessel so that a distal end thereof lies within a blood flow passage of the first vessel. A jaw member disposed at a distal end of the main body is opened, and the open jaw member is disposed so that a portion of tissue adjacent to the fistula is disposed between elements thereof. The elements of the jaw member are closed to clamp the portion of tissue therebetween. An electrode on the jaw member is energized to cut and weld the tissue to extend the fistula. The device is then withdrawn from the site.

The inserting step may further comprise a step of aligning a lumen in the main body over a guidewire, and sliding the device over the guidewire to the desired location. The energizing step may comprise applying thermal energy of about <NUM>-<NUM> watts to the clamped tissue. During the energizing step, the tissue temperature is increased to about <NUM>-<NUM> degrees C to cut and weld an extended aperture of about <NUM>-<NUM> from the primary blood vessel to the secondary blood vessel.

Imaging guidance is preferably used to insert the device into a procedural site and monitor the cutting and welding step.

The invention, together with additional features and advantages thereof, may best be understood by reference to the following description taken in conjunction with the accompanying illustrative drawings.

Referring now more particularly to the drawings, one embodiment of a device constructed in accordance with the principles of the present invention is shown. As illustrated in <FIG> and <FIG>, a device <NUM> comprises a handle <NUM> with an activation switch <NUM>, an electrical connector <NUM>, and a jaw lever <NUM>. A <NUM>-<NUM> F (French) flexible (<NUM>-<NUM> Shore A) polymer main body <NUM>, having a primary lumen <NUM> and rigid distal jaw member <NUM>, is provided. The main body is attached to the handle <NUM> at the proximal end and the jaw member <NUM> at the distal end. The electrical connector <NUM> allows connection to temperature display and power supply devices for temperature feedback and DC thermal energy delivery, though other modalities such as Radio Frequency (RF) or laser are can be employed. Lever <NUM> is constructed with a ratcheting mechanism to allow variable incremental pressure (approximately <NUM> mN/mm<NUM> - <NUM> mN/mm<NUM>) to electrodes <NUM> on jaw member <NUM> (<FIG>) as desired by the practitioner. To begin the inventive method of intravascular arteriovenous fistula extension or elongation, the practitioner selects an appropriate procedural site having each of a first blood vessel <NUM> and a second blood vessel <NUM> in close proximity to one another and having a previously created arteriovenous fistula <NUM> disposed therebetween (<FIG>). In currently preferred approaches, the first blood vessel <NUM> comprises a vein, and the second blood vessel <NUM> comprises an artery, but the invention is not limited to this arrangement. Under real time imaging guidance such as ultrasound or fluoroscopy, the main body <NUM> is inserted into the first vessel <NUM> so that a distal end <NUM> thereof lies within the blood flow passage of the first vessel. Preferably, this insertion step is performed using percutaneous technique, but open surgery and direct visualization may also be employed.

With reference now particularly to <FIG>, the jaw member <NUM> comprises an articulating element <NUM> and a stationary element <NUM>, including a secondary lumen <NUM>. The articulating element <NUM> is movable about a pivot point <NUM>, and is attached to a tendon wire <NUM>, as illustrated. It should be noted that the invention is not limited to a single articulating element <NUM>, pivot point <NUM>, and tendon wire <NUM>, though only one of each is shown in this particular embodiment. Articulating element <NUM> and stationary element <NUM> are preferably constructed of a rigid material such as metal or rigid (><NUM> Shore A) polymer, with <NUM>-<NUM> elongate electrodes <NUM> attached to the opposing surfaces. Electrodes <NUM>, preferably constructed of an electrically and thermally conductive material, such as aluminum, are attached to the electrical connector <NUM> on handle <NUM> via conductors <NUM>, which are preferably constructed of an electrically and thermally conductive material such as copper. A temperature sensor <NUM>, such as a thermocouple or thermistor, is attached to the stationary element <NUM> on one end and the electrical connector <NUM> on the opposite end. Tendon wire <NUM>, preferably constructed of <NUM>-<NUM> Ga (Gauge) wire, is attached to the articulating element <NUM> on one end and to the jaw lever <NUM> on the other end. Stationary element <NUM> includes the secondary lumen <NUM>, as noted above. These elements, including the primary lumen <NUM> of the main body shaft <NUM>, provide an externally communicating passage to allow advancement of the device <NUM> over a guidewire <NUM>.

Referring now particularly to <FIG> and <FIG>, the orientation of the articulating element <NUM> of the jaw member <NUM> can be rotationally adjustable between a range of rotation about the pivot point <NUM>. A first, or closed, position is illustrated in <FIG> where the articulating element <NUM> is substantially aligned with the longitudinal axis <NUM> of the primary lumen <NUM> and the secondary lumen <NUM>. As will be described more fully below, the closed orientation is utilized during the initial device insertion steps, as well as the device withdrawal steps, while variable rotated orientations are the operative for creating the extension or elongation of the arteriovenous fistula <NUM>. This variable orientation may be desirable by the practitioner to incrementally adjust the opening of the jaw member <NUM> to achieve an optimal size extension of the aperture <NUM> between primary vessel <NUM> and secondary vessel <NUM>.

Referring again to <FIG>, once the main body <NUM> is inserted into the first vessel <NUM> and advanced to the desired site determined by the practitioner using ultrasound or fluoroscopic imaging, as previously described, it may be desired to adjust the rotation of the articulating element <NUM> to increase the angle of the opening of jaw member <NUM>, by rotating the lever <NUM> of main body handle <NUM>. Since the jaw member <NUM> is configured to have echogenic and radiopaque properties to allow the practitioner to visualize the orientation under real time imaging guidance, this will allow the practitioner to more effectively adjust the opening of jaw member <NUM> through direct visualization as it is advanced into the desired position in the arteriovenous fistula aperture <NUM> between the primary blood vessel <NUM> and the secondary blood vessel <NUM> to achieve the desired length of extension of the aperture. This step may be repeated as desired by the practitioner rotating lever <NUM> of main body handle <NUM> to adjust the open position of articulating element <NUM>, until the desired arteriovenous fistula aperture extension has been achieved.

With reference now to <FIG>, once the practitioner has oriented the stationary element <NUM> of the jaw member <NUM> as desired through the arteriovenous fistula aperture <NUM> and within secondary blood vessel <NUM>, the lever <NUM> of the handle <NUM> is rotated to the fully closed position to compress the blood vessels within the jaw member <NUM>. Activation switch <NUM> is activated to deliver thermal energy of between about <NUM> -<NUM> W to the jaws <NUM>, sufficient to raise the tissue temperature to about <NUM>-<NUM> degrees C to cut and weld an extended aperture <NUM> of <NUM>-<NUM> from the primary blood vessel <NUM> to the secondary blood vessel <NUM>. This may be done under direct imaging guidance to verify energy delivery in the area desired by the practitioner, due to the creation of micro bubbles visible under transcutaneous ultrasound in the area of direct thermal energy. The practitioner may also verify acceptable extension of the aperture through direct visualization of the larger opening in the aperture under imaging guidance.

With reference now to <FIG>, once the extension of arteriovenous fistula aperture <NUM> from primary blood vessel <NUM> to secondary blood vessel <NUM> has been achieved as previously described, the practitioner withdraws device <NUM> completely from the body, thus leaving an extended aperture <NUM> in the anastomosis between the primary vessel <NUM> and the secondary vessel <NUM>.

Claim 1:
A device (<NUM>) for elongating, extending, or repairing an arteriovenous fistula between a first blood vessel and an adjacent second blood vessel, comprising:
a handle (<NUM>);
a body (<NUM>) connected to and extending distally from the handle (<NUM>), comprised of a flexible material and having a primary lumen (<NUM>);
a rigid jaw member (<NUM>) connected to and extending distally from the flexible body (<NUM>), the jaw member (<NUM>) including two elements (<NUM>, <NUM>) each having distal ends, wherein one of the elements (<NUM>, <NUM>) is pivotable relative to the other element (<NUM>, <NUM>) to create a spacing of varying sizes between the two elements at their respective distal ends;
a tissue cutting element (<NUM>) disposed on the jaw member (<NUM>);
a lever (<NUM>) on the handle (<NUM>) for moving at least one of the jaw member elements (<NUM>, <NUM>) relative to the other one to increase or decrease the spacing between the distal ends of the elements (<NUM>, <NUM>), thereby opening or closing the jaws of the jaw member (<NUM>);
a ratcheting mechanism on said lever (<NUM>) for applying variable incremental pressure to the jaw member (<NUM>);
characterized by
a wire (<NUM>) connecting the lever (<NUM>) to the jaw member (<NUM>) for opening or closing the jaw member (<NUM>); and
a secondary lumen (<NUM>) disposed in one of the jaw elements (<NUM>).