Site News  |   Monitor Keywords  |   Monitor Archive  |   Organizer  |   Account Info  |

Custom-length stent delivery system with independently operable expansion elements

Custom-length stent delivery system with independently operable expansion elements description/claims

The present application is a continuation of U.S. patent application Ser. No. 10/104,305 (Attorney Docket No. 021629-003300US), the entire contents of which are incorporated herein by reference.

The present invention relates generally to systems and methods for deploying stents at one or more treatment sites. More specifically, the invention relates to systems and methods for delivering multiple stents of various lengths to multiple treatment sites using a single device.

Stenting has become an increasingly important treatment option for patients with coronary artery disease. Stenting involves the placement of a tubular prosthesis within a diseased coronary artery to expand the arterial lumen and maintain the patency of the artery. Early stent technology suffered from problems with restenosis, the tendency of the coronary artery to become re-occluded following stent placement. However, improvements in stent design and the advent of drug-eluting stents have reduced restenosis rates dramatically. As a result, the number of stenting procedures being performed in the United States, Europe, and elsewhere has soared.

Stents are delivered to the coronary arteries using long, flexible vascular catheters typically inserted through a femoral artery. For self-expanding stents, the stent is simply released from the delivery catheter and it resiliently expands into engagement with the vessel wall. For balloon expandable stents, a balloon on the delivery catheter is expanded which expands and deforms the stent to the desired diameter, whereupon the balloon is deflated and removed.

Current stent delivery technology suffers from a number of drawbacks. For example, current stent delivery catheters are not capable of customizing the length of the stent in situ to match the size of the lesion to be treated. While lesion size may be measured prior to stenting using angiography or fluoroscopy, such measurements may be inexact. If a stent is introduced that is found to be of inappropriate size, the delivery catheter and stent must be removed from the patient and replaced with a different device of correct size.

Moreover, current stent delivery devices cannot treat multiple lesions with a single catheter. Current devices are capable of delivering only a single stent with a single catheter, and if multiple lesions are to be treated, a new catheter and stent must be introduced for each lesion to be treated.

For these and other reasons, stent delivery systems and methods are needed which enable the customization of stent length in situ, and the treatment of multiple lesions of various sizes, without requiring removal of the delivery catheter from the patient. Such stent delivery systems and methods should further be of minimal cross-sectional profile and should be highly flexible for endovascular positioning through tortuous vascular pathways. Ideally, such stent delivery systems would also allow for accurate and repeatable positioning of one or more stents in a desired position for deployment from a catheter in situ. At least some of these objectives will be met by the present invention.

The invention provides stent delivery systems and methods that overcome the challenges outlined above and provide other advantages. The invention enables the delivery of multiple stents from a single catheter during a single intervention, wherein the length of each stent may be customized in situ. In preferred embodiments, the invention provides systems and methods for the delivery of segmented stents, which enable greater control and precision during stent deployment so that optimal stent position and inter-segment spacing are achieved.

In various embodiments, stent delivery systems and methods are used in stenting of body lumens, typically blood vessels, and more typically coronary arteries. The methods and systems will also find significant use in the peripheral vasculature, the cerebral vasculature, and in other ducts, such as the biliary duct, the fallopian tubes, and the like. The terms “stent” and “stenting” are defined to include any of the wide variety of expandable prostheses and scaffolds which are designed to be intraluminally introduced to a treatment site and expanded in situ to apply a radially outward force against the inner wall of the body lumen at that site. The stents and prostheses of the present invention commonly comprise a closed or, less preferably, an open lattice structure, and are typically formed from a malleable or elastic metal. When formed from a malleable metal, such as stainless steel, gold, platinum, titanium, and super alloys, the stents will typically be expanded by a balloon which causes plastic deformation of the lattice so that it remains opened after deployment. When formed from an elastic metal, including super elastic metals such as nickel-titanium alloys, the lattice structures will usually be radially constrained when delivered and deployed by releasing the structures from such radial constraint so that they “self-expand” at the target site. The terms “stent” and “stent segments” refer broadly to all radially expansible stents, grafts, and other scaffold-like structures which are intended for deployment within body lumens.

In a first aspect of the invention, a stent delivery system for delivering a plurality of stent segments to at least one treatment site includes a catheter shaft having a proximal end and a distal end, a plurality of expandable members arranged axially along the catheter shaft near the distal end, a plurality of stent segments, and a selecting mechanism adapted for selecting one or more expandable members for expansion. In this embodiment, each expandable member is expandable independently of at least one other expandable member, and each expandable member has at least one stent segment positioned on it. One or more of the expandable members may be selectively expanded to deploy the one or more stent segments positioned thereon at the treatment site. It should be understood that, in many of the embodiments described herein, the invention will encompass either a plurality of separately constructed expandable elements each separately mounted to the catheter and operated independently of the others, or a single integral expandable element mounted to the catheter that has interior partitions to create a plurality of isolated independently-expandable compartments or segments.

In a typical embodiment, each of the plurality of expandable members and each of the plurality of stent segments is spaced apart from adjacent expandable members and stent segments, so that each stent segment can be expanded by each expandable member without interfering with adjacent stent segments. In some embodiments, each stent segment is crimped onto one of the expandable members so as to not be axially slidable along the expandable members. Alternatively, each stent segment may be axially slidable along the expandable members.

Some embodiments further include an inflation lumen in the catheter shaft and a plurality of apertures in communication with the inflation lumen, with each aperture being further in communication with at least one of the expandable members. In some embodiments, the selecting mechanism then comprises an isolating member movably disposed in the catheter shaft for isolating at least a first of the apertures from at least one other of the apertures. For example, the isolating member may comprise a first axially slidable seal. In one embodiment, the first axially slidable seal is coupled at or near a distal end of a first slidable shaft slidably coupled to the catheter shaft. In some embodiments, the catheter shaft has an inflation lumen therein, the first slidable shaft being disposed within the inflation lumen. Optionally, the selecting mechanism may further include a second isolating member for isolating a second aperture from at least one other aperture. Again, in one embodiment, the second isolating member comprises a second axially slidable seal. This second axially slidable seal may be coupled to a second shaft slidably coupled to the catheter shaft. In some embodiments, the first shaft defines a first lumen, and the second shaft is slidably disposed within the lumen. Optionally, a space between the first and second slidable tubular shafts may define an inflation lumen.

One alternative embodiment, includes multiple inflation lumens, each of which communicates with one of a plurality of expandable members or with an isolated section or compartment of a single expandable member. A proximal inflation lumen selector, usually including a manifold, is used to select which inflation lumen (or lumens) are used at any one time to expand one or more expandable members. In another alternative embodiment, rather than having multiple, separate expandable members, a stent delivery catheter may have a single, elongate expandable member with multiple septa dividing the balloon into multiple compartments.

Some embodiments further include at least a first axially movable sheath disposed over at least the expandable members and the stent segments. The system may optionally further include at least a second axially movable sheath disposed over part of the catheter shaft, the expandable members and the stent segments. In such an embodiment, the first sheath may be disposed proximally along the catheter shaft relative to the second sheath, and the first and second sheaths may be adapted to allow one or more selected stent segments to be deployed between the sheaths. In some embodiments, the second sheath is movable distally to allow for deployment of at least one stent segment and proximally to cover one or more of the expandable members from which at least one stent segment has been deployed. Optionally, the system may further include a pusher tube slidably disposed within the sheath and proximal to a proximal-most stent segment to advance and/or maintain an axial position of the stent segments relative to the expandable members.

In another aspect of the present invention, a stent delivery system for delivering a plurality of stent segments to at least one treatment site includes a catheter shaft having a proximal end and a distal end, a plurality of expandable members arranged axially along the catheter shaft near the distal end, a plurality of stent segments, and at least a first isolating member movably associated with the catheter shaft for selecting one or more expandable members for expansion. Each expandable member is expandable independently of at least one other expandable member, and each expandable member has at least one stent segment positioned on it. Thus, one or more of the expandable members may be selectively expanded to deploy the one or more stent segments positioned thereon at the treatment site. According to this aspect of the invention, the system may have any of the features described above.

In another aspect of the present invention, a method for delivering a plurality of stent segments to at least one treatment site first involves positioning a distal portion of a stent delivery catheter device at a first treatment site, the stent delivery catheter having a plurality of expandable members positioned thereto, and each of the expandable members having one or more stent segments positioned on it. The method then involves selecting one or more first expandable members for expansion and expanding only the one or more first expandable members to deploy at least a first stent segment at the first treatment site, while at least a second expandable member and at least a second stent segment on the stent delivery catheter remain unexpanded. In some embodiments, expanding only the one or more first expandable members comprises expanding two or more of the expandable members to deploy at least two of the stent segments.

Optionally, the method may further involve, after the step of expanding only the one or more first expandable members, expanding the second expandable member(s) to deploy the second stent segment(s). Such an embodiment may further comprise positioning the distal portion of the stent delivery catheter device at a second treatment site before expanding the second expandable member(s). In some embodiments, the method further includes, after the step of expanding the one or more first expandable members, axially repositioning the second stent segment from the second expandable member to a distal expandable member selected from the one or more first expandable members, and expanding the distal expandable member to deploy the second stent segment. Optionally, such a method may further comprise positioning the distal portion of the stent delivery catheter device at a second treatment site before expanding the second expandable member. In one embodiment, the second stent segment is repositioned by an axially movable pusher in the stent delivery catheter device. Some embodiments may further comprise selecting at least a third expandable member and expanding the third expandable member to deploy a third stent segment. Again, such a method may also include positioning the distal portion of the stent delivery catheter device at a third treatment site before expanding the third expandable member.

In some embodiments, selecting the first expandable member(s) comprises axially moving at least a first sealing member to seal off one or more first inflation apertures communicating with the first expandable member(s) from at least a second inflation aperture communicating with the second expandable member(s). For example, in one embodiment, axially moving the first sealing member comprises sliding a tubular shaft over an inner shaft. In such an embodiment, expanding may comprise introducing an inflation medium into the first expandable member(s) through an inflation lumen between the tubular shaft and the inner shaft. Such a method may also optionally involve axially moving the first sealing member to seal off the second inflation aperture(s) from at least a third inflation aperture communicating with one or more third expandable members, axially moving a second sealing member to seal off at least one of the first inflation apertures from the second inflation aperture(s), and expanding only the second expandable member(s) to deploy the second stent segment(s). In some embodiments, the first sealing member is coupled to a first shaft, the second sealing member is coupled to a second shaft, and axially moving the first and second sealing members comprises sliding the second shaft relative to the first shaft. For example, the first shaft may be tubular and the second shaft may be slidably disposed through the first shaft. In some embodiments, expanding comprises introducing an inflation medium into the second expandable member(s) through an inflation lumen between the first and second shafts.

• Provisional Patent
• Utility Patent

• What Is a Patent?
• What Is a Trademark or Servicemark?
• What Is a Copyright?
• Patent Laws