Description:FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(Section 10 and Rule 13)

1. TITLE OF THE INVENTION:
STENT DELIVERY SYSTEM

2. APPLICANT:
Meril Corporation (I) Private Limited, an Indian company of the address Survey No. 135/139, Muktanand Marg, Bilakhia House, Pardi, Vapi, Valsad-396191 Gujarat, India.

The following specification particularly describes the invention and the manner in which it is to be performed:

 
FIELD OF INVENTION
[01] The present disclosure relates to a medical device. More particularly, the present disclosure relates to a stent delivery system.
BACKGROUND OF INVENTION
[02] A common non-invasive procedure to treat a blocked or clogged vessel (e.g., a carotid artery or a peripheral artery) of a patient involves deploying a stent within the blocked vessel. A stent delivery system is used to deliver and deploy a stent at a target site within the affected vessel, to maintain its patency and prevent blockage.
[03] During a typical stent delivery procedure, a catheter is introduced into a patient’s body through a small incision and navigated to the target site using, for example, a guidewire. The stent is mounted on the catheter. Once the catheter reaches the target site, the stent is detached from the catheter and deployed at target site.
[04] In case of self-expandable stents, a stent remains in a crimped or compressed state within a delivery sheath. Once the catheter reaches the target site, the delivery sheath is retracted and the stent is exposed, allowing the stent to radially expand from its compressed state. Once the delivery sheath is retracted completely, the stent is fully deployed.
[05] It may be possible that the stent may be placed inaccurately during a deployment procedure. However, conventional delivery systems do not allow the stent retrieval or repositioning after partial deployment of the stent. The misplacement of a stent can lead to serious complications, including damage to blood vessels, reduced blood flow, increased risk of thrombosis, and stent migration. These issues can cause pain, tissue damage, and may pose serious health risks to a patient. Further interventions may be needed in such cases to reposition or replace the misplaced stent. This not only increases the medical cost for the patient but may also lead to adverse impact on the patient’s health.
[06] Hence, there is a need of a delivery system that can overcome the problems associated with the conventionally available delivery systems.
SUMMARY OF INVENTION
[07] Particular embodiments of the present disclosure are described herein below with reference to the accompanying drawings; however, it is to be understood that the disclosed embodiments are mere examples of the disclosure, which may be embodied in various forms. Well-known functions or constructions are not described in detail to avoid obscuring the present disclosure in unnecessary detail. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present disclosure in virtually any appropriately detailed structure.
[08] The present disclosure relates to a delivery system for deploying a stent. In an embodiment, the delivery system includes a slotted tube, a plurality of holding elements, a cutting tube, and a first control element. The slotted tube includes a plurality of first slots provided circumferentially on the slotted tube towards a distal end of slotted tube and a plurality of second slots provided circumferentially on the slotted tube proximal to the plurality of first slots. The plurality of holding elements is coupled to the stent to be deployed. Each holding element has a first end and a second end fixedly coupled to a corresponding first slot and a corresponding second slot of the slotted tube, respectively. The cutting tube has a lumen configured to receive the slotted tube. The first control element is capable of receiving a first actuation input. The first control element is coupled to the cutting tube such that, in response to the first control element receiving the first actuation input, the cutting tube is configured to longitudinally slide over the slotted tube from a first position to a second position, causing the cutting tube to cut the plurality of holding elements, thereby releasing the stent from the delivery system.
BRIEF DESCRIPTION OF DRAWINGS
[09] The summary above, as well as the following detailed description of illustrative embodiments, is better understood when read in conjunction with the apportioned drawings. For the purpose of illustrating the present disclosure, exemplary constructions of the disclosure are shown in the drawings. However, the disclosure is not limited to specific methods and instrumentality disclosed herein. Moreover, those in the art will understand that the drawings are not to scale.
[10] Fig. 1 depicts a side view of a delivery system 100, in accordance with an embodiment of the present disclosure.
[11] Fig. 2 depicts a side view of a stent 10 in a radially crimped state, in accordance with an embodiment of the present disclosure.
[12] Fig. 2a depicts a side view of the stent 10 in a radially expanded state, in accordance with an embodiment of the present disclosure.
[13] Fig. 3 depicts a cross-sectional view of a distal portion of the delivery system 100, in accordance with an embodiment of the present disclosure.
[14] Fig. 4 depicts a perspective view of a slotted tube 130, in accordance with an embodiment of the present disclosure.
[15] Fig. 5 depicts a perspective view of a cutting tube 150, in accordance with an embodiment of the present disclosure.
[16] Fig. 6 depicts a perspective view of a handle 200, in accordance with an embodiment of the present disclosure.
[17] Fig. 7 depicts a section view of the handle 200, in accordance with an embodiment of the present disclosure.
[18] Fig. 7a depicts a cross-sectional view of the handle 200, in accordance with an embodiment of the present disclosure.
[19] Figs. 7a1 – 7a3 depict detailed views of the coupling of an outer sheath 120, an inner tube 110 and a middle tube 140 with the handle 200, in accordance with an embodiment of the present disclosure.
[20] Fig. 8 depicts a flowchart of a method 800 for deploying a stent using the delivery system 100, in accordance with an embodiment of the present disclosure.
[21] Fig. 9 depicts the stent 10 attached to the delivery system 100, in accordance with an embodiment of the present disclosure.
[22] Fig. 10 depicts the stent 10 being detached from the delivery system 100, in accordance with an embodiment of the present disclosure.
[23] Fig. 11 depicts the stent 10 completely released from the delivery system 100, in accordance with an embodiment of the present disclosure.
DETAILED DESCRIPTION OF ACCOMPANYING DRAWINGS
[24] Prior to describing the invention in detail, definitions of certain words or phrases used throughout this patent document will be defined: the terms "include" and "comprise", as well as derivatives thereof, mean inclusion without limitation; the term "or" is inclusive, meaning and/or; the phrases "coupled with" and "associated therewith", as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have a property of, or the like. Definitions of certain words and phrases are provided throughout this patent document, and those of ordinary skill in the art will understand that such definitions apply in many, if not most, instances to prior as well as future uses of such defined words and phrases.
[25] Reference throughout this specification to “one embodiment,” “an embodiment,” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “in one embodiment,” “in an embodiment,” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment, but mean “one or more but not all embodiments” unless expressly specified otherwise. The terms “including,” “comprising,” “having,” and variations thereof mean “including but not limited to” unless expressly specified otherwise. An enumerated listing of items does not imply that any or all of the items are mutually exclusive and/or mutually inclusive, unless expressly specified otherwise. The terms “a,” “an,” and “the” also refer to “one or more” unless expressly specified otherwise.
[26] Although the operations of exemplary embodiments of the disclosed method may be described in a particular sequential order for convenient presentation, it should be understood that the disclosed embodiments can encompass an order of operations other than the particular sequential order disclosed. For example, operations described sequentially may in some cases be rearranged or performed concurrently. Further, descriptions and disclosures provided in association with one particular embodiment are not limited to that embodiment and may be applied to any embodiment disclosed herein. Moreover, for the sake of simplicity, the attached figures may not show the various ways in which the disclosed system, method, and apparatus can be used in combination with other systems, methods, and apparatuses.
[27] Furthermore, the described includes, advantages, and characteristics of the embodiments may be combined in any suitable manner. One skilled in the relevant art will recognize that the embodiments may be practiced without one or more of the specific includes or advantages of a particular embodiment. In other instances, additional includes and advantages may be recognized in certain embodiments that may not be present in all embodiments. These includes and advantages of the embodiments will become more fully apparent from the following description and apportioned claims or may be learned by the practice of embodiments as set forth hereinafter.
[28] The present disclosure provides a delivery system for delivering and deploying a stent at a target site within a patient’s body. The proposed delivery system includes a retrieval mechanism, which enables retrieval and repositioning of a partially deployed stent during a stent implantation procedure unlike conventional delivery systems that are not capable of retrieval and repositioning upon partial deployment of a stent. Thus, the proposed delivery system not only enhances precision of stent delivery but also provides increased flexibility and adaptability to a surgeon, thereby improving the procedural efficiency. The proposed system is designed to provide a versatile solution for complex interventions and caters to diverse anatomies and pathologies encountered in clinical practice. The delivery system of the present disclosure improves procedural outcomes in treating peripheral and carotid arterial conditions.
[29] Now referring to the figures, Fig. 1 depicts a side view of a delivery system 100 for deploying a stent, according to an embodiment. The delivery system 100 has a proximal end 100a and a distal end 100b. The delivery system 100 includes a handle 200, and a catheter 300. The handle 200 is used to control various components of the delivery system 100 to deploy and retract the stent 10 (explained later). The delivery system 100 is used to deliver a stent at a target site within a patient’s vasculature. Fig. 1 depicts the delivery system 100 coupled to an exemplary stent 10. The stent 10 is coupled to the delivery system 100 at the distal end 100b. An exemplary stent 10 is depicted in Figs. 2 and 2a. The stent 10 has a proximal end 10a and a distal end 10b. In an embodiment, the stent 10 is a self-expandable (or self-expanding) stent and may be made of a biocompatible, shape-memory material, for example, nitinol. The stent 10 has a tubular structure. The stent 10 is configurable to be in a radially collapsed state (shown in Fig. 2) and a radially expanded state (shown in Fig. 2a). The stent 10 may have a uniform or a non-uniform diameter (e.g., tapered, flared, etc.) along an axial length of the stent 10. The length and the diameter of the stent 10, when in the radially expanded state, may be chosen based upon clinical needs of the patient. The stent 10 may be a peripheral vascular stent, a carotid vascular stent, an airway stent, a coronary stent, a urinary tract stent, and the like. The stent 10 may be a drug eluting stent. The stent 10 may be a braided, laser cut, or the like. The stent 10 includes a plurality of struts arranged in a pre-defined pattern. In an embodiment, the stent 10 includes a plurality of cells 11 provided at the proximal end 10a. The plurality of cells 11 is utilized to couple the stent 10 with the catheter 300 as explained later. It should be appreciated that the stent 10 depicted herein is merely exemplary and the delivery system 100 is capable of delivering a stent of any design.
[30] Fig. 3 depicts a cross-sectional view of a distal section of the delivery system 100, according to an embodiment. The catheter 300 is disposed towards the distal end 100b of the delivery system 100 and is coupled to the handle 200 disposed towards the proximal end 100a. The catheter 300 has a proximal end (not shown) and a distal end 300b. The catheter 300 has an elongated, tubular structure, defining a plurality of lumens. In an embodiment, the catheter 300 includes an inner tube 110, an outer sheath 120, and a middle tube 140 disposed coaxially.
[31] The outer sheath 120 corresponds to an outermost tube of the catheter 300. The outer sheath 120 encloses the inner tube 110, the slotted tube 130, the middle tube 140, and the cutting tube 150. In an embodiment, the outer sheath 120 has an elongated, tubular structure, defining a lumen. The outer sheath 120 may be made from a biocompatible material including, but not limited to, poly urethane (PU), polyether ether ketone (PEEK), poly tetrafluoro ethylene (PTFE), polyether block amide (PEBAX), etc. In an embodiment, the outer sheath 120 is made from PEEK. The outer diameter and the inner diameter of the outer sheath 120 may be chosen based upon the clinical needs. In an embodiment, the outer diameter of the outer sheath 120 may range from 1.4 mm to 4 mm, and the inner diameter of the outer sheath 120 may range from 1.5 mm to 3.9 mm. In an example implementation, the outer sheath 120 has the outer diameter of 2.0 mm and the inner diameter of 1.8 mm. A proximal end of the outer sheath 120 is coupled to the handle 200. The outer sheath120 is movable between a proximal-most position and a distal-most position with the help of the handle 200 during an implantation procedure. In the distal-most position, the outer sheath 120 fully encloses the stent 10 (i.e., the distal end of the stent 10 is disposed within the outer sheath 120) and applies constraining force on the stent 10, keeping the stent 10 in the radially collapsed state. As the outer sheath 120 is moved (or retracted) gradually towards the proximal-most position, the stent 10 is gradually exposed. Without the constraining force of the outer sheath 120, the exposed portion of the stent 10 radially expands. In an embodiment, at the proximal most position, a distal end of the outer sheath 120 is disposed proximal to a proximal end of the stent 10.
[32] The inner tube 110 corresponds to an innermost tube of the catheter 300. The inner tube 110 has a proximal end 110a and a distal end (not shown). The inner tube 110 has an elongated, tubular structure and defines an inner lumen of the catheter 300. The inner lumen may be configured to provide a passage to a guidewire. The inner and outer diameters of the inner tube 110 may be chosen based upon clinical requirements. The inner diameter of the inner tube 110 may range between 0.75 mm and 3 mm. In an embodiment, the inner diameter of the inner tube 110 is 0.75 mm. The outer diameter of the inner tube 110 may range between 0.8 mm and 3.2 mm. In an embodiment, the outer diameter of the inner tube 110 is 0.8 mm. The inner tube 110 may be made of a biocompatible material including, but not limited to, PEEK, polyethylene (PE), PTFE, PABEX, and so forth. In an embodiment, the inner tube 110 is made of PEEK. The stent 10 is mounted on the inner tube 110 in the radially collapsed (or crimped) state at the distal end of the inner tube 110.
[33] The middle tube 140 is disposed between the outer sheath 120 and the inner tube 110 i.e., The middle tube 140 is disposed within the outer sheath 120 and the inner tube 110 is disposed within the middle tube 140. The middle tube 140 has a proximal end 140a (shown in Fig. 7) and a distal end 140b (shown in Fig. 3). The middle tube 140 has an elongated, tubular structure defining a lumen. The lumen of the middle tube 140 is configured to receive the inner tube 110. The middle tube 140 is configured to slide longitudinally over the inner tube 110. The proximal end 140a of the middle tube 140 extends into the handle 200. The inner diameter of the middle tube 140 may be equal to or greater than the outer diameter of the inner tube 110. In an embodiment, the inner diameter of the middle tube 140 is greater than the outer diameter of the inner tube 110 such that there is a gap therebetween. The inner diameter of the middle tube 140 ranges between 0.82 mm and 3.22 mm. In an embodiment, the inner diameter of the middle tube 140 is 0.82 mm. In an embodiment, the outer diameter of the middle tube 140 is smaller than the inner diameter of the outer sheath 120 such that there is a gap between the outer sheath 120 and the middle tube 140 as shown in Fig. 3. The outer diameter of the middle tube 140 ranges between 0.85 mm and 3.30 mm. In an embodiment, the outer diameter of the middle tube 140 is 0.9 mm. The middle tube 140 may be made of a material, such as, without limitation, PABEX, PTFE, PEEK, etc. In an embodiment, the middle tube 140 is made of PEEK.
[34] In an embodiment, the delivery system 100 includes a slotted tube 130. Fig. 4 depicts the slotted tube 130, according to an embodiment. The slotted tube 130 may be mounted on the inner tube 110 towards the distal end of the inner tube 110. The slotted tube 130 has an elongated tubular structure, defining a first lumen 135. The first lumen 135 is configured to receive the inner tube 110. A portion of the inner tube 110 resides within the first lumen 135 of the slotted tube 130. The slotted tube 130 has a proximal end 130a and a distal end 130b. In an embodiment, the slotted tube 130 is coupled to the inner tube 110 such that the distal end 130b of the slotted tube 130 is located proximal to the distal end of the inner tube 110 by a pre-defined distance. In other words, the distal end of the inner tube 110 extends out from the distal end 130b of the slotted tube 130. The pre-defined distance enables the stent 10 to be coupled to the inner tube 110 between the distal end of the inner tube 110 and the distal end 130b of the slotted tube 130. The pre-defined distance is chosen based upon the length of the stent 10 and is greater than or equal to the length of the stent 10. In an embodiment, the slotted tube 130 is fixedly coupled to the inner tube 110 using, for example, adhesive bonding, such that the slotted tube 130 and the inner tube 110 are not slidable (or movable) with respect to each other. The slotted tube 130 may have an inner diameter corresponding the outer diameter of the inner tube 110. The outer diameter of the slotted tube 130 may ranges between 0.75 mm and 3 mm. In an embodiment, the outer diameter of the slotted tube 130 is 1.2 mm. The slotted tube 130 may be made of a biocompatible material including, but not limited to, stainless steel, nitinol, etc. In an embodiment, the slotted tube 130 is made of stainless steel. Though in the depicted embodiment, the slotted tube 130 and the inner tube 110 are depicted as separate components coupled together, it is possible that they may be integrally coupled, e.g., the slotted tube 130 and the inner tube 110 may form an integrated structure.
[35] In an embodiment, the slotted tube 130 includes a plurality of first slots 131 and a plurality of second slots 133. The first slots 131 are disposed towards the distal end 130b of the slotted tube 130. The first slots 131 are provided circumferentially on the outer surface of the slotted tube 130 and extend longitudinally. The first slots 131 have a proximal end 131a and a distal end 131b. In an embodiment, the proximal end 131a aligns (or coincides) with the distal end 130b of the slotted tube 130 such that the first slots 131 are open-ended at the distal end 130b. In an embodiment, the first slots 131 have a rectangular shape, though the first slots 131 may have any other shape (e.g., oblong, rectangular with curved ends, oval, etc.). The depth of the first slots 131 may be less than or equal to the thickness of the slotted tube 130. In an embodiment, the depth of the first slots 131 is equal to the thickness of the slotted tube 130 such that the first slots 131 extend to the first lumen 135. The first slots 131 may be distributed uniformly or non-uniformly across the circumference of the slotted tube 130. In the depicted embodiment, the first slots 131 are distributed uniformly.
[36] The plurality of second slots 133 is located towards the distal end 130b of the slotted tube 130. Each second slot 133 has a proximal end 133a and a distal end 133b. The second slots 133 are provided circumferentially on the outer surface of the slotted tube 130, proximal to the plurality of first slots 131 and extend longitudinally. In an embodiment, the second slots 133 have a rectangular shape, though the second slots 133 may have any other shape (e.g., oblong, rectangular with curved ends, oval, etc.). The depth of the second slots 133 may be less than or equal to the thickness of the slotted tube 130. In an embodiment, the depth of the second slots 133 is equal to the thickness of the slotted tube 130 such that the second slots 133 extend to the first lumen 135. The second slots 133 may be distributed uniformly or non-uniformly across the circumference of the slotted tube 130. In the depicted embodiment, the second slots 133 are distributed uniformly. Each second slot 133 is longitudinally aligned with a respective first slot 131. The second slots 133 are disposed proximal to the first slots 131 at a pre-defined distance. The pre-defined distance may be chosen based upon on the length and the diameter of the stent 10. In an embodiment, the pre-defined distance may range between 2 mm and 10 mm. In an example implementation, the pre-defined distance is 3 mm. The number of second slots 133 corresponds to the number of first slots 131. In the depicted embodiment, the slotted tube 130 includes four first slots 131 and four second slots 133. In various embodiments, the number of the first slots 131 and the second slots 133 may be more or less than four and an actual number may be chosen depending upon requirements. The length of the second slots 133 may be the same as or may be greater than or smaller than the length of the first slots 131. In an embodiment, the length of the second slots 133 is greater than the length of the first slots 131. The lengths of the first slots 131 and the second slots 133 may be chosen based upon the pulling force required to pull the stent 10 during retrieval or repositioning, as needed. The greater the required pulling force, the longer are the first slots 131 and the second slots 133. In an embodiment, the length of the first slots 131 may range between 2 mm and 5 mm, and the length of the second slots 133 may range between 2 mm and 5 mm. In an example implementation, the length of the first slots 131 is 2 mm and the length of the second slots 133 is 5mm.
[37] The delivery system 100 includes a plurality of holding elements 170 (hereinafter, the holding elements 170). The holding elements 170 are coupled to the stent 10. The holding elements 170 are used to hold the stent 10 during the deployment and facilitates retraction and repositioning of the stent 10, for example, when the stent 10 is not positioned correctly. Each of the holding elements 170 has a first end 170a and a second end 170b. Each of the holding elements 170 passes through one of the cells 11 of the stent 10, and the first end 170a and the second end 170b of the holding element 170 are coupled to the slotted tube 130. The first end 170a of each holding element 170 is fixedly coupled to a respective first slot 131 of the first slots 131 and the second end 170b of each holding element 170 is fixedly coupled to a respective second slot 133 of the second slots 133. In an embodiment, the first end 170a of each holding element 170 is fixedly coupled to the proximal end 131a of a respective first slot 131 and the second end 170b of each holding element 170 is fixedly coupled to the proximal end 133a of a respective second slot 133. Coupling the first end 170a and the second end 170b of the holding elements 170 with the proximal end 131a of the first slots 131 and the proximal end 133a of the second slots 133, respectively. Such a coupling ensures that the holding elements 170 generate sufficient pulling force on the stent 10 during the retrieval of the stent 10 inside the outer sheath 120. It should be understood though that the first end 170a and the second end 170b of the holding element 170 may be fixedly coupled to the corresponding first slot 131 and the second slot 133 at any other location within the first slot 131 and the second slot 133, respectively, based upon requirements without deviating from the scope of the present disclosure. In an embodiment, at least a partial length of the portion of the holding elements 170 disposed within the second slots 133 is coupled with walls of the second slots 133. This provides additional strength to the holding elements 170 while pulling the stent 10 for retrieval and/or repositioning. When the first slots 131 are open-ended and extend into the first lumen 135 of the slotted tube 130, the first end 170a of the holding elements 170 may be passed from under the first slots 131(i.e., through the first lumen 135) and coupled with the first slots 131. This results in a compact radial profile of the distal portion of the delivery system 100 and allows for easier delivery and navigation.
[38] The first end 170a and the second end 170b of the holding elements 170 may be fixedly coupled to the respective first slots 131 and the second slots 133 using a technique including, without limitation, adhesive bonding, ultrasonic welding, press-fit, or the like. In an example implementation, the first end 170a and the second end 170b of the holding elements 170 are coupled to the respective first slots 131 and the second slots 133, respectively, using adhesive bonding. The holding elements 170 may be made of a biocompatible material that can be cut easily while having sufficient elasticity to resist a pulling force experienced by it during the stent retrieval. In an embodiment, the holding elements 170 are made of a biocompatible, polymeric material, such as, without limitation, PE, PTFE, PU, PEEK and like. In an embodiment, the holding elements 170 are made of PEEK. The holding elements 170 may include one of: a wire, a cord, a strip, a cable, etc. The holding elements 170 may have a desired cross-sectional shape, such as, circular, square, rectangular, oval, etc. Each holding element 170 includes a monofilament or includes multiple filaments braided together in a predefined manner. In an example implementation, the holding elements 170 are flat, monofilament wires having a rectangular cross-section.
[39] The holding elements 170 may be uniformly or non-uniformly distributed based upon the configuration of the first slots 131 and the second slots 133. In an example implementation, the holding element 170 are uniformly distributed since the first slots 131 and the second slots 133 are distributed uniformly. Such a uniform arrangement causes the force applied by the holding elements 170 on the stent 10 to be distributed evenly, resulting in uniform and accurate expansion and/or contraction of the stent 10, thereby improving the efficacy of the delivery system 100. The number of holding elements 170 may be chosen based upon requirements. In an embodiment, the delivery system 100 includes at least 2 holding elements 170. Preferably, the delivery system 100 includes between 4 and 8 holding elements 170. This allows for 100% retrievability of the stent 10, while minimizing the complexity of the delivery system 100. In an example implementation, the delivery system 100 includes four holding elements 170. The number of first slots 131 and the second slots 133 corresponds to the number of holding elements 170.
[40] In an embodiment, the delivery system 100 includes a cutting tube 150. The cutting tube 150 is used to cut the holding elements 170 to release the stent 10 from the delivery system 100. Fig. 5 depicts a distal portion of the cutting tube 150, according to an embodiment. The cutting tube 150 has a proximal end 150a and a distal end 150b. The cutting tube 150 has an elongated, tubular structure, defining a lumen 150c configured to receive the slotted tube 130. In an embodiment, the cutting tube 150 may have an inner diameter corresponding to the outer diameter of the slotted tube 130. The cutting tube 150 has an outer diameter. The outer diameter of the cutting tube 150 may range between 1.5 mm and 4 mm. In an embodiment, the outer diameter of the cutting tube 150 is 1.8 mm. The cutting tube 150 is configured to slide longitudinally on the outer surface of the slotted tube 130. The cutting tube 150 may be made of a material, such as, without limitation, PEBAX, PE, PU, PTFE, etc. In an example implementation, the cutting tube 150 is made of PEBAX.
[41] In an embodiment, the cutting tube 150 is partially disposed on the outer surface of the middle tube 140 towards the distal end 140b of the middle tube 140 such that a proximal portion of the cutting tube 150 resides in the gap between the middle tube 140 and the outer sheath 120 as shown in Fig. 3. In other words, the distal end 140b of the middle tube 140 is disposed inside the lumen 150c of the cutting tube 150 towards the proximal end 150a of the cutting tube 150. The cutting tube 150 is coupled to the middle tube 140 such that the cutting tube 150 is configured to move longitudinally in response to the longitudinal motion of the middle tube 140. The direction of the movement of the cutting tube 150 is the same as that of the middle tube 140. The portion of the cutting tube 150 may be fixedly coupled to the middle tube 140 using, for example, adhesive bonding or any other suitable coupling method. Though the cutting tube 150 and the middle tube 140 are described as separate components coupled together, it should not be considered as limiting. In an embodiment, the cutting tube 150 and the middle tube 140 are integrally coupled, for example, the cutting tube 150 and the middle tube 140 may form an integrated structure or the cutting tube 150 and the middle tube 140 may be a single tube.
[42] The cutting tube 150 includes a tapered portion 150d provided at the distal end 150b. The tapered portion 150d has a tapered profile such that the diameter of the tapered portion 150d reduces gradually from a proximal end of the tapered portion 150d to a distal end of the tapered portion 150d, forming an edge 150e at the distal end 150b of the cutting tube 150. The edge 150e at the distal end 150b is configured to cut the holding element 170 to release the stent 10 from the delivery system 100 as explained later. The tapered portion 150d is designed such that the edge 150e is sharp enough to the cut the holding elements 170. In an embodiment, the edge 150e and the outer surface of the slotted tube 130 have a minimal clearance therebetween. The cutting tube 150 is slidable between a first position and a second position. In the first position, the distal end 150b of the cutting tube 150 is disposed proximal to the proximal end 133a of the second slots 133. The cutting tube 150 is configured to be in the first position during the navigation of the catheter 300 through the patient’s vasculature to the target site. In the second position, the distal end 150b of the cutting tube 150 aligns with the distal ends 133b of the second slots 133. In an embodiment, when the cutting tube 150 moves from the first position to the second position, the edge 150e of the cutting tube 150 is configured to grind each holding element 170 against the distal end 133b of the respective second slot 133. Due to the minimal clearance between the edge 150e and the slotted tube 130, the edge 150e of the cutting tube 150 cuts the holding elements 170, thereby releasing the stent 10 from the catheter 300 and from the delivery system 100.
[43] The handle 200 allows a medical practitioner to hold and operate the delivery system 100. Fig. 6 depicts a perspective view of the handle 200, according to an embodiment. Figs. 7 and 7a depict section view and cross-sectional view of the handle 200 showing the coupling of the outer sheath 120, the inner tube 110, and the middle tube 140 with the handle 200. The handle 200 is positioned at the proximal end 100a of the delivery system 100. The handle 200 has a proximal end 200a and a distal end 200b. The handle 200 includes a casing 210, a first control element 230 and a second control element 250.
[44] In an embodiment, the casing 210 has a hollow body and may have an ergonomic design for a better grip. In an embodiment, the casing 210 may have a generally rectangular shape, though the casing 210 may have any other shape. The casing 210 may be made of a material including, but not limited to, acrylonitrile butadiene styrene (ABS), PU, PE, etc. In an example implementation, the casing 210 is made of ABS. In an embodiment, the casing 210 is provided with an undulating structure 215 having a protruding shape towards the distal end 200b of the handle 200 as shown in Fig. 6. The undulating structure 215 provides a better grip to the operator, minimizing fatigue. The casing 210 has a distal opening 217 at the distal end 200b. The distal opening 217 is configured to provide a passage to the outer sheath 120. The shape and dimensions of the distal opening 217 corresponds to the shape and dimensions of the outer sheath 120. In an embodiment, the distal opening 217 has a circular shape. The handle 200 includes a guidewire port 218 at the proximal end 200a of the handle 200. The guidewire port 218 is configured to provide a passage to a guidewire. In an embodiment the guidewire port 218 has a tubular shape defining a cavity configured to receive the guidewire. A distal end of the guidewire port 218 extends into the handle 200 and a proximal end of the guidewire port 218 protrudes out of the handle 200. The proximal end 110a of the inner tube 110 is fixedly coupled to the distal end of the guidewire port 218 (as depicted in Fig. 7a1) using, for example, adhesive bonding. In an embodiment, the guidewire port 218 may be provided with external threads to be coupled to a flushing system (or device) to inject sterile water or saline solution into the vasculature of the patient to flush out any debris or clogs in the vasculature.
[45] The first control element 230 is configured to move the cutting tube 150 between the first position and the second position. The first control element 230 may be provided towards the proximal end 200a of the handle 200. The first control element 230 is coupled to the cutting tube 150 via the middle tube 140. The first control element 230 is capable of receiving a first actuation input and a second actuation input. In response to the first control element 230 receiving the first actuation input, the middle tube 140 is configured to slide longitudinally in a distal (or forward) direction, causing the cutting tube 150 to slide longitudinally over the surface of the slotted tube 130 from the first position to the second position to cut the holding elements 170. In response to the first control element 230 receiving the second actuation input, the middle tube 140 is configured to slide longitudinally in a proximal (or backward) direction, causing the cutting tube 150 to slide longitudinally over the surface of the slotted tube 130 from the second position to the first position. The first control element 230 may be a roller, a sliding button, a rotating knob, etc. In an embodiment, the first control element 230 is a sliding button having a first body 233 and a first coupling portion 231 as shown in Fig. 7. The first body 233 is disposed at a top end of the first control element 230 and the first coupling portion 231 is disposed at a bottom end of the first control element 230. The first coupling portion 231 is coupled with the proximal end 140a of the middle tube 140 (shown in Fig. 7a2). In an embodiment, the first coupling portion 231 includes a first hole (not shown) configured to receive a proximal portion of the middle tube 140. The first hole is coupled with the proximal portion of the middle tube 140 using, for example, adhesive bonding, or any other suitable technique. The first hole is shaped and dimensioned according to the shape and dimensions of the middle tube 140. In an embodiment, the first coupling portion 231 is cylindrical, though the first coupling portion 231 may have any other shape. The first body 233 may be generally cuboidal, though the first body 233 may have any other shape. The first body 233 provides support and strength to the first control element 230. In an embodiment, a portion of the first body 233 protrudes out of the casing 210. The protruding portion allows the medical practitioner to hold and manipulate the first control element 230. For example, the first control element 230 may be moved back and forth as desired, providing a corresponding motion to the middle tube 140.
[46] The second control element 250 is positioned at a distance from the first control element 230. The second control element 250 may be a roller, a sliding button, a rotating knob, etc. In an embodiment, the second control element 250 is a sliding button. The second control element 250 may be structurally identical to the first control element 230 and includes a second coupling portion 251 and a second body 253. The structure of the second coupling portion 251, and the second body 253 of the second control element 250 may be referred from the first coupling portion 231 and the first body 233, of the first control element 230 respectively, and is not repeated for sake of brevity. The second coupling portion 251 of the second control element 250 is coupled with the outer sheath 120 (shown in Fig. 7a3). The second control element 250 is capable of receiving a first actuation input and a second actuation input. In response to the second control element 250 receiving the first actuation input, the outer sheath 120 is configured to slide longitudinally in the distal (or forward) direction, constraining the stent 10, causing the stent 10 to radially contract. In response to the first control element 230 receiving the second actuation input, the outer sheath 120 is configured to slide longitudinally in the proximal direction, exposing the stent 10, causing the stent 10 to radially expand. The second coupling portion 251 of the second control element 250 includes a hole configured to receive a portion of the outer sheath 120. The hole is coupled to the outer sheath 120 using, for example, adhesive bonding, or any other suitable technique. The second control element 250 is configured to control the motion of the outer sheath 120. The medical practitioner may move the second control element 250 in the proximal direction to retract the outer sheath 120 and in the distal direction to advance the outer sheath 120.
[47] In an embodiment, the handle 200 is provided with a first slot 211 configured to slidably receive the first control element 230. The first control element 230 is disposed in and is slidable within the first slot 211. The first slot 211 has a proximal end and a distal end. The first control element 230 is slidable between the proximal end and the distal end of the first slot 211. In the depicted embodiment, the first actuation input of the first control element 230 includes moving the first control element 230 from the proximal end to the distal end of the first slot 211. Similarly, the second actuation input of the first control element 230 includes moving the first control element 230 from the distal end to the proximal end of the first slot 211. The first slot 211 may be provided towards the proximal end of the handle 200. The first slot 211 may have a predefined shape, for example, rectangular, though the first slot 211 may have any other shape. When the first control element 230 is at the proximal end of the first slot 211, the cutting tube 150 is configured to be at the first position and when the first control element 230 is at the distal end of the first slot 211, the cutting tube 150 is configured to be at the second position (as explained earlier). One or more stoppers 219 may be provided at a distal end of the first slot 211 as shown in Fig. 6. The one or more stoppers 219 restrict any further movement of the first control element 230 in the distal direction, restricting any unwanted motion of the cutting tube 150 in the distal direction beyond the second position, thereby, preventing any accidental damage to the stent 10 due to the edge 150e of the cutting tube 150. In the depicted embodiment, the first slot 211 is provided with one stopper 219.
[48] A second slot 213 is provided on the casing 210 to receive the second control element 250. The second slot 213 may be provided towards the distal end 200b of the handle 200 at a distance from the first slot 211. The second slot 213 may have a predefined shape, for example rectangular, though the second slot 213 may have any other shape. The length of the second slot 213 may be greater than or equal to the length of the stent 10 to be deployed. The second control element 250 is movable between a proximal end of the second slot 213 and a distal end of the second slot 213. In an embodiment, the first actuation input of the second control element 250 includes moving the second control element 250 from the proximal end towards the distal end of the second slot 213. Similarly, the second actuation input of the second control element 250 includes moving the second control element 250 from the distal end towards the proximal end of the second slot 213. When the second control element 250 is at the proximal end of the second slot 213, the outer sheath 120 is at the proximal most position, exposing the stent 10 and distal portions of the slotted tube 130 and the cutting tube 150. When the second control element 250 is at the distal end of the second slot 213, the outer sheath 120 is at the distal most position, enclosing the stent 10 and the distal portions of the slotted tube 130 and the cutting tube 150. In an embodiment, the second slot 213 is provided with a plurality of serrations 213a on inner sides of the second slot 213. The serrations 213a are configured to provide structural strength to the handle 200 thereby increasing the durability of the handle 200. In an embodiment, the first slot 211 may also be provided with serrations 211a (shown in Fig. 7a) on inner sides of the first slot 211.
[49] Fig. 8 depicts a flowchart of an exemplary method 800 of using the delivery system 100 to deliver the stent 10. At step 801, the stent 10 is assembled with the delivery system 100. The stent 10 is crimped to a radially collapsed state and mounted on the inner tube 110 between the distal end of the inner tube 110 and the distal end 130b of the slotted tube 130. The stent 10 may be crimped using a crimping device (e.g., a loading system) known in the art. The second end 170b of each holding element 170 is fixedly coupled to the respective second slot 133 of the slotted tube 130. The first end 170a of each holding element 170 is passed through one of the cells 11 of the stent 10, looped back, and fixedly coupled to the respective first slot 131 of the slotted tube 130, thereby coupling the stent 10 with the slotted tube 130. It should be understood that, in another embodiment, the first ends 170a of the holding elements 170 may be first coupled to the respective first slots 131, and the second ends 170b may then be passed through a respective cell 11 of the stent 10, looped back and coupled to the respective second slots 133. The outer sheath 120 is set to the distal-most position by positioning the second control element 250 at the distal end of the second slot 213, causing the outer sheath 120 to enclose the stent 10. The cutting tube 150 is maintained in the first position by positioning the first control element 230 at the proximal end of the first slot 211.
[50] At step 803, the catheter 300 is inserted into a patient’s body via an appropriate vascular access point, e.g., through the transfemoral groin of a patient and navigated through the patient’s vasculature to a target site. A guidewire (not shown) disposed within the inner lumen of the inner tube 110 may be used to navigate the catheter 300 to the target site. At this stage, the outer sheath 120 is at the distal-most position and the cutting tube 150 is at the first position. The stent 10 remains enclosed within the outer sheath 120 in a crimped state. The holding elements 170 restrain the stent 10 and prevent the stent 10 from detaching from the delivery system 100.
[51] At step 805, once the catheter 300 is positioned at the target site, the outer sheath 120 is retracted towards the proximal most position to expose the stent 10. In an embodiment, the operator gradually retracts the outer sheath 120 in the proximal direction towards the proximal most position by sliding the second control element 250 towards the proximal end of the second slot 213. As the outer sheath 120 retracts, the stent 10 is gradually exposed from the distal end of the stent 10. Due to the shape-memory characteristics of the stent 10, the exposed portion of the stent 10 radially expands. The medical practitioner may retract the outer sheath 120 to a position where the first slots 131 and the second slots 133 of the slotted tube 130 and the tapered portion 150d of the cutting tube 150 are exposed. The holding elements 170 continue to hold the stent 10, preventing detachment from the delivery system 100. The medical practitioner may continually monitor the deployment of the stent 10 using, for example, fluoroscopy.
[52] It may happen that the stent 10 may not be delivered accurately at the target site or may have migrated. In these scenarios, the medical practitioner may want to retrieve the stent 10 so that the medical practitioner may re-adjust the position the stent 10. In such a situation, the medical practitioner may slide the second control element 250 towards the distal end of the second slot 213 to move the outer sheath 120 over the stent 10, causing the covered portion of the stent 10 to again be in the radially collapsed state. Once the stent 10 is fully covered by the outer sheath 120, the position of the catheter 300 may be adjusted as desired. The step 505 may be repeated until the catheter 300 is correctly positioned. The outer sheath 120 is then retracted to the proximal most position.
[53] At step 807, once the medical practitioner determines that the stent 10 is correctly implanted at the target site, the holding elements 170 are cut using the cutting tube 150 to detach the stent 10 from the delivery system 100. For example, the medical practitioner may provide the first actuation input to the first control element 230 (e.g., move the first control element 230 to the distal end of the first slot 211), causing the middle tube 140 to slide longitudinally. Consequently, the cutting tube 150 slides over the slotted tube 130 in the distal direction to the second position. Fig. 9 depicts a stage of the delivery system 100 where the tapered portion 150d of the cutting tube 150 has moved over the proximal ends 133a of the second slots 133. Once the first control element 230 is at the distal end of the first slot 211, the cutting tube 150 moves to the second position, i.e., the distal end 150b of the cutting tube 150 aligns with the distal ends 133b of the second slots 133. The edge 150e grinds the holding elements 170 against the distal ends 133b of the respective second slots 133, cutting the holding elements 170 as depicted in Fig. 10.
[54] At step 809, the catheter 300 is retracted in the proximal direction. The cut portion of the holding elements 170 comes out from the stent 10, thereby detaching the stent 10 completely from the delivery system 100 as depicted in Fig. 11. The stent 10 is thus fully deployed at the target site.
[55] At step 811, the catheter 300 is withdrawn from the patient’s body.
[56] Thus, the delivery system 100 accurately delivers and deploys the stent 10. The use of the holding elements 170 to restrain the stent 10 allows the medical practitioner to retract a partially deployed stent 10 and reposition the stent 10 in the event of inaccurate placement of the stent 10 during an implantation procedure. The use of polymeric material for the holding elements 170 gives the delivery system 100 the ability to retrieve the stent 10 even after 90% deployment of the stent 10.
[57] The delivery system of the present disclosure offers several advantages over conventional delivery systems. The proposed delivery system enables retrieval and reposition of a stent during an implantation procedure. provides increased flexibility and adaptability to the surgeon to adjust the position and diameter of the stent as needed during the surgery until the optimal position of the stent is achieved, thereby increasing the precision of deployment and reduces the risk of complications. The retractability of the stent offered by the proposed delivery system prevents incomplete coverage and reduces procedural complications compared to conventional systems that are rigid and are not capable of retrieving a stent during the surgery. Therefore, the surgeon can achieve precise placement and comprehensive coverage even in tortuous vessels or challenging lesions. Consequently, the delivery system of the present disclosure is capable of addressing complex vascular conditions more effectively compared to traditional devices. The retractable design of the proposed delivery system allows for controlled expansion and retraction post-deployment, optimizing procedural efficiency. Thus, the delivery system of the present disclosure provides a flexible, versatile and effective solution for treating complex vascular conditions, improving procedural outcomes and enhancing patient safety.
[58] The scope of the invention is only limited by the appended patent claims. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and/or configurations will depend upon the specific application or applications for which the teachings of the present invention is/are used. , Claims:WE CLAIM
1. A delivery system (100) for deploying a stent, the delivery system (100) comprising:
a. a slotted tube (130) comprising:
i. a plurality of first slots (131) provided circumferentially on the slotted tube (130) towards a distal end of the slotted tube (130); and
ii. a plurality of second slots (133) provided circumferentially on the slotted tube (130) proximal to the plurality of first slots (131);
b. a plurality of holding elements (170) coupled to a stent (10) to be deployed, each holding element (170) having a first end (170a) and a second end (170b) coupled to a corresponding first slot (131) and a corresponding second slot (133) of the slotted tube (130), respectively; and
c. a cutting tube (150) having a lumen (150c) configured to receive the slotted tube (130); and
d. a first control element (230) coupled to the cutting tube (150) and capable of receiving a first actuation input;
e. wherein in response to the first control element (230) receiving the first actuation input, the cutting tube (150) is configured to slide longitudinally over the slotted tube (130) from a first position to a second position, causing the cutting tube (150) to cut the plurality of holding elements (170), thereby releasing the stent (10) from the delivery system (100).
2. The delivery system (100) as claimed in claim 1, wherein the delivery system (100) comprises a catheter (300) comprising:
a. an outer sheath (120);
b. a middle tube (140) disposed within the outer sheath (120) and coupled to the first control element (230) and the cutting tube (150), wherein in response to the first control element (230) receiving the first actuation input, the middle tube (140) is configured to move longitudinally, causing the cutting tube (150) to move from the first position to the second position; and
c. an inner tube (110) disposed within the middle tube (140) and coupled to the slotted tube (130), wherein a portion of the inner tube (110) resides within the slotted tube (130) and a distal end of the inner tube (110) extends out from the distal end (130b) of the slotted tube (130), wherein the stent (10) is mounted on the inner tube (110) between the distal end of the inner tube (110) and the distal end (130b) of the slotted tube (130).
3. The delivery system (100) as claimed in claim 2, wherein the delivery system (100) comprises a second control element (250) coupled to the outer sheath (120) and capable of receiving a first actuation input and a second actuation input, wherein in response to the receiving the first actuation input and the second actuation input, the outer sheath (120) is configured to move in a proximal direction and a distal direction, respectively, causing the stent (10) to radially expand and contract, respectively.
4. The delivery system (100) as claimed in claim 1, wherein the cutting tube (150) comprises a tapered portion (150d) having a gradually reducing diameter from a proximal end to a distal end of the tapered portion (150d), forming an edge (150e) at a distal end (150b) of the cutting tube (150), wherein in response to the cutting tube (150) moving from the first position to the second position, the edge (150e) is configured to grind each holding element (170) against a distal end (133b) of the respective second slot (133), thereby cutting the holding element (170).
5. The delivery system (100) as claimed in claim 1, wherein one or more of:
a. the first end (170a) of each holding element (170) is fixedly coupled to a proximal end (131a) of the respective first slot (131); or
b. the second end (170b) of each holding element (170) is fixedly coupled to a proximal end (133a) of the respective second slot (133).
6. The delivery system (100) as claimed in claim 1, wherein the distal end (131b) of the plurality of first slots (131) aligns with the distal end (130b) of the slotted tube (130) such that the plurality of first slots (131) are open-ended at the distal end (131b).
7. The delivery system (100) as claimed in claim 1, wherein the plurality of first slots (131) and the plurality of second slots (133) extend into a first lumen (135) of the slotted tube (130).
8. The delivery system (100) as claimed in claim 1, wherein the first control element (230) is slidably disposed within a first slot (211) provided in a handle (200), wherein the first actuation input of the first control element (230) comprises moving the first control element (230) from a proximal end to a distal end of the first slot (211).
9. The delivery system (100) as claimed in claim 1, wherein the each holding element (170) passes through a respective cell (11) of the stent (10).
10. The delivery system (100) as claimed in claim 1, wherein each holding element (170) comprises a monofilament.
11. The delivery system (100) as claimed in claim 1, wherein each holding element (170) comprises a plurality of filaments braided together.
12. The delivery system (100) as claimed in claim 1, wherein the holding elements (170) are made of a biocompatible, polymeric material.