Removal assist catheter for engaging IVC filter strut independent of strut orientation

A device for assisting in the removal of items endovascularly includes a catheter, an engagement head, and a pull rod. The pull rod has a proximal portion and a distal end connected to the engagement head. The pull rod is movable within the catheter to selectively extend and retract the engagement head from the distal end of the catheter. The engagement head is arranged to grab an item without regard to a particular orientation of the item. The engagement head has a generally cylindrical outer shape that corresponds to an internal surface of the catheter. The engagement head has a serrated proximal edge arranged to grab and hold an item against the distal end of the catheter, and an internal relief area located radially inwardly from said serrated proximal edge to aid in engaging an item.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates generally to catheters, and in particular to catheters that can be used to assist in removal of items endovascularly.

Description of the Related Art

Inferior vena cava filters (“IVC filters”) are medical devices that can be implanted into the inferior vena cava to prevent pulmonary emboli (PE). IVC filters are sometimes recommended for patients with contraindications to anticoagulation who either have acute PE or acute proximal (above the knee) deep vein thrombosis. IVC filters are normally placed by compressing them into a thin catheter, and inserting them via a blood vessel, such as the femoral vein, the internal jugular vein, or the arm veins. Once the distal end of the catheter reaches the IVC, the IVC filter is pushed through the catheter and deployed into the desired location.

IVC filters are typically attached to the vena cava by hooks on their ends. Some IVC filters are compression springs, which compress outward onto the sidewall of the vena cava; however, they still have small hooks that retain their location. These hooks aid in the anchoring and healing process, but they make it difficult to retrieve the IVC filter from the vena cava.

FIG. 1shows an IVC filter1deployed in the inferior vena cava. IVC filters1are generally anchored by anchors4to prevent them from migrating. IVC filters1are removed by using a snare2and a retrieval sheath3. Coupling the snare with the IVC filter1is difficult. The IVC filter1may not be vertically aligned making it difficult to snare. Body movement due to respiration and blood flow also make snaring the IVC filter1difficult.

As can be seen inFIG. 1, the snare2is attached to the top of the filter1. As shown inFIG. 2, the sheath3is pushed down over the filter1, capturing the filter1and its contents and removing the filter anchors4from the vein wall. This allows the filter1to be removed. However, on occasion the filter anchors4or a portion of the filter1become embedded to the vein wall, and this removal procedure cannot be performed.

There is a need for an improved tool to assist with the removal of IVC filters after they have been deployed and to perform other endovascular operations.

SUMMARY OF THE INVENTION

The present invention provides a device for assisting in the removal of items endovascularly. The device includes a catheter, an engagement head, and a pull rod. The pull rod has a proximal portion and a distal end connected to the engagement head. The pull rod is movable within the catheter to selectively extend and retract the engagement head from the distal end of the catheter. The engagement head is arranged to grab an item without regard to a particular orientation of the item or the rotated position of the catheter. The engagement head has a generally cylindrical outer shape that corresponds to an internal surface of the catheter. The engagement head has a serrated proximal edge arranged to grab and hold an item against the distal end of the catheter, and an internal relief area located radially inwardly from the serrated proximal edge to aid in engaging an item.

According to one aspect of the invention, a device for assisting in the removal of items endovascularly is provided, comprising: a catheter having a proximal end and a distal end; an engagement head arranged to be extended from and retracted into the catheter; and a pull rod having a proximal portion and a distal end connected to the engagement head. The pull rod is movable within the catheter to selectively extend and retract the engagement head from the distal end of the catheter.

According to another aspect of the invention, a device for assisting in the removal of items endovascularly is provided, comprising: a catheter having a proximal end and a distal end; and an engagement head that can be extended from and retracted into the catheter. The engagement head comprises a cylindrical outer shape that corresponds to an internal surface of the catheter, and a proximal edge that is generally circular and faces in a proximal direction. The engagement head is arranged to grab and hold an item between the proximal edge and the distal end of the catheter. A pull rod having a proximal portion and a distal end is connected to the engagement head. The distal end of the pull rod is spaced radially inwardly from the proximal edge, and the pull rod is movable within the catheter to selectively extend and retract the engagement head from the distal end of the catheter.

Numerous other objects of the present invention will be apparent to those skilled in this art from the following description wherein there is shown and described an embodiment of the present invention, simply by way of illustration of one of the modes best suited to carry out the invention. As will be realized, the invention is capable of other different embodiments, and its several details are capable of modification in various obvious aspects without departing from the invention. Accordingly, the drawings and description should be regarded as illustrative in nature and not restrictive.

DETAILED DESCRIPTION OF THE INVENTION

A device10for assisting removal of items endovascularly will be described in detail with reference toFIGS. 3 to 7of the accompanying drawings.

The device10of the present invention can be used to assist in removal of items endovascularly, such as an IVC filter or filter strut11. As shown inFIGS. 3 to 7, the device10includes a catheter12, an engagement head13, and a pull rod14. The catheter12has a proximal end15and a distal end16. The engagement head13is arranged to be extended from and retracted into the distal end16of the catheter12.

The device10is intended to give a physician the ability to enter a cavity, such as a vein, and make contact with and hold or pull an item, such as an IVC filter or an IVC filter strut11. The device10can engage the IVC filter strut11independent of the orientation of the strut11and the catheter12. The device10can be used to grab a portion of the IVC filter and free it from the vein wall.

The device10can be used in combination with an IVC filter retrieval device having a side port, as described in Applicant's related U.S. Pat. Nos. 9,301,828 and 9,592,079. The device10can be used in place of the catheter with a C-shaped cutting head described in the related '828 and '079 patents. The C-shaped cutting head required a particular orientation of the C shape so that it would allow engagement of the IVC filter strut. In contrast, the engagement head13of the present invention does not require a particular orientation for operation.

The engagement head13is shown in detail inFIG. 7. The engagement head13has a generally cylindrical outer shape17that corresponds in shape and size to an internal surface18of the catheter. A serrated proximal edge19is provided on a proximal side of the engagement head13and is arranged to grab and hold an item between the serrated proximal edge19and the distal end16of the catheter12. The serrated proximal edge19is generally circular with a plurality of teeth19aprotruding in the proximal direction. The engagement head13has an internal relief area20located radially inwardly from the serrated proximal edge19to aid in engaging an item.

The pull rod14has a proximal portion21and a distal end22connected to the engagement head13. The pull rod14is movable within the catheter12to selectively extend and retract the engagement head13from the distal end16of the catheter12. The pull rod14is spaced radially inwardly from said serrated proximal edge19so that the pull rod14does not interfere with an item being placed between the distal end16of the catheter and the serrated proximal edge19of the engagement head13in any rotated orientation of the catheter12. For example, the pull rod14can be concentric with the serrated proximal edge19and attached to the engagement head13within the internal relief area20, as illustrated.

An interior guide23is attached to an interior surface of the catheter12near the distal end16of the catheter12to keep the pull rod14centered within the catheter12as the engagement head13is extended and retracted. The interior guide23is rigid to provide positive engagement of the pull rod14while allowing a remainder of the catheter12to be flexible. The pull rod14has a distal portion24that is more rigid than the proximal portion21of the pull rod14to allow positive orientation of the engagement head13to be maintained relative to the distal end16of the catheter12while allowing the proximal portion21of the pull rod14to be flexible.

InFIGS. 3 and 4, the catheter12is shown with the engagement head13in its retracted position. The catheter12can be inserted into a vein with the engagement head13retracted, and then extended, as shown inFIG. 5, by advancing the pull rod14. The interior guide23is attached to the interior of the catheter12and serves to keep proper orientation of the pull rod14as the engagement head13is advanced and retracted. The interior guide23can be fairly rigid, allowing positive encasement of the pull rod14while allowing the remainder of the catheter12to be flexible. The pull rod14can also be rigid at its distal portion24allowing positive orientation to be maintained, while the proximal portion21of the pull rod14can be flexible.

Once inserted, the catheter12can then be moved through torquing, rotating the dual lumen retrieval catheter, and/or advancing or retracting the catheter until the IVC filter or strut11of the filter is engaged, as shown inFIG. 6. Once engaged, the pull rod14is retracted to close the engagement head13onto the IVC filter strut11. The entire catheter12can then be advanced/retracted/torqued to dislodge the IVC filter from the vein wall.

While the invention has been specifically described in connection with a specific embodiment thereof, it is to be understood that this is by way of illustration and not of limitation, and the scope of the appended claims should be construed as broadly as the prior art will permit.