Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Arterial prosthesis – Stent combined with surgical delivery system
Reexamination Certificate
1999-03-11
2001-02-06
Mancene, Gene (Department: 3732)
Prosthesis (i.e., artificial body members), parts thereof, or ai
Arterial prosthesis
Stent combined with surgical delivery system
Reexamination Certificate
active
06183505
ABSTRACT:
FIELD OF THE INVENTION
The present invention pertains generally to stent delivery catheters. More particularly, the present invention pertains to stent retainers which are incorporated into a stent delivery system for the purpose of holding a stent against the balloon of a balloon catheter during its advancement into the vasculature of a patient. The present invention is particularly, but not exclusively, useful as a stent retainer which relies on a mechanical reconfiguration of the retainer to separate the retainer from the stent during its deployment.
BACKGROUND OF THE INVENTION
The introduction of a foreign object into the vasculature of a patient presents obviously complex problems. Specifically, both the object and its delivery system must be capable of being advanced into the vasculature for its intended purpose, without unduly traumatizing the patient. Further, this advancement must be accomplished accurately and with great precision. To this end, interventional systems are typically designed to be as smooth as possible, to have as small a profile as possible, and to be as easily controlled as possible. These design characteristics, however, do not directly address the different set of problems which are confronted when, after being advanced into the vasculature by a delivery system, an object is thereafter deployed or disengaged from the delivery system to remain in situ.
In order to deploy or disengage an object from a delivery system in the vasculature of a patient, it is necessary to somehow reconfigure the object and the delivery system for this purpose. The structures used for these functions, however must not be allowed to interfere with the aforementioned task of advancing the object into the vasculature. Furthermore, the structure used to deploy or disengage an object from its delivery system must not itself create problems which would traumatize the patient while the system is in the vasculature. In sum, it is important for a delivery system to function reliably and safely. It happens that several devices have been disclosed which are directed toward this result.
U.S. Pat. No. 3,902,501 which issued to Citron et al. for an invention entitled “Endocardial Electrode,” and which is assigned to the same assignee as the present invention, discloses an interventional device for the deployment of a medical electrode. Specifically, the invention disclosed by Citron et al. incorporates a shroud which is axially fixed in its position on the device. As so positioned, the shroud overlaps and holds the exposed ends of the electrode's tines against the electrode body until the tines are to be deployed. To deploy the tines, a balloon on the electrode body is inflated to withdraw the tines from the shroud. Another example of this same basic deployment scheme, but for a slightly different application, is provided by U.S. Pat. No. 4,950,227 which issued to Savin et al. for an invention entitled “Stent Delivery System.” According to the invention of Savin et al., a stent is positioned over the balloon of a balloon catheter. A pair of sleeves are axially fixed on the device with one end of each sleeve anchored to the catheter while the other end overlaps a respective end of the stent to hold the stent on the balloon. The result is that the sleeve is fixed at an axial location on the catheter. In an action similar to that disclosed for the device of Citron et al., when the balloon is inflated, the ends of the stent are withdrawn from their respective sleeve and the stent is thus deployed.
A difficulty not resolved by either the Citron et al. device or the Savin et al. device is the fact that the sleeves of Savin et al., like the shroud of Citron et al., are axially fixed and therefore substantially immobile. Stated differently, both of these devices rely solely on a change in the configuration of the object being deployed to disengage the object from the shroud or sleeves which hold the object against the balloon. Neither of these devices rely on a mechanical change in either the shroud or the stent for this disengagement. Thus, because the shroud (Citron et al.) or the sleeves (Savin et al.) do not mechanically withdraw axially from the tines or stent during deployment, less of the tines or stent can be covered by the respective shroud or sleeves than would otherwise be possible prior to deployment. Consequently, with less overlapping coverage, there is an increased risk of premature dislodgment of the object being deployed, and an increased risk of a system malfunction during deployment.
In light of the above it is an object of the present invention to provide a system for selectively holding a stent on a balloon delivery catheter which incorporates retainers that will mechanically shorten with an inflation of the balloon to facilitate disengagement of the stent from the system. Still another object of the present invention is to provide a system for selectively holding a stent on a balloon delivery catheter which effectively covers the projecting ends of a stent to protect the patient from snags, hang-ups or entanglements that might otherwise occur during advancement of the system into the vasculature of the patient. Yet another object of the present invention is to provide a system for selectively holding a stent on a balloon delivery catheter which includes stent retainers that revert to a low profile after stent deployment to facilitate withdrawal of the system from the vasculature of the patient. Another object of the present invention is to provide a system for selectively holding a stent on a delivery catheter which is relatively easy to manufacture, simple to use and comparatively cost effective.
SUMMARY OF THE PREFERRED EMBODIMENTS
In accordance with the present invention, a system for selectively holding a stent on a balloon delivery catheter includes both a proximal retainer and a distal retainer which respectively interact with the proximal end and the distal end of the stent. During advancement of the system into the vasculature of a patient, and prior to deployment of the stent, the retainers are used to hold the stent on the catheter. During actual deployment of the stent, however, as the balloon is being inflated the retainers are designed to mechanically withdraw from the stent and thereby facilitate disengagement of the stent from the system. Finally, after deployment of the stent, the retainers collapse with the deflated balloon to provide a low profile for the system during its withdrawal from the patient's vasculature.
In accordance with the present invention a stent is initially positioned over the central, or working, portion of an elongated inflatable balloon. Each of the retainers is then positioned over a respective cone at the ends of the balloon and each retainer has one end which is anchored to the catheter, the other, unanchored end is then positioned to overlap an end of the stent. For example, the proximal end of the proximal retainer is anchored, or bonded, to the catheter, while the distal end of the proximal retainer overlaps the proximal end of the stent. Similarly, the distal end of the distal retainer is anchored to the catheter while the proximal end of the distal retainer overlaps the distal end of the stent.
The structure of both the proximal retainer and the distal retainer are essentially the same. Specifically, each retainer includes a first plurality of filaments which are woven together with a second plurality of filaments to create a braided tube. With this structure, when the retainer is mounted on the catheter, the first plurality of filaments are helically disposed with a positive pitch angle relative to the longitudinal axis of the catheter, and the second plurality of filaments are likewise helically disposed, but with a negative pitch angle. The overall result is that the retainer is axially movable whenever the retainer expands in response to an inflation of the balloon. More specifically, this movement is between a first configuration wherein the retainer has a first length, and a second configuration wherein the
Cruz Rey O.
Lentz David J.
Mohn, Jr. Michael A.
Stiger Mark L.
Mancene Gene
Medtronic Ave Inc.
Robert Eduardo C.
Sterne Kessler Goldstein & Fox P.L.L.C.
LandOfFree
Method of stent retention to a delivery catheter... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of stent retention to a delivery catheter..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of stent retention to a delivery catheter... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2586819