Patent Description:
Stents and stent-grafts, or other implantable medical devices, may be utilized to radially support a variety of tubular passages in the body, including arteries, veins, airways, gastrointestinal tracts, and biliary tracts. The preferred method of placing these devices has been to use specialized delivery systems to precisely place and deploy a device at the site to be treated. These delivery systems allow the practitioner to minimize the trauma and technical difficulties associated with device placements. Attributes of delivery systems include: low profile; ability to pass through introducer sheaths; ability to negotiate tortuous vasculature, smoothly and atraumatically; protection of constrained devices; and ability to accurately position and deploy the device.

Stents or stent-grafts may be deployed and plastically deformed, such as by using an inflatable balloon, or to self-expand, such as through elastic recovery, from a collapsed or constrained delivery diameter to an expanded and deployed diameter. Some stents are designed to elastically recover by being manufactured at their functional diameter out of a material that has elastic recovery properties, and then radially compressed to be mounted on a delivery catheter.

These stent and stent-graft devices may be held, compressed, or constrained in the delivery configuration prior to and during delivery to a target location.

US patent specification No. <CIT> discloses a thin tubular multiple filament (film or fiber) structure that can hold high internal pressures. When desired, an extension of the filaments can be pulled in any direction to unfurl the structure. This device is disclosed for use in self expanding stent or stent graft delivery systems, balloon dilatation catheters, removable guide wire lumens for catheters, drug infusion or suction catheters, guide wire bundling casings, removable filters, removable wire insulation, removable packaging and other applications.

According to the present invention, a medical device deployment apparatus includes at least one first constraining fiber arranged as a series of multiple loops to form a warp knit surrounding the medical device in a constrained configuration, the warp knit being configured to separate and be removed to deploy the medical device; and at least one second constraining fiber arranged with the at least one first constraining fiber, the at least one second constraining fiber having at least one loop arranged in a non-warp knit pattern.

The foregoing Examples are just that, and should not be read to limit or otherwise narrow the scope of any of the inventive concepts otherwise provided by the instant disclosure. While multiple examples are disclosed, still other embodiments will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative examples. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature rather than restrictive in nature.

As the terms are used herein with respect to ranges of measurements "about" and "approximately" may be used, interchangeably, to refer to a measurement that includes the stated measurement and that also includes any measurements that are reasonably close to the stated measurement, but that may differ by a reasonably small amount such as will be understood, and readily ascertained, by individuals having ordinary skill in the relevant arts to be attributable to measurement error, differences in measurement and/or manufacturing equipment calibration, human error in reading and/or setting measurements, adjustments made to optimize performance and/or structural parameters in view of differences in measurements associated with other components, particular implementation scenarios, imprecise adjustment and/or manipulation of objects by a person or machine, and/or the like.

This disclosure is not meant to be read in a restrictive manner. For example, the terminology used in the application should be read broadly in the context of the meaning those in the field would attribute such terminology.

With respect terminology of inexactitude, the terms "about" and "approximately" may be used, interchangeably, to refer to a measurement that includes the stated measurement and that also includes any measurements that are reasonably close to the stated measurement. Measurements that are reasonably close to the stated measurement deviate from the stated measurement by a reasonably small amount as understood and readily ascertained by individuals having ordinary skill in the relevant arts. Such deviations may be attributable to measurement error or minor adjustments made to optimize performance, for example. In the event it is determined that individuals having ordinary skill in the relevant arts would not readily ascertain values for such reasonably small differences, the terms "about" and "approximately" can be understood to mean plus or minus <NUM>% of the stated value.

Certain terminology is used herein for convenience only. For example, words such as "top", "bottom", "upper," "lower," "left," "right," "horizontal," "vertical," "upward," and "downward" merely describe the configuration shown in the figures or the orientation of a part in the installed position. Indeed, the referenced components may be oriented in any direction. Similarly, throughout this disclosure, where a process or method is shown or described, the method may be performed in any order or simultaneously, unless it is clear from the context that the method depends on certain actions being performed first.

A coordinate system is presented in the Figures and referenced in the description in which the "Y" axis corresponds to a vertical direction, the "X" axis corresponds to a horizontal or lateral direction, and the "Z" axis corresponds to the interior / exterior direction.

Persons skilled in the art will readily appreciate that various aspects of the present disclosure can be realized by any number of methods and apparatus configured to perform the intended functions. It should also be noted that the accompanying drawing figures referred to herein are not necessarily drawn to scale, but may be exaggerated to illustrate various aspects of the present disclosure, and in that regard, the drawing figures should not be construed as limiting.

Various aspects of the present disclosure are directed toward apparatuses, systems, and methods that include forming or manufacturing a constraint. The constraining mechanisms are configured to hold, compress, or constraint an implantable medical device (e.g., a stent, stent-graft, balloon, filter, or other expandable medical device) in a delivery configuration prior to and during delivery to a target location. In certain instances, constraints may include one or more fibers that are arranged together. The fibers may be interwoven, stitched, or otherwise interlocked together circumferentially about the device. To remove the constraint, one or more of the fibers may be unknitted or disrupted from the other fibers in the constraint.

Constrained devices may store energy as a result of being constrained in a diameter smaller than a natural or deployed diameter. Thus, the devices may exhibit a radial displacement force against the zipper. During deployment of constrained devices, the radial force may force unknitting of the constraint without user involvement such that the constraint self un-knitts. The aspects of the present disclosure, however, eliminate this accelerated deployment. As discussed in further detail below, the constraint may include a pattern or knot structure that lessens accelerated deployment.

<FIG> is a top plan view of a catheter <NUM> with a constraint <NUM>, according to some embodiments. As shown in <FIG>, the constraint <NUM> is configured to constraint an implantable medical device <NUM> to a delivery configuration. The constraint <NUM> may include one or more fibers <NUM> arranged about the implantable medical device <NUM> to maintain the constraint <NUM> in a constrained configuration.

The constraint <NUM> is arranged along a length of the implantable medical device <NUM>. The constraint <NUM> is also circumferentially arranged about the implantable medical device <NUM> and may substantially cover the implantable medical device <NUM> for delivery. The one or more fibers <NUM> may be arranged within a lumen (not shown) of the catheter <NUM> and extend toward a proximal end of the catheter <NUM> that is arranged external to a patient during delivery of the implantable medical device <NUM>. The one or more fibers <NUM> include a proximal end <NUM> that a user may apply tension to in order to release the constraint <NUM> and deploy the implantable medical device <NUM>.

In certain instances, the one or more fibers <NUM> release similar to a rip cord such that interlocking portions (e.g., overlapping fibers or knots) sequentially release along the length of the implantable medical device <NUM>. As is explained in greater detail below, the constraint <NUM> is formed by interlocking together the one or more fibers <NUM> directly on the implantable medical device <NUM>. As compared to prior multiple fiber constraints which are knitted together and then subsequently arranged about a constrained device, the constraint <NUM> is formed directly on the implantable medical device <NUM>. The expandable medical device <NUM> may be a stent, stent-graft, a balloon, or a similar device.

<FIG> is a side view of the device <NUM> including the constraint <NUM>, in accordance with an embodiment. As shown, the device <NUM> includes a delivery diameter D1 and a deployed diameter D2 (not shown) that is larger than the delivery diameter D1. The removable constraint <NUM> is attached to the device <NUM> at its delivery diameter D1. As shown, the constraint <NUM> includes at least one constraining fiber in the form of a warp knit. For example, the constraint <NUM> may include a first constraining fiber <NUM> and a second constraining fiber <NUM>. The first and/or the second constraining fiber(s) <NUM>, <NUM> may operate, for example, as a deployment line <NUM> configured to release the constraint <NUM> and transition the device <NUM> from the delivery diameter D1 to the deployed diameter D2 in response to a force applied to the deployment line <NUM> (which may be coupled to one or more of the knot rows <NUM> as discussed in further detail below).

The device <NUM> may have a desired deployed diameter D2 from about <NUM>-<NUM>, or <NUM>-<NUM>, or <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>, for example, and a delivery diameter D1 that is less than the deployed diameter D2. For example, in some instances, a ratio of the delivery diameter D1 of the device <NUM> to the deployed diameter D2 (not shown) of the device <NUM> is less than about <NUM>, less than about <NUM>, less than about <NUM>, less than about <NUM>, or less than about <NUM>. For reference, the term "diameter" is not meant to require a circular cross-section, and is instead to be understood broadly to reference a maximum transverse cross-sectional dimension of a device <NUM>.

<FIG> is an illustration of a first constraining fiber <NUM> and a second constraining fiber <NUM>, in accordance with an embodiment. The first constraining fiber <NUM> and the second constraining fiber <NUM> each include a series of loops <NUM>, <NUM>, respectively. A single one of the series of loops <NUM>, <NUM> is shown highlighted in <FIG> for ease of illustration. The first constraining fiber <NUM> and the second constraining fiber <NUM> may form a medical device deployment apparatus in certain instances. In certain instances, the first constraining fiber <NUM> and the second constraining fiber <NUM> are formed of a single constraining fiber that is looped upon itself to form two lines <NUM>, <NUM>.

In addition, the loops <NUM> of the first constraining fiber <NUM> may form a warp knit that surrounds a medical device in a constrained configuration as shown in <FIG>. As discussed in further detail below with reference to <FIG>, the first constraining fiber <NUM> forming a warp knit may be one of a group of fibers that form a warp knit in one or more rows of a constraint <NUM>. The loops <NUM> of the second constraining fiber <NUM> may be arranged with the first constraining fiber <NUM> with the second constraining fiber <NUM> having at least one loop <NUM> arranged in a non-warp knit pattern. As shown in <FIG>, the at least one loop <NUM> is a distal most loop of the multiple loops <NUM>. In certain instances, each of the loops <NUM> of the second constraining fiber <NUM> may include the non-warp knit pattern. As noted above, the first constraining fiber <NUM> and the second constraining fiber <NUM> may form a constraint <NUM>. In certain instances, the loop <NUM> having the non-warp knit pattern is arranged at a distal end of the constraint <NUM>. In certain instances, the loop <NUM> may be arranged in a chain-link stich. The at least one loop <NUM> arranged in a non-warp knit pattern is arranged with the non-warp knit pattern and interrupts the warp knit
The first constraining fiber <NUM> may be interwoven with the second constraining fiber <NUM> to form the constraint <NUM> with each of the first constraining fiber <NUM> and the second constraining fiber <NUM> forming a row of knots. As shown in <FIG>, the first constraining fiber <NUM> and the second constraining fiber <NUM> are interwoven to form a single knot row <NUM>. As discussed and shown in <FIG>, the constraint <NUM> may include additional knot rows <NUM>.

The constraint <NUM> may be deployed by interrupting the knot row <NUM> by applying tension to a deployment line. In certain instances, the first constraining fiber <NUM> and the second constraining fiber <NUM> may be combined to form a deployment line.

The knot row <NUM> may be one of a number of rows formed in the constraint <NUM>. In certain instances, the first constraining fiber <NUM> may include multiple fibers knitted together. The first constraining fiber <NUM> may be a group or type of fiber that forms a pattern. Similarly, the second constraining fiber <NUM> may be a group or type of fiber that forms a pattern. For example, the first constraining fiber <NUM> (group) may form a first row of the row of knots in a warp knit pattern and a second row of the row of knots is formed by the second constraining fiber <NUM> (group) in a non-warp knit pattern. In certain instances, the non-warp knit pattern of the second row comprises chain-link stiches. In these instances the at least one first constraining fiber <NUM> includes the first constraining fiber <NUM> and a third constraining fiber and the at least one second constraining fiber <NUM> includes the second constraining fiber <NUM> and a fourth constraining fiber with the first constraining fiber, second constraining fiber, the third constraining fiber, and the fourth constraining fiber being interwoven to form a constraint <NUM> as discussed with reference to <FIG>.

The non-warp knit pattern, knot or stitch, used in a constraint <NUM> , that includes one or more additional knot rows with these rows formed in a knit or warp knit lessens the opportunity for self-deployment of the constraint <NUM>. In certain instances, a chain stitch, formed by the one loop <NUM> in a row <NUM> or all loops in a row of a constraint <NUM>, that includes one or more additional knot rows with these rows formed in a knit or warp knit, facilitates controlled deployment of the constraint <NUM>.

<FIG> is an illustration of a constraint <NUM> in a first arrangement, in accordance with an embodiment. The constraint <NUM> is shown as a sheet of interwoven fibers, however, the constraint <NUM> may be arranged circumferentially about an implantable medical device. The constraint <NUM> can include a first constraining fiber <NUM> and a second constraining fiber <NUM> as described above with reference to <FIG> that form multiple knot rows. For example and as shown in <FIG>, the constraint <NUM> includes a first constraining fiber <NUM>, a second constraining fiber <NUM>, a third constraining fiber <NUM>, and a fourth constraining fiber <NUM>. The constraining fibers <NUM>, <NUM>, <NUM>, <NUM> may be arranged together to form multiple knot rows <NUM>, <NUM>, <NUM>, <NUM>. In certain instances, the number of constraining fibers <NUM>, <NUM>, <NUM>, <NUM> may be equal to the number of knot rows <NUM>, <NUM>, <NUM>, <NUM>. In addition, the constraining fibers <NUM>, <NUM>, <NUM>, <NUM> may be interwoven or interlocked with one another to form the knot rows <NUM>, <NUM>, <NUM>, <NUM>.

In certain instances, the first row of knots <NUM> of the constraint <NUM> may be formed by the first constraining fiber <NUM> interwoven with the second constraining fiber <NUM>. As shown, the first constraining fiber <NUM> are interwoven with the second constraining fiber <NUM> to form the knot row <NUM> in a warp knit. The knot row <NUM> may be a warp knit when the constraint <NUM> is surrounding the medical device in the constrained configuration.

In addition, the second row of knots <NUM> may be formed by the second constraining fiber <NUM> interwoven with the third constraining fiber <NUM>. The second constraining fiber <NUM> may be interwoven with the third constraining fiber <NUM> to form a non-warp knit with the row of knots <NUM>. The knot row <NUM> may be a warp knit when the constraint <NUM> is surrounding the medical device in the constrained configuration.

As shown in <FIG>, the constraint <NUM> includes the multiple knot rows <NUM>, <NUM>, <NUM>, <NUM> with the first row of knots <NUM> being formed by the first constraining fiber <NUM> interwoven with the second constraining fiber <NUM>, the second row of knots <NUM> formed by the second constraining fiber <NUM> interwoven with the third constraining fiber <NUM>, the third row of knots <NUM> formed by the third constraining fiber <NUM> interwoven with the fourth constraining fiber <NUM>, and the fourth row of knots <NUM> formed by the fourth constraining fiber <NUM> interwoven with the first constraining fiber <NUM>.

In certain instances, one or more of the rows <NUM>, <NUM>, <NUM>, <NUM> forms a knit or a warp knit pattern with loops of the constraining fibers <NUM>, <NUM>, <NUM>, <NUM> and another of the one or more of the rows <NUM>, <NUM>, <NUM>, <NUM> forms a non-knit or non-warp knit pattern with one or more of the loops (e.g., a distal loop as described with reference to <FIG>) of the constraining fibers <NUM>, <NUM>, <NUM>, <NUM>. In certain instances, at least one of the third row <NUM> and the fourth row <NUM> forms a warp knit surrounding the medical device in the constrained configuration and another of the third row <NUM> and the fourth row <NUM> forms a non-warp knit surrounding the medical device in the constrained configuration. The constraint <NUM> may include three of the rows <NUM>, <NUM>, <NUM>, <NUM> in the warp pattern and one of the rows <NUM>, <NUM>, <NUM>, <NUM> in a non-warp pattern. The one or more rows <NUM>, <NUM>, <NUM>, <NUM> being in the non-warp pattern includes a single knot being arranged in a non-warp stitch (e.g., a chain stitch), two or more of the knots of the one or more rows <NUM>, <NUM>, <NUM>, <NUM> being a non-warp stitch, multiple knots of the one or more rows <NUM>, <NUM>, <NUM>, <NUM> being a non-warp stitch, alternating knots of the one or more rows <NUM>, <NUM>, <NUM>, <NUM> being a non-warp stitch, two or more or all of the knots of the one or more rows <NUM>, <NUM>, <NUM>, <NUM> being in a non-warp stitch.

The non-warp pattern of one or more of the rows <NUM>, <NUM>, <NUM>, <NUM> may lessen the opportunity for accelerated or unwanted deployment of the constraint <NUM>. The different non-warp pattern of one or more of the rows <NUM>, <NUM>, <NUM>, <NUM> interrupts the pattern of the constraint <NUM>.

A deployment line <NUM> may be coupled to an end of the second constraining fiber <NUM> (e.g., the fiber having the non-warp knit knot or knots) to force deployment of the constraint <NUM>. An end of the first constraining fiber <NUM> is joined with an end of the second constraining fiber <NUM>, which may be combined to form the deployment line <NUM>. In other instances, the deployment line <NUM> is the second constraining fiber <NUM> or a separate line or wire. In certain instances, the deployment line <NUM> is configured to unknit the second constraining fiber <NUM> and deploy the implantable medical device from the constrained configuration. As noted above, the constraint <NUM> may be circumferential arranged about the implantable medical device and the deployment line <NUM> may be configured to axially interrupt the constraint <NUM> to unknit the second constraining fiber <NUM> as is shown in <FIG>.

<FIG> are illustrations of the constraint, shown in <FIG>, in different steps of the constraint <NUM> unknitting. A-H, as shown in <FIG>, are location indicators of portions or sections of the second constraining fiber <NUM>. In comparing the arrangement of the second constraining fiber <NUM> in <FIG> and <FIG>, the loop or chain stitch D has been pulled axially. Additional pulling of the A section of the second constraining fiber <NUM> removes the slack remnants from loop D section of the second constraining fiber <NUM> and shows that a warp knit rows <NUM>, <NUM>, <NUM> is holding the constraint <NUM> together (e.g., as shown in <FIG>).

In certain instances, the second constraining fiber <NUM> may include a warp knit in the knot row <NUM> subsequent to loop or chain stitch D. Pulling the second constraining fiber <NUM> or the deployment line <NUM> would also untie the warp knit E section of the second constraining fiber <NUM>. <FIG> shows loop E of the second constraining line <NUM> pulled out of the row <NUM>. The next knot in row <NUM> may be chain stitch which requires an axial load applied to the second constraining fiber <NUM> or deployment line <NUM>. As sections of the second constraining fiber <NUM> are removed from the knot row <NUM>, the sections become a part of the deployment line <NUM>. Remaining sections of the second constraining fiber <NUM> may be warp knit or non-warp knit knots.

<FIG> is an image of a delivery system <NUM> in a delivery configuration, in accordance with an embodiment. 6B is an image of a delivery system <NUM> in a semi-deployed configuration, in accordance with an embodiment. As shown, disrupting one of the constraining fibers (e.g., the second constraining fiber <NUM>, for example) of a knot row initiates unravelling of at least a portion of the constraint <NUM>, as shown in <FIG>.

Claim 1:
A medical device deployment apparatus, the apparatus comprising:
at least one first constraining fiber (<NUM>) arranged as a series of multiple loops (<NUM>) to form a warp knit surrounding the medical device in a constrained configuration, the warp knit being configured to separate and be removed to deploy the medical device; and
at least one second constraining fiber (<NUM>) arranged with the at least one first constraining fiber (<NUM>), the at least one second constraining fiber (<NUM>) having at least one loop (<NUM>) arranged in a non-warp knit pattern.